Wet cleaning devices and cleaning heads

Abstract

A wet cleaning device (278) is provided, comprising a cleaning head (100). The cleaning head has at least one dirt inlet (142A) and a porous material (168) comprising a porous material layer hermetically attached to the at least one dirt inlet. The wet cleaning device also includes an undervoltage generator device (280) comprising an undervoltage generator (178). The undervoltage generator has an undervoltage generator outlet. The undervoltage generator is capable of being activated to provide flow from the at least one dirt inlet to and through the undervoltage generator outlet, and is capable of being deactivated to stop the flow. The undervoltage generator device is configured to restrict the passage of fluid from the undervoltage generator outlet toward the at least one dirt inlet, at least when the undervoltage generator is deactivated. In another aspect, the cleaning head includes a valve assembly configured to restrict backflow toward the porous material layer hermetically attached to the dirt inlet.

Description

Technical Field

[0001] The present invention relates to a cleaning head and a wet cleaning device comprising such a cleaning head, such as a wet mopping device. The wet cleaning device can be used, for example, to clean floors, indoor surfaces or windows. Background Art

[0002] Known wet cleaning devices that remove water from the surface to be cleaned, such as wet mopping equipment. Such wet cleaning devices can also apply a cleaning liquid, such as water, to the surface to be cleaned and then remove the liquid, such as with a suitable cloth.

[0003] Some wet cleaning devices have a powered pickup function for removing water from the surface to be cleaned. For example, a wet vacuum cleaner can suck up liquid by generating sufficient air velocity (e.g., at least 10 m / s) and / or brush force to exert sufficient shear forces on the droplets so that the droplets enter the device. Typical power consumption values ​​for such vacuum cleaners are relatively high, e.g., on the order of several hundred watts.

[0004] Further challenges arise when the wet cleaning apparatus is arranged to deliver cleaning liquid as well as to draw up the liquid using suction. In at least some designs, providing both functions may present a risk that the cleaning liquid is used inefficiently.

[0005] There may also be a risk of poorly controlled delivery of cleaning liquid causing the environment to be soaked with cleaning liquid during or even after use. In at least some cases, particularly when a relatively low-power pickup system is employed, such soaking of the surface to be cleaned may not be easily addressed by the pickup function of the device.

[0006] In some designs, the pick-up function may also risk hindering the movement of the cleaning head of such a wet cleaning device over the wet surface to be cleaned.

[0007] KR 940 001 037Y1 discloses a vacuum cleaner having a wet dust collector.

[0008] EP 3366182A1 discloses a cleaning device, which comprises a surface interaction layer, a cleaning fluid supply device provided with a cleaning fluid channel at the surface interaction layer, for supplying a cleaning fluid to the surface through the surface interaction layer in contact with the surface. The cleaning device also comprises a dirty fluid discharge device, the dirty fluid discharge device having a dirty fluid channel at the surface interaction layer, the dirty fluid channel for discharging dirty water from the surface through the surface interaction layer in contact with the surface by means of underpressure.

[0009] US2019 / 082925A1 discloses a surface cleaning device having a surface cleaning head, the surface cleaning head including a hard floor cleaning brush and a carpet cleaning brush. The surface cleaning device can be operated in a hard floor cleaning configuration, wherein liquid is delivered from at least one nozzle to the soft brush bar, and the surface cleaning device can be operated in a carpet cleaning configuration, wherein liquid is delivered from at least one nozzle to the carpet cleaning brush.

[0010] DE 3143355A1 discloses a suction nozzle for sucking liquid from a substantially horizontal surface. The suction nozzle has a nozzle body, which is equipped with a suction nozzle and can be connected to a self-priming pump or a suction fan.

[0011] US2020 / 187737A1 discloses an apparatus and method for receiving and holding debris in a collection chamber of a vacuum cleaner. The collection chamber has an inlet opening through which debris entrained air enters the collection chamber. When the vacuum cleaner is closed, an internal valve prevents debris from leaving the collection chamber through the inlet opening. The internal valve can be moved from a first sealed position in which the internal valve covers the chamber inlet opening to a second non-sealed position in which the internal valve does not cover the chamber inlet opening.

[0012] WO 2016 / 008773A1 discloses a surface cleaning device comprising a cloth placed on a porous material, a reservoir for collecting liquid absorbed by the cloth, and means for applying an underpressure in the reservoir to transfer liquid from the cloth to the reservoir. The porous material has a pore diameter between 1 μm and 50 μm. Summary of the invention

[0013] The invention is defined by the claims.

[0014] According to an example based on one aspect of the present invention, a wet cleaning device is provided, which includes: a cleaning head having at least one dirty inlet and a porous material, the porous material including a porous material layer sealingly connected to the at least one dirty inlet; and an underpressure generator device, including an underpressure generator having an underpressure generator outlet, the underpressure generator being startable to provide a flow for drawing fluid from the at least one dirty inlet to the underpressure generator outlet and through the underpressure generator outlet, and the underpressure generator device being deactivated to stop the flow, wherein the underpressure generator device is configured to restrict the passage of fluid from the underpressure generator outlet toward the at least one dirty inlet at least when the underpressure generator is deactivated.

[0015] A layer of porous material sealingly attached to the dirty inlet(s) may help maintain underpressure in the dirty inlet(s) with or without applied flow, for example by an underpressure generator included in a wet cleaning apparatus.

[0016] The liquid pickup area of ​​the porous material layer may for example be defined by a sealed connection of the porous material layer around for example each of the at least one dirt inlet.

[0017] The sealing attachment may be achieved in any suitable manner, such as by gluing or welding a porous material layer around each of the at least one dirty inlet, such as gluing and / or welding a porous material layer around one or more tubes, the openings of which define the dirty inlet(s). In some non-limiting examples, the impermeable portion (e.g., a polymer film) is sealed to a surface of the porous material layer that is exposed to the dirty inlet(s) and surrounds the dirty inlet(s).

[0018] The porous material, although not necessarily a layer of porous material included in the porous material, may be arranged to contact the liquid on the surface to be cleaned.

[0019] The porous material may, for example, include porous fabric and / or porous foam. The porous fabric may, for example, be a microfiber fabric.

[0020] The surface tension of the liquid retained in the pores of the porous material can help maintain the underpressure. This surface tension can be overcome, which means that the air-liquid surface is removed at the point (or points) on the outside of the porous material that contacts the liquid on the surface to be cleaned, so that the liquid is transported through the porous material in the direction of the dirty inlet (s).

[0021] However, when the underpressure generator is deactivated, for example by being switched off after using a wet cleaning device, a loss of underpressure may be caused by fluid (eg ambient air) intruding via the underpressure generator outlet. This may result in liquid being released from the porous material, for example dripping.

[0022] After cleaning, e.g. wiping the surface to be cleaned, it is undesirable for liquid to be released through the porous material when the underpressure generator is deactivated, e.g. back onto the surface to be cleaned (or cleaned) and / or during transport of the wet cleaning device to its storage location.

[0023] To this end, the underpressure generator device is configured to restrict, e.g. block, the passage of fluid from the underpressure generator outlet towards the dirty inlet at least when the underpressure generator is deactivated, e.g. when the underpressure generator is switched off. In this way, after deactivation of the underpressure generator, the underpressure in the covered dirty inlet(s) can be better maintained. This can mitigate problematic release of liquid from the porous material, e.g. after cleaning the surface to be cleaned and / or during loading of the wet cleaning device in a storage area after use.

[0024] In some embodiments, the underpressure generator is configured to restrict a backflow of fluid from the underpressure generator outlet in the direction of the at least one dirty inlet at least when the underpressure generator is deactivated.

[0025] The underpressure generator may include a positive displacement pump. Since the design of the pump inherently limits backflow from the pump outlet, such a positive displacement pump may help maintain underpressure in the dirty inlet(s) after the underpressure generator is deactivated (e.g., turned off). This in turn may mitigate problematic liquid release from porous materials, such as after cleaning the surface to be cleaned and / or during loading of the wet cleaning device into a storage area after use.

[0026] When the underpressure generator comprises or is such a positive displacement pump, the underpressure generator device can for example be constituted by the underpressure generator, since the underpressure generator itself restricts the passage of fluid from the underpressure generator outlet towards the at least one dirty inlet when the underpressure generator is inactive.

[0027] In some embodiments, the underpressure generator is a peristaltic pump, a diaphragm pump or a piston pump. These pump types can be considered as examples of the positive displacement pumps described above.

[0028] The peristaltic pump may, for example, include a compressible hose having an end defining an underpressure generator outlet, and a rotatable compression shoe assembly including at least one compression shoe. Rotation of the compression shoe assembly and concomitant compression of the compressible hose by the at least one compression shoe may provide the flow. When the peristaltic pump is deactivated, rotation of the compression shoe assembly may cease, but the compression shoe is retained to compress the compressible hose and thereby restrict the passage of fluid from the underpressure generator outlet toward the at least one dirty inlet.

[0029] The above-mentioned diaphragm pumps and piston pumps may use a similar type of arrangement, wherein the stationary state of the pump, in other words when the pump is deactivated, restricts the backflow from the pump outlet in the direction of the dirty inlet.

[0030] In some embodiments, the underpressure generator device comprises a valve assembly configured to restrict a backflow of fluid towards the at least one dirty inlet at least when the underpressure generator is deactivated.

[0031] The underpressure generator may have an underpressure generator inlet, and the valve assembly may be configured to restrict backflow of the fluid between the underpressure generator inlet and the at least one dirty inlet.

[0032] Alternatively or additionally, the passage of the fluid may be restricted between the underpressure generator outlet and the underpressure generator inlet, for example as described above with respect to a positive displacement pump included in or defining the underpressure generator.

[0033] The valve assembly may be of any suitable design.In some embodiments, the valve assembly is configured to restrict backflow of said fluid towards the at least one dirty inlet in response to the underpressure generator being deactivated.

[0034] Such a valve assembly may be considered to include an "active" valve that is triggered by the deactivated underpressure generator to shut down the system (by restricting the backflow of fluid towards the dirty inlet(s)).

[0035] Alternatively or additionally, the valve assembly may comprise a one-way valve configured to prevent fluid from being conveyed in the direction of the at least one dirty inlet.

[0036] The one-way valve may be considered a "passive" valve. Such a one-way valve may be arranged to allow a fluid, such as air and / or liquid, to flow out of the porous material, but prevent the fluid, such as air and / or liquid, from returning toward the dirty inlet(s) when and after the underpressure generator is deactivated. Any suitable one-way valve design may be envisioned, such as a ball check valve.

[0037] In a non-limiting example, an additional porous material portion, for example made of a microfiber fabric, is arranged between the porous material layer and the underpressure generator outlet. The additional porous material portion can allow a fluid flow (for example air and / or liquid) to leave the porous material layer, but (at least) restrict the return of the fluid (for example air and / or liquid) toward the porous material layer when the underpressure generator is deactivated.

[0038] In some embodiments, a sealed flow path is defined between the dirty inlet(s) and the underpressure generator outlet.

[0039] This helps maintain undervoltage.

[0040] In alternative embodiments, the inlet of fluid (eg, air) may be via one or more regions of the wet cleaning apparatus other than the underpressure generator outlet and the pores of the porous material.

[0041] However, in such alternative embodiments, the configuration of the underpressure generator arrangement may still contribute to maintaining underpressure by (at least) restricting the passage of fluid from the underpressure generator outlet in the direction of the dirty inlet.

[0042] In some embodiments, the underpressure generator device comprises a valve assembly, such as the valve assembly described above, which is positioned between the one or more zones and the dirty inlet(s) so as to restrict backflow from the one or more zones towards the dirty inlet. In such embodiments, in addition to restricting the passage of fluid from the underpressure generator outlet in the direction of the dirty inlet(s), the valve assembly may, for example, restrict backflow from the one or more zones.

[0043] In some embodiments, the limiting pore diameter of the porous material measured using ASTM F316-03, 2019, Test A is equal to or greater than 15 μm.

[0044] It has been found empirically (as further described below) that a limiting pore diameter equal to or greater than 15 μm can help maintain a relatively large underpressure while ensuring that the pores are large enough to effectively transport liquid therethrough. With respect to the latter, it is noted that this observation is supported by theory, noting that when approximated using the Poiseuille equation, the flow resistance can increase to a power of 4 for smaller pores.

[0045] Likewise, the bubble point pressure of the porous material measured using ASTM F316-03, 2019, Test A may be equal to or less than 13500 Pa.

[0046] In some embodiments, the limiting pore diameter of the porous material is equal to or less than 105 μm as measured using ASTM F316-03, 2019, Test A. Limiting the upper limit of the pore diameter helps ensure that the porous material can maintain sufficient underpressure.

[0047] Likewise, the bubble point pressure of the porous material measured using ASTM F316-03, 2019, Test A may be equal to or greater than 2000 Pa.

[0048] In some embodiments, the limiting pore diameter of the porous material measured using ASTM F316-03, 2019, Test A is equal to or greater than 15 μm and equal to or less than 105 μm.

[0049] Limiting the flow rate to an upper limit may help to minimize the risk of the orifice being unable to withstand the underpressure and thus "bursting", with the result that a large amount of air enters the interior of the wet cleaning device, which in turn may require a larger pump consuming more power.

[0050] In some embodiments, the undervoltage generator is configured to provide less than or equal to 2000 cm 3 / min flow rate through the porous material.

[0051] This flow rate can be significantly lower than the flow rate of the conventional wet vacuum cleaner described above. Since power is equal to flow rate multiplied by pressure difference, by reducing the maximum 2000cm 3 The combination of a flow rate of 0.03 l / s per minute and a maximum pressure difference of 13500 Pa as the maximum power consumption scheme can minimize the power consumption of the wet cleaning device. This can enable the wet cleaning device to be made relatively compact, for example, using a smaller battery, and / or having a relatively long operating time.

[0052] Alternatively or additionally, the undervoltage generator may be configured to provide a voltage equal to or greater than 15 cm 3 / min flow rate through the porous material.

[0053] This can help to pick up the liquid from the surface to be cleaned quickly enough. In some embodiments, 15 cm 3The lower limit of 100 Å / minute may be set to be equal to or exceed the flow rate of the cleaning liquid from the cleaning liquid outlet(s) also included in the cleaning head.

[0054] More generally, the undervoltage generator may be configured such that when flow is provided by the activated undervoltage generator, the flow is at 15 cm 3 / min to 2000cm 3 / minute, preferably 40cm 3 / min to 2000cm 3 / minute, more preferably 80cm 3 / min to 750cm 3 / min, most preferably 100cm 3 / min to 300cm 3 The suction is provided at a flow rate in the range of / min.

[0055] This flow, i.e. the flow rate, can exploit the underpressure holding capability of the porous material and can ensure adequate liquid pickup while limiting energy consumption.

[0056] Alternatively or additionally, the flow rate provided by the underpressure generator on the inner side of the wet cleaning device between the porous material and the underpressure generator is set so that the pressure difference between the pressure on the inner side of the wet cleaning device and the atmospheric pressure is in the range of 2000Pa to 13500Pa, preferably 2000Pa to 12500Pa, more preferably 5000Pa to 9000Pa, and most preferably 7000Pa to 9000Pa.

[0057] The underpressure generator may be or include, for example, a positive displacement pump, such as a peristaltic pump. Since the design of the pump inherently limits backflow from the pump outlet, such a positive displacement pump may help maintain underpressure in the dirty inlet(s) after the underpressure generator is deactivated (e.g., turned off). This in turn may mitigate release of problematic liquids from the porous material, such as after cleaning the surface to be cleaned and / or during loading of the wet cleaning device into a storage area after use.

[0058] Alternatively or additionally, the cleaning head may (whether or not an underpressure generator is present) comprise a valve assembly configured to: allow flow for drawing fluid through the porous material into the at least one dirty inlet; and restrict backflow towards the porous material layer.

[0059] In some embodiments the wet cleaning apparatus comprises a dirty liquid collection tank for collecting liquid, wherein the underpressure generator arrangement is arranged such that the flow draws the liquid from the at least one dirty inlet to the dirty liquid collection tank.

[0060] In some embodiments, the cleaning head comprises at least one cleaning liquid outlet through which cleaning liquid can be delivered.

[0061] The wet cleaning apparatus may comprise a cleaning liquid supply including a cleaning liquid reservoir for containing a cleaning liquid, the cleaning liquid reservoir being connectable or in fluid communication with the at least one cleaning liquid outlet.

[0062] Such a cleaning liquid supply may, for example, comprise a cleaning liquid reservoir and a delivery device, for example comprising a pump, for delivering the cleaning liquid to and through the at least one cleaning liquid outlet.

[0063] The cleaning liquid supply and the at least one cleaning liquid outlet may for example be configured to provide a continuous delivery of the cleaning liquid towards the surface to be cleaned.Such continuous delivery may for example be provided while the underpressure generator provides suction to at least one dirty inlet.

[0064] In some embodiments, the cleaning liquid supply comprises a pump arranged to pump the cleaning liquid from the cleaning liquid reservoir to and through the at least one cleaning liquid outlet.

[0065] In some embodiments, the cleaning liquid supply and the underpressure generator are configured such that the flow rate of cleaning liquid delivered through the at least one cleaning liquid outlet is lower than the flow rate provided by the underpressure generator.

[0066] This helps to ensure that the surface to be cleaned is not over-wetted by the cleaning liquid. For example, the flow rate of the cleaning liquid can be 20 cm 3 / min to 60cm 3 / minute, the flow rate provided by the undervoltage generator can be within 40cm 3 / min to 2000cm 3 / minute, more preferably in the range of 80cm 3 / min to 750cm 3 / minute, most preferably within 100 cm 3 / min to 300cm 3 / minute range.

[0067] In at least some embodiments, the wet cleaning device is a wet mopping apparatus.

[0068] In other examples, the wet cleaning device may be or include, for example, a window cleaner, a sweeper, or a wet vacuum cleaner, such as a canister, pole, or upright wet vacuum cleaner.

[0069] In some examples, the wet cleaning device can be or include a robotic wet vacuum cleaner or a robotic wet mopping device that is configured to autonomously move a cleaning head over a surface to be cleaned (e.g., the surface of a floor) in, for example, a cleaning direction.

[0070] The wet cleaning device may be a battery powered wet cleaning device, wherein the undervoltage generator may be powered by a battery electrically connected to the undervoltage generator.

[0071] The power consumption reduction effect that may be provided by the porous material covering the dirty inlet(s) providing the suction of the underpressure generator may make the wet cleaning apparatus particularly suitable for battery powered operation.

[0072] According to another aspect, a cleaning head for a wet cleaning device is provided, the cleaning head comprising: at least one dirty inlet; a porous material, comprising a porous material layer sealingly attached to the at least one dirty inlet; and a valve assembly, the valve assembly being configured to: allow flow for drawing fluid through the porous material into the at least one dirty inlet; and restrict backflow toward the porous material layer.

[0073] The cleaning head may provide an alternative solution to the same problems associated with wet cleaning devices described above. To this end, the cleaning head includes a valve assembly configured to limit backflow toward the porous material layer. By limiting backflow toward the porous material layer by the valve assembly, the valve assembly may help maintain underpressure in the covered dirty inlet(s) and thereby mitigate the above-mentioned problematic release of liquid through the porous material, for example when the underpressure generator is deactivated.

[0074] Note that the dirty inlet(s) can be connected to such an underpressure generator comprised in a wet cleaning apparatus to provide a flow for drawing fluid through the porous material into at least one dirty inlet.

[0075] The valve assembly may be of any suitable design.In some embodiments, the valve assembly is configured to restrict backflow of the fluid in response to an actuation, for example in response to the underpressure generator being deactivated.

[0076] Such a valve assembly may be considered to comprise an "active" valve that is triggered in response to a stimulus to restrict backflow.

[0077] Alternatively or additionally, the valve assembly may comprise a one-way valve configured to prevent fluid from being transported in the direction of the layer of porous material.

[0078] A one-way valve may be considered a "passive" valve. Such a one-way valve may be arranged to allow a fluid flow (e.g., air and / or liquid) to leave the porous material, but prevent the fluid (e.g., air and / or liquid) from returning to the porous material layer, e.g., when and after the underpressure generator is deactivated. Any suitable one-way valve design may be envisioned, such as a ball check valve.

[0079] In a non-limiting example, the valve assembly comprises an additional porous material portion, for example made of a microfiber fabric. The additional porous material portion is capable of allowing a fluid flow (e.g., air and / or liquid) to leave the porous material layer, but restricting the fluid (e.g., air and / or liquid) from returning toward the porous material layer, for example, when the underpressure generator is deactivated.

[0080] More generally, embodiments described herein with respect to cleaning heads may be applicable to wet cleaning devices, and embodiments described herein with respect to wet cleaning devices may be applicable to cleaning heads. BRIEF DESCRIPTION OF THE DRAWINGS

[0081] Examples of the present invention will now be described in detail with reference to the accompanying drawings, in which:

[0082] Figure 1 schematically illustrates the underside of a cleaning head according to one example;

[0083] Figure 2 Provided including Figure 1 A schematic cross-sectional view of a cleaning liquid dispensing strip in a cleaning head is shown;

[0084] Figure 3 schematically illustrates the underside of a cleaning head according to a second example, with the cleaning liquid applicator material separated from the cleaning head;

[0085] Figure 4 Schematically shows Figure 3 the underside of the cleaning head shown with the cleaning liquid applicator fabric attached thereto;

[0086] Figure 5A schematically illustrates a porous material layer and a dirty inlet of an exemplary cleaning head;

[0087] Figure 5B Provided Figure 5A A schematic cross-sectional view of a porous material layer and a dirty inlet is shown;

[0088] Fig. 6A An example of a sealed attachment of a porous material layer around a dirty inlet is schematically depicted;

[0089] Figure 6B Provided Fig. 6A A schematic cross-sectional view of an exemplary sealing attachment shown in ;

[0090] Fig. 7A Schematically shows Fig. 6A and Figure 6B A variation of the seal attachment shown in ;

[0091] Figure 7B Provided Fig. 7A a schematic cross-sectional view of an exemplary sealing attachment shown;

[0092] Figure 8 Provided Fig. 7A and Figure 7B Schematic cross-sectional view of a variant of the seal attachment shown in ;

[0093] Fig. 9 Provided Figure 8 Schematic cross-sectional view of a variation of the seal attachment shown;

[0094] Fig.10 Schematic diagrams of fluid transport through three exemplary porous materials are provided;

[0095] Fig.11 Schematically shows a test arrangement for testing the behavior of a porous material when liquid and suction are applied to it;

[0096] Fig.12 Provides access from Fig.11 A graph of undervoltage versus time for data obtained using the test arrangement shown in;

[0097] Fig.13 Several pressure-time diagrams for porous materials including different numbers of porous material layers are provided;

[0098] Fig.14 schematically illustrates a sequence of liquid transport states, intermediate states, and final states of a porous material when suction is applied to the porous material;

[0099] Fig.15 Several pressure-time graphs for porous materials with different pore sizes are provided;

[0100] Fig.16 schematically illustrates an exemplary cleaning head moving over a surface to be cleaned;

[0101] Figures 17 to 23 A schematic cross-sectional view of a porous material mounted to a support member is provided;

[0102] Figures 24 to 30 Various exemplary cleaning heads are schematically shown;

[0103] Fig.31 Schematically illustrates an exemplary cleaning head that can be swung on a protruding element so that a portion of the underside of the cleaning head is brought into contact with a surface to be cleaned;

[0104] Fig.32A An example of a sealed attachment of a porous material layer around a dirty inlet is schematically depicted;

[0105] Fig.32B Provided Fig.32A A schematic cross-sectional view of an exemplary sealing attachment shown in ;

[0106] Fig.33A A view of an end of a cleaning head according to one example is provided;

[0107] Fig.33B Provided Fig.33A A view of the top side of the cleaning head is shown;

[0108] Fig.33C A schematic cross-sectional view of a protruding element / detachable member according to one example is provided;

[0109] Fig.33D A schematic cross-sectional view of a protruding element / detachable member according to another example is provided;

[0110] Fig.33E Provides a schematic cross-sectional view of an exemplary separable element including additional porous material layer(s) and a cleaning liquid applicator material;

[0111] Fig.33F Provides Fig.33C or the protruding element / detachable member shown in 33D and Fig.33E A perspective view of the cleaning head showing the detachable elements;

[0112] Fig.34 Schematically illustrates an exemplary wet cleaning apparatus before (left panel), during (center panel), and after (right panel) pumping liquid through a porous material;

[0113] Fig.35 Schematically shows an exemplary wet cleaning device with an undervoltage generator, wherein the undervoltage generator is activated (left-hand square) and deactivated (right-hand square);

[0114] Fig.36 An underpressure generator in the form of a peristaltic pump is schematically shown;

[0115] Fig.37A schematically illustrates the pores of a porous material layer of an exemplary wet cleaning device;

[0116] Fig.37B Schematically shows Fig.37A Foam accumulation in wet cleaning device shown;

[0117] Fig.37C The operating window of the wet cleaning device is graphically illustrated, particularly when the wet cleaning device is started;

[0118] Fig.38 Schematically illustrates an exemplary wet cleaning device including an underpressure generator device having an underpressure generator, a pressure sensor, and a controller;

[0119] Fig.39 Schematically shows an exemplary wet cleaning device with an undervoltage generator device having an undervoltage generator and a mechanical regulator;

[0120] Fig.40 An exemplary wet cleaning device is schematically shown, the underpressure generator of which includes a pressure-limiting liquid pump;

[0121] Fig.41 An exemplary wet cleaning device is schematically shown, wherein the underpressure generator includes a pressure-limiting air pump;

[0122] Fig.42 An exemplary wet cleaning device in the form of a wet vacuum cleaner is schematically shown; and

[0123] Fig.43 An exemplary wet cleaning device in the form of a robotic wet vacuum cleaner is schematically shown. DETAILED DESCRIPTION

[0124] The present invention will be described with reference to the accompanying drawings.

[0125] It should be understood that the detailed description and specific examples, although indicating exemplary embodiments of the device, system and method, are for illustrative purposes only and are not intended to limit the scope of the invention. These and other features, aspects and advantages of the device, system and method of the present invention will become better understood from the following description, the appended claims and the accompanying drawings. It should be understood that the drawings are only schematic and are not drawn to scale. It should also be understood that the same reference numerals are used throughout the drawings to represent the same or similar components.

[0126] A wet cleaning device including a cleaning head is provided. The cleaning head has at least one dirty inlet and a porous material, the porous material including a porous material layer sealingly connected to the at least one dirty inlet. The wet cleaning device also includes an underpressure generator device, which includes an underpressure generator. The underpressure generator has an underpressure generator outlet. The underpressure generator can be activated to provide flow from at least one dirty inlet to and through the underpressure generator outlet, and can be deactivated to stop the flow. The underpressure generator device is configured to restrict the passage of fluid from the underpressure generator outlet toward the at least one dirty inlet at least when the underpressure generator is deactivated. On the other hand, the cleaning head includes a valve assembly, which is configured to limit backflow toward the porous material layer sealingly connected to the dirty inlet.

[0127] Figure 1 A cleaning head 100 is shown according to a non-limiting example. In particular, Figure 1 1 shows the underside 102 of the cleaning head 100. The underside 102 faces the surface to be cleaned using the cleaning head 100 ( Figure 1 (not visible in the image).

[0128] from Figure 1 As can be clearly seen in the illustrated view, at least one cleaning liquid outlet 104 is included in the cleaning head 100. Cleaning liquid can be delivered through, for example, each of the at least one cleaning liquid outlet 104. It should be noted that the at least one cleaning liquid outlet need not be provided on the underside 102 of the cleaning head 100, and may alternatively be provided elsewhere in the cleaning head 100, as long as the cleaning liquid can be delivered via the cleaning liquid outlet(s) to reach the surface to be cleaned.

[0129] The cleaning liquid may include water or be made up of water. Therefore, the cleaning liquid may be an aqueous cleaning liquid. In some non-limiting examples, which will be discussed in more detail below, the cleaning liquid is an aqueous detergent solution.

[0130] exist Figure 1 In the non-limiting example shown, the cleaning liquid outlets 104 are arranged in a row along the length 106 of the cleaning head 100. This can help the cleaning head 100 wet the surface to be cleaned with the cleaning liquid along the length 106 of the cleaning head 100. Nevertheless, it should be noted that any suitable configuration or pattern of the cleaning liquid outlets 104 is contemplated as long as other components capable of accommodating the cleaning head 100 are provided.

[0131] exist Figure 1In the particular example shown, sixteen cleaning liquid outlets 104 are included in the cleaning head 100, and it should be noted that more cleaning liquid outlets 104 can help increase the uniformity of wetting the surface to be cleaned. However, any suitable number of cleaning liquid outlets 104 can be provided in the cleaning head 100, such as one, two, three, four, five, six, seven, eight, nine, ten, eleven, twelve, thirteen, fourteen, fifteen, sixteen, seventeen, eighteen, nineteen, twenty or more.

[0132] In some embodiments, Figure 1 As shown, the cleaning head 100 includes a cleaning liquid dispensing strip 108. As shown, at least some, or in this example all, of the cleaning liquid outlets 104 may be included in the cleaning liquid dispensing strip 108.

[0133] Figure 2 Provided including Figure 1 1 is a cross-sectional view of a cleaning liquid dispensing strip 108 in an exemplary cleaning head 100 shown. In this non-limiting example, the cleaning liquid dispensing strip 108 includes a channel 110 that can, for example, be dispensed from a suitable cleaning liquid reservoir ( Figure 2 The cleaning liquid is supplied via the inlet 112 (not visible in FIG. 1 ).

[0134] exist Figure 2 In the example shown, the inlet 112 is disposed at or near the end of the cleaning liquid dispensing strip 108, however, it is also conceivable that the inlet 112 is disposed at a central position along the length of the cleaning liquid dispensing strip 108. Alternatively or additionally, the cleaning liquid dispensing strip 108 includes a plurality of inlets 112, such as a pair of inlets 112 disposed at opposite ends of the cleaning liquid dispensing strip 108.

[0135] Cleaning liquid may exit the cleaning liquid dispensing strip 108 through orifices in the cleaning liquid dispensing strip 108 that define cleaning liquid outlets 104. Such orifices may be sized such that when the channel 110 is being filled, cleaning liquid, such as an aqueous cleaning liquid, is restricted from passing through the orifices due to the surface tension of the cleaning liquid, but once the channel 110 has been filled, cleaning liquid is simultaneously allowed to pass through all orifices of the cleaning liquid dispensing strip 108. This may result in relatively uniform wetting of the surface to be cleaned across the length 106 of the cleaning head 100.

[0136] To this end, each cleaning liquid outlet 104 may have a diameter of, for example, less than 1 mm, such as in the range of 0.1 mm to 1 mm, preferably 0.1 mm to 0.8 mm, most preferably 0.1 mm to 0.5 mm, such as about 0.3 mm.

[0137] The cleaning liquid dispensing strip 108 may be formed from any suitable material, such as metal, metal alloys (eg, stainless steel), and / or polymers. Forming the cleaning liquid dispensing strip 108 from a polymer can make the cleaning liquid dispensing strip 108 lighter and / or cheaper to manufacture.

[0138] Back to Figure 1 , the cleaning head 100 further comprises a porous material, which comprises, or in some embodiments consists of, a porous material layer 114. Figure 1 Although not visible in the figure, the cleaning head 100 has at least one dirt inlet. Each of the (multiple) dirt inlets is covered by a porous material layer 114.

[0139] The porous material layer 114 may be arranged between the dirty inlet(s) and the surface to be cleaned, so that dirty liquid on the surface to be cleaned is first transported to the pores of the porous material layer 114 and then enters the dirty inlet(s) from the porous material layer 114 .

[0140] Figure 1 The view provided in FIG. 1 shows the outer surface 116 of the porous material layer 114 , which faces the surface to be cleaned.

[0141] The porous material layer 114 is disposed at or near the underside 102 of the cleaning head 100. More generally, the porous material, although not necessarily specifically the porous material layer 114 included therein, may contact a surface to be cleaned and / or a liquid on the surface to be cleaned.

[0142] wherein the porous material comprises one or more additional porous material layers ( Figure 1 In a non-limiting example (not visible in the drawing), an outer surface of an additional porous material layer that is farthest from the at least one dirty inlet in the thickness direction of the porous material may contact the surface to be cleaned.

[0143] The porous material layer 114 covering each of the at least one dirty inlet may help maintain underpressure in the dirty inlet(s) with or without applying a constant flow to the dirty inlet(s), for example by an underpressure generator (e.g., a pump) fluidly connected to the dirty inlet.

[0144] The porous material layer 114 may, for example, include or consist of a porous fabric and / or a porous foam. The porous fabric may, for example, be a microfiber fabric.

[0145] Similarly, each of the one or more further porous material layers mentioned above may comprise or consist of a porous fabric (eg a microfiber fabric) and / or a porous foam.

[0146] As used herein, the term "microfiber fabric" refers to a fabric formed of synthetic fibers, the fabric being formed of filaments having a denier of less than 1 dtex.

[0147] Such microfiber fabrics may include, for example, polyester fibers, polyamide fibers, and combinations of polyester and polyamide fibers.

[0148] The microfiber fabric may be, for example, microfiber chamois.

[0149] In other examples, the porous fabric is a natural suede, such as made from suede, deerskin, goatskin, or sheepskin.

[0150] The surface tension of the liquid retained in the pores of the porous material layer 114 can help maintain the underpressure. This surface tension can be overcome at a point (or points) on the outer surface 116 of the porous material layer 114 that contacts the liquid, thereby transporting the liquid through the porous material layer 114 in the direction of the dirty inlet (s).

[0151] For example, porous materials including microfiber fabrics may be particularly susceptible to wear and tear, and such wear and tear may risk compromising the underpressure holding / liquid pickup performance of the porous material. Therefore, the porous material may include multiple layers of different colors that gradually wear away through use of the cleaning head 100, so that the color of the porous material serves as a wear indicator.

[0152] In some embodiments, for example Figure 1 In the illustrated embodiment, the porous material and / or the porous material layer 114 included in the porous material is elongated, thereby having a largest dimension extending parallel to the length 106 of the cleaning head 100 .

[0153] exist Figure 1 In the non-limiting example shown, the porous material layer 114 is located at different locations along the width 118 of the cleaning head 100 relative to the cleaning liquid outlet 104 .

[0154] In some embodiments, such as Figure 1 As shown, the cleaning head 100 comprises a portion 120 for facing the surface to be cleaned. One or more cleaning liquid outlets 104 may be arranged to deliver cleaning liquid to the portion 120 of the cleaning head 100.

[0155] Although in Figure 1 Not visible in the view provided, but a protruding element may be mounted adjacent to the portion 120, wherein the protruding element protrudes from the cleaning head 100 in the direction of the surface to be cleaned. The protruding element may be considered as an element mounted separately in the cleaning head 100 relative to the portion 120.

[0156] Due to the protruding nature of the protruding elements, the protruding elements may have limited contact with the surface to be cleaned. The protruding elements may, for example, have a smaller contact area with the surface to be cleaned than portion 120.

[0157] In at least some embodiments, the protruding element comprises a porous material. Since the contact area between the porous material and the surface to be cleaned is limited, the movement resistance of the cleaning head 100 on the surface to be cleaned can be reduced. This will be referred to below. Fig.31 Described in further detail.

[0158] In some embodiments, cleaning head 100 may swing on the protruding element in a first direction to bring portion 120 into contact with the surface to be cleaned, and swing on the protruding element in a second direction opposite the first direction to separate portion 120 from the surface to be cleaned.

[0159] In such an embodiment, the protruding element may be considered a rocker that allows the cleaning head 100 to be swung onto the portion 120. To achieve this swung function, the contact of the protruding element with the surface to be cleaned is limited.

[0160] In some embodiments, for example, Figure 3 In the non-limiting example shown, the cleaning head 100 comprises a portion 120 for facing the surface to be cleaned and a further portion 122. In such an embodiment, the porous material layer 114 may be arranged between the portion 120 and the further portion 122.

[0161] Although in Figure 3 It is not visible in the provided view, but when the cleaning head 100 includes the above-mentioned protruding element, the protruding element can be mounted between the portion 120 and the further portion 122. Thus, the protruding element can be an element that is separately mounted relative to both the portion 120 and the further portion 122. In this way, the cleaning head 100 can be swung forward on the protruding element to bring the portion 120 into contact with the surface to be cleaned, and swung backward to bring the further portion 122 into contact with the surface to be cleaned.

[0162] Regardless of whether the cleaning head 100 comprises protruding elements, the cleaning liquid outlet(s) 104 may be arranged to deliver cleaning liquid to the portion 120 and the further portion 122 of the cleaning head 100 .

[0163] exist Figure 3 In the non-limiting example shown, the cleaning head 100 includes a cleaning liquid dispensing strip 108 and an additional cleaning liquid dispensing strip 124, the orifice of the cleaning liquid dispensing strip 108 defining a cleaning liquid outlet 104 that delivers cleaning liquid to the portion 120, as described above with respect to Figure 1 and Figure 2As mentioned, the further orifice of the further cleaning liquid dispensing strip 124 defines a cleaning liquid outlet 104 which delivers cleaning liquid to the further portion 122 .

[0164] Both the cleaning liquid dispensing strip 108 and the additional cleaning liquid dispensing strip 124 may extend parallel to the length 106 of the cleaning head 100, such as Figure 3 shown.

[0165] In some embodiments, for example Figure 4 In the illustrated embodiment, the cleaning head 100 includes a cleaning liquid applicator material 126, 128 adjacent to each of the at least one cleaning liquid outlet 104, the cleaning liquid applicator material 126, 128 being arranged to apply the cleaning liquid to the surface to be cleaned. In other words, the cleaning liquid applicator material 126, 128 can receive the cleaning liquid delivered from the (multiple) cleaning liquid outlets 104 and convey the cleaning liquid to the surface to be cleaned.

[0166] The cleaning liquid applicator material 126, 128 may, for example, include polyamide and / or polyester fibers.

[0167] Alternatively or additionally, the cleaning liquid applicator material 126, 128 includes a combination of thinner fibers and thicker fibers.

[0168] The thinner fibers may, for example, be less than or equal to 1 dtex, and the thicker fibers may have a thickness greater than 0.01 mm, for example the thicker fibers may have a thickness of about 0.05 mm.

[0169] Thicker fibers, which may be made of polyamide or polyester, may help reduce friction between the cleaning liquid applicator material 126, 128 and the surface to be cleaned, while thinner fibers, such as made of polyamide or polyester, may help enhance dirt retention.

[0170] Thicker fibers may also provide resiliency to the cleaning liquid applicator materials 126 , 128 , thereby minimizing compression of the cleaning liquid applicator materials 126 , 128 .

[0171] The compression reducing capability of the thicker fibers is particularly useful in embodiments where the cleaning liquid applicator material 126, 128 is included in the portion 120 adjacent the protruding element rocker and / or in the additional portion 122. This is because minimized compression can help ensure that over continued use of the cleaning head 100, a consistent degree of oscillation on the protruding element causes the cleaning liquid applicator material 126, 128 to contact the surface to be cleaned.

[0172] The thickness of the cleaning liquid applicator material 126 , 128 may alternatively or additionally be selected or limited, for example taking into account the extent of protrusion of the protruding element relative to the portion 120 and / or the further portion 122 , so as to minimize compression of the cleaning liquid applicator material 126 , 128 during use of the cleaning head 100 .

[0173] In the embodiment that cleaning liquid applicator material 126,128 comprises the combination of thinner fiber and thicker fiber, these fibers can be arranged relative to each other in any suitable manner.For example, cleaning liquid applicator material 126,128 can comprise the thicker fiber band adjacent to the thinner fiber band.These bands can extend along the length 106 of cleaning head 100 separately, so that the fiber thickness alternates in width 118 directions.When cleaning head 100 moves in the direction parallel to width 118 directions, this configuration can contribute to reduce friction.

[0174] In the embodiment where the cleaning liquid applicator materials 126, 128 include both polyamide and polyester fibers, these fibers can be arranged relative to each other in any suitable manner. For example, the cleaning liquid applicator materials 126, 128 can include a polyamide fiber band adjacent to a polyester fiber band. These bands can each extend along the length 106 of the cleaning head 100 so that the fiber types alternate in the width 118 directions.

[0175] The cleaning liquid applicator material 126, 128 may, for example, include a backing layer supporting a material that contacts the surface to be cleaned, such as a material containing polyamide and / or polyester fibers. The backing layer may be formed from any suitable backing fabric material, such as polyester.

[0176] Such a backing layer may be provided with tufts, for example formed of polyamide and / or polyester fibers. Such tufts may help the cleaning liquid applicator material 126, 128 to follow the contours of the surface to be cleaned and / or may help the cleaning liquid applicator material 126, 128 to retain dirt particles while also minimizing the risk of scratching the surface to be cleaned.

[0177] In some embodiments, the cleaning liquid applicator material 126, 128 may be distinguished from the porous material by (at least) a backing layer (eg, a backing layer supporting the tufts described above) included in the cleaning liquid applicator material 126, 128 but not included in the porous material.

[0178] In some non-limiting examples, the fibers that make up the cleaning liquid applicator material 126, 128 are the same fibers that make up the porous material.

[0179] In an alternative example, one of the ways in which the cleaning liquid applicator material 126, 128 can be distinguished from the porous material is the fineness, such as the denier, of the threads and / or fibers of the corresponding material (e.g., the threads and / or fibers of the corresponding material that contact the surface to be cleaned). For example, the fibers that make up the (multiple) porous material layers of the porous material can be thinner than the fibers of the cleaning liquid applicator material 126, 128. Alternatively or additionally, the threads that make up the (multiple) porous material layers of the porous material can be thinner than the threads of the cleaning liquid applicator material 126, 128.

[0180] The porous material may generally be denser than the cleaning liquid applicator material 126, 128, such as due to a tighter weave of the microfiber fabric.

[0181] In some embodiments, the cleaning liquid applicator material 126, 128 includes multiple differently colored layers that gradually wear away through use of the cleaning head 100 such that the color of the cleaning liquid applicator material 126, 128 serves as a wear indicator.

[0182] In some embodiments, the cleaning liquid applicator material 126, 128 can be detached from each of the at least one cleaning liquid outlet 104. This can enable replacement of the cleaning liquid applicator material 126, 128, for example once the cleaning liquid applicator material 126, 128 has become excessively worn, and / or enable the cleaning liquid applicator material 126, 128 to be cleaned between uses. For example, wear can be indicated by the colored layer comprising the cleaning liquid applicator material 126, 128 as described above.

[0183] The cleaning liquid applicator materials 126, 128 may be attached to the cleaning head 100 in any suitable manner, particularly in Figures 1 to 4 Attached to the underside 102 of the cleaning head 100 in the non-limiting example shown.

[0184] Back to Figure 3 , the depicted cleaning head 100 includes at least one fastening member 130A, 130B, 132A, 132B, in this example in the form of a Velcro strip, which engages with additional fastening member(s) (not visible) on the cleaning liquid applicator material 126, 128. The additional fastening member(s) may, for example, be included in or attached to the above-mentioned backing layer of the cleaning liquid applicator material 126, 128.

[0185] Alternative ways of attaching (eg, detachably coupling) the cleaning liquid applicator material 126, 128 to the cleaning head 100, and in particular the at least one cleaning liquid outlet 104, are contemplated, such as using ejectors, button-to-button hole arrangements, zippers, and the like.

[0186] In some embodiments, Figure 4 As shown, the cleaning liquid applicator material 126 , 128 includes a first applicator portion 126 and a second applicator portion 128 with the porous material layer 114 disposed between the first applicator portion 126 and the second applicator portion 128 .

[0187] When the first applicator portion 126 is included in the cleaning head 100 , the first applicator portion 126 may be included in the above-mentioned portion 120 of the cleaning head 100 .

[0188] In embodiments where a cleaning liquid applicator material (eg, first applicator portion 126) is included in portion 120, the portion may be adapted to contact and facilitate cleaning of a surface to be cleaned, such as by facilitating application of a cleaning liquid to the surface to be cleaned.

[0189] However, it is also conceivable that no cleaning liquid applicator material is included in portion 120, for example if cleaning head 100 is supplied without such cleaning liquid applicator material. In this case, although portion 120 has a potentially less cleaning capability than if cleaning liquid applicator material (e.g., first applicator portion 126) were included in portion 120, portion 120 may still be suitable for contacting a surface to be cleaned (portion 120 may contact a surface to be cleaned without requiring portion 120 to include a cleaning liquid applicator material).

[0190] The first applicator portion 126 may include the aforementioned additional fastening member(s) that engage with the fastening member(s) 130A, 130B provided on the cleaning head 100 for incorporating the first applicator portion 126 into the portion 120 .

[0191] Similarly, when the second applicator portion 128 is included in the cleaning head 100 , the second applicator portion 128 may be included in the above-described additional portion 122 of the cleaning head 100 .

[0192] In such an embodiment, the second applicator portion 128 may include the above-mentioned (multiple) additional fastening members, which engage with the (multiple) fastening members 132A, 132B provided on the cleaning head 100 for integrating the second applicator portion 128 into the additional portion 122.

[0193] In some embodiments, the at least one cleaning liquid outlet 104 includes at least one pair of cleaning liquid outlets 104 , and the porous material layer 114 is disposed between each pair of cleaning liquid outlets 104 .

[0194] In embodiments where the cleaning liquid applicator material 126, 128 includes a first applicator portion 126 and a second applicator portion 128, the first applicator portion 126 may be adjacent to one of the pair of cleaning liquid outlets 104, while the second applicator portion 128 is adjacent to the other of the pair of cleaning liquid outlets 104. Figure 3 and Figure 4 Such an example is shown in .

[0195] In at least some embodiments, the porous material (although not necessarily specifically the porous material layer 114 included in the porous material) contacts the cleaning liquid applicator fabrics 126 , 128 .

[0196] By the porous material contacting the cleaning liquid applicator material 126, 128, some cleaning liquid can be transferred from the cleaning liquid applicator material 126, 128 to the porous material and into the (multiple) dirty inlet. This configuration can help prevent excess cleaning liquid from accumulating in the cleaning liquid applicator material 126, 128, and thus can help minimize over-wetting of the surface to be cleaned, for example by dripping cleaning liquid from the cleaning liquid applicator material onto the surface to be cleaned. Alternatively or additionally, by the porous material contacting the cleaning liquid applicator material 126, 128, the cleaning liquid in the latter can be used to effectively rinse the porous material covering the (multiple) dirty inlet.

[0197] In a non-limiting example, the porous material layer 114 contacts the cleaning liquid applicator materials 126, 128. The porous material includes one or more additional porous material layers (in Figure 3 and Figure 4 In examples (not visible in the illustration), the porous material layer 114 and / or (multiple) additional porous material layers may contact the cleaning liquid applicator materials 126, 128.

[0198] Although the porous material contacts the cleaning liquid applicator materials 126, 128, these materials may also be arranged to contact the surface to be cleaned. This may be achieved in any suitable manner. In some embodiments, such as Figure 3 and Figure 4 As shown, an edge portion 134 of the porous material abuts an opposing edge portion 136 of the cleaning liquid applicator material 126, 128. Thus, the cleaning liquid may first be delivered into the cleaning liquid applicator material 126, 128, and only subsequently delivered from the cleaning liquid applicator material 126, 128 into the porous material via the abutting edge portions 134, 136 of the respective materials. This may provide enhanced control over the wetness of the cleaning liquid applicator material 126, 128.

[0199] Alternatively or additionally, the cleaning liquid applicator material 126, 128 may be deformable such that at least a portion of the cleaning liquid applicator material 126, 128 is in contact with the porous material.

[0200] By making the cleaning liquid applicator material 126, 128 deformable so that at least a portion of the cleaning liquid applicator material 126, 128 contacts the porous material, some of the cleaning liquid can be transferred from the cleaning liquid applicator material 126, 128 to the porous material in a particularly controlled manner. In this way, overwetting of the surface to be cleaned can be minimized, for example by dripping the cleaning liquid from the cleaning liquid applicator material 126, 128 onto the surface to be cleaned. Alternatively or additionally, by deforming the cleaning liquid applicator material 126, 128 so that at least a portion of the cleaning liquid applicator material 126, 128 contacts the porous material, the cleaning liquid in the latter can be used to effectively rinse the porous material.

[0201] In at least some embodiments, the cleaning liquid applicator materials 126, 128 are configured to deform when in contact with a surface to be cleaned and / or when wetted by a liquid (eg, water).

[0202] Such wetting may be a result of cleaning liquid being delivered to the cleaning liquid applicator material 126, 128 from the cleaning liquid outlet(s) and / or due to the presence of liquid on the surface to be cleaned.

[0203] In a non-limiting example, the cleaning liquid applicator material 126, 128 includes tufts formed of fibers and a backing layer supporting the tufts. Such tufts can be deformed to contact the porous material, such as when in contact with a surface to be cleaned and / or when wetted by a liquid such as water.

[0204] Cleaning liquid may be transferred from the cleaning liquid applicator material 126, 128 to the porous material via the tufts while the tufts remain in contact with the porous material.

[0205] In some embodiments, the cleaning liquid applicator material may be deformed so that an edge portion 136 of the cleaning liquid applicator material 126 , 128 contacts the porous material, such as contacting an edge portion 134 of the porous material.

[0206] For example, when the cleaning liquid applicator material 126, 128 is deformed to bring the edge portion 136 of the cleaning liquid applicator material 126, 128 into contact with the porous material, the edge portion 136 of the cleaning liquid applicator material 126, 128 may abut the (opposing) edge portion 134 of the porous material.

[0207] In some embodiments, the edge portion 136 of the cleaning liquid applicator material 126, 128 is arranged to contact the surface to be cleaned at least when the cleaning liquid applicator material 126, 128 is deformed to bring the edge portion 136 of the cleaning liquid applicator material 126, 128 into contact with the porous material. Thus, the wetness of the cleaning liquid applicator material 126, 128 can be controlled where the cleaning liquid applicator material 126, 128 contacts the surface to be cleaned, thereby minimizing the risk of over-wetting the surface to be cleaned.

[0208] In a non-limiting example, the cleaning liquid applicator material 126, 128 can be deformed so that at least a portion of the cleaning liquid applicator material 126, 128 contacts the porous material layer 114 of the porous material. In examples where the porous material includes one or more additional porous material layers, the deformation of the cleaning liquid applicator material 126, 128 causes at least a portion of the cleaning liquid applicator material 126, 128 (e.g., edge portion 136) to contact the porous material layer 114 and / or the additional porous material layer(s).

[0209] In embodiments where the cleaning head 100 includes the above-described protruding elements, the adjacent opposing edge portions 134, 136 of the porous material and the cleaning liquid applicator material 126, 128 are preferably positioned between the protruding element and the portion 120. In this manner, excess cleaning liquid squeezed out of the cleaning liquid applicator material 126, 128, for example by oscillating the cleaning head 100 via the protruding element, can be effectively transported via the porous material into the dirty inlet(s).

[0210] It should be noted that the contact between the porous material and the cleaning liquid applicator material 126, 128 can be provided on the surface contacting side of the material to be cleaned. This can help avoid the cleaning liquid from directly entering the porous material without properly wetting the cleaning liquid applicator material 126, 128 or flushing the porous material.

[0211] In some embodiments, the cleaning liquid applicator material 126 , 128 may be deformed so that at least a portion of the cleaning liquid applicator material 126 , 128 is in contact with the porous material between the protruding elements and the portion 120 .

[0212] Thus, excess cleaning liquid squeezed out of the cleaning liquid applicator materials 126, 128, for example, between the protruding elements and the cleaning liquid applicator material, caused by oscillation of the cleaning head 100 over the protruding elements, may be effectively transported into the dirty inlet(s) via the porous material.

[0213] In embodiments where the cleaning liquid applicator materials 126, 128 include the first applicator portion 126 and the second applicator portion 128 described above, the opposing edge portions 136 of the cleaning liquid applicator materials 126, 128 may be included in the first applicator portion 126, such as Figure 4 In addition, a further edge portion 138 of the porous material may abut a further opposing edge portion 140 of the second applicator portion 128. Figure 3 and Figure 4 Such an example is described in .

[0214] When the above-mentioned protruding element is arranged between part 120 and the other part 122, the adjacent relative edge portions 134, 136 of the porous material and the first applicator part 126 are preferably positioned between the protruding element and the part 120, and the adjacent relative further edge portions 138, 140 of the porous material and the second applicator part 128 are preferably positioned between the protruding element and the other part 122.

[0215] In this way, excess cleaning liquid squeezed out of the cleaning liquid applicator material 126, 128 between the protruding element and the first and second cleaning liquid applicator portions 126, 128, for example by swinging the cleaning head 100 forward and backward, respectively, can be effectively transported to the (multiple) dirty inlets via the porous material.

[0216] The opposing edge portions 136 and / or the further opposing edge portions 140 (when present) of the cleaning liquid applicator materials 126, 128 may, for example, be arranged to contact the surface to be cleaned. Thus, the wetness of the cleaning liquid applicator materials 126, 128 may be controlled where the cleaning liquid applicator materials 126, 128 contact the surface to be cleaned, thereby minimizing the risk of overwetting the surface to be cleaned.

[0217] In some embodiments, first applicator portion 126 can be deformed so that at least a portion of first applicator portion 126 contacts the porous material between portion 120 and the protruding element, and / or second applicator portion 128 can be deformed so that at least a portion of second applicator portion 128 contacts the porous material between another portion 122 and the protruding element.

[0218] Figure 5A A plan view illustrating the porous material layer 114 and at least one dirt inlet 142A, 142B of an exemplary cleaning head 100 is provided. Figure 5B Provided Figure 5A Schematic cross-sectional view of the porous material layer 114 and at least one dirty inlet 142A, 142B is shown in FIG.

[0219] In some embodiments, Figure 5Aand Figure 5B As shown, each of the at least one dirty inlet 142A, 142B is fluidly connected or fluidly connectable to an underpressure generator (at Figure 5A and Figure 5B The openings of one or more tubes 144A, 144B (not visible) are defined.

[0220] exist Figure 5A and Figure 5B In the non-limiting example shown, the cleaning head 100 includes a pair of dirt inlets 142A, 142B, although any suitable number of dirt inlets 142A, 142B is contemplated, such as one, two, three, four, five, six, or more.

[0221] When multiple dirt inlets 142A, 142B are included in the cleaning head 100, they may, for example, be the same size as one another.

[0222] Alternatively or additionally, when multiple (e.g., a pair) dirt inlets 142A, 142B are employed, the dirt inlets 142A, 142B may be spaced apart along the length 106 of the cleaning head 100 to provide relatively uniform suction along the length 106 of the cleaning head 100. For example, the distance between a central location along the length 106 of the cleaning head 100 and the center of the dirt inlet 142A may be the same or substantially the same as the distance between a central location along the length 106 and the center of the dirt inlet 142B.

[0223] If a single dirt inlet is employed, this may be located in the centre of the cleaning head 100 to provide a relatively symmetrical suction profile along the length 106 of the cleaning head 100 .

[0224] More generally, the liquid pickup region PR of the porous material layer 114 is defined by a sealed attachment of the porous material layer 114 around, for example, each of the at least one dirt inlet 142A, 142B.

[0225] Such a sealed attachment may help maintain underpressure in the covered dirty inlets 142A, 142B because loss of underpressure through leakage between the dirty inlets 142A, 142B and the porous material layer 114 is minimized or prevented.

[0226] The sealed attachment can be achieved in any suitable manner, for example by gluing or welding the porous material layer 114 around each of the at least one dirty inlet 142A, 142B, for example gluing and / or welding the porous material layer 114 to the above-mentioned (multiple) tubes 144A, 144B around the (multiple) openings defining the (multiple) dirty inlets 142A, 142B.

[0227] Particular mention is made of sealingly attaching the porous material layer 114 to the dirty inlet(s) 142A, 142B by heat sealing (e.g. ultrasonic welding). It has been found that this provides a particularly airtight seal in a straightforward manner, which helps maintain underpressure in the dirty inlet(s) 142A, 142B.

[0228] Reference Figure 5B , Fig. 6A and Figure 6B A non-limiting example of a sealed attachment of the porous material layer 114 to the dirty inlets 142A, 142B is achieved by a cleaning head 100 that includes an impermeable portion 146 sealed to the porous material layer 114 (e.g., sealed to an inner surface 148 of the porous material layer 114) and surrounding the dirty inlets 142A, 142B, whereby the dirty inlets 142A, 142B are exposed to a sealed cavity 150 between the porous material layer 114 and the impermeable portion 146.

[0229] The impermeable portion 146 may, for example, comprise or consist of a polymer film, such as a thermoplastic film. Various alternative sealing arrangements are described below, some of which do not comprise such a polymer film.

[0230] exist Fig. 6A and Figure 6B In the non-limiting example shown, a seal 152 formed, for example, via bonding and / or welding of an impermeable portion 146 (eg, a polymer film) extends around the perimeter of the porous material layer 114 and around the dirty inlets 142A, 142B.

[0231] In at least some embodiments, for example Fig. 7A and Figure 7B In the embodiment shown in , the liquid pick-up area PR is arranged relative to the at least one cleaning liquid outlet 104 to allow cleaning liquid to bypass, eg pass around the periphery of the liquid pick-up area PR to reach or at least be directed towards the surface to be cleaned.

[0232] This may allow for a more efficient use of the cleaning liquid because the cleaning liquid has a greater opportunity to reach the surface to be cleaned, for example via the cleaning liquid applicator materials 126, 128 (when included in the cleaning head 100) described above.

[0233] In other examples, the porous material may be sucked against the dirty inlet(s) 142A, 142B at least in part by a flow provided by an underpressure generator, for example against the cleaning head 100 or a component of the cleaning head 100 attached around the dirty inlet(s) 142A, 142B.

[0234] In some embodiments, the cleaning head 100 includes a liquid transport support structure 154 in the cavity 150, which is arranged to provide one or more flow paths between the porous material layer 114, in particular the pores of the porous material layer 114, and at least one dirt inlet 142A, 142B in the liquid pickup region PR.

[0235] The porous material layer 114 (e.g., a microfiber fabric) and / or the impermeable portion 146 (e.g., a polymer film) may be flexible, so that underpressure may cause the porous material layer 114 and the impermeable portion 146 to be stretched toward each other. This may present a risk of restricting the flow of liquid from the porous material layer 114 to the at least one dirty inlet 142A, 142B. Although the porous material layer 114 and the impermeable portion 146 are stretched toward each other, the liquid transport support structure 154 may help ensure that liquid can still be transported from the porous material layer 114, and in particular the pores of the porous material layer 114, to the at least one dirty inlet 142A, 142B.

[0236] The liquid delivery support structure 154 may be implemented in any suitable manner. Fig. 7A and Figure 7B In the non-limiting example shown, the liquid transport support structure 154 includes one or more mesh layers or is defined by one or more mesh layers. In such an example, the one or more flow paths described above can be provided by the spaces between the elements constituting the (multiple) mesh layers. Alternative examples of the liquid transport support structure 154 will be described below.

[0237] As described above, in some embodiments, in addition to the porous material layer 114, the porous material may include one or more additional porous material layers 156, 158. Examples of which are described in Figure 8 and Fig. 9 Described in.

[0238] At this point, it should be noted that when the porous material is dry, the porous material can be considered to be in an "air delivery state", in which air is delivered through each dry hole of the porous material. The "liquid delivery state" corresponds to a liquid, such as water, being delivered through the (wetted) holes of the porous material. When there is no longer liquid supplying the (multiple) holes, a "fluid blocking state" can be adopted. The "fluid blocking state" corresponds to a state in which the surface tension of the (residual) liquid retained in the wetted (multiple) holes of the porous material prevents the fluid from being delivered through the (multiple) holes. In the latter state, a surface or barrier is created at the boundary between air and liquid (such as water). This barrier can help maintain the above-mentioned underpressure in the (multiple) dirty inlets 142A, 142B. The pressure required to "destroy" this barrier can be called the "bursting pressure".

[0239] It should be noted that woven porous fabrics with finer weaves may have smaller pores, such as micropores, thereby producing higher burst pressures. However, there may be limitations on how small pores can be made using weaving techniques. At the same time, it is possible that certain fibers, such as fibers selected for their favorable cleaning and / or wear properties, can only be woven to provide a more open structure that is not suitable for maintaining sufficient underpressure in the dirty inlet (multiple) 142A, 142B.

[0240] However, the "bursting pressure" can be adjusted in various ways. Figure 8 In the non-limiting example shown, the porous material comprises or is defined by the porous material layer 114 and the first further porous material layer 156 .

[0241] For example, the porous material layer 114 is a microfiber fabric and the further first porous material layer 156 is a microfiber fabric.

[0242] By including a stack of porous material layers 114 , 156 in this manner, the rupture pressure may be increased, for example relative to a situation where the porous material consists solely of porous material layer 114 .

[0243] Without wishing to be bound by any particular theory, it is believed that this effect arises from variations in pore size and shape, such as statistical variations. For example, a microfiber fabric may be made from many fibers and yarns that are woven together into a fabric sheet. Thus, pores, such as micropores, may be created between the fibers and yarns, and therefore the pore size present in the fabric is not precisely fixed to one size and shape, but varies statistically.

[0244] The single porous material layer 114 may include a small number of relatively large pores (the surface tension of the residual liquid against these pores is small), so that these relatively large pores contribute to the lower bursting pressure of the single porous material layer 114. By stacking the additional porous material layer 156 on the porous material layer 114, the possibility that the above-mentioned small number of relatively large pores of the porous material layer 114 are aligned / communicated with the relatively large pores included in the additional porous material layer 156 may be relatively small. Therefore, the stacking of the porous material layers 114, 156 may help increase the bursting pressure of the porous material.

[0245] Although in Figure 8 In the non-limiting example shown, the porous material is formed by the porous material layer 114 and a first further porous material layer 156, but more than one further porous material layer 156 may be included in the porous material, for example to further increase the bursting pressure. Fig. 9In the non-limiting example shown, the porous material comprises or is defined by the porous material layer 114 , the first further porous material layer 156 and the second further porous material layer 158 .

[0246] For example, the porous material layer 114 is a microfiber fabric, the further first porous material layer 156 is a microfiber fabric, and the further second porous material layer 158 is a microfiber fabric.

[0247] The porous material layers 114, 156, 158 of the porous material may or may not be adhered to each other. In the non-limiting example where the porous material layers 114, 156, 158 are adhered to each other, such as via a suitable adhesive applied between the porous material layers, this may help to further increase the rupture pressure of the porous material.

[0248] Without wishing to be bound by any particular theory, this is believed to be due to the binder hindering horizontal fluid transport between the adhered porous material layers. Fig.10 , fluid transport through the pores 160A, 160B of the porous material layer 114 is schematically depicted in the upper left panel, while horizontal fluid transport between the non-adherent porous material layer 114 and the pores 162A of the additional first porous material layer 156 is schematically depicted in the lower left panel. Fig.10 By comparing the right hand pane of , it is apparent that the adhesive 164 between the porous material layer 114 and the first additional porous material layer 156 restricts or prevents horizontal fluid transport between the pores 160A of the porous material layer and the pores 162A, 162B of the first additional porous material layer 156.

[0249] Any suitable adhesive 164 may be used to bond the porous material layers 114, 156, 158 to one another, such as heat activated fabric glue. Commercially available examples of heat activated fabric glues are

[0250] An advantage of the porous material layers 114, 156, 158 of the porous material not adhering to each other may be that the resistance to the transport of liquid through the porous material may be reduced, for example by allowing horizontal transport of liquid between the porous material layers 114, 156, 158, or at least less restricting horizontal transport of liquid between the porous material layers 114, 156, 158 than when an adhesive 164 is present between the porous material layers 114, 156, 158.

[0251] As an alternative or in addition to the porous material comprising one or more further porous material layers 156 , 158 in addition to the porous material layer 114 , the porous material layer 114 (eg a microfiber fabric) may be subjected to a densification process, for example by ultrasonic welding.

[0252] In an exemplary densification process, a porous material layer 114 (eg, a porous fabric such as a microfiber fabric) is placed (eg, compressed) between two elements (eg, rollers) and relatively high frequency (eg, approximately 40 kHz) vibrations are emitted into the porous material layer 114 .

[0253] Such vibrations may cause the fibers of a porous fabric (e.g., a microfiber fabric) to move and rub against each other, generating heat, which may cause individual fibers to be welded together. Such welding may be controlled to provide a more dense porous structure, rather than a dense solid block. Since this process may be performed while the porous fabric is in compression, the density of the fabric may be increased, thereby increasing the bursting pressure.

[0254] Such a densification process may alternatively or additionally be used to densify one or more further porous material layers 156 , 158 , when such further porous material layer(s) are included in the porous material.

[0255] Fig.11 An exemplary testing apparatus 166 for testing the burst pressure characteristics of a porous material 168 is schematically shown. The porous material 168 is clamped between a clamping member 170 and a base plate 172. The clamping member 170 defines a hole for a bolt 174, which is received in a threaded hole in the base plate 172. Turning the bolt 174 in the appropriate direction can tighten / loosen the porous material 168.

[0256] In this specific example, the clamping member 170 is an aluminum ring with a thickness of 10 mm, and the base plate 172 is made of poly(methyl methacrylate) with a thickness of 10 mm. The sample of porous material is a disk with a diameter of 140 mm. Eight bolts 174 are used to fix the sample.

[0257] The dirt inlet 142A in the test device 166 is defined by the opening of a delivery conduit 176 provided in the base plate 172. In the cavity between the porous material 168 and the dirt inlet 142A, the above-mentioned liquid delivery support structure 154 is provided, which in this case is in the form of a mesh having a diameter of 80 mm.

[0258] The test device 166 comprises an underpressure generator 178 for generating an underpressure in the dirty inlet 142A, and a pressure sensor 180, such as a pressure gauge, arranged to measure the pressure in the dirty inlet 142A.

[0259] In this specific example, the pressure sensor 180 includes a data acquisition unit ( 2) An integrated pressure gauge to be able to monitor pressure as a function of time.

[0260] In this specific example, the underpressure generator 178 is in the form of a peristaltic pump or a syringe pump, such as a 250 mL syringe pump. A peristaltic pump can provide a pulsed water flow. It has been found that a syringe pump allows for more accurate measurements than a peristaltic pump.

[0261] The test device 166 also includes a pressure line filter 182 in the form of a chamber that is configured to prevent liquid from entering a pressure sensor line 184 connecting the pressure line filter 182 and the pressure sensor 180. Downstream of the pressure line filter 182 and the pump 178 is a collection reservoir 186 for collecting liquid pumped through the porous material 168.

[0262] The test procedure involves clamping a sample of porous material 168 between clamping member 170 and substrate 172 and then setting pump 178 to deliver 100 cm 3 / min flow rate. Check the pressure line filter 182 to ensure it is empty and zero the pressure gauge of the pressure sensor 180 and reconnect it before each measurement. Then connect the 25cm 3 100 cm of water is poured onto the sample of porous material 168, leaving a water layer of about 4 mm depth on the porous material. A flushing run is then performed by starting pump 178 so that water is drawn through the sample of porous material 168. After the flushing run, pump 178 is stopped and 25 cm 3 of water is poured over the sample of porous material 168 and a measurement run is carried out by triggering the data acquisition unit to start data acquisition and starting the pump 178.

[0263] Fig.12 A typical plot of underpressure versus time from data acquisition is provided in , along with a schematic diagram of the porous material 168. Initially, the "liquid delivery state" 188 described above is employed, wherein a liquid 190 (water in this example) is delivered through the (pre-wetted) pores 192. The "delivery pressure" recorded in this case corresponds to the pressure differential required to deliver the liquid 190 through the porous material 168 and the mesh liquid delivery support structure 154.

[0264] The governing equation describing the "liquid transport state" 188 may be the following Poiseuille equation:

[0265]

[0266] Where ΔP is the pressure difference across the hole 192; η is the dynamic viscosity of the liquid; L is the length of the hole 192; φ is the volume flow rate; and r is the radius of the hole 192.

[0267] For example, assuming a pore diameter of 20 μm and a pore extending through a porous material 168 having a thickness of 0.8 mm, the estimated volume flow rate is approximately 4.96*10 -14 m 3 / s each hole 192 (from 100cm 3 / minute typical fluid flow rate), and η 水 1*10 -3 Pa·s, ΔP=10.1Pa.

[0268] After the "liquid delivery state" 188, an intermediate state 194 is adopted, in which almost all of the liquid 190 has been removed from the surface of the sample of porous material 168, so that most of the pores are in the above-mentioned "fluid blocking state", in which the surface tension of the (residual) liquid 190 retained in the wetted (multiple) pores of the porous material 168 prevents air 196 from being transported through the pores 192. In the intermediate state 194, an ever-decreasing number of pores 192 may be in the "liquid delivery state". The "fluid blocking state" allows for significantly higher underpressures, so the underpressure increases relatively quickly during the intermediate state 194, as shown.

[0269] The governing equation describing the “fluid blockage state” can be the following droplet dP equation:

[0270]

[0271] Where Pi is the internal pressure, P O is the external pressure, R is the radius of the fluid droplet, such as Fig.12 Schematically shown in . T is the surface tension.

[0272] For example, assume that for a typical 20 μm diameter hole 192, R is 10 μm, and T 水 0.073N / m, P i -P O =ΔP=14600Pa.

[0273] When detergent is added to water, this ΔP can increase to 18000 Pa. When detergent is added, the surface tension of water decreases (T 肥皂水 =0.045 N / m), at which point two surfaces are created in the bubble on the hole 192: the inside and outside of the bubble. Therefore, the bursting pressure in the case where detergent is added to water can be about twice the bursting pressure of a single-layer surface:

[0274]

[0275] After the intermediate state 194, a final state 198 is adopted, in which all free water has been removed from the surface of the porous material 168, and all pores 192 are initially in a "fluid blocking state". As the pump 178 continues to draw water through the porous material 168, an underpressure is increased, which may cause some fluid blocks to rupture, so that air 196 is delivered through the corresponding pores 192 in an "air delivery state". The associated air ingress may reach equilibrium in the final state 198, in which the applied flow results in an underpressure that no longer causes fluid blocks to rupture. The latter corresponds to the "rupture pressure" of the porous material 168 under investigation.

[0276] The governing equation describing the "air transport regime" can be the Poiseuille equation provided above for the "liquid transport regime". For example, assuming a pore diameter of 20 μm and a pore extending through a porous material 168 having a thickness of 0.8 mm, the estimated volume flow rate is approximately 4.96*10 -14 m 3 / s each hole 192 (from 100cm 3 / minute typical fluid flow rate), and η 空气 18.1*10 -6 Pa·s, ΔP=0.18Pa.

[0277] In general, both the air delivery pressure (eg, 0.18 Pa) and the water delivery pressure (eg, 10.1 Pa) may be significantly smaller, such as negligible, compared to the pressure difference generated by surface tension (eg, 14600 Pa).

[0278] Fig.13 Several pressure-time graphs are provided for porous materials 168 tested using the test apparatus 166 and test procedure described above. Curve 200 is for porous material 168 having only porous material layer 114; curve 202 is for porous material 168 having porous material layer 114 and additional first porous material layer 156; curve 204 is for porous material 168 having porous material layer 114, additional first porous material layer 156, and additional second porous material layer 158; and, curve 206 is for porous material 168 having porous material layer 114 and three additional porous material layers. These data show that, as previously described, including more stacked porous material layers in porous material 168 increases the rupture pressure.

[0279] Furthermore, each curve in the set of curves 202, 204, and 206 is for a porous material 168 where the porous material layers are either adhered to one another or not adhered. It is observed that using an adhesive to adhere the porous material layers to one another further increases the rupture pressure, as described above.

[0280] Fig.14The above-mentioned "liquid transport state" 188 is schematically shown, wherein in a) the liquid is pumped through all the pores 192, in b) the end of the liquid transport state 188, in c) the intermediate state 194, and in d) the final state 198. The porous material 168 is Fig.14 , covering the dirty inlet(s) 142A, 142B connected to an underpressure generator 178 (eg, a pump).

[0281] The porous material 168 has pores 192, such as micropores, each having a different bursting pressure. Fig.14 The numbers are represented by the numbers provided below each hole 192. For simplicity, each number is rounded to a single digit.

[0282] When the underpressure generator 178 (e.g., a pump) is activated, all liquid (e.g., water) is pumped out of the floor, and the required pressure is the water delivery pressure, which is set to "1" in this example. The underpressure in the dirty inlet 142A, in this example the underpressure in the cavity 150 behind the porous material 168, is correspondingly "1". Therefore, Fig.14 a) schematically represents the "liquid delivery state" 188, and b) shows the end of the "liquid delivery state" 188. In b), a point is reached where the underpressure starts to rise.

[0283] When all of the liquid, such as water, has been removed from the floor, all of the holes 192 may be blocked by surface tension of the residual liquid therein. In the non-limiting example shown, the underpressure generator 178 is a fixed flow pump, so continued operation of the pump may increase the underpressure. At some point, the underpressure in the dirty inlet 142A behind the porous material 168 may rise to the level of the bursting pressure of the weakest hole 192, such as "4", which will be exceeded and air may begin to be transported therethrough. Since the pressure in the dirty inlet 142A behind the porous material 168 may already be significant when these first holes 192 are "burst", the air transported through these holes 192 at this point may be significant. Therefore, Fig.14 Step c) in can be seen as schematically representing the intermediate state 194.

[0284] In the intermediate state 194, the hole 192 may be blocked, while other holes 192 are still delivering liquid from other areas (away from the dirty inlet(s) 142A), thus creating more underpressure near the dirty inlet(s) 142A. This can cause the underpressure to rise relatively slowly until all the free liquid is gone. This can all be affected by the pump speed, and in at least some examples, the properties of the liquid delivery support structure 154, along with the flexibility of all components to deform when underpressure is applied.

[0285] As a simplified explanation, if the flow rate is set to 100 cm 3 / min, ignoring the flow resistance between the porous material and the pump, and all components are infinitely rigid, then the intermediate state 194 can be Fig.12 The vertical line in the figure numerically moves from the "liquid delivery state" 188 to the end state 198.

[0286] This process can continue until the delivered air equals the pumping rate in this example and the underpressure in the dirty inlet 142A behind the porous material 168 is below the rupture pressure of the remaining "unruptured" holes 192 with the lowest rupture pressure. Fig.14 Step d) in the process can be seen as schematically representing the above-mentioned final state 198.

[0287] It should be noted that the pressure measured in the test device 166 can define the burst pressure of the porous material 168. Different flow rates have been tested, such as 150 cm 3 / minute, but showing the same burst pressure, note that more holes 192 can "burst" to compensate for the increased flow.

[0288] The pore size (in other words, pore diameter) of the pores 192 of the porous material 168 may be selected to balance a relatively high underpressure with a relatively low liquid delivery resistance / liquid delivery pressure of the porous material 168 .

[0289] Smaller pores 192 can increase the underpressure that can be generated in the dirty inlet 142A, for example, using a relatively low-power underpressure generator 178 (e.g., a pump). A denser porous material 168 with smaller pores 192 can produce a higher bursting pressure. Also to investigate the lower limit of pore size, a study was conducted using the above-described test apparatus 166 and test procedure using beer filters specified according to the particle size they can retain as the porous material 168: 0.25 μm, 3 μm, 10 μm, and 25 μm filters were tested. For this experiment, the latter beer filter specification was assumed to be the same as the "pore size / diameter".

[0290] refer to Fig.15 , curve 208 is for a 0.25 μm filter; curve 210 is for a 3 μm filter; curve 212 is for a 10 μm filter; curve 214 is for a 25 μm filter; and curve 216 is for a reference microfiber fabric.

[0291] from Fig.15 It can be seen that the pore size / diameter of the porous material 168 has a significant impact on the performance. Based on the results, it is estimated that an average 40 μm pore size / diameter of the porous material 168 (eg, equivalent to a 40 μm beer filter) may correspond to a maximum value based on underpressure considerations.

[0292] Based on liquid delivery pressure considerations, an average 0.25 μm pore diameter / diameter of the porous material 168 (eg, equivalent to a 0.25 μm beer filter) may correspond to a minimum value.

[0293] from Fig.15 It is evident from the results that a 0.25 μm filter may result in significantly higher water delivery pressures than in the case of a 3 μm filter. In the case of a 0.25 μm filter, the underpressure during water delivery may rise to approximately 23,000 Pa. Furthermore, the time to reach a dry state may be significantly longer for a 0.25 μm filter, which means that it may take significantly more time to deliver the liquid / water from the surface to be cleaned.

[0294] In a non-limiting example, an average pore size / diameter of about 3 μm (eg, equivalent to a 3 μm beer filter) for the porous material 168 may provide a favorable balance of properties.

[0295] Fig.15 It is shown that there is a limited difference between the liquid / water delivery pressure and the bursting pressure of the porous material 168. The relatively small pores 192 can lead to an increase in the bursting pressure, for example up to 39000Pa in the case of a 0.25μm filter, but can also lead to an increase in the water / liquid delivery pressure, for example up to 33000Pa in the case of a 0.25μm filter. It should be noted that the difference between the water delivery pressure and the bursting pressure is similar to that of the reference microfiber fabric (1000Pa water delivery pressure; 7000Pa bursting pressure).

[0296] Bacteria tend to be characterized by having a relatively small size. For example, an Escherichia coli cell is approximately 2 μm long and 0.5 μm in diameter.

[0297] Therefore, a porous material 168 having a pore size greater than 2 μm may allow such bacteria to pass through. In this way, the bacteria may be removed from the surface to be cleaned.

[0298] Depending on the porous material 168 selected, up to 99.9% of the bacteria may be drawn away from the surface to be cleaned through the porous material 168 .

[0299] In some embodiments, the porous material 168 is defined by one or more layers of a microfiber fabric having pores with a pore size / diameter in the range of 0.25 μm to 40 μm (eg, equivalent to a 0.25 μm to 40 μm beer filter).

[0300] For example, such a porous material 168 (defined by one or more layers of microfiber fabric) may have a pore size / diameter distribution in the above-mentioned range of 0.25 μm to 40 μm, and an average pore size of 20 μm to 40 μm, for example, about 35 μm. Since the size of the pores is significantly larger than the size of bacteria, the bacteria can pass through the porous material 168 and be removed from the surface to be cleaned.

[0301] Although the above description focuses on the working principle of the porous material 168, it should be noted that the porous material 168 can be in contact with the surface to be cleaned and move on the surface to be cleaned at a certain speed. Fig.16 As schematically shown in Fig.16 An exemplary cleaning head 100 is shown, which includes a dirt inlet 142A covered with a porous material 168 on a surface to be cleaned 218. In this non-limiting example, the surface to be cleaned 218 is the surface of a floor 220, and there is a liquid layer 222, such as water, between the surface to be cleaned 218 and the porous material 168. An underpressure generator 178, such as a pump, is used to draw fluid through the holes 192 of the porous material 168 in the direction of arrow 224. Arrow 226 represents the internal underpressure that pulls the liquid toward the dirt inlet 142A. Arrow 228 represents the speed of the cleaning head 100.

[0302] Fig.16 A velocity distribution 234 in the fluid layer 222 is schematically shown. Arrows 230 represent fluid shear forces on the porous material 168 resulting from the velocity distribution 234 in the fluid layer 222. Arrows 232 represent shear forces pulling water toward the floor 220.

[0303] This behavior can be approximated using the following Bernoulli equation:

[0304]

[0305] Where ρ is the density of the fluid, υ is the fluid flow rate, P is the pressure, h is the height above the reference plane (in this case the floor 220), and g is the acceleration due to gravity.

[0306] The above Bernoulli equation can be rewritten for the pressure below the porous material 168:

[0307]

[0308] For a speed of 1.5 m / s, ΔP=1125 Pa; for a speed of 3.16 m / s, ΔP=5000 Pa.

[0309] This indicates that at higher speeds, more liquid will remain on the floor 220 because at higher speeds, the floor 220 will pull the liquid more strongly, and this has been observed with the cleaning head 100 according to the present disclosure.

[0310] The movement of the cleaning head 100, for example at a speed of about 1.5 m / s, can generate shear flow in the liquid layer 222, generating shear forces 232 acting on the liquid in the porous material 168, which pull the liquid toward the surface to be cleaned 218. The water is also pushed in the direction of the dirty inlet 142A by the underpressure 226. The underpressure can be selected so that the force that moves the liquid 222 toward the dirty inlet (multiple) 142A exceeds the shear force 232.

[0311] The liquid pickup performance of an exemplary cleaning head 100 including a porous material 168 and a cleaning liquid applicator material 126, 128 for applying a liquid (e.g., water) to a surface 218 to be cleaned, the cleaning liquid applicator material 126, 128 moving over the surface 218 to be cleaned at a speed of 1.5 m / s and with different dirty inlet underpressures was evaluated. The results are listed in Table 1.

[0312]

[0313] Table 1

[0314] Another advantage of the liquid pickup principles described herein may be lower power consumption, particularly in examples where the undervoltage generator 178 is powered.

[0315] Conventional vacuum cleaners capable of picking up water need to generate significant air velocity and / or brush force in order to generate sufficient shear forces on the water droplets to force them into the vacuum cleaner. Typical power consumption values ​​for such vacuum cleaners are several hundred watts.

[0316] The following calculations illustrate the relatively low mechanical power required for liquid (eg, water) pickup according to the present disclosure.

[0317] P=Φ*ΔP

[0318] Where P is the mechanical power in Watts; Ф is in m 3 / s; and ΔP is the underpressure in the dirty inlet(s) 142A in Pa.

[0319] For example, using an underpressure of 5000Pa and a 3 / minute fluid flow, power is 8.3*10 -3 watt.

[0320] If the undervoltage generator 178 is powered using a conventional battery which provides, for example, a runtime of 28 minutes in a wet cleaning device with a mechanical power consumption of approximately 50 Watts, the runtime in the present case would be 168,000 minutes, in other words more than 100 days.

[0321] Thus, an electric wet cleaning device having a cleaning head 100 according to the present disclosure may only rarely need to recharge its battery (in examples where such a battery is included to power the wet cleaning device), and / or may be lighter due to the minimum battery capacity required for, for example, 1 hour of run time. With respect to the latter, it is noted that a battery for a conventional handheld wet cleaning device may weigh about 0.5 kg, and thus may significantly increase the overall weight of the wet cleaning device.

[0322] Table 2 provides a mechanical power comparison between a conventional vacuum cleaner and the various conditions described above with respect to a wet cleaning device according to the present disclosure.

[0323]

[0324]

[0325] Table 2

[0326] More generally, the present invention provides a wet cleaning device including a cleaning head 100. The cleaning head 100 has at least one dirty inlet 142A, 142B and a porous material 168 covering the at least one dirty inlet 142A, 142B. The wet cleaning device also includes an underpressure generator 178, which is configured to provide a pressure difference between the interior of the wet cleaning device and the atmospheric pressure for drawing fluid through the porous material 168 and into the at least one dirty inlet 142A, 142B.

[0327] The underpressure generator 178 is comprised in an underpressure generator arrangement configured to restrict the passage of fluid from an underpressure generator outlet of the underpressure generator 178 towards the at least one dirty inlet 142A, 142B at least when the underpressure generator 178 is deactivated.

[0328] In some embodiments, the pressure difference is in the range of 2000Pa to 13500Pa.

[0329] The two end points of the range of 2000 Pa to 13500 Pa for the pressure difference were chosen purposefully.

[0330] The 2000Pa lower limit reflects that the cleaning head 100 will typically be moving over the surface to be cleaned, such as the floor, and as the speed of the cleaning head 100 over the floor increases, the accompanying drop in static pressure means that the liquid is pulled towards the floor. As mentioned above, this behavior can be approximated by the Bernoulli equation.

[0331] Referring to Table 1 above, it has been found that below 2000 Pa, excessive liquid may remain on the surface to be cleaned when the cleaning head 100 is moved over the surface to be cleaned at typical speeds.

[0332] The minimum underpressure of 2000Pa is set accordingly based on the minimum typical speed at which the user moves the cleaning head 100 over the surface to be cleaned, thereby ensuring that the underpressure is sufficient to draw liquid into the interior of the wet cleaning device without the user having to significantly slow down or stop the movement of the cleaning head 100 over the surface to be cleaned in order to pick up the liquid.

[0333] The purpose of defining the upper limit of 13500 Pa is to ensure that the liquid transport through the porous material 168 is fast enough.

[0334] There is a trade-off between the magnitude of the underpressure that can be maintained and the resistance to flow through the porous material 168, which determines the rate at which liquid can pass through the porous material 168. This trade-off is reflected in the choice of 13500 Pa as the upper limit of the range.

[0335] In some embodiments, the pressure differential is 2000 Pa to 12500 Pa, preferably 5000 Pa to 9000 Pa, and most preferably 7000 Pa to 9000 Pa. These ranges may reflect the particularly enhanced liquid pickup observed during movement of the cleaning head 100 , combined with the relatively low flow resistance through the porous material 168 .

[0336] This pressure difference can be verified directly and positively in a given wet cleaning device by, for example, drilling a hole in a tube of the wet cleaning device that is fluidly connected to the dirty inlet(s) 142A, 142B and using this hole to connect to the pneumatic pressure sensor itself, which itself has a tube with a membrane covering its ends; the sensor is thus connected using an airtight connection. The sensor can be arranged to avoid disturbing the flow, so a person skilled in the art will arrange the sensor to avoid, for example, creating a bypass flow. No flow flows to or from the sensor: only pressure is transmitted. In this way, the flow of the appliance is never impaired (and therefore remains at the set level despite the installation of the sensor).

[0337] The pressure sensor is connected between the porous material 168 and the underpressure generator 178 and as close to the porous material 168 as possible to minimize the influence of other factors (such as flow resistance, etc.) on the sensed pressure difference.

[0338] The sensing element / membrane of the pressure sensor / pressure gauge is ideally arranged / positioned in the pressure sensor so that the sensing element can be placed directly (no connecting tubes required) in the tube, or in the cavity 150 behind the porous material 168.

[0339] As will be appreciated by those skilled in the art, measurement errors can be minimized by positioning the membrane of the pressure sensor (in other words, a membrane pressure gauge) so that the membrane is positioned at the wall of the tube (or exposed to the cavity 150) (in other words, in line with the wall of the tube).

[0340] It should be noted that bubbles within narrow tubes can create drag (capillary / surface tension effects) and can therefore affect the measurement.Thus, those skilled in the art will further appreciate that care should also be taken that bubbles (water-air surface) do not unduly affect the differential pressure measurement.

[0341] It should also be noted that the water column present between the pressure sensor and the porous material 168 should be subtracted from the measurement results (if such a water column is present during the measurement) to compensate for the static pressure created by the water column.

[0342] Once the pressure sensor is arranged as described above, it can be determined that the maintenance of the underpressure is due to the porous material 168 and not some other element, such as a valve. Any such element that affects the underpressure presented to the porous material 168 should be rendered inoperable for the purpose of performing the measurement.

[0343] While the differential pressure measurement is being performed, the component(s) dispensing the cleaning liquid (if the wet cleaning apparatus is configured to deliver a cleaning liquid) is disengaged.

[0344] The wet cleaning device is turned on (at the desired setting) so that the pickup system is activated including the underpressure generator 178. The recording of data from the pressure sensor begins.

[0345] The pickup area of ​​the cleaning head 100 is suspended in a layer of water with a maximum depth of 5 mm.

[0346] The pick-up area is then raised from the water without tilting it in any way (so that the cleaning head 100 remains in the cleaning position as if it were positioned to clean a floor) so that the water no longer contacts the porous material 168. At this point, the "free water" will be removed from the porous material 168, all pores will enter their "blocked state", and the bursting pressure can be determined. The measurement result will be similar to Fig.12 , again noting that equilibrium is established in the final state 198 where the applied flow results in an underpressure that does not cause further fluid block break-ups.

[0347] The burst pressure obtained from this measurement, with reference to the end state 198, is the "pressure difference between the interior of the wet cleaning device and the atmospheric pressure used to draw the fluid through the porous material 168 and into the at least one dirty inlet 142A, 142B". It is verified from the measurement whether the range of 2000Pa to 13500Pa is met.

[0348] It should be noted that the porous material 168 can be arranged to contact the liquid on the surface to be cleaned, as previously described. Therefore, the porous material 168 can be defined from the outer surface of the porous material 168 that can be exposed to the liquid on the surface to be cleaned to the inner surface of the porous material 168 that is exposed to at least one dirty inlet.

[0349] ASTM F316-03, 2019, Test A provides a bubble point pressure measurement. Although this standard method was developed for non-fibrous membrane filters, the procedure can be replicated for porous materials 168 according to the present disclosure.

[0350] In short, a bubble point test for determining the limiting pore diameter, in other words the maximum pore diameter, is performed by pre-wetting a sample of the porous material 168, increasing the gas pressure upstream of the porous material 168 at a predetermined rate, and observing bubbles downstream to indicate the passage of gas through the largest diameter pores of the porous material 168.

[0351] Like the membrane filter described in ASTM F316-03, 2019, Test A, the porous material 168 may (at least approximately) have discrete pores extending from one side of the porous material 168 to the other, similar to capillaries. The bubble point test is based on the principle that the wetting liquid is held in these capillary pores by capillary attraction and surface tension, and the minimum pressure required to force the liquid out of these pores is a function of the pore diameter. The pressure at which a steady stream of bubbles appears in this test is called the "bubble point pressure."

[0352] It should be noted that ASTM F316-03, 2019, Test A is based on the pore approximation as a capillary pore with a circular cross-section, and therefore the limiting pore diameter should be considered merely an empirical estimate of the maximum pore diameter based on this premise.

[0353] As with the test procedure, replicate the test apparatus specified in ASTM F316-03, 2019, Test A.

[0354] 1. A sample of porous material (2 inch (50.8 mm) diameter; held in a circular holder (e.g., with a 47 mm diameter opening / active area) is completely wetted by floating it on a pool of liquid (note that a vacuum chamber can be used to help wet the sample if necessary). For water wettable samples, place the sample in water and completely wet it.

[0355] 2. Place the wetted sample of porous material in the filter holder of the test apparatus.

[0356] 3. Place a fine mesh (100 x 100 mesh) over the sample of porous material; the fine mesh is the first part of the 2-layer construction specified by the standard.

[0357] 4. The second part of the 2-layer construction in the form of a perforated metal part to increase rigidity is placed on the fine mesh.

[0358] 5. The support ring is placed on the stack and bolted into place. Slight gas pressure may be applied at this point to eliminate possible liquid backflow.

[0359] 6. The perforated metal parts are covered with 2 mm to 3 mm of test liquid (Type IV water as required by the standard when the sample is wetted with water).

[0360] 7. The gas pressure is then increased, and the lowest pressure at which a steady stream of bubbles rises from the central area of ​​the reservoir is recorded (see Figure 5 of ASTM F316-03, 2019, Test A; note that bubbles observed at the edge of the reservoir are ignored for bubble point determination).

[0361] It has been found appropriate to first increase the pressure relatively quickly (e.g. at about 200 Pa / sec) to roughly determine the bubble point. The pressure is then released from the sample to allow water to flow back into the sample. The pressure is then increased to about 80% of the expected pressure value, held at the 80% level for about 15 seconds (to ensure that all "free" water is pressed out of the sample), and then the pressure is increased again at a lower rate of ≤ Pa / sec until a constant stream of bubbles is observed.

[0362] The limiting pore diameter d was then determined from the recorded bubble point pressure p using Equation 1 of ASTM F316-03, 2019, Test A: D = Cγ / p, where γ is the surface tension in mM / m (72.75 for distilled water at 20°C), and C is 2860 when p is in Pa.

[0363] The bubble point pressures from ASTM F316-03, 2019, Test A were found to be comparable to the burst pressures described above for the samples of porous material 168, except in the case of the 0.25 μm beer filter, which can be directly explained by the presence of forced flow in the burst pressure test but not in the bubble point test. The results for various samples of porous material 168 are provided in Table A.

[0364]

[0365]

[0366] Table A

[0367] In some embodiments, the limiting pore diameter of the porous material 168 measured using ASTM F316-03, 2019, Test A is equal to or greater than 15 μm.

[0368] This limiting pore diameter of 15 μm or greater can help maintain a relatively large underpressure while ensuring that the pores are large enough to effectively deliver liquid. With respect to the latter, it should be noted that this observation is supported by theory, noting that when using the Poiseuille equation approximation provided above, the flow resistance can increase to a power of 4 for smaller pores.

[0369] In some embodiments, the limiting pore diameter of the porous material 168 is equal to or less than 105 μm, measured using ASTM F316-03, 2019, Test A. The upper limit of the limiting pore diameter helps ensure that the porous material 168 can maintain sufficient underpressure.

[0370] As noted above, ASTM F316-03, 2019, Test A employs a cylindrical hole. For purposes of explanation / illustration only (and therefore should not be considered as limiting values ​​for the limiting hole diameter from ASTM F316-03, 2019, Test A provided herein), it should be noted that the limiting hole diameter can be adjusted to compensate for hole non-roundness using the Tortuoise Factor (TF), which is an empirical factor derived from solid wire filters. The 1.3-1.65 expansion of the TF recommended in ASTM E3278-21 (see Section 4.2.1 of that standard) can result in a hole size expansion of approximately 27%. For purposes of illustration only, Table B shows the above limiting hole diameter endpoints when the TF adjustment is used. Note that the limiting hole diameter of ASTM F316-03, 2019, Test A provides a measure of the maximum hole size through which a particle passes, so the TF can compensate for the fact that a "triangular" hole can only allow spherical particles that are much smaller than the triangular surface to pass.

[0371]

[0372] Table B

[0373] In some embodiments, the undervoltage generator is configured to provide less than or equal to 2000 cm 3 The flow rate through the porous material 168 is / min.

[0374] This flow rate can be significantly lower than the flow rate of the conventional wet vacuum cleaners mentioned above. Since power is equal to flow rate multiplied by pressure difference, by reducing the maximum 2000cm 3The combination of the flow rate of 1000 rpm and the maximum pressure difference of 13500 Pa as the maximum power consumption scheme can minimize the power consumption of the wet cleaning device. Referring to Table 2 above, this can enable the wet cleaning device to be made relatively compact, for example, using a smaller battery, and / or having a relatively long operating time.

[0375] Alternatively or additionally, the undervoltage generator may be configured to provide a voltage equal to or greater than 15 cm 3 / minute flow rate through the porous material 168. This can help to pick up the liquid from the surface to be cleaned quickly enough. In some embodiments, 15cm 3 The lower limit of 100 Å / min may be set to be equal to or exceed the flow rate of the cleaning liquid from the cleaning liquid outlet(s) 104 also included in the cleaning head 100 .

[0376] In some embodiments, the undervoltage generator is configured to provide a voltage equal to or greater than 40 cm 3 / min flow rate through the porous material 168. In addition to facilitating efficient liquid pickup, in some embodiments, the 40 cm 3 / minute may be set to equal or exceed the flow rate of the cleaning liquid from the cleaning liquid outlet also included in the cleaning head, and the minimum cleaning liquid flow rate is set to ensure that the cleaning liquid is adequately supplied to the surface to be cleaned.

[0377] The undervoltage generator can be configured to provide 80 cm of 3 / min-750cm 3 / min, more preferably 100cm 3 / min-300cm 3 / min, most preferably 150cm 3 / min-300cm 3 Such a flow rate can take advantage of the underpressure holding capability of the porous material 168 and can ensure adequate liquid pickup while limiting energy consumption.

[0378] In some embodiments, the porous material 168 has a thickness less than or equal to 10 mm, more preferably less than or equal to 5 mm, and most preferably less than or equal to 3 mm. Such a maximum thickness can help minimize flow resistance through the porous material 168.

[0379] The thickness of the porous material 168 can be determined by using a 0.01 mm precision gauge and two grounded metal plates for receiving the porous material 168 therebetween (the upper plate through which the positive pressure is applied is 70 mm x 30 mm, and the lower plate on which the porous material sample is supported has a larger area than the 70 mm x 30 mm surface of the upper plate to facilitate alignment). The arrangement is configured to apply 864.2 N / m to the porous material sample (70 mm x 30 mm). 2 The relevant measurement parameters are shown in Table C:

[0380]

[0381] Table C

[0382] The thickness of several samples was determined using this method and the data are provided in Table D:

[0383]

[0384] Table D

[0385] In some embodiments, 200 cm 3 The fluid delivery pressure at 100 psi / min flowing through the porous material 168 is less than 0.25 times the bubble point pressure as determined by ASTM F316-03, 2019, Test A.

[0386] This may mean that the resistance to flow through the porous material 168 is kept relatively low.

[0387] Another set of burst pressure tests (similar to the above tests) were conducted using porous materials corresponding to Sample No. 18 in Table A, Sample Nos. 22-25 in Table D, and Supplier F fabric with a thickness of 0.8 mm. The flow pressure drop and burst pressure were recorded for each sample and the results (average of at least two measurements) are listed in Table E. In these experiments, an 89 cm 3 The flow rate was 200 μm / min and the diameter of the circular mesh below the sample (extending through the "active area" of the sample) was 80 mm.

[0388]

[0389]

[0390] Table E

[0391] It can be seen that the burst pressure increases as more layers are stacked on top of each other, as previously described. However, as more layers are added, the transport flow pressure can increase faster than the burst pressure, and in the case of sample numbers 22 to 27, when the porous material has four stacked double layers (at sample number 25), the transport flow pressure exceeds the burst pressure.

[0392] The transport flow pressure rises faster with more layers than is evident from samples 22 to 27; however, air in the system may mean that the data begins to show compressibility, particularly for sample numbers 25 to 27.

[0393] More generally, these data may indicate that the wet cleaning device may be operable when the delivery flow pressure (at a desired flow rate) is below the burst pressure.

[0394] For the tests whose results are listed in Table E, the flow rate was 89 cm 3 / minute, the effective area of ​​the fabric is 5030mm 2 In the case of cleaning head 100, the effective area may be approximately 1750 mm 2 Therefore, when a delivery flow pressure is applied to the porous material 168 of the cleaning head 100, the actual flow rate through the porous material 168 may be 0.35 times lower (1750 / 5030) than the flow rate used in these tests.

[0395] This may mean that at the point where the delivery flow pressure is equal to the burst pressure (e.g., at sample number 24), the maximum flow rate that the porous material 168 can withstand is approximately (0.35*98)31cm 3 Even if more layers are added in the porous material 168, the burst pressure can remain approximately the same while the delivery flow pressure increases, thus reducing this value even more.

[0396] Note that in the above-mentioned burst pressure test, the entire surface of the test sample is covered with water, so the entire area of ​​the porous material 168 delivers water. However, in practice, the area (e.g., 5 mm wide and 350 mm long) where the cleaning head 100 contacts the floor delivers water, while the area of ​​the porous material 168 adjacent to this area can also deliver air. This may mean that when, for example, four double layers are used (in the case of sample number 25), and the burst pressure of the porous material is lower than the water delivery pressure, the periphery of the porous material 168 may begin to rupture, thereby releasing air, thus causing sedimentation at the burst pressure. The active / pickup area can maintain a relatively low pressure, so that the liquid can be picked up relatively slowly, so that the liquid can remain on the surface to be cleaned. On the contrary, in the case where the porous material 168 has a relatively low delivery flow pressure and a significantly larger burst pressure (e.g., in the case of a 0.8 mm thick supplier F fabric, where the burst pressure is 50 times higher than the delivery flow pressure), the pickup flow may be very high.

[0397] In summary, the wet cleaning device may operate with a burst pressure higher than the delivery flow pressure, but to enable pick-up at higher speeds, the burst pressure may be at least twice the delivery flow pressure.

[0398] In some non-limiting examples, the cleaning head 100 may be 40 cm 3 The flow rate through the porous material 168 is 85% of the flow rate of the cleaning liquid on the smooth surface to be cleaned, i.e. 34 cm 3 In the case of a pick-up rate of 31 cm / min, the pick-up rate can be compared with the 31 cm / min estimated above for sample number 24. 3 / minute compared to.

[0399] In some non-limiting examples, some tolerances may be introduced, for example to account for 20 cm 3 / min of cleaning liquid flow, thus resulting in an upper limit of the thickness of the porous material 168 of about 5 mm (see sample number 25).

[0400] As described above, the porous material 168 may include one or more of a porous fabric, a porous plastic, and a foam.

[0401] Such a porous plastic may, for example, take the form of a sintered web of plastic particles.

[0402] In embodiments where the porous material 168 comprises such a porous plastic, one or more additional porous material layers, for example comprising a porous fabric, such as a woven porous fabric, may be disposed on the outer surface of the porous plastic. Such additional porous material layer(s) may be more wettable by water than the porous plastic and therefore more suitable for contacting the surface to be cleaned when wetted by water.

[0403] Particularly mentioned porous materials include porous woven fabrics, most preferably woven microfiber fabrics. Such woven microfiber fabrics can facilitate obtaining the required underpressure in wet cleaning devices.

[0404] Such porous woven fabrics, in particular such woven microfiber fabrics, can be configured in particular by the tightness of their weaving in order to meet the above-mentioned range of limiting pore diameters.

[0405] Specifications for particularly suitable woven fabrics are provided in Table F as illustrative, non-limiting examples.

[0406]

[0407] Table F

[0408] Figures 17 to 23 An example of how the porous material 168 may be installed in the cleaning head 100 is schematically depicted.

[0409] The porous material 168 can be mounted in any suitable manner. Fig.17As shown, the cleaning head 100 includes a support member 236, such as a rigid support member 236, for supporting the porous material 168. The support member 236 may be formed from any suitable material, such as an engineering thermoplastic.

[0410] In some embodiments, the cleaning head 100 includes an elastomeric material 238 on which the porous material 168 is disposed. This elastic deformation of the elastomeric material 238 can reduce the risk of damaging the porous material 168 if, for example, relatively hard protrusions are present on the surface 218 to be cleaned in contact with the porous material 168. Alternatively or additionally, the elastomeric material 238 can help the porous material 168 to follow any contours of the surface 218 to be cleaned.

[0411] The elastomeric material 238 may be or include, for example, silicone rubber. Other elastomeric materials, such as polydienes, for example, polybutadiene, thermoplastic elastomers, etc. may also be considered to be included in or define the elastomeric material 238.

[0412] Alternatively or additionally, the elastomeric material may be less than 50 Shore A, preferably less than 20 Shore A, most preferably less than 10 Shore A.

[0413] In a non-limiting example, the elastomeric material is 4 Shore A silicone rubber.

[0414] In embodiments where the cleaning head 100 includes a support member 236 , such as a rigid support member 236 , the elastomeric material 238 may be disposed between the support member 236 and the porous material 168 . Fig.17 Such an example is shown in .

[0415] In embodiments where the cleaning head 100 includes the protruding elements described above, the protruding elements may include an elastomeric material 238, as will be described in greater detail below.

[0416] Back to Fig.17 In the non-limiting example shown, the impermeable portion 146 is in the form of a polymer (e.g., thermoplastic) film, with the seal 152 disposed between the polymer film and the porous material layer 114 included in the porous material 168. Furthermore, the liquid transport support structure 154 included in this particular example is in the form of a mesh or a stack of mesh layers.

[0417] In some embodiments, for example Fig.18 In the non-limiting embodiment shown, the impermeable portion 146 is defined by (multiple) impermeable sealing portions, such as multiple pieces of polymer film, of the porous material layer 114 extending from the elastomeric material 238 to the porous material 168. In this case, it may not be necessary for the polymer film to extend laterally on the inner surface of the porous material layer 114.

[0418] In some embodiments, the elastomeric material 238 includes an impermeable portion 146 that is sealed to the porous material layer 114 of the porous material 168. Therefore, the above-mentioned polymer film and multiple polymer films are eliminated in this embodiment and can be omitted. In this way, the number of parts in the cleaning head 100 can be reduced, thereby facilitating manufacturing.

[0419] In some embodiments, Fig.19 As shown, the liquid transport support structure 154 is at least partially or entirely provided by a surface pattern on and / or in the surface of the porous material layer 114 of the elastomeric material 238 facing the porous material 168. Replacing the (multiple) meshes with the surface pattern on the surface of the elastomeric material 238 can help reduce the number of components in the cleaning head 100. In other aspects, Fig.19 The example shown corresponds to Fig.18 Example shown.

[0420] In some embodiments, Fig. 20 As shown, the support member 236 includes an impermeable portion 146 that seals against the porous material layer 114 of the porous material 168. In other words, the seal between the support member 236 and the porous material 168 is provided by the protruding portion of the support member 236 that seals against the porous material 168. Therefore, the above-mentioned polymer film is not necessary in this example, because a direct connection between the porous material layer 114 and the support member 236 can be used to create the seal. In other aspects, Fig. 20 The example shown corresponds to Fig.17 Example shown.

[0421] Fig.21 The non-limiting example shown in corresponds to Fig. 20 , except that the liquid transport support structure 154 is at least partially or completely provided by a surface pattern on and / or in the surface of the porous material layer 114 of the elastomeric material 238 that faces the porous material 168.

[0422] Fig. 22 The non-limiting example shown in corresponds to Fig.18 , except that the elastomeric material 238 is disposed within the cavity 150 provided between the polymer membrane as the impermeable portion 146 and the porous material layer 114 of the porous material 168 .

[0423] Fig.23 The non-limiting example shown in corresponds to Fig. 22 , except that the liquid transport support structure 154 is at least partially or completely provided by a surface pattern on and / or in the surface of the porous material layer 114 of the elastomeric material 238 that faces the porous material 168.

[0424] At this point, it is reiterated that the above-mentioned liquid pickup area PR of the porous material layer 114 (defined around, for example, the sealed attachment of the porous material layer 114 to each of the at least one dirty inlet 142A, 142B) can be arranged relative to each of the at least one cleaning liquid outlet 104 to allow cleaning liquid to bypass the liquid pickup area PR to reach or at least be directed towards the surface to be cleaned 218. This arrangement of the liquid pickup area PR relative to each of the cleaning liquid outlet(s) 104 can be achieved in any suitable manner.

[0425] In some embodiments, for example Fig.24 As shown, each of the cleaning liquid outlets 104 is arranged in one or more distribution components that are spatially separated from the porous material layer 114. By arranging the (multiple) cleaning liquid outlets 104 in such separate one or more distribution components, the cleaning liquid can flow along the porous material layer 114. Fig.24 The direction of arrow 240 in FIG. 2 is toward the surface 218 to be cleaned without initially contacting the porous material layer 114 .

[0426] exist Fig.24 In the non-limiting example shown, the dispensing member corresponds to the cleaning liquid dispensing strips 108, 124 described above.

[0427] exist Fig.24 In the embodiment shown in FIG. 1 , the spatial separation is evident by a gap 242 , such as an air gap 242 , provided between the porous material layer 114 and the cleaning liquid distribution strips 108 , 124 .

[0428] In some embodiments, Fig.25 As shown, the porous material 168 includes one or more additional porous material layers 156 described above, and the cleaning head 100 includes a detachable element 244, which includes one or more additional porous material layers 156, and the separation of the detachable element 244 separates the one or more additional porous material layers 156 from the porous material layer 114.

[0429] In some embodiments, the detachable element 244 includes the above-described cleaning liquid applicator material 126, 128. In this way, one or more additional porous material layers 156 can be replaced directly while replacing the cleaning liquid applicator material 126, 128. For example, the cleaning liquid applicator material 126, 128 can be attached to (e.g., adhered to) the one or more additional porous material layers 156 in the detachable element 244.

[0430] In some embodiments, such as in Fig.25In the non-limiting example shown, the cleaning liquid applicator material 126, 128 includes the above-described first and second applicator portions 126, 128, wherein a first attachment 246A connects one or more additional porous material layers 156 to the first applicator portion 126, and a second attachment 246B connects one or more additional porous material layers 156 to the second applicator portion 128. Fig.33E Another example is described.

[0431] In some embodiments, the cleaning head 100 includes a support for supporting the porous material layer 114, and the cleaning head 100 includes a detachable (and / or attachable) member 248, the detachable member 248 includes the porous material layer 114, and separation of the detachable member 248 separates the porous material layer 114 from the support.

[0432] In addition to the porous material layer 114 , such a detachable member 248 may include the above-mentioned impermeable portion 146 , for example comprising or being in the form of a polymer film, wherein the at least one dirt inlet 142A is defined by one or more apertures in the impermeable portion 146 .

[0433] In some non-limiting examples, for example Fig.26 As shown, the detachable (and / or attachable) component 248 also includes the liquid delivery support structure 154 described above.

[0434] For example, the liquid transport support structure 154 may be disposed in the cavity 150 between the porous material layer 114 and the impermeable portion 146 .

[0435] When the cleaning head 100 includes both the detachable element 244 and the detachable element 248 , the detachable element 244 may, for example, be detachable independently of the detachable element 248 , and the detachable element 248 may be detachable independently of the detachable element 244 .

[0436] In some embodiments, Fig. 27 As shown, the detachable member 248 also includes the cleaning liquid applicator material 126, 128. For example, when the detachable member 248 includes the impermeable portion 146, the cleaning liquid applicator material 126, 128 may be attached to (eg, adhered to) the impermeable portion 146.

[0437] exist Fig. 27 In the non-limiting example shown, the cleaning liquid applicator material 126, 128 includes the above-mentioned first and second applicator portions 126, 128, and the first connection 250A connects the first side of the impermeable portion 146 to the first applicator portion 126, and the second connection 250B connects the second side of the impermeable portion 146 to the second applicator portion 128.

[0438] Fig.28 An exemplary cleaning head 100 is schematically illustrated that includes a detachable member 248 that does not include the cleaning liquid applicator material 126, 128. However, the cleaning liquid applicator material 126, 128 is still detachable, and in this example, each of the first and second applicator portions 126, 128 can be separated from the cleaning liquid outlet 104 independently of each other and independently of the detachable member 248.

[0439] More generally, the present disclosure provides an attachable (and / or detachable) member 248 itself. The attachable member 248 can be adapted to be attached to a wet cleaning device having an underpressure generator 178. In at least some embodiments, the attachable member 248 includes a porous material layer 114; and at least one dirty inlet 142A, 142B to which the underpressure generator 178 can be fluidly connected when the attachable member 248 is attached to the wet cleaning device, wherein a liquid pickup region PR of the porous material layer 114 is defined by a sealed attachment of the porous material layer 114 around the at least one dirty inlet 142A, 142B.

[0440] Such an attachable member 248 enables replacement of the porous material layer 114 without requiring resealing of the porous material layer 114 to the dirty inlet(s) 142A, 142B.

[0441] In some embodiments, the attachable member 248 includes an impermeable portion 146, and the at least one dirty inlet 142A, 142B is defined by one or more apertures disposed in the impermeable portion 146 and / or between the impermeable portion 146 and the porous material layer 114. Such an attachable member 248 may enable replacement of the porous material layer 114 without requiring resealing of the impermeable portion 146 to the porous material layer 114.

[0442] In some embodiments, at least one dirty inlet 142A, 142B is exposed to the cavity 150 between the porous material layer 114 and the impermeable portion 146, and the liquid transport support structure 154 is arranged in the cavity 150 and provides one or more flow paths in the liquid pickup area PR between the porous material layer 114 and the at least one dirty inlet 142A, 142B.

[0443] A wet cleaning device, such as a cleaning head 100 included therein, may include at least one cleaning liquid outlet 104 through which, as previously described, cleaning liquid may be delivered. When at least one dirty inlet of the attachable member 248 is fluidly connected to the underpressure generator 178, the liquid pickup region PR may be arranged relative to each of the at least one cleaning liquid outlet 104 so that the liquid pickup region PR is bypassed by the cleaning liquid delivered toward the surface 218 to be cleaned.

[0444] Fig.29 An exemplary cleaning head 100 is schematically shown including a detachable element 244, which in this example includes one or more additional porous material layers 156. Furthermore, in this non-limiting example, each of the first and second applicator portions 126, 128 can be separated from the cleaning liquid outlet 104 independently of each other and independently of the detachable element 244.

[0445] Fig.30 An exemplary cleaning head 100 is shown in which a porous material, in this case a porous material layer 114, contacts a cleaning liquid applicator fabric 126, 128. As previously explained, this configuration can help prevent excess cleaning liquid from accumulating in the cleaning liquid applicator material 126, 128, and thus can help minimize over-wetting of the surface 218 to be cleaned, such as by dripping cleaning liquid from the cleaning liquid applicator material 126, 128 onto the surface 218 to be cleaned.

[0446] In this particular example, because the edge portion 134 of the porous material layer 114 abuts the opposing edge portion 136 of the cleaning liquid applicator materials 126 , 128 , enhanced control over the wetness of the cleaning liquid applicator materials 126 , 128 may be achieved.

[0447] More specifically, in this non-limiting example, the cleaning liquid applicator material 126, 128 includes a first applicator portion 126 and a second applicator portion 128, such that an opposing edge portion 136 of the cleaning liquid applicator material is included in the first applicator portion 126, as shown. In addition, in this example, another edge portion 138 of the porous material layer 114 abuts another opposing edge portion 140 of the second applicator portion 128.

[0448] However, in Fig.30In the example shown, the liquid pickup area PR of the porous material layer 114 (defined by the sealed attachment of the porous material layer 114 around, for example, each of the at least one dirty inlet 142A, 142B) is arranged relative to each of the clean liquid outlets 104, so as to allow the clean liquid to bypass the liquid pickup area PR. In this respect, in this example, the clean liquid outlets 104 are arranged in a distribution part, in this example in the form of a clean liquid distribution strip 108, 124, which is spatially separated from the porous material layer 114. The latter is reflected by a gap 242 (for example an air gap 242) provided between the porous material layer 114 and the distribution part 108, 124.

[0449] To reiterate, the porous material 168 comprising the porous material layer 114 is distinguished from the cleaning liquid applicator materials 126 , 128 in that the porous material 168 is denser than the cleaning liquid applicator materials 126 , 128 , such as due to a tighter weave of the microfiber fabric.

[0450] In some embodiments, Fig.31 As shown, the cleaning head 100 includes a portion 120 facing a surface 218 to be cleaned, and a protruding element 252 is mounted near the portion 120. Therefore, the protruding element 252 is an element mounted separately relative to the portion 120. The protruding element 252 protrudes from the cleaning head 100 in the direction of the surface 218 to be cleaned. In this way, the cleaning head 100 can be swung on the protruding element 252 in a first direction to make the portion 120 contact the surface to be cleaned, and swung on the protruding element 252 in a second direction opposite to the first direction to separate the portion 120 from the surface 218 to be cleaned, as described above.

[0451] In some embodiments, Fig.31 As shown, the cleaning head 100 includes a support member 236, such as a rigid support member 236, and the protruding element 252 is mounted to the support member 236 by an attachment.

[0452] It should be noted that the cleaning head 100 can be attached or attachable to a suitable handle (not visible) to assist in moving the cleaning head 100. To this end, the cleaning head 100 may include a coupling point 254 to which such a handle may be coupled, for example pivotably coupled.

[0453] refer to Fig.31 , the cleaning head 100 applies a force F 运动 Movement over the surface 218 to be cleaned may not be free of resistance. The weight F of the cleaning head 100 重力 And / or the user pressing the cleaning head 100 toward the surface 218 to be cleaned may generate a force Fn perpendicular to the surface 218 to be cleaned.

[0454] The cleaning head 100 can be wet and thus can operate in both a viscous friction regime and a dry regime; the former generating a viscous friction force Fv, while the latter generates a Coulomb friction force Fc, governed by the normal force Fn and the friction coefficient f. The resulting drag force Fr is approximated in the following equation.

[0455]

[0456] The forces Fr, Fv, Fc and Fn are in Newtons; μ is the dynamic viscosity in Pa·s; A is in m 2 is the contact area in m / s; u is the velocity in m / s; and y is the thickness of the liquid layer in m.

[0457] The above equations show that a larger contact area A and a liquid layer with a thickness y approaching zero can both increase the viscous friction term, thereby increasing the resulting drag Fr.

[0458] It should also be noted that the relatively large contact area A required to effectively pick up liquid on an uneven surface 218 to be cleaned may result in a relatively high drag force Fr, especially on relatively flat / smooth surfaces 218 to be cleaned.

[0459] Therefore, in at least some embodiments, the protruding element 252 includes a porous material 168. Since the contact area A between the porous material 168 and the surface to be cleaned 218 is limited, the movement resistance of the cleaning head 100 on the surface to be cleaned can be reduced.

[0460] The porous material layer 114 of the porous material 168 may be included in the protruding element 252 .

[0461] In some embodiments, the liquid pickup region PR of the porous material layer 114 is included in the protruding elements 252 and terminates between the protruding elements 252 and the portion 120. In this way, the area of ​​the porous material layer 114 where suction is applied is limited to the protruding elements 252, thereby helping to reduce the resistance to movement.

[0462] Alternatively or additionally, at least one dirt inlet 142A, 142B may be defined in the protruding element 252. Thus, suction may be applied to the portion of the cleaning head 100 that is in contact with the surface 218 to be cleaned, in other words, to the protruding element 252, the contact of which with the surface 218 to be cleaned being mitigated, for example due to its swinging function.

[0463] In an embodiment where the cleaning head 100 comprises a portion 120 and a further portion 122 facing the surface 218 to be cleaned, the protruding element 252 may be mounted between the portion 120 and the further portion 122. In this way, the cleaning head 100 may be swung forward on the protruding element 252 to bring the portion 120 into contact with the surface 218 to be cleaned. Fig.31 As shown, the rear portion 122 is swung back so that the other portion 122 contacts the surface 218 to be cleaned.

[0464] In such an embodiment, the liquid pickup region PR of the porous material layer 114 may extend between the portion 120 and the further portion 122 and terminate between the protruding element 252 and the portion 120 , and between the protruding element 252 and the further portion 122 .

[0465] exist Fig.31 In the non-limiting example shown, the porous material 168 and the adjacent opposing edge portions 134, 136 of the cleaning liquid applicator materials 126, 128 are positioned between the protruding element 252 and the portion 120. In this manner, excess cleaning liquid squeezed out of the cleaning liquid applicator materials 126, 128 between the protruding element 252 and the cleaning liquid applicator materials 126, 128, for example by oscillation of the cleaning head 100, can be effectively transported via the porous material 168 into the dirty inlet(s) 142A, 142B.

[0466] In particular, Fig.31 The illustrated portion 120 includes a first applicator portion 126, and the further portion 122 includes a second applicator portion 128. Furthermore, in this example, the adjoining opposing edge portions 134, 136 of the porous material 168 and the first applicator portion 126 are positioned between the protruding element 252 and the portion 120, and the adjoining opposing further edge portions 138, 140 of the porous material 168 and the second applicator portion 128 are positioned between the protruding element 252 and the further portion 122. Thus, excess cleaning liquid squeezed out of the cleaning liquid applicator materials 126, 128 between the protruding element and the first applicator portion 126 and between the protruding element and the second applicator portion 128, for example, by swinging the cleaning head 100 forward and backward, respectively, can be effectively transported to the dirty inlet(s) 142A, 142B via the porous material 168.

[0467] In some embodiments, Fig.31 As shown, the protruding element 252 has a curved surface arranged to contact the surface 218 to be cleaned.

[0468] Such a curved (eg, rounded) surface of the protruding element 252 may further help minimize the contact area of ​​the protruding element 252 with the surface 218 to be cleaned, and thereby help minimize the resistance to movement of the cleaning head 100 over the surface 218 to be cleaned.

[0469] The curved surface of the protruding element 252 may be curved, for example, between the portion 120 and the further portion 122, such as Fig.31 shown.

[0470] In some embodiments, the protruding element 252 includes the above-described elastomeric material 238 with the porous material 168 disposed thereon. The elastomeric material 238 may be or include, for example, silicone rubber and / or have a durometer of less than 50 Shore A, preferably less than 20 Shore A, and most preferably less than 10 Shore A.

[0471] Reference Fig.31 , the elastomeric material 238 can be arranged between the support member 236 (e.g., a rigid support member 236) and the porous material 168.

[0472] This elastic deformation of the elastomeric material 238 can reduce the risk of damaging the porous material 168 if, for example, relatively hard protrusions are present on the surface 218 to be cleaned in contact with the porous material 168. Alternatively or additionally, the elastomeric material 238 can help the porous material 168 to follow any contours of the surface 218 to be cleaned.

[0473] Alternatively or additionally, the protruding element 252 may be resiliently mounted adjacent the portion 120. For example, the protruding element 252 may be spring mounted to the support member 236. This may help the porous material 168 to follow any contours of the surface 218 to be cleaned, thereby facilitating liquid pickup.

[0474] In embodiments where the elastomeric material 238 is included in the protruding element 252 , the curvature of the curved surface of the elastomeric material 238 (eg, the arc between portion 120 and further portion 122 ) may be followed by the porous material 168 to provide a curved surface of the protruding element 252 .

[0475] Although in Fig.31 142B. Although not visible in the drawings, the protruding element 252 may also include the above-mentioned impermeable portion 146, which includes or is in the form of a polymer film sealed to the porous material layer 114 and surrounding the dirt inlets 142A, 142B. In such an example, underpressure that exists behind the porous material 168 during use of the cleaning head 100 may not exist in the elastomeric material 238, but rather be contained within the sealed cavity 150 between the porous material layer 114 and the impermeable portion 146. This may help ensure that the elastomeric material 238 is substantially unaffected by underpressure, particularly in examples where the elastomeric material 238 is itself porous and therefore may otherwise be susceptible to compaction due to underpressure.

[0476] In other non-limiting examples, the elastomeric material 238 itself is non-porous, such that the elastomeric material 238 can be included in the impermeable portion 146 of the porous material layer 114 that is sealed to the porous material 168, for example as described above with respect to Fig.18 described.

[0477] exist Fig.31 In the non-limiting example shown, the above-mentioned liquid transport support structure 154 is also disposed between the porous material 168, in particular the porous material layer 114, and the impermeable portion 146. The liquid transport support structure 154 can be defined by or include, for example, one or more mesh layers and / or surface patterns on and / or in a surface of the elastomeric material 238, such as a curved surface.

[0478] More generally, the protruding element 252 may include, for example, a liquid transport support structure 154 disposed between the porous material layer 114 and the at least one dirty inlet 142A, 142B.

[0479] The porous material 168 may be disposed on the elastomeric material 238 in any suitable manner, such as on a curved surface of the elastomeric material 238 .

[0480] Fig.32A and Fig.32B An example of sealingly attaching a porous material layer 114 around the dirty inlets 142A, 142B to define a liquid pickup region PR is schematically shown. Fig.32A and Fig.32B 14 is a laminate of a plurality of porous materials. The laminate is further evident in the embodiment of the present invention is an impermeable portion 146 (in this case in the form of a polymer film) and a liquid transport support structure 154 (in this case in the form of a mesh or multiple stacked mesh layers). The porous material 168 in this example includes or is defined by the porous material layer 114 and the further porous material layers 156, 158. Thus, the laminate comprises the further porous material layers 156, 158, the porous material layer 114, the liquid transport support structure 154 and the impermeable portion 146, wherein the tubes 144A, 144B providing the dirty inlet 142A, 142B are partially captured between the impermeable portion 146 and the porous material layer 114.

[0481] exist Fig.32A and Fig.32B In the non-limiting example shown, the impermeable portion 146, the porous material layer 114 and the further porous material layers 156, 158 extend beyond the liquid transport support layer 154 in the direction of the tubes 144A, 144B. The seal 152, in this case a heat seal, also extends beyond the liquid transport support layer 154 in the direction of the tubes 144A, 144B.

[0482] The tubes 144A, 144B are guided into the impermeable portion 146 by introducing clay in the area between the porous material layer 114 and the impermeable portion 146 to provide a seal 152, i.e., an airtight seal, between the porous material layer 114 and the impermeable portion 146. In this example, a piece of tape is then wrapped around the porous material layer 114, the impermeable portion 146, the tubes 144A, 144B, and the clay to encapsulate the clay and prevent it from sticking to another object.

[0483] The laminate may be flexible enough to be arranged on a curved surface, such as the elastomeric material 238. In addition, for example, the laminate may be provided with one or more suitable fasteners 256A-D, in which case the fasteners 256A-D are In the form of a strip for securing the laminate in the cleaning head 100.

[0484] Go to Fig.33A and Fig.33B The non-limiting example shown in FIG. 1 includes a porous material layer 114 and an additional first porous material layer 156 similar to the above with respect to Fig.32A and Fig.32B The laminate is disposed on the curved surface 258 of the elastomeric material 238 and is secured to the laminate via fastener(s) 256A-D (e.g. ) is fixed to the support member 236. Therefore, the protruding element 252 in this example includes the elastomeric material 238 and the porous material layer 114,156.

[0485] Since the porous material layer 114 , 156 follows the curvature of the curved surface 258 of the elastomeric material 238 in this example, the protruding element 252 itself comprises a curved surface arranged to contact the surface 218 to be cleaned.

[0486] exist Fig.33A and Fig.33B In the non-limiting example shown, the protruding element 252 is mounted adjacent to the portion 120 (and in this example, particularly between the portion 120 and the further portion 122) by an elastomeric material 238 attached to the support member 236 of the cleaning head 100. In this non-limiting example, the attachment is at least partially achieved by the elastomeric material 238 including a protrusion 260 that is received within and engages with a slot 262 defined in the support member 236. The protrusion 260 may be, for example, a push fit in the slot 262.

[0487] Fig.33ADeformation of the cleaning liquid applicator material 126, 128 is shown to bring at least a portion of the cleaning liquid applicator material 126, 128 into contact with the porous material. In this way, some of the cleaning liquid can be transferred from the cleaning liquid applicator material 126, 128 to the porous material in a particularly controlled manner.

[0488] exist Fig.33A In the non-limiting example shown, the cleaning liquid applicator material 126, 128 includes a tuft formed by fibers and a backing layer (not visible) supporting the tuft. As shown, this tuft can be deformed to contact the porous material, such as when contacting the surface to be cleaned and / or when wetted by a liquid such as water.

[0489] In some embodiments, the wet cleaning apparatus includes a cleaning head 100 and an underpressure generator 178 (at the position of the cleaning head 100) fluidly connected to at least one dirty inlet 142A, 142B. Fig.33A and Fig.33B This fluid connection can be achieved through the tubes 144A, 144B, which in this specific non-limiting example extend to a single tube that leads to the underpressure generator at the bifurcation point 266.

[0490] Underpressure generator 178 can be or include a pump, such as a positive displacement pump (the technical advantages of positive displacement pumps are described in more detail below). Any suitable pump can be used as long as the pump can withstand the working pressure selected for the wet cleaning device, such as about 5000Pa (see Table 1 above).

[0491] In some embodiments, undervoltage generator 178 is configured to provide a 15 cm 3 / min to 2000cm 3 / minute, preferably 40cm 3 / min to 2000cm 3 / minute, more preferably 80cm 3 / min to 750cm 3 / min, most preferably 100cm 3 / min to 300cm 3 / minute range to provide suction.

[0492] This flow, ie, flow rate, can take advantage of the underpressure holding capability of the porous material 168 and can ensure adequate liquid pickup while limiting energy consumption.

[0493] The wet cleaning device may also include a dirty liquid collection tank (in Fig.33A and Fig.33B In such an embodiment, the underpressure generator may be arranged to draw liquid from at least one dirty inlet 142A, 142B to a dirty liquid collection tank.

[0494] In such an embodiment, the dirty liquid collection tank may be arranged in any suitable manner relative to the underpressure generator 178 , such as upstream or downstream of the underpressure generator 178 .

[0495] In some embodiments, a wet cleaning device including cleaning head 100 includes a cleaning liquid supply (in Fig.33A and Fig.33B 104 ), the cleaning liquid supply is used to supply cleaning liquid to the cleaning head 100 for delivery toward the surface to be cleaned through the at least one cleaning liquid outlet 104. Such a cleaning liquid supply may, for example, include a cleaning liquid reservoir and a delivery device, such as a delivery device including a pump, for delivering the cleaning liquid to and through the at least one cleaning liquid outlet 104.

[0496] The cleaning liquid supply and the at least one cleaning liquid outlet 104 may be configured to provide continuous delivery of the cleaning liquid toward the surface 218 to be cleaned.

[0497] The cleaning liquid supply and underpressure generator 178 can be configured, for example, so that the flow rate of cleaning liquid delivered through the at least one cleaning liquid outlet 104 is lower than the flow rate provided to the at least one dirty inlet 142A, 142B by the underpressure generator 178. This helps to ensure that the surface 218 to be cleaned is not over-wetted by the cleaning liquid. For example, the flow rate of the cleaning liquid can be 20 cm / s. 3 / min to 60cm 3 / minute, the flow rate provided by the undervoltage generator 178 can be 40cm 3 / min to 2000cm 3 / minute, more preferably in the range of 80cm 3 / min to 750cm 3 / minute, most preferably within 100 cm 3 / min to 300cm 3 / minute range.

[0498] If a positive displacement pump is used as underpressure generator 178, at a flow rate of 1 or 2 liters per minute, such a pump may become relatively bulky and noisy, so a lower flow rate may help keep the wet cleaning apparatus relatively small, quiet, and lightweight.

[0499] In principle, it is sufficient for the flow rate of the underpressure generator 178 to be equal to the flow rate of the cleaning liquid provided by the cleaning liquid supply.

[0500] However, if, for example, the porous material 168 (e.g. newly attached) were to experience an overflow of water, this could present a risk of a relatively significant disturbance of the system balance (necessary underpressure).3 / min clean liquid flow rate and 50cm provided by underpressure generator 178 3 / min flow rate encountered by the wet cleaning device 50cm 3 A puddle of water may mean that it takes about 5 minutes to suck in all the water (resulting in a 5 minute drop in underpressure, so the floor remains noticeably wetter for a 5 minute period (as the puddle continues to expand)). On the other hand, the 250 cm provided by underpressure generator 178 3 A flow rate of 100 t / min can reduce this to a period of 14 seconds. A flow rate provided by underpressure generator 178 that is higher than the flow rate of clean liquid provided by the clean liquid supply can allow the system to return to equilibrium more quickly after such a disturbance.

[0501] exist Fig.33A and Fig.33B In the non-limiting example shown, cleaning liquid is delivered, for example, from the above-mentioned cleaning liquid reservoir via tube 268, which branches to supply cleaning liquid to the cleaning liquid outlet 104 of the cleaning liquid dispensing belt 108 via a first tube 270A and to the cleaning liquid outlet 104 of another cleaning liquid dispensing belt 124 via a second tube 270B.

[0502] In an embodiment where the wet cleaning device includes a cleaning head 100, an underpressure generator and a cleaning liquid supply, the underpressure generator can be configured to provide suction to at least one dirty inlet 142A, 142B while the cleaning liquid supply supplies cleaning liquid to and through at least one cleaning liquid outlet 104 (in other words, synchronously).

[0503] exist Fig.33A and Fig.33B In the illustrated exemplary cleaning head 100, the cleaning liquid dispensing strips 108, 124 are engaged to each other and to the support member 236 by engagement members 272A, 272B.

[0504] In some embodiments, the wet cleaning device includes a handle coupled or attachable to the cleaning head 100 (in Fig.33A and Fig.33B Such a handle may facilitate movement of the cleaning head 100.

[0505] exist Fig.33A and Fig.33BIn the non-limiting example shown, the connection point 254 to which such a handle can be connected includes a vertically extending slot for adjusting the height of the connection provided. In this example, such a connection point 254 is provided in each of a pair of mounting members 274A, 274B, and a handle engagement member 276 is pivotally mounted between the mounting members 274A, 274B. The handle engagement member 276 can engage with the end of the handle, for example, to receive the end of the handle.

[0506] In some embodiments, the handle may support or include at least a portion of an underpressure generator 178 fluidly connected to at least one dirty inlet 142A, 142B and / or a dirty liquid collection tank. Alternatively or additionally, at least a portion of the cleaning liquid supply, such as the cleaning liquid reservoir and / or the delivery device, may be supported by or included in the handle.

[0507] In some embodiments, Fig.33C and Fig.33D As shown, the attachable member 248 described above (wherein the liquid pickup region PR of the porous material layer 114 is defined by the sealed attachment of the porous material layer 114 around at least one dirt inlet 142A, 142B) includes (or defines) a protruding element 252 .

[0508] exist Fig.33C In the non-limiting example shown, the protruding element 252 includes an elastomeric material 238 having disposed thereon a porous material layer 114. In this particular example, the porous material layer 114 is sealingly attached to the support member 236 via a seal 152 (eg, a heat seal).

[0509] In this manner, the porous material layer 114 is sealingly attached to the dirt inlet(s) 142A, which in this example are defined in, i.e., bounded by, the support member 236 and the elastomeric material 238. In this particular example, the dirt inlets 142A, 142B are in the form of channels extending through the support member 236 and the elastomeric material 238.

[0510] More generally, a support member 236 to which the porous material layer 114 is sealingly attached can be included in the attachable member 248. In such an example, the support member 236 can be attached to a support included in (the remainder of) the cleaning head 100.

[0511] The attachable member 248 can be attached to the support member in any suitable manner, such as by having the attachable member 248, such as the support element 236, having a ridge member that is push-fit into a narrow groove defined in the support member, or by having a support member having such a ridge member that is push-fit into a narrow groove defined in the attachable member 248, such as the support element 236.

[0512] exist Fig.33C In the example shown, a further porous material layer 156 is also included in the protruding element 252. It should be noted that the process of heat sealing the porous material layer 114 to the plastic support member 236, such as via ultrasonic welding, also causes the further porous material layer 156 to become adhered to the porous material layer 114.

[0513] Fig.33C and Fig.33D The examples shown in the examples differ from each other in that Fig.33C The liquid transport support structure 154 shown in FIG. 1 is defined by a surface pattern disposed on and / or in the surface of the elastomeric material 238, while Fig.33D The liquid transport support structure 154 shown in FIG. 1 is in the form of a mesh layer.

[0514] Fig.33E An exemplary detachable element 244 is shown, which includes additional porous material layers 158A, 158B and cleaning liquid applicator materials 126, 128. This example is similar to Fig.26 The separable element 244 shown has some similarities except that in this case the cleaning liquid applicator materials 126, 128 are mounted on additional porous material layers 158A, 158B.

[0515] It should be noted that the further layers of porous material 158A, 158B may be adhered to each other, for example via heat sealing (eg ultrasonic welding).

[0516] exist Fig.33E Further evident in FIG. 1 are the backing layer BL and the tufts TU included in the cleaning liquid applicator material 126, 128. As previously mentioned, the backing layer BL supports the tufts TU.

[0517] Fig.33F A perspective view of a cleaning head 100 is provided, which includes Fig.33C or Fig.33D The protruding element 252 / attachable member 248 and Fig.33E The detachable element 244 is shown. Thus, in this case, the porous material 168 includes the porous material layer 114 and the further porous material layer 156 contained in the protruding element 252 / attachable member 248, as well as the further porous material layer(s) 158A, 158B contained in the detachable element 244.

[0518] The detachable element 244 can be detachably coupled to the remainder of the cleaning head 100 in any suitable manner, such as by the detachable element 244 including a set of shoes disposed along one longitudinal side of the detachable element 244 and a set of shoes disposed on the opposite longitudinal side. In this example, each of a set of shoes receives and engages a foot disposed on one longitudinal side of the remainder of the cleaning head 100, and The belt may be joined to a complementary belt disposed on an opposite longitudinal side of the remainder of the cleaning head 100. This set of feet-set shoes arrangement can help minimize unwanted movement of the detachable element 244 relative to the remainder of the cleaning head 100 in both lateral and longitudinal directions.

[0519] exist Fig.33F Further evident in FIG. 1 is a label LA of the detachable element 244. The label may provide attachment / detachment and / or cleaning instructions for cleaning the detachable element 244 after the detachable element 244 is detached from the rest of the cleaning head 100.

[0520] More generally, a wet cleaning apparatus according to one aspect of the present disclosure comprises an underpressure generator apparatus and a cleaning head 100 having at least one dirty inlet 142A, 142B and a porous material 168 comprising a porous material layer 114 sealingly attached to the at least one dirty inlet 142A, 142B.

[0521] The cleaning head 100 may be, for example, according to any of the embodiments described herein.

[0522] The underpressure generator arrangement includes an underpressure generator 178 having an underpressure generator outlet that can be activated to provide flow from at least one dirty inlet 242A, 242B to and through the underpressure generator outlet and can be deactivated to stop the flow.

[0523] In at least some embodiments, the underpressure generator arrangement is configured to restrict the passage of fluid from the underpressure generator outlet toward the at least one dirty inlet 242A, 242B at least when the underpressure generator is deactivated.

[0524] The flow provided by the underpressure generator 178 can generate an underpressure in at least one of the dirty inlets 142A, 142B. The porous material 168, particularly a wetted porous material 168, can help maintain the underpressure, and liquid can be drawn through the porous material 168 and into the dirty inlet(s), as previously described.

[0525] Fig.34An exemplary wet cleaning device 278 is schematically illustrated before (left-hand panel), during (center panel), and after (right-hand panel) pumping liquid 190 through porous material 168 . Fig.34 The left hand square of can be viewed as depicting a completely dry system, for example at the beginning of a cleaning cycle. Fig.34 The central grid of shows the wet cleaning device 278 in operation, during which the liquid 190 (e.g. water) in contact with the porous material 168 is conveyed through the wet cleaning device 278 in the direction of the dirty inlet(s) 142A. Thus, the surface 218 to be cleaned can become dry or at least drier, but not all of the liquid 190 can be conveyed away from the cleaning head 100, for example to a dirty liquid collection tank (in the case of the wet cleaning device 278). Fig.34 142A). In this non-limiting example, some liquid 190 may remain in the flow path(s) of the liquid delivery support structure 154, as shown. During operation, this liquid 190 may be beneficial because it serves to keep the porous material 168 wet, even when no liquid 190 is present on the surface 218 to be cleaned. As previously described, residual liquid 190 in the pores 192 of the porous material 168 helps maintain the underpressure. When the underpressure is maintained in the dirty inlet(s) 142A, the liquid 190 remains on the dirty inlet(s) side of the porous material 168, as shown. Fig.34 as shown in the central square of .

[0526] However, when the underpressure generator 178 is deactivated, for example by being turned off after using the wet cleaning device 278, a loss of underpressure may be caused by fluid (e.g., ambient air) entering through the underpressure generator outlet. This may cause the liquid 190 to be released from the porous material 168, for example by dripping, such as Fig.34 as shown in the right hand square of .

[0527] After cleaning, e.g. wiping the surface to be cleaned, it is undesirable for the liquid 190 to be released through the porous material 168 when the underpressure generator 178 is deactivated, e.g. back onto the surface 218 to be cleaned (or cleaned) and / or during transport of the wet cleaning device 278 to its storage location.

[0528] To this end, the underpressure generator device can be configured to restrict (e.g., block) the passage of fluid (e.g., ambient air) from the underpressure generator outlet toward the dirty inlet(s) at least when the underpressure generator 178 is deactivated, e.g., when the underpressure generator 178 is turned off. This can mitigate the release of problematic liquids from the porous material 168, e.g., after cleaning the surface 218 to be cleaned and / or during loading of the wet cleaning device in a storage area after use.

[0529] Fig.35An exemplary wet cleaning device 278 including such an undervoltage generator device 280 is schematically shown. Fig.35 In the left hand square of , the undervoltage generator 178, in this example a pump, is activated. This is indicated as "Pump On". Fig.35 In the right hand pane of , the undervoltage generator 178 is disabled, indicating "pump off". Fig.34 Contrary to the described liquid leakage, the passage of the fluid from the underpressure generator outlet toward the dirty inlet(s) 142A is restricted, e.g. blocked, e.g. Fig.35 282. In this way, after the underpressure generator 178 is deactivated, the underpressure can be better maintained, thereby mitigating the release of problematic liquid from the porous material 168.

[0530] Any suitable manner of configuring the underpressure generator device 280 to restrict the passage of fluid from the underpressure generator outlet toward the dirty inlet(s) 142A is contemplated, at least when the underpressure generator 178 is deactivated.

[0531] In some embodiments, the underpressure generator 178 itself is configured to restrict a backflow of fluid, such as air, from the underpressure generator outlet in the direction of the dirty inlet(s) 142A when the underpressure generator 178 is deactivated.

[0532] In some embodiments, Fig.36 As shown, the underpressure generator 178 is or comprises a positive displacement pump. The design of such a positive displacement pump means that the backflow of fluid (eg air) from the underpressure generator outlet (in other words, the pump outlet) in the direction of the dirty inlet(s) 142A is inherently restricted.

[0533] Examples of such positive displacement pumps include peristaltic pumps, diaphragm pumps, and piston pumps. Thus, the underpressure generator 178 may include or consist of one or more of a peristaltic pump, a diaphragm pump, and a piston pump.

[0534] refer to Fig.36 , the depicted peristaltic pump may include a compressible hose 284 between the pump / underpressure generator inlet 286 and the pump / underpressure generator outlet 288, which is compressed in at least one position when the peristaltic pump is deactivated. Thus, when the peristaltic pump is deactivated, the backflow of fluid, such as air, from the pump outlet toward the (multiple) dirty inlet 142A can be limited, such as blocked. Thus, the selection of a peristaltic pump can minimize the underpressure loss in the (multiple) dirty inlet, thereby minimizing the release of problematic liquids through the porous material 168 to the exterior of the cleaning head 100.

[0535] The peristaltic pump may, for example, include a rotatable compression shoe assembly 290 including at least one compression shoe 292 , rotation of the compression shoe assembly 290 and concomitant compression of the compressible hose 284 by the at least one compression shoe 292 providing flow.

[0536] The diaphragm pumps and piston pumps described above use a similar type of construction, wherein the quiescent state of the pump, ie, when the pump is deactivated, restricts backflow from the pump outlet 288 in the direction of the dirty inlet(s) 142A.

[0537] In some embodiments, for example, as an alternative or in addition to the above-mentioned positive displacement pump constituting the underpressure generator 178, the underpressure generator device 280 includes, for example, Fig.35 The cross 282 in FIG. 1 represents a valve assembly configured to restrict the passage of fluid from the underpressure generator outlet 288 toward the at least one dirty inlet 142A.

[0538] exist Fig.35 In the non-limiting example shown, the valve assembly is configured to restrict the passage of the fluid between the underpressure generator inlet 286 and the at least one dirty inlet 142A.

[0539] Alternatively or additionally, the passage of fluid may be restricted between the underpressure generator outlet 288 and the underpressure generator inlet 186 , for example, as described above with respect to a positive displacement pump included in or defining the underpressure generator 178 .

[0540] The valve assembly may be of any suitable design. In some embodiments, the valve assembly is configured to restrict the passage of the air in response to the underpressure generator 178 being deactivated. This may be considered an "active" valve that is triggered by the deactivated underpressure generator 178 to shut down the system (by restricting the passage of fluid from the underpressure generator outlet 288 toward the dirty inlet(s) 142A).

[0541] In some embodiments, the valve assembly includes a one-way valve configured to prevent fluid from being delivered in the direction of at least one dirty inlet 142A. The one-way valve may be considered a "passive" valve. Such a one-way valve may be configured to allow fluid, such as air and / or liquid, to flow out of the porous material 168, but prevent the fluid (e.g., air and / or liquid) from returning toward the dirty inlet(s) 142A when and after the underpressure generator 178 is deactivated. Any suitable one-way valve design may be contemplated, such as a ball check valve.

[0542] In a non-limiting example, an additional porous material portion, for example made of a microfiber fabric, is arranged between the porous material layer 114 and the underpressure generator outlet 288. The additional porous material portion is capable of allowing a fluid flow (for example air and / or liquid) to leave the porous material layer 114, but limiting a return of the fluid (for example air and / or liquid) toward the porous material layer 114 (at least) when the underpressure generator 178 is deactivated.

[0543] More generally, the underpressure generator 178 may be configured such that when flow is provided by the (activated) underpressure generator 178, the flow rate is 15 cm 3 / min to 2000cm 3 / minute, preferably within 40cm 3 / min to 2000cm 3 / minute, more preferably in the range of 80cm 3 / min to 750cm 3 / minute, most preferably within 100 cm 3 / min to 300cm 3 / minute range.

[0544] This flow, ie, flow rate, can take advantage of the underpressure holding capability of the porous material 168 and can ensure adequate liquid pickup while limiting energy consumption.

[0545] It is reiterated that the wet cleaning device 278 may include a dirty liquid collection tank (in Fig.35 and Fig.36 2 (not visible in the figure), the underpressure generator device 280 is arranged so that the flow to and through the underpressure generator outlet 288 draws dirty liquid from the at least one dirty inlet 142A to the dirty liquid collection tank. In such an embodiment, the valve assembly described above can be arranged in any suitable manner relative to, for example, upstream or downstream of the dirty liquid collection tank.

[0546] In some embodiments, a sealed flow path is defined between the dirty inlet(s) 142A and the underpressure generator outlet 288 .

[0547] This helps maintain undervoltage.

[0548] In alternative embodiments, fluid (eg, air) may enter through one or more areas of wet cleaning device 278 other than underpressure generator outlet 288 and apertures 192 of porous material 168 .

[0549] However, in such alternative embodiments, the configuration of the underpressure generator device 280 may still help maintain underpressure by (at least) restricting the passage of fluid from the underpressure generator outlet 288 in the direction of the dirty inlet 142A.

[0550] In some embodiments, the underpressure generator device 280 includes a valve assembly 282, such as the valve assembly 282 described above, positioned between the one or more zones and the dirty inlet(s) 142A to restrict backflow from the one or more zones toward the dirty inlet(s) 142A. In such embodiments, the valve assembly 142A may, for example, restrict backflow from the one or more zones in addition to restricting the passage of fluid from the underpressure generator outlet 288 in the direction of the dirty inlet(s) 142A.

[0551] More generally, a wet cleaning device according to another aspect of the present disclosure includes an underpressure generator device 280 and a cleaning head 100, the cleaning head 100 having at least one dirty inlet 142A, 142B and a porous material 168 covering at least one dirty inlet 142A, 142B. In some embodiments, the porous material 168 includes a porous material layer 114 sealingly attached to at least one dirty inlet 142A, 142B. The cleaning head 100 can be, for example, according to any embodiment described herein. In this aspect, the underpressure generator device 280 includes an underpressure generator 178, the underpressure generator 178 is configured to provide flow inside the wet cleaning device for sucking fluid through the porous material 168 into the at least one dirty inlet, the underpressure generator device 280 is configured to control the flow based on the pressure between the porous material 168 and the underpressure generator 178, for example, on the inside of the wet cleaning device in at least one covered dirty inlet 142A, 142B.

[0552] By controlling the flow through the porous material 168 based on the pressure on the inside of the wet cleaning device between the porous material 168 and the underpressure generator 178, the fluid delivery through the porous material 168 can be advantageously controlled. In some non-limiting examples, such control can minimize foam accumulation in the porous material 168 and downstream of the porous material 168.

[0553] In some embodiments, the underpressure generator device 280 is configured to control the flow rate such that the pressure remains at or above a predetermined pressure threshold.

[0554] By controlling the flow to maintain the pressure at or above a predetermined threshold (in other words, at or below an underpressure threshold), stable and efficient operation of the wet cleaning device 278 can be facilitated. In particular, maintaining the pressure at or above a predetermined threshold can mean that the underpressure generator 178 can operate more efficiently, such as by intermittently deactivating / disconnecting, thereby utilizing the above-mentioned ability of the porous material 168 to help maintain underpressure in the covered (multiple) dirty inlets 142A, 142B.

[0555] As previously mentioned, control of flow rate can also help control the wetness of the surface to be cleaned.

[0556] Fig.37A Schematically shown are pores 192, such as micropores 192, of the porous material layer 168, which are filled with a liquid 190, such as water. The retained liquid 190 can thus help maintain an underpressure in the dirty inlet(s) 142A, with or without flow imposed by the underpressure generator 178, as previously described.

[0557] As also previously explained, each pore 192 of the porous material 168 can have a certain bursting pressure at which the surface tension of the (residual) liquid 190 residing in the pore 192 can no longer withstand the internal underpressure and give way. When this occurs, the pore 192 is no longer effectively closed by the liquid contained therein, but can begin to deliver air into the dirty inlet(s) 142A.

[0558] A typical pump used as underpressure generator 178 may be, for example, a flow-driven pump or a positive displacement pump, such as a piston pump, and when the porous material 168 is blocked, may move towards its maximum operating pressure, for example 20000 Pa. The latter may be higher than the average bursting pressure of the porous material 168, for example about 5000 Pa, so that the porous material 168 may start at a certain point to allow air to pass therethrough.

[0559] Operations using, for example, pure water as the liquid 190 may cause few, if any, difficulties. However, problems may arise when a foaming detergent is included in the cleaning liquid 190. Fig.37B , the ruptured hole 294 may begin to deliver air at the rate of the underpressure generator 178 (e.g., a pump), which may risk generating a relatively large amount of foam 296 that may, for example, flood the dirty liquid collection tank (in Fig.37B (not visible in the image).

[0560] In a specific non-limiting example, the cleaning liquid supply pump (in Fig.37B Not visible in) Delivery 40cm 3 / minute of clean liquid flow. In this way, there may be only 40cm 3 A cleaning liquid (e.g., water) may be used for pickup. In this example, an underpressure generator 178 (e.g., a pump) delivers approximately 150 cm 3 / min flow rate. This combination can produce at least (150cm 3 / min-40cm 3 / min=)110cm 3 / minute of foam. For example, when 400cm 3When a dirty liquid collection tank of capacity is included in the wet cleaning device 278, this can be filled to capacity in about 4 minutes (at 40 cm 3 / min pick-up rate reaches capacity in approximately 10 minutes).

[0561] This means that if no remedial measures are taken, particularly when the cleaning liquid includes an aqueous detergent, rapid foam accumulation can lead to interruptions in the use of the wet cleaning device 278. Such interruptions may include frequent interruptions in cleaning to empty the dirty liquid collection tank.

[0562] Thus, the predetermined pressure threshold may be set, for example, to avoid reaching a bursting pressure of at least some (eg, most or all) pores 192 of the porous material 168. This helps avoid operational issues associated with foaming when using cleaning agents.

[0563] The pressure threshold may be set / predetermined based on the bursting pressure of the porous material 168 (as measured using the test apparatus 166 and test procedure described above). Thus, the predetermined pressure threshold may be set to limit the underpressure, in other words, the pressure difference between the inside of the wet cleaning apparatus between the porous material and the underpressure generator and the outside of the cleaning head 100, e.g. atmospheric pressure, to a value in the range of (e.g. at most) 2000Pa to 13500Pa, preferably 2000Pa to 12500Pa, more preferably 5000Pa to 9000Pa, and most preferably 7000Pa to 9000Pa.

[0564] Studies have shown that the higher the underpressure, the drier the surface to be cleaned may become, as explained previously (see Table 1 above). This leads to the conclusion that the wet cleaning device 278 is ideally operated at the burst pressure of the porous material 168.

[0565] The above studies indicate that operating at 5000 Pa underpressure can provide favorable surface drying results. Therefore, an operating window can be defined in which foaming can be prevented. Table 3 provides specific non-limiting examples of operating parameters for an exemplary wet cleaning device 278.

[0566]

[0567]

[0568] Table 3

[0569] The above parameters may reflect that the porous material 168 may exhibit favorable surface drying capabilities at 5000 Pa, and may only begin to “crack” at 6500 Pa.

[0570] Therefore, by adjusting the pressure, in other words selecting the above-mentioned pressure threshold, such that the underpressure behind the porous material 168 does not reach the bursting pressure of the porous material 168, blistering can be minimized or prevented.

[0571] Fig.37C The diagram illustrates the operating window of a wet cleaning device, particularly when the wet cleaning device is started up. Fig.37C Pressure relative to atmospheric pressure versus time is shown.

[0572] The bursting pressure BP of the porous material 168 can be considered as negative (with reference to atmospheric pressure). Therefore, the pressure inside the wet cleaning device between the porous material 168 and the underpressure generator 178 can be kept above this underpressure BP. On the other hand, if the bursting pressure of the porous material is an absolute pressure (with reference to vacuum, 0 Pa), the pressure inside the wet cleaning device between the porous material 168 and the underpressure generator 178 can still be kept above such an absolute pressure, in particular by a controlled flow so as to keep the pressure at or above a predetermined threshold PT.

[0573] Fig.37C Also shown is a "safe zone" SZ at or above a predetermined threshold PT where the wet cleaning device can be operated without approaching the rupture pressure BP of the porous material 168. Fig.37C An optimum operating zone OZ is shown where the requirement to avoid reaching the burst pressure BP of the porous material 168 is combined with the achievement of sufficient liquid pick-up from the surface to be cleaned.

[0574] More generally, controlling flow based on pressure in at least one covered dirty inlet 142A can be accomplished in any suitable manner. Fig.38 In the illustrated embodiment, the underpressure generator device 280 includes a sensor 180 and a controller 298, wherein the sensor 180 is arranged to sense a measurement of the pressure on the inner side of the wet cleaning device between the porous material 168 and the underpressure generator 178, and the controller 298 is configured to control the underpressure generator 178 to provide a flow rate based on the sensed pressure measurement.

[0575] The controller 298, such as a microcontroller, can receive sensor signals from the sensor 180, such as Fig.38 As shown by arrow 300 , a control signal 302 is sent to the undervoltage generator 178 based on the sensor signal.

[0576] For example, the control signal 302 may trigger the undervoltage generator 178 to activate to provide flow or deactivate to stop flow. Alternatively or additionally, the control signal 302 may increase or decrease the flow rate based on the sensor signal 300. Deactivation or reduction of the flow rate provided by the undervoltage generator 178 in this manner may help reduce power consumption of the wet cleaning device 278. This may help preserve battery power in examples where the wet cleaning device is battery powered / battery powered, and thereby increase run time.

[0577] As previously mentioned, control of flow rate can also help control the wetness of the surface to be cleaned.

[0578] In some embodiments, the controller 298 is configured to control the flow rate provided by the underpressure generator 178 so that the pressure on the inner side of the wet cleaning device between the porous material 168 and the underpressure generator 178 is maintained at or above the above-mentioned predetermined pressure threshold. In a non-limiting example, if the sensed pressure measurement indicates that the pressure is below the predetermined pressure threshold, the underpressure generator 178 may control the underpressure generator 178 to be deactivated to stop or reduce the flow rate.

[0579] In a non-limiting example, the controller 298 (e.g., including or in the form of a proportional-integral controller) is configured to compare the sensed measurement of pressure with a desired operating pressure (e.g., with reference to a rupture pressure setting of the porous material 168, as previously described) and control the underpressure generator 178 based on the comparison.

[0580] In some embodiments, the sensor 180 is arranged to sense a measurement of pressure in at least one of: the cavity 150 between the porous material 168 and the at least one dirty inlet 142A, and the tube 144A (or multiple tubes 144A, 144B) connecting the at least one dirty inlet 142A to the underpressure generator 178.

[0581] Sensing pressure measurements in the cavity 150 may be particularly advantageous because the flow rate may be more directly tuned to the characteristics of the porous material 168 during use.

[0582] Arranging the sensor 180 so that the pressure measurements are sensed in the tube(s) 144A, 144B may provide a relatively straightforward way of incorporating the sensor 180 into a wet cleaning apparatus.

[0583] In embodiments where the underpressure generator 178 is arranged downstream of the dirty liquid collection tank, the sensor 180 may also be positioned in the dirty liquid collection tank. In this case, the height of the dirty liquid collection tank, for example, arranged on or in the handle, may generate noise (dP = H*cos(α)*ρ*g, where H is the height of the dirty liquid collection tank in a vertical position and α is the angle of the handle relative to the vertical). However, this noise can be compensated by including an angle sensor (e.g., an accelerometer) in the sensor 180.

[0584] More generally, sensor 180 may be any suitable type of sensor capable of sensing a measurement of pressure on the inside of the wet cleaning device between porous material 168 and underpressure generator 178. For example, the sensor includes a pressure sensor, such as a microelectromechanical system (MEMS) pressure sensor.

[0585] In some embodiments, for example Fig.39 In the illustrated embodiment, the underpressure generator device 280 includes a mechanical regulator 304 configured to control flow based on the pressure on the inside of the wet cleaning device between the porous material 168 and the underpressure generator 178 .

[0586] The mechanical regulator 304 may, for example, include valves 306 , 308 arranged to control fluid communication between the underpressure generator 178 and the at least one dirty inlet 142A depending on the pressure in the at least one covered dirty inlet 142A.

[0587] exist Fig.39 In the non-limiting example shown, the valves 306, 308 include a valve seat 306 and a valve member 308, the valve member 308 being configured to adopt an initial position and a closed position, in which the valve member 308 is separated from the valve seat 306 to allow fluid communication between the underpressure generator 178 and the at least one dirty inlet 142A, and in which the valve member 308 abuts against the valve seat 306 to limit fluid communication between the underpressure generator 178 and the at least one dirty inlet 142A.

[0588] In some embodiments, the valves 306, 308 are configured such that the valve member 308 is moved against the valve seat 306 by the pressure in the at least one covered dirty inlet 142A when the pressure is below the predetermined pressure threshold mentioned above.

[0589] The valve member 308 can be in the form of a flexible rubber membrane, for example, which adopts a flat profile in the initial position and is therefore spatially removed from the valve seat 306 when there is no underpressure in the covered dirty inlet(s) 142A. After starting the underpressure generator 178 (e.g. a pump), an underpressure can be generated in the covered dirty inlet(s) 142A and the mechanical regulator 304. The underpressure can act on the exposed surface of the rubber membrane in the mechanical regulator 304, which can therefore begin to deflect inwardly in the direction of the valve seat 306.

[0590] In this non-limiting example, the threshold pressure may be set / predetermined by the distance between the flexible rubber membrane and the valve seat 306. The greater the distance, the higher the underpressure in the covered dirty inlet(s) 142A required to deform the rubber membrane to contact the valve seat 306 (or equivalently, the lower the pressure).

[0591] Once the underpressure reaches a level that causes the rubber membrane to contact the valve seat, the fluid communication between the underpressure generator 178 and the porous material 168 can be removed, thereby preventing the underpressure from reaching a higher level than that set by the mechanical regulator 304. The underpressure generator 178 can continue to operate toward its maximum operating underpressure at the same rate. When the underpressure in the covered (multiple) dirty inlet 142A decreases, the flexible membrane can move back toward the above-mentioned flat state, thereby opening the valves 306, 308 and allowing the underpressure generator 178 to restore the desired underpressure level.

[0592] In another non-limiting example, the mechanical regulator 304 includes a switch, actuation of which controls the undervoltage generator 178, and a deflectable member, such as a diaphragm, configured to actuate the switch in response to pressure.

[0593] Such a mechanical regulator, in this case an electromechanical regulator, may be configured such that when, for example, the pressure is at or above a predetermined pressure threshold, a switch is actuated via a diaphragm, for example to deactivate the underpressure generator 178 .

[0594] This switch-diaphragm arrangement can provide a simple and inexpensive way to control flow based on pressure without the need for an additional controller, such as a microcontroller.

[0595] In some embodiments, Fig.40 and Fig.41 As shown in FIG. 1 , the underpressure generator 178 itself comprises a pump configured to control flow in response to pressure in at least one covered dirty inlet 142A.

[0596] Such a pump can be considered as a pressure-limited pump. A pressure-limited pump is able to generate a certain pressure difference across the pipe to which it is connected. In principle, the pump pressure can be tuned to the pressure required to cover the porous material 168 of the dirty inlet(s) 142A.

[0597] The pressure limiting pump may include or be, for example, a centrifugal pump. The pump, for example, a centrifugal pump, may be or include a liquid pump. Such a liquid pump may, for example, be arranged between the dirty inlet 142A and the dirty liquid collection tank 310 .

[0598] exist Fig.40 In the non-limiting example shown, an underpressure generator 178 , such as a centrifugal pump and / or a liquid pump, is arranged in the cleaning head 100 .

[0599] Alternatively, the pump, for example a centrifugal pump, may be or include an air pump. Such an air pump may be arranged downstream of the dirty liquid collection tank 310, for example.

[0600] It should be noted that the dirty liquid collection tank 310 may be arranged at a certain height 312 on the handle, for example 0.5 m. Therefore an additional head of water may be required:

[0601] P=h*ρ*g=0.5*1000*9.81~5000Pa

[0602] When the position of the handle is taken into account, including the position where the handle is flat on the horizontal surface 218 to be cleaned, such as the floor surface (where the water head becomes zero), the pressure variation on the porous material 168 can be equal to its working pressure. The latter can be solved by attaching the tube 144A at a fixed height relative to the floor, regardless of the position of the handle, such as by attaching (a portion of) the dirty liquid collection tank 310 directly to the porous material 168.

[0603] Fig.41 A wet cleaning device 278 is schematically shown in which an underpressure generator 178 is used to limit the pressure of an air pump (e.g., a centrifugal air pump) to regulate the pressure. This can provide relative Fig.40 The example shown provides a starting benefit because the pump can always be operated using air, thereby ensuring that the pump is able to generate the required underpressure at start-up (porous material 168 is completely dry).

[0604] In some embodiments, undervoltage generator 178, regardless of its design, is configured such that when providing flow, the flow is at 15 cm 3 / min to 2000cm 3 / minute, preferably within 40cm 3 / min to 2000cm 3 / minute, more preferably in the range of 80cm 3 / min to 750cm 3 / minute, most preferably within 100 cm 3 / min to 300cm 3 / minute range.

[0605] Such a flow, i.e. flow rate, can exploit the underpressure holding capability of the porous material and can ensure adequate liquid pick-up while limiting energy consumption, as previously described.

[0606] More generally, wet cleaning device 278 may be or include, for example, a wet mopping apparatus, a window cleaner, a sweeper, or a wet vacuum cleaner, such as a canister, pole, or upright wet vacuum cleaner.

[0607] In a specific non-limiting example, the wet cleaning device 278 is a battery-powered (or battery-powerable) wet cleaning device, such as a battery-powered (or battery-powerable) wet mopping device, wherein the undervoltage generator 178 (e.g., a pump) is powered (or powerable) by a battery electrically connected (or electrically connectable) thereto. This example is specifically mentioned due to the above-mentioned effect of reducing power consumption, which can be provided by the porous material 168 covering the (multiple) dirty inlet(s) 142A, 142B, and the suction of the undervoltage generator 178 is provided to the dirty inlet 142A, 142B.

[0608] Fig.42 An exemplary wet cleaning device 278 in the form of a wet vacuum cleaner is schematically shown. In this non-limiting example, the wet cleaning device 278 comprises the above-mentioned dirty liquid collection tank 310 and a cleaning liquid reservoir 313. The cleaning head 100 included in the wet vacuum cleaner can be moved over the surface 218 to be cleaned, assisted in this example by wheels 314 included in the wet vacuum cleaner.

[0609] In some examples, wet cleaning device 278 may be or include a robotic wet vacuum cleaner or a robotic wet mopping device configured to autonomously move cleaning head 100 over a surface to be cleaned (eg, the surface of a floor).

[0610] Fig.43 An exemplary wet cleaning device 278 in the form of a robotic wet vacuum cleaner is schematically shown. The robotic wet vacuum cleaner may be moved autonomously over the surface 218 to be cleaned, for example by automatic control of the wheels 314.

[0611] During autonomous movement of the robotic wet vacuum cleaner, cleaning liquid stored in the cleaning liquid reservoir 313 may be delivered to the surface to be cleaned, and the liquid may be picked up via the covered dirty inlet(s) 142A of the cleaning head 100 and collected in the dirty liquid collection tank 310. The underpressure generator 278 / underpressure generator device 280 and / or the cleaning liquid supply may also be automatically controlled.

[0612] Other variations of the disclosed embodiments may be understood and effected by those skilled in the art in practicing the claimed invention by studying the drawings, the disclosure and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. The fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope.

Claims

1. A wet cleaning device (278), comprising: A cleaning head (100) having at least one dirt inlet (142A, 142B) and a porous material (168) comprising a porous material layer (114) sealingly attached to the at least one dirt inlet; and An underpressure generator device (280) comprises an underpressure generator (178) having an underpressure generator outlet (288), the underpressure generator being capable of being activated to provide a flow for drawing fluid from the at least one dirty inlet to the underpressure generator outlet and through the underpressure generator outlet, and the underpressure generator device being capable of being deactivated to stop the flow, wherein the underpressure generator device is configured to restrict the passage of fluid from the underpressure generator outlet toward the at least one dirty inlet at least when the underpressure generator is deactivated.

2. A wet cleaning device (278) according to claim 1, wherein the underpressure generator (178) is configured to limit a backflow of fluid from the underpressure generator outlet (288) in the direction of the at least one dirty inlet (142A, 142B) at least when the underpressure generator is deactivated.

3. The wet cleaning device (278) of claim 1 or 2, wherein the underpressure generator (178) comprises a positive displacement pump.

4. The wet cleaning device (278) according to any one of claims 1 to 2, wherein the underpressure generator (178) comprises at least one of a peristaltic pump, a diaphragm pump and a piston pump.

5. A wet cleaning device (278) according to any one of claims 1 to 2, wherein the underpressure generator device (280) includes a valve assembly (282), which is configured to limit the backflow of fluid toward the at least one dirty inlet (142A, 142B) at least when the underpressure generator (178) is deactivated.

6. The wet cleaning device (278) of claim 5, wherein the underpressure generator (178) has an underpressure generator inlet (286), and the valve assembly (282) is configured to limit backflow of the fluid between the underpressure generator inlet (286) and the at least one dirty inlet (142A, 142B).

7. The wet cleaning device (278) of claim 5, wherein the valve assembly (282) is configured to restrict backflow of the fluid in response to the underpressure generator (178) being deactivated.

8. The wet cleaning device (278) of claim 5, wherein the valve assembly (282) includes a one-way valve configured to prevent fluid from being delivered in the direction of the at least one dirty inlet (142A, 142B).

9. A wet cleaning device (278) according to any one of claims 1 to 2 and 6 to 8, comprising a dirty liquid collection tank (310) for collecting liquid, the underpressure generator device (280) being arranged so that the flow draws the liquid from the at least one dirty inlet (142A, 142B) to the dirty liquid collection tank.

10. The wet cleaning device (278) of any one of claims 1 to 2 and 6 to 8, wherein the cleaning head (100) comprises at least one cleaning liquid outlet (104) through which cleaning liquid can be delivered.

11. The wet cleaning device (278) according to claim 10, comprising a cleaning liquid supply, the cleaning liquid supply including a cleaning liquid reservoir (313) for containing the cleaning liquid, the cleaning liquid reservoir being fluidly connectable or in fluid communication with the at least one cleaning liquid outlet (104).

12. A wet cleaning device (278) according to claim 11, wherein the cleaning liquid supply includes a pump, which is arranged to pump the cleaning liquid from the cleaning liquid reservoir (313) to and through the at least one cleaning liquid outlet (104); and / or wherein the cleaning liquid supply and the underpressure generator (178) are configured so that the flow rate of the cleaning liquid delivered through the at least one cleaning liquid outlet (104) is lower than the flow rate provided by the underpressure generator.

13. The wet cleaning device (278) according to any one of claims 1 to 2, 6 to 8 and 11 to 12, wherein the wet cleaning device is a wet mopping device.

14. The wet cleaning device (278) according to any one of claims 1 to 2, 6 to 8 and 11 to 12, wherein the undervoltage generator (178) is configured to provide a pressure less than or equal to 2000 cm 3 / min flow rate through the porous material (168).

15. A wet cleaning device (278) according to any one of claims 1 to 2, 6 to 8 and 11 to 12, wherein the underpressure generator (178) is configured to provide a pressure difference between the inside of the wet cleaning device and the atmospheric pressure for drawing fluid through the porous material (168) and into the at least one dirty inlet (142A, 142B), the pressure difference being in the range of 2000 Pa to 13500 Pa.

16. The wet cleaning device (278) according to any one of claims 1 to 2, 6 to 8 and 11 to 12, wherein the underpressure generator (178) is configured so that when a flow rate is provided, the flow rate is 15 cm / s. 3 / min to 2000cm 3 / minute range.

17. The wet cleaning device (278) according to any one of claims 1 to 2, 6 to 8 and 11 to 12, wherein the underpressure generator (178) is configured so that when a flow rate is provided, the flow rate is 40 cm 3 / min to 2000cm 3 / minute range.

18. The wet cleaning device (278) according to any one of claims 1 to 2, 6 to 8 and 11 to 12, wherein the underpressure generator (178) is configured so that when a flow rate is provided, the flow rate is 80 cm 3 / min to 750cm 3 / minute range.

19. The wet cleaning device (278) according to any one of claims 1 to 2, 6 to 8 and 11 to 12, wherein the underpressure generator (178) is configured so that when a flow rate is provided, the flow rate is 100 cm 3 / min to 300cm 3 / minute range.

20. The wet cleaning device (278) according to any one of claims 1 to 2, 6 to 8 and 11 to 12, wherein the wet cleaning device is a battery-powered wet cleaning device, wherein the undervoltage generator (178) can be powered by a battery electrically connected to the undervoltage generator.

21. A cleaning head (100) for a wet cleaning device, the cleaning head comprising: at least one dirty inlet (142A, 142B); a porous material (168) comprising a porous material layer (114) sealingly attached to the at least one dirty inlet; and A valve assembly (282), the valve assembly being configured to: allowing flow for drawing fluid through the porous material into the at least one dirty inlet; and Backflow toward the porous material layer is restricted.

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