System and method for dispensing liquid foam, in particular direct foam cleaning products

Abstract

The invention relates to a system for dispensing a liquid foam, in particular a direct foam cleaning product, comprising a container for a liquid and a dispensing device connected to the container. Here, the dispensing device comprises a pump comprising a pump chamber in fluid communication with the container and a piston arranged in the pump chamber, the piston and the pump chamber being movable relative to each other; an outlet channel connecting the pump chamber to a nozzle; a pre-compression valve arranged between the outlet channel and the nozzle; and a buffer comprising a buffer chamber connected to the outlet channel, the buffer chamber comprising a compressible variator arranged therein for varying the usable volume of the buffer chamber; wherein the nozzle, the buffer and the pump are configured and dimensioned such that the foam is dispensed in a predetermined spray pattern.

Description

[0001] This application is a divisional application of Chinese Patent Application No. 201680077253.6, filed on October 31, 2016, entitled "System and Method for Dispensing Liquid Foam, Particularly Direct Foam Cleaning Products". TECHNICAL FIELD

[0002] The present invention relates to the dispensing of liquid foam, particularly direct foam cleaning products. More particularly, the present invention relates to a system for dispensing liquid foam comprising a container, a pump, and a buffer. BACKGROUND

[0003] Hand washing of dishes is typically done by applying dishwashing detergent to a sponge or cleaning implement and scrubbing the dishes with the implement; or adding detergent to a water bath in a sink and soaking / scrubbing the dishes in the detergent water bath. These traditional methods can take longer than necessary to clean the dishes when the dishes are not heavily soiled or when there are only a few items to be cleaned (e.g., knives, spatulas, spoons, etc. used briefly to prepare food). These traditional methods can also result in waste of dishwashing detergent product (i.e., more dose than is needed to clean the dishes).

[0004] Many consumers desire to find an efficient way to clean dishes. One approach to faster cleaning is to apply dishwashing detergent directly on the soiled dishes, followed by optional light scrubbing and followed by a water rinse. One attempt in the art at direct foam cleaning is the "Dawn Power Foam Dishwashing Soap" dishwashing detergent sold by The Procter & Gamble Company (Cincinnati, OH). The Procter & Gamble Company provides a dishwashing composition in a traditional spray bottle. However, dispensing direct foam dishwashing product from a traditional spray bottle can not effectively clean dishes and can not provide good surface area foam coverage and / or persistent foam coverage for efficient cleaning. To compensate for lack of coverage and persistent coverage, multiple spray actions are needed, which can negatively impact the user experience, result in over-consumption of cleaning product, and can also increase the risk of product rebounding off the surface when sprayed. This rebounding can result in waste of product and risk of inhalation of product.

[0005] Accordingly, it would be desirable to improve cleaning efficiency by providing a dispensing system that would ensure good coverage on a surface with minimal rebound and without impacting tenacity food cleaning with each dose of direct foam cleaning product. SUMMARY

[0006] To this end, the present invention provides a system for dispensing a liquid foam, in particular a direct foam cleaning product, comprising a container for a liquid and a dispensing device connected to the container. According to the invention, the dispensing device comprises a pump comprising a pump chamber in fluid communication with the container and a piston arranged in the pump chamber, the piston and the pump chamber being movable relative to each other; an outlet channel connecting the pump chamber to a nozzle; a pre-compression valve arranged between the outlet channel and the nozzle; and a buffer comprising a buffer chamber connected to the outlet channel, the buffer chamber comprising a compressible variator arranged therein for varying the available volume of the buffer chamber, wherein the nozzle, the buffer and the pump are configured and dimensioned such that the foam is dispensed in a predetermined spray pattern. By dispensing the foam in a predetermined spray pattern, the effectiveness of the foam is increased.

[0007] In one embodiment of the dispensing system, the pre-compression valve and the buffer chamber are arranged to define a lower and upper limit of the dispensing pressure of the foam, respectively. In this way, the pressure at which the foam is sprayed lies within a relatively narrow bandwidth, thereby ensuring a more uniform foam.

[0008] In a further embodiment, the pre-compression valve has a break pressure of about 2 to 4.5 bar, preferably about 3 to 3.5 bar. With this lower limit of the pressure, the liquid is sprayed in relatively small droplets, which results in a better foam.

[0009] In a further embodiment, the buffer chamber and the variator define a maximum value of the dispensing pressure of between 3 and 5.5 bar, preferably about 5 bar. This upper limit for the spraying pressure ensures that the droplets do not become too small, which results in a risk of inhalation.

[0010] In some embodiments, the pump has a displacement volume that is larger than the maximum output of the nozzle. In this way, not all of the liquid from the pump can pass through the nozzle and part of the liquid will have to be stored for later spraying.

[0011] The maximum output of the nozzle can be about 1.45 cubic centimeters per second.

[0012] The dispensing system can comprise a buffer chamber having a maximum available volume that is larger than the displacement volume of the pump. In this way, the output of one or more pump strokes can be buffered for later dispensing.

[0013] In one embodiment of the dispensing system, the nozzle has a plurality of swirl slots leading to an inlet funnel, the funnel opening into a nozzle orifice. The swirl slots and the funnel result in a last acceleration and energizing of the liquid flow before exiting the nozzle orifice.

[0014] The nozzle can have a central hole upstream of the inlet funnel, which central hole is arranged to accommodate a protruding part of the distributor frame, and wherein the central hole is dimensioned such that a space is formed between the end face of the protruding frame part and the bottom of the hole. In this way, part of the liquid is forced through the cyclone slots, and part of the liquid is allowed to bypass the cyclone slots and pass through the space between the nozzle and the distributor frame. This results in improved flow characteristics of the liquid before it enters the nozzle orifice. For some liquids, this results in improved flow characteristics of the liquid before it enters the nozzle orifice. For other liquids, the protruding part of the distributor frame can be dimensioned such that no space is left between the protruding frame part and the bottom of the hole.

[0015] In some embodiments, the inlet funnel can be conical and have an apex angle of 20°- 150°, preferably 50°-120°, more preferably about 100°. This angle is chosen to provide optimal acceleration of the liquid.

[0016] To ensure an optimal amount of rotation in the liquid, the nozzle can have an odd number of cyclone slots, preferably 3 or 5 cyclone slots.

[0017] In one embodiment, the nozzle has a dispersion expansion zone downstream of the nozzle orifice. In this expansion zone, the pressure of the liquid can drop almost instantaneously, thereby causing the formation of a foam.

[0018] In some embodiments, the expansion zone can have a vent opening to allow air to enter the expanding liquid flow, thereby speeding up the foaming process.

[0019] The expansion zone can be conical and have an apex angle of between 20°-120°, preferably between 30°-90°, and more preferably about 50°. A conical nozzle is relatively easy to manufacture and can form a surface on which liquid droplets in the expanding liquid flow can break up.

[0020] In one embodiment of the dispensing system, the variator can comprise a piston movable in the buffer chamber and a compression spring engaging the piston of the variator. Such a spring-loaded piston is mechanically simple and robust.

[0021] In an alternative embodiment, the variator can comprise a bag filled with a compressible medium. This embodiment has no movable parts like a piston and a spring, which improves the long-term reliability of the dispensing system.

[0022] In such a dispensing system, the buffer chamber can be integrated in the outlet channel. In this way, the bag is directly acted upon by the liquid pressure in the outlet channel, and the dispensing system can be more compact.

[0023] In a preferred embodiment of the dispensing system, the container can be a bag-in-bottle type container. In such a bag-in-bottle container, the liquid to be dispensed can be kept completely isolated from ambient air throughout its entire lifetime. Thereby, the liquid is not contaminated or aged.

[0024] In another embodiment, the dispensing system further comprises a movable trigger connected to the piston or pump chamber of the pump for actuating the associated components and generating the liquid pressure. In this way, the dispensing system is realized as a trigger sprayer, which is a structurally simple and cost-effective dispenser.

[0025] The present invention further relates to a method for dispensing a liquid foam, in particular a direct foam cleaning product. According to the present invention, such a method comprises the steps of: drawing liquid from a container and pressurizing the liquid by actuating a pump, wherein the container and the pump form part of a dispensing system; directing at least a portion of the pressurized liquid to a dispensing nozzle of the dispensing system; dispensing the liquid from the nozzle; storing another portion of the pressurized liquid in a buffer, and dispensing the stored liquid from the nozzle when the pump is not actuated, wherein the nozzle, the buffer and the pump are configured and dimensioned such that the foam is dispensed in a predetermined spray pattern.

[0026] Preferred embodiments of the dispensing method are defined in dependent claims 21 to 27.

[0027] And finally, the present invention relates to a nozzle, which is particularly suitable for use in a dispensing system of the above defined type. BRIEF DESCRIPTION OF DRAWINGS

[0028] Further features of the present invention are set forth in the detailed description of some embodiments of the present invention below and in the attached drawings, wherein like reference numerals identify similar elements throughout.

[0029] Figure 1 is a scanned image of a direct foam spray pattern realized using a dispensing system according to the present invention;

[0030] Figure 2 is a cross-sectional view of a first embodiment of a dispensing device of the present invention;

[0031] Figure 3 shows the liquid flow path through Figure 2 a dispensing system;

[0032] Figure 4 is an enlarged perspective cross-sectional view of the spray nozzle defined by the dashed boundary "4" shown in Figure 3 ;

[0033] Figure 5 is a perspective view of the nozzle shown in Figure 4 ;

[0034] Figure 6 is a longitudinal cross-sectional view of the nozzle shown in Figure 4 and Figure 5 ;

[0035] Figure 7 is a rear view of the swirled groove and inner cone of the nozzle of Figures 4 to 6 ;

[0036] Figure 8 is a graphical representation of the manner in which the pre-compression valve and the damper of the dispensing device define a narrow bandwidth of pressure for liquid foam dispensing;

[0037] Figure 9 is a cross-sectional view of a second embodiment of the dispensing device of the present invention;

[0038] Figure 10 is a cross-sectional view of a third embodiment of the dispensing device of the present invention; and

[0039] Figure 11 is an enlarged longitudinal cross-sectional view of the nozzle of Figures 4 to 6 when mounted on a dispensing system. DETAILED DESCRIPTION

[0040] The direct foam cleaning product of the present invention comprises a cleaning composition that is dispensed from a spray dispenser to form a direct foam. As used herein, "direct foam" or "direct product" is a product that forms a foam on the surface to which it is applied without the need for additional physical, chemical or similar intervention. For example, a product that produces a foam on a surface upon manual rubbing of the product once it has been dispensed from its container is not a direct foam product. A direct foam product is applied directly to a surface from the container in which it is stored.

[0041] The cleaning composition can be dispensed from a dispensing system according to the present invention. As will be described in detail below, the dispensing system comprises a container for the liquid cleaning composition and a dispensing device connected to the container. A suitable container can be a bag-in-bottle type container using the technology of the Applicant's The dispensing device comprises a pump, a pre-compression valve and a damper. The pre-compression valve controls the minimum pressure required to release liquid from the dispensing device and the damper mechanism controls the maximum pressure required to pump liquid into and out of the damper chamber. Upon dispensing of the composition from the dispensing system of the present invention, the cleaning composition provides a direct foam product having a wide annular foam pattern as shown in Figure 1 However, other foam pattern shapes are contemplated and achievable through variations in the nozzle design of the dispensing device.

[0042] Reference is made to Figure 2FIG. 1 shows a dispensing device 1 from which the direct foam cleaning composition of the present invention is dispensed. The dispensing device 1 includes a spray engine frame 10 fluidly connecting a liquid inlet 16 to a pump chamber 20, a buffer chamber 30, a pre-compression valve 40, and a nozzle 50. Liquid composition 100 travels through the flow path 200 shown and is dispensed as a direct foam product. The liquid inlet 16 can be fluidly connected to an optional dip tube 18 to draw liquid composition 100 from a bottle or reservoir (not shown) through the flow path 200 of the sprayer 1. The bottle and liquid composition 100 can be sold separately or provided as a replacement for a direct foam cleaning product. Liquid composition 100 from a reservoir can also be drawn into the sprayer 1 without a dip tube 18, for example using known airless systems with collapsible internal structure (such as a bag inside a bottle) such as the applicant's Figure 3 tiered bottle of the bottle technology or other airless technology known in the art.

[0043] The dispensing device 1 can include an actuation element, such as a trigger 14 as shown, or other known actuation elements (such as a button, etc.) that is mechanically connected to the piston 22. In operation, when the spring-loaded trigger 14 is actuated by the user, the piston 22 moves down, and upon release of the trigger 14, the force of the spring moves the piston 22 back up. This expands the volume of the chamber and creates a low pressure in the pump chamber 20 that opens the inlet valve 12, closes the outlet valve 36, and causes liquid composition 100 to be drawn into the pump chamber 20. When the inlet valve 12 is open, the outlet valve 36 is closed (the low pressure moves the outlet valve up to the closed position). Figure 2

[0044] When the trigger 14 is actuated or pulled in by the user, the trigger 14 creates a down stroke in the pump chamber 20. The piston 22 moves down and pushes liquid into the outlet passage 60 leading to the pre-compression valve 40. The buffer chamber 30 is also connected to this outlet passage 60. The inlet valve 12 is closed and the outlet valve 36 is open, thereby letting the liquid composition 100 pass to the outlet passage 60 and to the pre-compression valve 40. When the pressure created by the down stroke of the pump piston 22 exceeds the burst pressure of the pre-compression valve 40, the diaphragm 41 of the valve elastically deforms and the valve moves into its open position. Liquid then flows to the nozzle 50 where it is dispensed as a foam.

[0045] When the trigger 14 is actuated, the inlet valve 12 is closed, preventing liquid from the pump chamber 20 from being pushed back into the bottle / reservoir (the pressure moves it down to the closed position). This allows pressure to build in the outlet passage 60 and the buffer chamber 30. Because the pump's displacement volume is greater than the maximum output of the nozzle 50, the pressure in the outlet passage 60 rises during the down stroke of the pump piston 22.

[0046] ​​The pressure acts on an elastically compressible volume changer 70 arranged in the buffer chamber 30 for changing the available volume of the buffer chamber. In this embodiment, the volume changer 70 comprises a buffer piston 32 and a buffer spring 34 engaging the piston.

[0047] The pressure of the liquid composition 100 in the buffer chamber 30 pushes down on the buffer piston 32 and the buffer spring 34 below the buffer piston 32 is thus compressed, thereby increasing the available volume of the buffer chamber 30 and allowing the liquid composition to be temporarily stored under pressure in the buffer chamber 30.

[0048] At a certain depth of the buffer chamber 30 there is an overflow opening (not shown). This is done to prevent excessive build-up of liquid pressure and thereby it is an outlet at a certain defined point beyond which the buffer piston 32 cannot travel down. Thus, when the buffer piston 32 moves beyond a certain point (at the maximum desired pressure / spring force), the liquid will flow back into the reservoir through the overflow opening in the wall of the buffer chamber 30. The liquid overflow opening can be set for the maximum buffer spring 34 pressure in the buffer chamber 30, e.g. 0.5 to 3.0 bar, or 0.5 to 1.0 bar, above the pre-set opening pressure or break pressure of the pre-compression valve 40. In exemplary embodiments of the invention, such pre-compression valve opening pressure can be e.g. 1.5, 2.5, 3.5 or even 6 bar or more. In preferred embodiments of the invention, the opening pressure is between 2 and 4.5 bar, more particularly about 3 to 3.5 bar.

[0049] It should be noted that in exemplary embodiments of the invention, the pre-compression valve 40 has an opening pressure lower than the maximum pressure that can be built up in the buffer chamber 30. In this way, the pre-compression valve 40 will open before the buffer chamber 30 is completely filled with liquid and thereby reaches its maximum pressure, and spraying will take place sufficiently. This allows for continuous spraying situations. More specifically, when more liquid is available in the sprayer than the nozzle 50 is able to spray (limited by the maximum flow rate through the nozzle), the remaining liquid is stored in the buffer chamber 30 and gradually released over time until the pressure drops below the pre-compression valve closing pressure, which cuts off the liquid flow. This allows for long spraying times with a single actuation and for continuous spraying with multiple actuations with a certain actuation interval. For example, if the nozzle 50 is only able to spray 1 ml / s and 1.4 ml of liquid is pumped in one actuation, the spraying will last 1.4 seconds. If three actuations of 1.4 ml of liquid would be pumped in 2 seconds, the sprayer will continue to spray for 4.2 seconds.

[0050] The pre-compression valve 40 controls the spraying action from the nozzle 50. The pre-compression valve 40 has a defined pressure; when the pressure of the liquid exceeds this defined pressure, the pre-compression valve opens and a spray is created. When the pressure falls below the defined closing pressure of the pre-compression valve 40, the pre-compression valve closes, ensuring that only properly pressurized liquid can travel to the nozzle 50, ensuring a continuous spray. Due to the liquid pressure in the outlet passage 60 and the buffer chamber 30, the pre-compression valve 40 opens, and the liquid composition 100 is thereby transmitted to the nozzle 50, creating the desired spray.

[0051] As described above, when the trigger 14 is actuated, the inlet valve 12 closes, preventing liquid from the pump chamber 20 from being pushed back into the bottle / reservoir. Although the dispensing device 1 can be in a subsequent trigger release and liquid intake step, the liquid composition 100 can still pass through the pre-compression valve 40 and through the orifice 50 to continue spraying. In this way, the user can cause a continuous spray - as long as the user moves the trigger 14 back and forth continuously so that the liquid intake stroke catches up to the spray, the liquid composition 100 is continuously drawn out and sent to the pressure chamber and pre-compression valve. In this regard, it should be noted that by varying the relative volumes of the pump chamber 20 and the buffer chamber 30, various pumping speeds can be designed.

[0052] Reference is now made to Figure 4 , which shows the nozzle 50 with a liquid swirler shaft 44 placed in the liquid discharge passage 42. The swirler shaft 44 opens into a swirl chamber 52 at one end adjacent to the nozzle orifice 55. The swirler shaft 44 extends axially in a downstream direction toward the orifice 55. The orifice 55 opens into a conical expansion zone 58, which directs the spray angle of the liquid exiting the orifice 55.

[0053] Reference is made to Figure 5 , the nozzle 50 includes a plurality of swirl slots 54 and an orifice 55 that provides an exit path through the nozzle 50. The swirl slots 54 can number one to five, three to five, or three. Internally in the nozzle 50, the swirl slots 54 direct the liquid into an inner funnel or cone 56 that terminates at its narrow end into a short cylindrical orifice 55.

[0054] As Figure 11As shown, the spinner shaft 44 does not extend fully to the cyclone chamber 52. In fact, the end face 45 of the spinner shaft 44 is spaced from the bottom 57 of the central bore 59 of the nozzle 50. In this way, a portion of the liquid is not forced through the cyclone slots 54, but can bypass these and flow through the center of the inner funnel or cone 56 of the nozzle. The liquid flow thus consists of two branches, one flowing through the cyclone slots 54 and one through the center, with different velocities. Without wishing to be bound by theory, it can be assumed that the higher velocity flow entrains the lower velocity flow, so that the entire body of liquid flowing towards the nozzle orifice is energized. The observed end result of this arrangement is an improvement in the foam properties.

[0055] The cyclone slots 54 can vary in shape, width and depth, and can taper from wide to narrow to accommodate the optimum acceleration of the liquid flow with minimal resistance and pressure drop. The inner cone 56 can have an angle of about 20° to about 150°, preferably about 50° to about 120°, and more preferably about 100°. The inner cone 56 defines how much of the spinning liquid is further accelerated before the orifice 55, and thus how wide the spray is that unfolds or comes out of the orifice 55. The cyclone slots 54 accelerate under pressure and spin the liquid into the inner cone 56, where the gradual decrease in diameter further compresses and accelerates the liquid, which is thus sprayed out through the narrow orifice 55 at high pressure. The sudden pressure drop at the exit of the orifice 55 allows the highly compressed and energized liquid to expand and break up into small droplets. The speed, direction and width of the spray droplets are defined by the energy and trajectory introduced by the angle on the cyclone slots 54 and the inner cone 56. The short cylindrical path in the orifice 55 should technically be kept as short as possible to not affect the width of the spray.

[0056] Outside or downstream of the orifice 55, an expansion zone in the shape of an outer cone 58 is provided, which directs the spray angle of the liquid droplets exiting the orifice. This outer cone 58 can have an angle of about 20° to about 120°, preferably about 30° to about 90°, and more particularly about 50°. The outer cone 58 is further provided with a plurality of vent openings 51. The sudden pressure drop at the exit creates a low pressure within the center of the spray. This low pressure sucks in air from the environment into the spray. As a result, the small droplets formed at the exit are transformed into small foam bubbles. This effect is further enhanced by the outer cone 58, which also directs the liquid flow outward to further break up the spray into a wide foam spray pattern. The foam particles can be further adjusted by introducing more air through the vent holes 51 in the outer cone 58 placed close to the region with the highest low pressure. Via the Venturi effect, this low pressure sucks in more air into the droplet flow, resulting in a thicker, more pronounced foam.

[0057] Orifice 55 can have a constant diameter or can be axially tapered, expanding in diameter as the spray travels from the proximal end of nozzle 50 (i.e., closest to orifice 55 and flow path 200) to the distal end. A constant orifice diameter can be about 0.10 mm to about 0.60 mm, or about 0.30 mm to about 0.40 mm, or about 0.32 mm to about 0.37 mm, or about 0.36 mm. When tapered, orifice 55 can taper from a proximal end diameter of about 0.13 mm to a distal end diameter of about 1 mm to about 5 mm, to a distal end diameter of about 0.10 mm to about 0.60 mm or about 0.30 mm to about 0.40 mm.

[0058] Exemplary nozzle configurations are provided in Table 1.

[0059] Table 1

[0060]

[0061]

[0062] As described above, the arrangement of the pump, buffer, and nozzle is such that the liquid is dispensed at a pressure that lies within a relatively narrow bandwidth. The lower limit of the dispensed pressure is determined by the burst pressure of pre-compression valve 40. As soon as the pump 20 generates a pressure above the burst pressure, pre-compression valve 40 opens, allowing liquid to flow from pump 20 through outlet passage 60 to nozzle 50. Because nozzle 50 is designed to have a maximum output that is less than the discharge capacity of pump 20, the pressure of the liquid in outlet passage 60 rises because the liquid cannot exit nozzle 50 at the same rate at which it is forced into outlet passage 60 by pump 20. This pressure rise continues until the pressure of the liquid in outlet passage 60 equals the pressure of elastically compressible accumulator 70. As soon as this pressure is reached, accumulator 70 begins to compress, thereby increasing the available volume in buffer chamber 30 for accommodating liquid that cannot exit through nozzle 50. In this way, the pressure for dispensing liquid from nozzle 50 is maximized to be the value of the pressure of accumulator 70 in buffer chamber 30. As described above, the buffer chamber can include an overflow opening, allowing liquid to return to the reservoir if the pressure generated by the pump in the outlet passage and buffer chamber is excessive. The narrow bandwidth of the dispensed pressure is shown in FIG. 8, where each curve represents the pressure established due to pump stroke, and the upper and lower limit lines 80, 90 represent the burst pressure of pre-compression valve 40 and the pressure of accumulator 70 in buffer chamber 30, respectively. Figure 8

[0063] In alternative embodiments of the dispensing system, the accumulator can be a spring-loaded piston, a spring-loaded diaphragm, or a spring-loaded bellows. Figure 9 ​), the resiliently compressible accumulator 170 comprises a bag 172 filled with pressurized medium, in particular pressurized gas. The bag 172 is arranged in the buffer chamber 130 and essentially occupies the entire inner volume of the buffer chamber, so that no liquid can remain in the buffer chamber 130. In the present embodiment, the bag 172 comprises a plastic tube filled with gas at a predetermined maximum dispensing pressure and sealed at its opposite ends by weld lines 174. The gas-filled bag accumulator 170 essentially functions in the same way as the spring-loaded piston accumulator 32 of the previous embodiment. When the liquid pressure in the outlet channel 160 exceeds the gas pressure in the tubular bag 172, the bag will start to be compressed, thereby freeing up space in the buffer chamber 130 for liquid to enter. When the pump piston 122 reaches its end of stroke and the pressure build-up stops, liquid will continue to flow from the buffer chamber 130 through the outlet channel 160 to the nozzle 150, since the pressure in the system still exceeds the burst pressure of the pre-compression valve 140. As liquid continues to be dispensed, the pressure in the outlet channel 160 and the buffer chamber 130 will decrease, and the resilient accumulator 170 will expand. In this way, liquid will be forced out of the buffer chamber 130 until the buffer chamber is emptied. As soon as the pressure falls below the burst pressure of the pre-compression valve 140, the flow of liquid out through the nozzle 150 will stop.

[0064] In a further embodiment of the dispensing system Figure 10 ), the buffer chamber 230 is effectively formed by a widening of the outlet channel 206, which in turn is partially accommodated in the piston 222 of the pump 220. Here, the resiliently compressible accumulator 270 is again realized as a plastic bag 272 filled with gas under pressure, which essentially occupies the entire inner volume of the buffer chamber 230. Liquid can flow past the gas-filled bag 272 through spaces 273 left between the periphery of the gas-filled bag 272 and the inner wall 233 of the buffer chamber 230. In the present embodiment, the inner wall 233 has a sawtooth-like configuration when viewed in cross-section, defining ridges or ribs that engage the gas-filled bag 272, separated by recesses that serve as liquid flow channels 273. These liquid flow channels 273 together form the nominal outlet channel 260. These liquid flow channels 273 converge at an opening 235 at the top of the buffer chamber 230, which opening is sealed off by the pre-compression valve 240.

[0065] In the present embodiment, the piston 222 is disposed on the lower end of the buffer chamber 230, held stationary, and the pump chamber 220 is movable upward relative to the stationary piston 222 upon actuation of the trigger 214. As the pump chamber 220 moves upward relative to the piston 222, liquid in the pump chamber 220 is compressed and forced out of the pump chamber 220 through a central opening 225 disposed in the bottom 226 of the piston 222. The central opening 225 is closed by a valve 227 during the inlet stroke, the central opening being in fluid communication with a liquid flow passage 273 disposed in the wall 233 of the buffer chamber 230.

[0066] The pump creates a pressure above the burst pressure of the pre-compression valve 240, which opens, and fluid can flow to the nozzle 250 to be dispensed as foam. Again, as the pressure builds and reaches the gas pressure in the bag 272, the changer 270 begins to compress and creates additional space in the buffer chamber 230 for liquid to occupy. And as the pump chamber 220 reaches its end of stroke and pressure build stops, liquid continues to flow to the nozzle 250, thereby allowing the gas to fill the changer bag 272 to expand again and the buffer chamber 230 to be evacuated. When the buffer chamber 230 has been completely evacuated, the liquid pressure drops below the burst pressure of the pre-compression valve 240, and no more foam is dispensed.

[0067] Cleaning composition

[0068] Direct foam cleaning products dispensed using the dispensing system of the present invention include a cleaning composition that includes a surfactant system, and optionally an organic oil and grease cleaning solvent. The suds produced upon spraying the cleaning composition are robust enough to withstand the impact forces upon the direct foam cleaning product as it contacts the items to be washed (i.e., minimize bounce-back, suck-back, and product waste), but at the same time are easy to rinse. The direct foam cleaning product provides good cleaning, including cleaning of tenacious food soils, such as cooked, baked, and burned soils, and provides good cleaning of light oil soils. The direct foam cleaning product dispensed using the dispensing system of the present invention also provides good detergent spread, requiring less scrubbing by the consumer.

[0069] The dimensions and values disclosed herein are not to be understood as being strictly limited to the exact numerical values recited. Instead, unless otherwise specified, each such dimension is intended to mean both the recited value and a functionally equivalent range surrounding that value. For example, a dimension disclosed as "40 mm" is intended to mean "about 40 mm." Further, it is to be understood that every maximum numerical limitation given throughout this specification is intended to include every lower numerical limitation, as if such lower numerical limitations were expressly written herein. Similarly, every minimum numerical limitation given throughout this specification is intended to include every higher numerical limitation, as if such higher numerical limitations were expressly written herein. Every numerical range given throughout this specification is intended to include every narrower numerical range that falls within such broader numerical range, as if such narrower numerical ranges were expressly written herein.

[0070] Every document cited herein, including any cross referenced or related patent or application, is hereby incorporated herein by reference in its entirety unless expressly excluded or otherwise limited. The citation of any document is not an admission that it is prior art with respect to any application disclosed or claimed herein or that it alone, or in any combination with any other reference or references, teaches, suggests or discloses any such application. Further, to the extent that any meaning or definition of a term in this document conflicts with any meaning or definition of the same term in a document incorporated by reference, the meaning or definition assigned to that term in this document shall govern.

[0071] While particular embodiments of the present application have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the application. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this application.

Claims

1. System for dispensing a liquid foam, comprising a container for the liquid and a dispensing device (1; connected to the container; 101; 201), wherein said dispensing device (1; 101; 201) comprises: - a pump comprising a pump chamber (20; 120; 220) in fluid communication with said container and a piston (22; 122; 222) arranged in said pump chamber (20; 120; 220), said piston (22; 122; 222) and said pump chamber (20; 120; 220) being movable relative to each other; - an outlet channel (60; 160; 260) connecting said pump chamber (20; 120; 220) to a nozzle (50; 150; 250), said nozzle (50; 150; 250) comprising a nozzle orifice (55); - a pre-compression valve (40; 140; 240) arranged between said outlet channel (60; 160; 260) and said nozzle (50; 150; 250); and - a buffer comprising a buffer chamber (30; 130; 230) connected to said outlet channel (60; 160; 260), said buffer chamber (30; 130; 230) comprising a compressible variator (70; 170; 270) arranged therein for varying the available volume of said buffer chamber (30; 130; 230), wherein said nozzle (50; 150; 250), said buffer and said pump are configured and dimensioned so that said foam is dispensed from said nozzle orifice (55) in a predetermined spray pattern, wherein said pre-compression valve (40; 140; 240) and said buffer chamber (30; 130; 230) are arranged to define a lower and an upper limit, respectively, of the dispensing pressure of said foam, wherein said pre-compression valve (40; 140; 240) has a breaking pressure of 200 to 450 kiloPascal (2 to 4.5 bar), and wherein said buffer chamber (30; 130; 230) and said variator (70; 170; 270) define a maximum value of the dispensing pressure of between 300 and 550 kiloPascal (3 and 5.5 bar), wherein said nozzle (50; 150; 250) has a plurality of swirled slots (54) leading to an inlet funnel (56) opening into said nozzle orifice (55), and wherein said nozzle (50; 150; 250) has a central hole (59) upstream of said inlet funnel (56), said central hole (59) being arranged to accommodate a protrusion (44) of a dispenser frame, and wherein said central hole (59) is dimensioned so that an end face (45) of said protrusion (44) is spaced apart from a bottom (57) of said hole (59) to form a space between the end face (45) of said protrusion (44) and the bottom (57) of said hole (59) so that part of said liquid flows through said swirled slots (54) while part of said liquid bypasses said swirled slots and flows through said space and through the center of said inlet funnel (56) of said nozzle.

2. The system of claim 1, wherein the pre-compression valve (40; 140; 240) has a burst pressure of 300 to 350 kiloPascal (3 to 3.5 bar), and the buffer chamber (30; 130; 230) and the variator (70; 170; 270) define a maximum of 500 kiloPascal (5 bar) for the dispense pressure.

3. The system of claim 1, wherein the pump has a displacement volume greater than a maximum output volume of the nozzle (50; 150; 250).

4. The system of claim 3, wherein the nozzle (50; 150; 250) is constructed and sized to have a maximum output volume of 1.45 cubic centimeters per second.

5. The system of any one of claims 1-4, wherein the buffer chamber (30; 130; 230) has a maximum available volume greater than the displacement volume of the pump.

6. The system of any one of claims 1-4, wherein the inlet funnel (56) is conical and has an apex angle of 20°-150°.

7. The system of claim 6, wherein the inlet funnel (56) has an apex angle of 50°-120°.

8. The system of claim 7, wherein the inlet funnel (56) has an apex angle of 100°.

9. The system of claim 6, wherein the nozzle (50; 150; 250) has an odd number of swirl slots (54).

10. The system of claim 9, wherein the nozzle (50; 150; 250) has 3 or 5 swirl slots (54).

11. The system of any one of claims 1-4, wherein the nozzle (50; 150; 250) has a diverging expansion zone (58) downstream of the nozzle orifice (55).

12. The system of claim 11, wherein the expansion zone (58) has a vent opening (51).

13. The system of claim 11, wherein the expansion zone (58) is conical and has an apex angle of between 20°-120°.

14. The system of claim 13, wherein the expansion zone (58) has an apex angle of between 30°-90°.

15. The system of claim 14, wherein the expansion zone (58) has an apex angle of 50°.

16. The system of any one of claims 1-4, wherein the variator (70) includes a variator piston (32) movable in the buffer chamber (30) and a compression spring (34) engaging the variator piston (32).

17. The system of any one of claims 1-4, wherein the variator (170; 270) includes a bag (172; 272) filled with a compressible medium.

18. The system of claim 17, wherein the buffer chamber (230) is integrated in the outlet passage (260).

19. The system of any one of claims 1-4, wherein the container is a bag-in-bottle type container.

20. The system according to any one of claims 1-4, further comprising a movable trigger (14; 114; 214) connected to a piston (22; 122; 222) or pump chamber (20; 120; 220) of the pump.

21. Method for dispensing a liquid foam, comprising the steps of: - drawing the liquid (100) from a container and pressurizing the liquid by actuating a pump, wherein the container and the pump form part of a dispensing system, - directing at least a portion of the pressurized liquid to a dispensing nozzle (50; 150; 250) of the dispensing system, the dispensing nozzle comprising a nozzle orifice (55), - dispensing the liquid from the nozzle (50; 150; 250), - storing another portion of the pressurized liquid in a buffer, and - dispensing the stored liquid from the nozzle (50; 150; 250) without actuating the pump, wherein the nozzle (50; 150; 250), the buffer and the pump are configured and dimensioned such that the foam is dispensed from the nozzle orifice (55) in a predetermined spray pattern, wherein the liquid is dispensed from the nozzle (50; 150; 250) only if the pressure of the liquid exceeds a burst pressure of a pre-compression valve (40; 140; 240) arranged upstream of the nozzle (50; 150; 250), the burst pressure being 200 to 450 kPa (2 to 4.5 bar), and wherein the pressurized liquid is stored in the buffer as long as the pressure of the liquid exceeds a pressure generated by a compressible expander (70; 170; 270) in the buffer, the pressure generated by the expander having a maximum of between 300 and 550 kPa (3 and 5.5 bar), wherein upon reaching the nozzle (50; 150; 250), at least a portion of the pressurized liquid is brought into rotation by a swirler (54) and accelerated in an inlet funnel (56) towards the nozzle orifice (55), and wherein a portion of the pressurized liquid bypasses the swirler (54) and flows through the center of the inlet funnel (56) of the nozzle.

22. The method according to claim 21, wherein the burst pressure is 300 to 350 kPa (3 to 3.5 bar), and the pressure generated by the expander has a maximum of 500 kPa (5 bar).

23. The method according to claim 21 or 22, wherein actuating the pump results in a volume of liquid to be drawn from the container and pressurized that is larger than a maximum output of the nozzle (50; 150; 250), thereby resulting in an additional volume of the liquid to be stored in the buffer.

24. The method according to claim 21 or 22, wherein upon passing through the nozzle orifice (55), the liquid expands in a dispersion nozzle portion to form a foam.

25. The method according to claim 24, wherein during expansion and foaming, the liquid mixes with ambient air drawn into the expanding liquid stream.

26. A nozzle (50; 150; 250) for use in a system according to any one of claims 1 to 14, comprising a plurality of swirl slots (54) leading to an inlet funnel (56) which opens into the nozzle orifice (55).

27. A nozzle (50; 150; 250) according to claim 26, wherein the inlet funnel (56) is conical and has an apex angle of 20°-150°.

28. A nozzle (50; 150; 250) according to claim 27, wherein the inlet funnel (56) has an apex angle of 50°-120°.

29. A nozzle (50; 150; 250) according to claim 28, wherein the inlet funnel (56) has an apex angle of 100°.

30. A nozzle (50; 150; 250) according to any one of claims 26-29, wherein the nozzle (50; 150; 250) has an odd number of swirl slots (54).

31. A nozzle (50; 150; 250) according to claim 30, wherein the nozzle (50; 150; 250) has 3 or 5 swirl slots (54).

32. A nozzle (50; 150; 250) according to any one of claims 26-29, further comprising a dispersion expansion zone (58) downstream of the nozzle orifice (55).

33. A nozzle (50; 150; 250) according to claim 32, wherein the expansion zone (58) has a vent opening (51).

34. A nozzle (50; 150; 250) according to claim 32, wherein the expansion zone (58) is conical and has an apex angle of between 20°-120°.

35. A nozzle (50; 150; 250) according to claim 34, wherein the expansion zone (58) has an apex angle of between 30°-90°.

36. A nozzle (50; 150; 250) according to claim 35, wherein the expansion zone (58) has an apex angle of 50°.

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