Suction device and method for its operation

Abstract

A suction device having a collection container, having a filter for cleaning the air flow loaded with suction material, and having a motor for driving a turbine, wherein the turbine is specified to generate a vacuum and thus an air flow for inducting the suction material. The suction device has a piston which is designed to be movable for carrying out filter cleaning and releases a first duct in a suction operation position and closes the first duct by moving into a filter cleaning position, wherein the air between the piston and the filter is compressed so that a surge of compressed air is forced through the filter and the filter is cleaned in this way. A method for operating such a suction device, in which filter cleaning can be effected by the movement of a single piston is also provided.

Description

[0001] The present invention relates to a suction device having a collection container, having a filter for cleaning the air flow loaded with suction material, and having a motor for driving a turbine.BACKGROUND OF THE INVENTION

[0002] In the field of industrial or construction vacuum cleaners it is known that the filters of the vacuum cleaners must be cleaned regularly in order to enable an efficient operation of the appliance. Various systems and procedures are known in the state of the art for carrying out filter cleaning. The most common mechanisms comprise backwashing or mechanical agitating of the filter.

[0003] In mechanical agitation, a special device such as a comb, an agitator or the like, is often provided to cause mechanical agitating of the filter.SUMMARY OF THE INVENTION

[0004] During backwashing, external air is usually admitted into the vacuum cleaner, wherein the external air is preferably passed through the suction device at an abrupt rate in the opposite suction flow direction. In this way, the filter to be cleaned can be flushed and cleaned. However, the disadvantage of backwashing is that the suction flow must be reversed or paused during cleaning in order to clean the filter. This means that during cleaning, the suction or suction operation of the suction device only functions to a limited extent. If the suction device is connected to a machine tool to remove the dust produced when working with the machine tool, the dust load to which the machine tool user is exposed can increase during filter cleaning.

[0005] Until now, this disadvantage has often been addressed by the use of two filters and two cleaning systems in the vacuum cleaners. In these 2-filter systems, one filter can always remain active, allowing the suction flow to pass through this active filter, while the other “inactive” filter is cleaned. However, the disadvantage of these 2-filter systems is that they are installation space-intensive and take up a lot of space in a construction vacuum cleaner, because the corresponding cleaning system must be installed twice, once for each filter.

[0006] It is an object of the present invention to overcome the shortcomings and disadvantages of the prior art described above and to provide an alternative method or mechanism for cleaning a filter in a suction device. In doing so, mechanical agitation as well as a 2-filter system are to be dispensed with. In particular, an effective, compact and space-saving cleaning mechanism is to be provided, with which suction operation can be maintained even during the cleaning process.

[0007] Provided according to the invention is a suction device, wherein the suction device comprises a collection container for receiving suction material, a filter for cleaning the air flow loaded with suction material and a motor for driving a turbine, wherein the turbine is designed to generate a vacuum and thus an air flow or suction flow for inducting the suction material. The suction device has a piston which is designed to be movable for carrying out filter cleaning and releases a first duct in a suction operation position and closes the first duct by moving into a filter cleaning position, wherein the air between the piston and the filter is compressed so that a surge of compressed air is forced through the filter and the filter is cleaned in this way.

[0008] The piston is preferably designed to release the first duct in the suction operation position and to close the first duct in the filter cleaning position. In the context of the invention, the piston can preferably also be referred to as a single piston. This wording is preferably intended to express that the suction device comprises exactly one piston for carrying out the filter cleaning. Thus, the invention departs from such systems known from the prior art for filter cleaning, in which two pistons are provided to clean in each case one filter or a filter portion of a filter, while the suction operation is maintained via the respective other filter or filter portion. Due to the design of a single piston described in this document, a particularly space-saving and compact filter cleaning mechanism can be provided, which also requires a very small amount of backwash air and nevertheless achieves a good cleaning effect. Surprisingly, by the provision of a second duct, which is formed as a bypass duct and is described below, the suction operation can also be maintained during filter cleaning. With the present invention, the advantages of so-called 2-filter systems are furthermore implemented without the disadvantages, such as high space requirements, occurring.

[0009] In the context of the invention, it is preferred that air loaded with suction material is inducted through an opening within the suction device (“suction inlet”) and forms a suction flow. The suction flow flows through the collection container for collecting suction material (“dust collection container”), where a large part of the suction material or dust is deposited. The suction flow is then passed through a filter by which the suction flow is further cleaned. The suction flow is generated by a turbine which is driven by a motor of the suction device. The turbine and the motor are disposed behind the filter in the suction direction, wherein the suction device can have a piston chamber directly behind the filter and then an intermediate portion, before the turbine and the motor adjoin. In other words, the suction device can have an intermediate portion disposed between the motor and the piston chamber, the intermediate portion forming a portion of the first duct. A potential design embodiment of the suction device is illustrated in the figures.

[0010] The suction device can be connected to a machine tool such as a drill, saw, chisel, or a cutting or grinding device, wherein the suction device is specified to suction off the dust generated when working with the machine tool. This means that the suction material may include dust or dust particles in particular. However, it can also be prefera-ble that the suction device is designed as a wet-dry vacuum cleaner and can suction wet dust or a mixture of suction material and liquid. The machine tool and the suction device can be communicatively, mechanically and / or electrically connected to one another in a known manner.

[0011] The suction device comprises a piston, which is designed to be movable for carrying out filter cleaning. In the context of the invention this preferably means that the piston can move back and forth at least between a suction operation position and a filter cleaning position, wherein carrying out filter cleaning, or a filter cleaning procedure, can be started by the movement of the piston from the suction operation position to the filter cleaning position. The movement of the single piston can be effected, for example, by incoming external air or by guided process air, i.e. air present in the suction device.

[0012] It is preferred within the context of the invention that the filter to be cleaned has no contact with the air by which the movement of the piston is effected. Advantageously, in the context of the present invention, the filter is not impinged with external air. Instead, the filter is cleaned by a pressure pulse generated by the movement of the piston and by the compression of the air in the compression zone. This compressed air is forced through the filter by the piston, so that the pressure pulse agitates the filter mechanically and backwashes the latter. In this way, the filter cleaning system with a single piston combines the advantages of the known cleaning systems, without being installation space-intensive and without suctioning coming to a standstill during filter cleaning. In particular, the invention offers an alternative option for a filter cleaning mechanism, which is particularly well suited if a compact filter cleaning unit for a suction device is desired or little installation space is available.

[0013] It is preferred in the context of the invention that the first duct is disposed between the motor of the suction device and the filter, wherein the first duct is formed as a suction duct and at least in portions runs through a piston chamber of the suction device. The piston chamber is preferably disposed behind the filter and in front of the motor or turbine in the direction of the suction flow. The piston of the suction device can be movably received in the piston chamber, so that the piston can carry out a linear or axial movement in the piston chamber. Depending on the design of the suction device, the piston can move from top to bottom or sideways, for example. An intermediate portion of the first duct can be disposed between the piston chamber and the motor or turbine. The first duct is a suction duct for the suction flow, wherein the first duct is preferably specified to receive a larger proportion of the suction flow and to guide it toward the motor or turbine, while a second duct is specified to receive a smaller portion of the suction flow and direct it toward the motor or turbine.

[0014] It is preferred within the context of the invention that the suction device comprises a second duct, which is formed as a bypass duct, wherein the second duct is specified to bypass the piston and / or the piston chamber of the suction device. In this way, the induction of suction material, which is preferably referred to as “suction operation” in the context of the invention, can advantageously also be maintained during filter cleaning. It is a substantial advantage that a suction device with a small, compact filter cleaning mechanism can be provided by the invention, in which it is nevertheless possible that the suction operation can be maintained by the second duct of the suction device during filter cleaning. Tests have shown that the achieved filter cleaning effect is very positive. It is preferred in the context of the invention that the wording that “the second duct is formed as a bypass duct” and that “the second duct bypasses the piston or the piston chamber of the suction device” are used synonymously in the context of the present application. This preferably means that the second duct does not run through the piston chamber. In particular, there should be no fluidic connection between the piston chamber and the second duct. Rather, the second duct can be specified to connect the filter of the suction device to the first duct, the intermediate portion or an antechamber of the motor of the suction device.

[0015] It is preferred within the context of the invention that a size of a cross-sectional area of the second duct is in a range of 1-25%, preferably in a range of 2-15%, and most preferably in a range of 3-10%, of a cross-sectional area of a motor inlet of the suction device, wherein the motor inlet delimits the first duct on the turbine side. Preferably, a cross section of the second duct can be formed to be much smaller than a cross section of the first duct, measured at the motor inlet, i.e. at the transition of the first duct to the motor of the suction device. In a particularly preferred design embodiment of the invention, the cross section of the bypass duct can be between 3 and 10% of the cross section of the first duct in the region of the motor inlet. This size ratio of the cross sections of the channels has proven to be particularly favorable if the invention is intended to maintain an effective suction operation during filter cleaning, but effective filter cleaning is to be provided at the same time.

[0016] It is preferred in the context of the invention that the first duct is delimited on the motor side by a motor inlet, wherein the motor inlet has a cross-sectional area. The first duct, which is preferably also referred to as “suction duct” in the context of the invention, preferably begins at the turbine, wherein the transition between the turbine and the first duct in the context of the invention is preferably referred to as motor inlet. An intermediate portion of the suction duct can be disposed between the turbine and the piston chamber. This intermediate portion can, for example, have a tapered cross section. This preferably means in the context of the invention that the cross section of the intermediate portion at the motor inlet is larger than in the region in which the intermediate portion opens into the piston chamber of the suction device. This mouth region can preferably be referred to as the motor opening of the first duct, or of the piston chamber, in the context of the invention. In other words, the intermediate portion of the first duct is delimited by a motor inlet on the turbine or motor side, and by the motor opening on the piston chamber side. The first duct preferably passes through the piston chamber, wherein the filter, and optionally the collection container for suction material, adjoins / adjoin the piston chamber. It should be noted that this description of the first duct is provided in the reverse direction of the suction flow. In the suction direction, the air flow loaded with suction material is inducted into the suction device via a suction inlet and first guided through the collection container, where most of the suction material is separated. The air flow is then suctioned through the filter in the suction operation, where further cleaning of the air flow takes place. The air flow is then guided through the piston chamber in the direction of the turbine, wherein an intermediate portion of the first duct can be disposed between the piston chamber or the motor opening on one side and the turbine or the motor inlet on the other side. When viewed from the motor opening, a cross section of the intermediate portion can increase in the direction of the turbine or in the direction of the motor inlet, so that a cross section of the intermediate portion in the region of the motor inlet is larger than in the region of the motor opening.

[0017] It is preferred within the context of the invention that the cross section or the cross-sectional area of the second duct is substantially constant over its length. In other words, the bypass duct has essentially the same or a similar cross section at different points. For example, the second duct can start in the intermediate portion of the first duct or—depending on the point of view—open into the latter. In particular, the second duct can run through the suction device in such a way that the bypass duct bypasses the piston or piston chamber. The term “bypass” in the context of the invention preferably means that the second or bypass duct is not guided through the piston chamber, but just avoids the latter. However, it may also be preferred within the context of the invention that there is no fixed spatial separation between the piston chamber and the second duct. It is preferred within the context of the invention that there is no direct fluidic connection between the piston chamber and the second duct of the suction device. However, it may also be preferred that a limited, minimal fluidic connection exists between the second duct and the piston chamber. While a first end of the bypass duct can open into the intermediate portion of the first duct, a second end of the bypass duct preferably opens into the filter of the suction device. In other words, the second duct connects the first suction duct to the filter, wherein it is very particularly preferred in the context of the invention that the second duct connects the intermediate portion of the first duct to the filter. This allows a small part of the air flow to flow through the bypass duct while a larger part of the air flow can flow through the first duct in the suction operation of the suction device.

[0018] It is preferred within the context of the invention that at least one contact face which delimits the movement of the piston from the suction operation position to the filter cleaning position is provided in the piston chamber. If the movement of the piston from the suction operation position to the filter cleaning position represents a movement from top to bottom, the at least one contact face may be disposed, for example, on a lower side of the piston chamber, so that the piston is decelerated by the contact face when the piston moves from the suction operation position to the filter cleaning position to carry out filter cleaning.

[0019] It is preferred within the context of the invention that the piston chamber has a compression zone, wherein the compression zone extends between the at least one contact face and a motor opening of the piston chamber. It is particularly preferred within the context of the invention that the compression zone extends between the at least one contact face and a lower edge of a motor opening of the piston chamber. The compression or air volume that can be compressed by the movement of the piston is present in the compression zone. This compression of the compression volume is preferably performed in a so-called compression phase of the filter cleaning procedure, which preferably begins with the piston performing a movement from the suction operation position to the filter cleaning position. During this movement, the piston sweeps across the motor opening of the piston chamber and seals the latter. This will cut off the larger part of the suction flow from the turbine, causing said suction flow to come to a standstill. The provision of the second duct, which is not closed by the movement of the piston, allows the suction operation to continue even when the first duct is closed. As a result, the suction operation is restricted by the closing of the motor opening due to the piston or its movement to such a minor extent that the suction operation can be continued almost unnoticed by the user during filter cleaning.

[0020] When the piston moves from the suction operation position to the filter cleaning position and closes the motor opening between the first duct and the piston chamber, the suction operation is interrupted by the first duct. However, the piston does not stop its movement upon sweeping across and closing the motor opening, but the piston continues its movement in the direction of the filter. This movement preferably occurs very quickly or abruptly, so that the air in the compression zone is compressed by the piston movement. By the continuous piston movement, this compressed air is pushed through the filter of the suction device, wherein this process is preferably referred to as “surge” within the context of the invention. On the one hand, this surge causes backwashing of the filter, i.e. an air flow through the filter in a direction that is opposite to the direction of the suction flow in suction operation. In addition, the surge causes mechanical agitation of the filter. This double effect of the surge can provide particularly effective filter cleaning, despite only one piston and a very small amount of backwash air being used. The piston movement continues beyond the motor opening over a length h, which is preferably referred to as the “height of the compression zone”. It is preferred within the context of the invention that the piston moves by a length L during the movement from the suction operation position to the filter cleaning position, the length L corresponding to at least a sum of the diameter of the motor opening and the height of the compression zone.

[0021] It is preferred within the context of the invention that a height h of the compression zone [in mm] is in a range of less than ( 1 / 1500·mm) of a cross-sectional area of the piston [in mm2]. Preferably, the height of the compression zone is measured between the at least one contact face and the lower edge of the motor opening of the piston chamber (see figures). It was completely surprising that a pressure surge can be generated so strong that effective filter cleaning is made possible with such a small height of the compression zone and with just one piston. In one exemplary embodiment of the invention, the height of the compression zone can, for example, be in a range of 2-17 mm, while the cross-sectional area of the piston (“piston face”) can be, for example, 250 cm2 or 25000 mm2. Thus, the height h of the compression zone corresponds to less than 1 / 1500 of the piston face, taking into account the corresponding or identical units of measurement. In this comparison, in particular the height h of the compression zone in units of mm is compared with the piston face in units of mm2.

[0022] In a second aspect, the invention relates to a method for operating a suction device. The terms, definitions and technical advantages introduced for the suction device preferably apply in an analogous manner to the operating procedure for the suction device. The operating method is characterized by the following method steps:

[0023] a) providing the suction device and operating the suction device in a suction operation;

[0024] b) carrying out a filter cleaning procedure by moving a piston from a suction operation position to a filter cleaning position, by this movement closing a first duct so that air between the piston and a filter is compressed in such a way that a surge of compressed air is forced through the filter and the filter is cleaned in this way.

[0025] In other words, in addition to providing the suction device and its operation in a suction operation, the method also comprises, in particular, a movement of the piston from a suction operation position to a filter cleaning position, wherein the filter cleaning is initiated by this movement of the piston. As a result of the movement of the piston, the first duct which receives the greater part of the suction flow during suction operation is closed, so that the suction operation can be maintained by a second duct during filter cleaning. The filter cleaning procedure preferably begins with closing of the motor opening of the piston chamber, whereby the first duct is closed. This is preferably followed by the compression phase in which the air in the compression volume of the piston chamber is compressed and pushed through the filter. After the filter cleaning procedure has been completed, the piston moves back to its initial position, which preferably corresponds to the suction operation position of the piston. It was completely surprising that with the invention an effective suction operation during filter cleaning can be maintained yet an effective filter cleaning can be provided at the same time.

[0026] It is preferred within the context of the invention that in suction operation a larger proportion of a suction flow flows through the first duct and a smaller proportion of the suction flow flows through a second duct. Preferably, the second duct is formed as a bypass duct, wherein the second duct is in particular specified to bypass the piston chamber of the suction device or to avoid the piston chamber.

[0027] Preferably, the suction flow during the suction operation of the suction device flows through the first and through a second duct, wherein a larger proportion of the suction flow flows through the wider, i.e. larger, first duct, while a smaller portion of the suction flow flows through the second duct, which preferably has a smaller cross section than the first duct. Thus, the suction operation of the suction device differs from the per-formance of filter cleaning (“filter cleaning procedure”) preferably in that in the suction operation the suction flow flows through the suction duct and the bypass duct, while in the course of a filter cleaning procedure the suction flow flows only through the second duct, i.e. the bypass duct. This switching off of the first duct, i.e. the suction duct, is caused in particular by the movement of the one piston which can move back and forth in a piston chamber of the suction device. Depending on the design of the piston chamber, this can be an up-and-down (i.e. an upward-downward) or a sideways movement of the piston. The piston is preferably designed to carry out a linear motion for starting or carrying out a filter cleaning procedure. The movement of the piston allows the first duct to be closed so that there is no longer any fluidic connection between the motor of the suction device and the filter. To do this, the piston can stroke over the motor opening of the piston chamber, thereby closing the motor opening and thus the first duct. In this way, there is no longer any suction flow flowing through the first duct. The suction operation of the suction device during a filter cleaning procedure, i.e. during the filter cleaning phase, is maintained by the second duct, which preferably bypasses the piston chamber. The second duct is a bypass or a targeted bypass of the suction device piston chamber. This is advantageously made possible by the fact that the second duct, for example, is guided past the outside of the piston chamber.

[0028] The wording that suction operation is maintained through the bypass duct is not contradictory to the statement that suction flow flows through the first duct and through a second duct during suction operation of the suction device, while during a filter cleaning procedure the suction flow flows only through the second duct, i.e. the bypass duct. The suction operation, or the suction phase, of the suction device is preferably characterized in that the suction device only suctions, but the filter is not being cleaned. The filter cleaning phase of the suction device is preferably characterized in that the filter of the suction device is cleaned, while the suction operation of the suction device is maintained by the second or bypass duct—quasi in a special operation. This maintenance of the suction operation during the performance of a filter cleaning procedure represents a particular advantage of the invention.

[0029] It is preferred within the context of the invention that the piston is returned pneumatically and / or mechanically to an initial position. The piston is conveyed back to its initial position particularly after the filter cleaning procedure has been completed. The initial position preferably corresponds to the suction operation position of the piston. The return of the piston can be performed in different ways. For example, the piston can be returned mechanically. In an alternative design embodiment of the invention, the piston can be conveyed back to its initial position in a pneumatic manner. The return of the piston to its initial position represents in particular a movement counter to the movement by which the piston is conveyed from the suction operation position to the filter cleaning position. In other words, the piston is conveyed back from the filter cleaning position to the suction operation position by the returning action, wherein the suction operation position represents the initial position of the piston.

[0030] Further advantages can be found in the description of the figures hereunder. The figures, the description and the claims contain numerous features in combination. The person skilled in the art will expediently also consider the features individually and com-bine them into useful further combinations.BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In the figures, identical and equivalent components are provided with the same reference signs. In the figures:

[0032] FIG. 1 shows a view of a preferred design embodiment of the suction device during the suction operation;

[0033] FIG. 2 shows a view of a preferred design embodiment of the suction device at the beginning of filter cleaning; and

[0034] FIG. 3 shows a view of a preferred design embodiment of the suction device during filter cleaning.DETAILED DESCRIPTION

[0035] FIG. 1 shows a preferred design embodiment of the suction device 10 during the suction operation. The suction device 10 can be designed as a vacuum cleaner or as an industrial vacuum cleaner and comprises a motor 16, which generates an air or suction flow 18. The suction device 10 can consist of an upper part (suction head) and a lower part, wherein the lower part of the suction device 10 can comprise a collection container 12 for suction material 14, such as dust. In the suction device 10 an opening which can be connected to a suction hose can be provided. The suction hose can be connected to a floor nozzle or a machine tool, so that a floor can be cleaned or dust created when working with the machine tool can be suctioned with the suction device 10. The dust 14 is inducted into the suction device 10 by means of the suction flow 18, wherein a large part of the dust 14 can be deposited in the collection container 12. The suction flow 18 is furthermore fed through a filter 20 within the suction device 10, wherein the suction flow 18 is further cleaned through the filter 20. When the suction flow 18 passes through the filter 20, individual dust particles 14 can be trapped in the filter so that these dust particles 14 are filtered out of the air flow 18. In the case of heavy dust load, the filter 20 of the suction device 10 may become clogged, whereby the performance of the suction device 10 or its suction strength may be reduced. In the field of industrial vacuum cleaners, it is therefore known to regularly clean the filter or filters 20 of the suction device 10. In the context of the present invention, it is provided that a piston 22 is moved in the direction of the filter 20. This movement of the piston 22 is indicated in FIG. 2 by an arrow with the letter “v”. The piston 22 can move in particular linearly in a piston chamber 26 and have a piston face 42 with a specific cross-sectional area on its lower side. If the piston 22 moves from top to bottom in the piston chamber 26 during implementation, for example, the air in a compression zone (see FIG. 2) can be compressed in the compression zone 38. This in particular owing to the fact that the filter 20 initially represents a resistance for the air in the compression zone 38, but this resistance can be overcome by the downward movement of the piston 22 and the increase in the pressure on the air. The continued movement of the piston 22 allows the compressed air to be pushed abruptly through the filter 20. This advantageously achieves two effects: on the one hand, there is so-called backwashing of the filter 20, i.e. air is passed through the filter 20 in the reverse suction direction. On the other hand, mechanical agitating of the filter 20 occurs as a result of the surge of compressed air passing through. Both effects of the piston movement lead to effective cleaning of the filter 20, wherein any adhering filter cake can be released from the filter 20 and falls into the collection container 12.

[0036] However, the invention not only provides effective filter cleaning. As a result of an arrangement of a first duct 24 and a second duct 28 described below, the suction operation of the suction device 10 can also be maintained while carrying out filter cleaning. The first duct 24, which is preferably also referred to as “suction duct” in the context of the invention, is specified to receive a larger proportion 18a of the suction flow 18. The second duct 28, which is preferably also referred to as “bypass duct” in the context of the invention, is specified to receive a smaller proportion 18b of the suction flow 18. The larger portion 18a of the suction flow 18 is shown in FIG. 1 with a stronger dashed line than the smaller portion 18b of the suction flow 18. The smaller portion 18b and the larger portion 18a conjointly form the suction flow 18, as is represented by the curly bracket in FIG. 1. The larger portion 18a of the suction flow 18 is guided in the first duct 24 from the filter 20 in the direction of the motor 16 or the turbine (not shown) of the suction device 10. In the process, the suction flow 18a passes through the piston chamber 26 in the suction operation and leaves the piston chamber 26 through a motor opening 40, wherein the motor opening 40 has a diameter d. An intermediate portion 44 of the first duct 24 through which the larger part 18a of the suction flow 18 is guided can be disposed between the piston chamber 26 and the motor 16. At the end of the intermediate portion 44 is a motor inlet 34 which has a cross-sectional area 32. In other words, the intermediate portion 44 on the turbine side can be delimited by the motor inlet 34, while the intermediate portion 44 on the piston chamber 26 side is delimited by the motor opening 40. Thus, the intermediate portion 44 extends between the motor opening 40 on one side and the motor inlet 34 on the other side. The intermediate portion 44 can have a tapered profile, wherein a cross section 32 of the motor inlet 34 can be larger than a cross-sectional area of the motor opening 40, wherein the motor opening 40 has a diameter d. This preferably means in the context of the invention that the cross section of the first duct 24, or its intermediate portion 44, in the region of the motor inlet 34 is greater than a cross section of the first duct 24, or its intermediate portion 44, in the region of the motor opening 40, wherein the motor opening 40 marks or forms the transition between the intermediate portion 44 or the motor 16 on one side and the piston chamber 26 on the other side. It has proven to be particularly advantageous if the cross-sectional area 30 of the second duct 28 is significantly smaller than the cross-sectional area 32 of the motor inlet 34. Preferably, the size of the cross-sectional area 30 of the second duct 28 can be in a range of 3-10% of a cross-sectional area 32 of the motor inlet 34. For example, if the cross-sectional area 32 of the motor inlet 34 is 100 cm2, the cross-sectional area 30 of the second duct 28 can, for example, lie in a range between 3 and 10 cm2. It has been demonstrated that a good split between the larger part 18a and the smaller part 18b of the suction flow 18 can be achieved by such a ratio of the cross-sectional areas. Thus, on the one hand, effective backwashing of the filter 20 for the purpose of filter cleaning can be achieved and, on the other hand, the suction operation of the suction device 10 via the second duct 28 can be maintained to such an extent that further suction material 14 can be inducted into the suction device 10 with a sufficient suction force.

[0037] The suction device 10 can have in addition to the first duct 24 a second duct 28, which extends, for example, between the intermediate portion 44 and the filter 20. The second duct 28 is designed in particular as a bypass duct in order to bypass the piston chamber 26 and to direct a smaller part of the suction flow 18b past the piston chamber 26 from the filter 20 to the turbine or to the motor 16 of the suction device 10. By providing the second duct 28, the suction operation can be maintained even when the filter 20 of the suction device 10 is being cleaned. The first duct 24 is preferably closed during the filter cleaning, specifically by the piston 22, which in order to start filter cleaning moves from a suction operation position to a filter cleaning position in the piston chamber 26. In other words, the piston 22 is specified to start filter cleaning by moving the piston 22 from a suction operation position to a filter cleaning position. For this purpose, the piston 22 can reliably move, for example, from a higher suction operation position to a lower filter cleaning position, i.e. carry out a movement from top to bottom, following gravity. FIG. 1 shows in particular a suction device 10, in which the piston 22 in the piston chamber 26 is present in the suction operation position. This means in the exemplary embodiment of the invention shown in FIG. 1 that the piston 22 in the suction operation is disposed in an upper region of the piston chamber 26. The larger part 18a of the suction flow 18 can flow only in the suction operation position of the piston 22, while the smaller part 18b of the suction flow 18 can flow both in the suction operation position (FIG. 1), as well as in the intermediate position (FIG. 2), and in the filter cleaning position (FIG. 3) of the piston 22. The flow of the larger part 18a of the suction flow 18 through the first duct 24 is interrupted in particular by the downward movement of the piston 22 by way of which filter cleaning is initiated. Preferably, in the context of the present invention, only a much smaller suction flow 18 flows during filter cleaning compared to the suction operation.

[0038] When the piston 22 moves from the suction operation position to the filter cleaning position, the piston 22 preferably sweeps across the motor opening40 of the piston chamber 26 and thus closes the motor opening 40. In this way, the suction flow 18a through the first duct 24 comes to a standstill, while the suction flow 18b can continue to flow through the second duct 28. The second duct 28 has a substantially constant diameter over its length in the exemplary embodiments of the invention shown in the figures. Thus, the cross-sectional area 30 of the second duct 28 is also substantially constant over its length.

[0039] The situation in which the piston 22 moves downward and closes the motor opening 40 of the piston chamber 26 is shown in FIG. 2. The (downward) movement of the piston 22 is symbolized in particular by the downward pointing arrow, which is marked with the letter “v”. FIG. 2 thus shows an intermediate position of the piston 22, which is located between the suction operation position and the filter cleaning position. In this intermediate position, the compression zone 38 is located below the piston 22, or the piston face 42, which comprises a compression volume. The compression volume is formed by the air located in this lower region of the piston chamber 26. In other words, a lower region of the piston chamber 26, which extends between the filter 20 and the piston 22 or the piston face 42, can form the compression zone 38 which comprises a certain amount of air, the latter being able to be compressed by the ongoing movement of the piston 22—in the exemplary embodiment shown in FIG. 2: in a spatial direction downward. The air in the compression zone 38 is compressed as a result. The spatial direc-tions O (upward) and U (downward) are symbolized in FIG. 2 by the double arrow, with the tips of the double arrow pointing in the spatial direction upward (O) or downward (U).

[0040] The compression zone 38 has a height h, wherein the height h can correspond, for example, to the spacing between the at least one contact face 36 and the lower edge of the motor opening 40. In other words, the compression zone 38 can extend in the top-to-bottom orientation between the motor opening 40 (top) and the at least one contact face 36 (bottom). It is preferred in the context of the invention that the height h of the compression zone 38 is in a range of less than 1 / 1500·mm of a cross-sectional area 42 of the piston 22. The height h of the compression zone 38 is expressed in millimeters [mm], while the cross-sectional area 42 of the piston 22 is expressed in square-millime-ters [mm2]. The optimum height h of the compression zone 38 in units of mm can thus be determined by multiplying the area of the piston (in units of mm2) by the factor ( 1 / 1500 mm). The movement of the piston 22, for example, has a length L, which is shown in FIG. 1. The length L of the movement of the piston 22 can correspond to the sum of the height h of the compression zone 38 and the diameter d of the motor opening 40, i.e. L=h+d.

[0041] If the piston 22 moves further down in the piston chamber 26, in the direction of the filter 20, the piston 22 pushes the compressed air in front of itself. The compressed air forms a surge of compressed air which can move through the filter 20 and thus clean the filter 20. The surge of compressed air, or compressed air pulse, acts in two ways: on the one hand, the surge of compressed air leads to backwashing of the filter 20, so that any filter cake is released and can fall into the collection container 12 of the suction device 10. On the other hand, the surge of compressed air can cause a mechanical vibration of the filter 20, which can also lead to the possibly adhering filter cake coming off the filter 20.

[0042] The movement of the piston 22 ends when the piston 22 impacts the at least one contact face 36 and thus comes to a stop. The piston 22 has then reached its filter cleaning position. The filter cleaning position of the piston 22 is shown in FIG. 3.

[0043] The second duct 28 is advantageously not closed by the downward movement of the piston 22. This is ensured by the contact faces 36, which can be provided, for example, above the filter 20 in the piston chamber 26. The contact faces 36 decelerate the movement of the piston 22 so that the piston 22 comes to rest on the contact faces 36. In this filter cleaning position of the piston 22, only the smaller part 18b of the suction flow 18 can flow, wherein the suction operation of the suction device 10 can be maintained via this smaller part 18b of the suction flow 18, and the suction device 10 can also continue to be used for inducting suction material 14 during the filter cleaning. After completion of filter cleaning, the piston 22 can be returned pneumatically and / or mechanically to its initial position, the initial position preferably corresponding to the suction operation position of the piston 22.

[0044] FIG. 2 shows a potential design embodiment of the suction device 10 at the beginning of the filter cleaning, wherein the piston 22 is in an intermediate position, while FIG. 3 shows a potential design embodiment of the suction device 10 during the filter cleaning, wherein the piston 22 is in a filter cleaning position.LIST OF REFERENCE SIGNS10 Suction device

[0046] 12 Collection container

[0047] 14 Suction material

[0048] 16 Motor

[0049] 18 Suction flow

[0050] 18a Larger part of the suction flow

[0051] 18b Smaller part of the suction flow

[0052] 20 Filter

[0053] 22 Piston

[0054] 24 First duct

[0055] 26 Piston chamber

[0056] 28 Second duct

[0057] 30 Cross-sectional area of the second duct

[0058] 32 Cross-sectional area of the motor inlet

[0059] 34 Motor inlet

[0060] 36 Contact face

[0061] 38 Compression zone

[0062] 40 Motor opening of the piston chamber

[0063] 42 Cross-sectional area of the piston

[0064] 44 Intermediate portion

[0065] h Height of the compression zone

[0066] d Diameter of the motor opening

[0067] L Length of the movement of the piston

[0068] V Movement of the piston

[0069] O Upward spatial direction

[0070] U Downward spatial direction

Examples

Embodiment Construction

[0035]FIG. 1 shows a preferred design embodiment of the suction device 10 during the suction operation. The suction device 10 can be designed as a vacuum cleaner or as an industrial vacuum cleaner and comprises a motor 16, which generates an air or suction flow 18. The suction device 10 can consist of an upper part (suction head) and a lower part, wherein the lower part of the suction device 10 can comprise a collection container 12 for suction material 14, such as dust. In the suction device 10 an opening which can be connected to a suction hose can be provided. The suction hose can be connected to a floor nozzle or a machine tool, so that a floor can be cleaned or dust created when working with the machine tool can be suctioned with the suction device 10. The dust 14 is inducted into the suction device 10 by means of the suction flow 18, wherein a large part of the dust 14 can be deposited in the collection container 12. The suction flow 18 is furthermore fed through a filter 20 w...

[0001] The present invention relates to a suction device having a collection container, having a filter for cleaning the air flow loaded with suction material, and having a motor for driving a turbine.BACKGROUND OF THE INVENTION

[0002] In the field of industrial or construction vacuum cleaners it is known that the filters of the vacuum cleaners must be cleaned regularly in order to enable an efficient operation of the appliance. Various systems and procedures are known in the state of the art for carrying out filter cleaning. The most common mechanisms comprise backwashing or mechanical agitating of the filter.

[0003] In mechanical agitation, a special device such as a comb, an agitator or the like, is often provided to cause mechanical agitating of the filter.SUMMARY OF THE INVENTION

[0004] During backwashing, external air is usually admitted into the vacuum cleaner, wherein the external air is preferably passed through the suction device at an abrupt rate in the opposite suction flow direction. In this way, the filter to be cleaned can be flushed and cleaned. However, the disadvantage of backwashing is that the suction flow must be reversed or paused during cleaning in order to clean the filter. This means that during cleaning, the suction or suction operation of the suction device only functions to a limited extent. If the suction device is connected to a machine tool to remove the dust produced when working with the machine tool, the dust load to which the machine tool user is exposed can increase during filter cleaning.

[0005] Until now, this disadvantage has often been addressed by the use of two filters and two cleaning systems in the vacuum cleaners. In these 2-filter systems, one filter can always remain active, allowing the suction flow to pass through this active filter, while the other “inactive” filter is cleaned. However, the disadvantage of these 2-filter systems is that they are installation space-intensive and take up a lot of space in a construction vacuum cleaner, because the corresponding cleaning system must be installed twice, once for each filter.

[0006] It is an object of the present invention to overcome the shortcomings and disadvantages of the prior art described above and to provide an alternative method or mechanism for cleaning a filter in a suction device. In doing so, mechanical agitation as well as a 2-filter system are to be dispensed with. In particular, an effective, compact and space-saving cleaning mechanism is to be provided, with which suction operation can be maintained even during the cleaning process.

[0007] Provided according to the invention is a suction device, wherein the suction device comprises a collection container for receiving suction material, a filter for cleaning the air flow loaded with suction material and a motor for driving a turbine, wherein the turbine is designed to generate a vacuum and thus an air flow or suction flow for inducting the suction material. The suction device has a piston which is designed to be movable for carrying out filter cleaning and releases a first duct in a suction operation position and closes the first duct by moving into a filter cleaning position, wherein the air between the piston and the filter is compressed so that a surge of compressed air is forced through the filter and the filter is cleaned in this way.

[0008] The piston is preferably designed to release the first duct in the suction operation position and to close the first duct in the filter cleaning position. In the context of the invention, the piston can preferably also be referred to as a single piston. This wording is preferably intended to express that the suction device comprises exactly one piston for carrying out the filter cleaning. Thus, the invention departs from such systems known from the prior art for filter cleaning, in which two pistons are provided to clean in each case one filter or a filter portion of a filter, while the suction operation is maintained via the respective other filter or filter portion. Due to the design of a single piston described in this document, a particularly space-saving and compact filter cleaning mechanism can be provided, which also requires a very small amount of backwash air and nevertheless achieves a good cleaning effect. Surprisingly, by the provision of a second duct, which is formed as a bypass duct and is described below, the suction operation can also be maintained during filter cleaning. With the present invention, the advantages of so-called 2-filter systems are furthermore implemented without the disadvantages, such as high space requirements, occurring.

[0009] In the context of the invention, it is preferred that air loaded with suction material is inducted through an opening within the suction device (“suction inlet”) and forms a suction flow. The suction flow flows through the collection container for collecting suction material (“dust collection container”), where a large part of the suction material or dust is deposited. The suction flow is then passed through a filter by which the suction flow is further cleaned. The suction flow is generated by a turbine which is driven by a motor of the suction device. The turbine and the motor are disposed behind the filter in the suction direction, wherein the suction device can have a piston chamber directly behind the filter and then an intermediate portion, before the turbine and the motor adjoin. In other words, the suction device can have an intermediate portion disposed between the motor and the piston chamber, the intermediate portion forming a portion of the first duct. A potential design embodiment of the suction device is illustrated in the figures.

[0010] The suction device can be connected to a machine tool such as a drill, saw, chisel, or a cutting or grinding device, wherein the suction device is specified to suction off the dust generated when working with the machine tool. This means that the suction material may include dust or dust particles in particular. However, it can also be prefera-ble that the suction device is designed as a wet-dry vacuum cleaner and can suction wet dust or a mixture of suction material and liquid. The machine tool and the suction device can be communicatively, mechanically and / or electrically connected to one another in a known manner.

[0011] The suction device comprises a piston, which is designed to be movable for carrying out filter cleaning. In the context of the invention this preferably means that the piston can move back and forth at least between a suction operation position and a filter cleaning position, wherein carrying out filter cleaning, or a filter cleaning procedure, can be started by the movement of the piston from the suction operation position to the filter cleaning position. The movement of the single piston can be effected, for example, by incoming external air or by guided process air, i.e. air present in the suction device.

[0012] It is preferred within the context of the invention that the filter to be cleaned has no contact with the air by which the movement of the piston is effected. Advantageously, in the context of the present invention, the filter is not impinged with external air. Instead, the filter is cleaned by a pressure pulse generated by the movement of the piston and by the compression of the air in the compression zone. This compressed air is forced through the filter by the piston, so that the pressure pulse agitates the filter mechanically and backwashes the latter. In this way, the filter cleaning system with a single piston combines the advantages of the known cleaning systems, without being installation space-intensive and without suctioning coming to a standstill during filter cleaning. In particular, the invention offers an alternative option for a filter cleaning mechanism, which is particularly well suited if a compact filter cleaning unit for a suction device is desired or little installation space is available.

[0013] It is preferred in the context of the invention that the first duct is disposed between the motor of the suction device and the filter, wherein the first duct is formed as a suction duct and at least in portions runs through a piston chamber of the suction device. The piston chamber is preferably disposed behind the filter and in front of the motor or turbine in the direction of the suction flow. The piston of the suction device can be movably received in the piston chamber, so that the piston can carry out a linear or axial movement in the piston chamber. Depending on the design of the suction device, the piston can move from top to bottom or sideways, for example. An intermediate portion of the first duct can be disposed between the piston chamber and the motor or turbine. The first duct is a suction duct for the suction flow, wherein the first duct is preferably specified to receive a larger proportion of the suction flow and to guide it toward the motor or turbine, while a second duct is specified to receive a smaller portion of the suction flow and direct it toward the motor or turbine.

[0014] It is preferred within the context of the invention that the suction device comprises a second duct, which is formed as a bypass duct, wherein the second duct is specified to bypass the piston and / or the piston chamber of the suction device. In this way, the induction of suction material, which is preferably referred to as “suction operation” in the context of the invention, can advantageously also be maintained during filter cleaning. It is a substantial advantage that a suction device with a small, compact filter cleaning mechanism can be provided by the invention, in which it is nevertheless possible that the suction operation can be maintained by the second duct of the suction device during filter cleaning. Tests have shown that the achieved filter cleaning effect is very positive. It is preferred in the context of the invention that the wording that “the second duct is formed as a bypass duct” and that “the second duct bypasses the piston or the piston chamber of the suction device” are used synonymously in the context of the present application. This preferably means that the second duct does not run through the piston chamber. In particular, there should be no fluidic connection between the piston chamber and the second duct. Rather, the second duct can be specified to connect the filter of the suction device to the first duct, the intermediate portion or an antechamber of the motor of the suction device.

[0015] It is preferred within the context of the invention that a size of a cross-sectional area of the second duct is in a range of 1-25%, preferably in a range of 2-15%, and most preferably in a range of 3-10%, of a cross-sectional area of a motor inlet of the suction device, wherein the motor inlet delimits the first duct on the turbine side. Preferably, a cross section of the second duct can be formed to be much smaller than a cross section of the first duct, measured at the motor inlet, i.e. at the transition of the first duct to the motor of the suction device. In a particularly preferred design embodiment of the invention, the cross section of the bypass duct can be between 3 and 10% of the cross section of the first duct in the region of the motor inlet. This size ratio of the cross sections of the channels has proven to be particularly favorable if the invention is intended to maintain an effective suction operation during filter cleaning, but effective filter cleaning is to be provided at the same time.

[0016] It is preferred in the context of the invention that the first duct is delimited on the motor side by a motor inlet, wherein the motor inlet has a cross-sectional area. The first duct, which is preferably also referred to as “suction duct” in the context of the invention, preferably begins at the turbine, wherein the transition between the turbine and the first duct in the context of the invention is preferably referred to as motor inlet. An intermediate portion of the suction duct can be disposed between the turbine and the piston chamber. This intermediate portion can, for example, have a tapered cross section. This preferably means in the context of the invention that the cross section of the intermediate portion at the motor inlet is larger than in the region in which the intermediate portion opens into the piston chamber of the suction device. This mouth region can preferably be referred to as the motor opening of the first duct, or of the piston chamber, in the context of the invention. In other words, the intermediate portion of the first duct is delimited by a motor inlet on the turbine or motor side, and by the motor opening on the piston chamber side. The first duct preferably passes through the piston chamber, wherein the filter, and optionally the collection container for suction material, adjoins / adjoin the piston chamber. It should be noted that this description of the first duct is provided in the reverse direction of the suction flow. In the suction direction, the air flow loaded with suction material is inducted into the suction device via a suction inlet and first guided through the collection container, where most of the suction material is separated. The air flow is then suctioned through the filter in the suction operation, where further cleaning of the air flow takes place. The air flow is then guided through the piston chamber in the direction of the turbine, wherein an intermediate portion of the first duct can be disposed between the piston chamber or the motor opening on one side and the turbine or the motor inlet on the other side. When viewed from the motor opening, a cross section of the intermediate portion can increase in the direction of the turbine or in the direction of the motor inlet, so that a cross section of the intermediate portion in the region of the motor inlet is larger than in the region of the motor opening.

[0017] It is preferred within the context of the invention that the cross section or the cross-sectional area of the second duct is substantially constant over its length. In other words, the bypass duct has essentially the same or a similar cross section at different points. For example, the second duct can start in the intermediate portion of the first duct or—depending on the point of view—open into the latter. In particular, the second duct can run through the suction device in such a way that the bypass duct bypasses the piston or piston chamber. The term “bypass” in the context of the invention preferably means that the second or bypass duct is not guided through the piston chamber, but just avoids the latter. However, it may also be preferred within the context of the invention that there is no fixed spatial separation between the piston chamber and the second duct. It is preferred within the context of the invention that there is no direct fluidic connection between the piston chamber and the second duct of the suction device. However, it may also be preferred that a limited, minimal fluidic connection exists between the second duct and the piston chamber. While a first end of the bypass duct can open into the intermediate portion of the first duct, a second end of the bypass duct preferably opens into the filter of the suction device. In other words, the second duct connects the first suction duct to the filter, wherein it is very particularly preferred in the context of the invention that the second duct connects the intermediate portion of the first duct to the filter. This allows a small part of the air flow to flow through the bypass duct while a larger part of the air flow can flow through the first duct in the suction operation of the suction device.

[0018] It is preferred within the context of the invention that at least one contact face which delimits the movement of the piston from the suction operation position to the filter cleaning position is provided in the piston chamber. If the movement of the piston from the suction operation position to the filter cleaning position represents a movement from top to bottom, the at least one contact face may be disposed, for example, on a lower side of the piston chamber, so that the piston is decelerated by the contact face when the piston moves from the suction operation position to the filter cleaning position to carry out filter cleaning.

[0019] It is preferred within the context of the invention that the piston chamber has a compression zone, wherein the compression zone extends between the at least one contact face and a motor opening of the piston chamber. It is particularly preferred within the context of the invention that the compression zone extends between the at least one contact face and a lower edge of a motor opening of the piston chamber. The compression or air volume that can be compressed by the movement of the piston is present in the compression zone. This compression of the compression volume is preferably performed in a so-called compression phase of the filter cleaning procedure, which preferably begins with the piston performing a movement from the suction operation position to the filter cleaning position. During this movement, the piston sweeps across the motor opening of the piston chamber and seals the latter. This will cut off the larger part of the suction flow from the turbine, causing said suction flow to come to a standstill. The provision of the second duct, which is not closed by the movement of the piston, allows the suction operation to continue even when the first duct is closed. As a result, the suction operation is restricted by the closing of the motor opening due to the piston or its movement to such a minor extent that the suction operation can be continued almost unnoticed by the user during filter cleaning.

[0020] When the piston moves from the suction operation position to the filter cleaning position and closes the motor opening between the first duct and the piston chamber, the suction operation is interrupted by the first duct. However, the piston does not stop its movement upon sweeping across and closing the motor opening, but the piston continues its movement in the direction of the filter. This movement preferably occurs very quickly or abruptly, so that the air in the compression zone is compressed by the piston movement. By the continuous piston movement, this compressed air is pushed through the filter of the suction device, wherein this process is preferably referred to as “surge” within the context of the invention. On the one hand, this surge causes backwashing of the filter, i.e. an air flow through the filter in a direction that is opposite to the direction of the suction flow in suction operation. In addition, the surge causes mechanical agitation of the filter. This double effect of the surge can provide particularly effective filter cleaning, despite only one piston and a very small amount of backwash air being used. The piston movement continues beyond the motor opening over a length h, which is preferably referred to as the “height of the compression zone”. It is preferred within the context of the invention that the piston moves by a length L during the movement from the suction operation position to the filter cleaning position, the length L corresponding to at least a sum of the diameter of the motor opening and the height of the compression zone.

[0021] It is preferred within the context of the invention that a height h of the compression zone [in mm] is in a range of less than ( 1 / 1500·mm) of a cross-sectional area of the piston [in mm2]. Preferably, the height of the compression zone is measured between the at least one contact face and the lower edge of the motor opening of the piston chamber (see figures). It was completely surprising that a pressure surge can be generated so strong that effective filter cleaning is made possible with such a small height of the compression zone and with just one piston. In one exemplary embodiment of the invention, the height of the compression zone can, for example, be in a range of 2-17 mm, while the cross-sectional area of the piston (“piston face”) can be, for example, 250 cm2 or 25000 mm2. Thus, the height h of the compression zone corresponds to less than 1 / 1500 of the piston face, taking into account the corresponding or identical units of measurement. In this comparison, in particular the height h of the compression zone in units of mm is compared with the piston face in units of mm2.

[0022] In a second aspect, the invention relates to a method for operating a suction device. The terms, definitions and technical advantages introduced for the suction device preferably apply in an analogous manner to the operating procedure for the suction device. The operating method is characterized by the following method steps:

[0023] a) providing the suction device and operating the suction device in a suction operation;

[0024] b) carrying out a filter cleaning procedure by moving a piston from a suction operation position to a filter cleaning position, by this movement closing a first duct so that air between the piston and a filter is compressed in such a way that a surge of compressed air is forced through the filter and the filter is cleaned in this way.

[0025] In other words, in addition to providing the suction device and its operation in a suction operation, the method also comprises, in particular, a movement of the piston from a suction operation position to a filter cleaning position, wherein the filter cleaning is initiated by this movement of the piston. As a result of the movement of the piston, the first duct which receives the greater part of the suction flow during suction operation is closed, so that the suction operation can be maintained by a second duct during filter cleaning. The filter cleaning procedure preferably begins with closing of the motor opening of the piston chamber, whereby the first duct is closed. This is preferably followed by the compression phase in which the air in the compression volume of the piston chamber is compressed and pushed through the filter. After the filter cleaning procedure has been completed, the piston moves back to its initial position, which preferably corresponds to the suction operation position of the piston. It was completely surprising that with the invention an effective suction operation during filter cleaning can be maintained yet an effective filter cleaning can be provided at the same time.

[0026] It is preferred within the context of the invention that in suction operation a larger proportion of a suction flow flows through the first duct and a smaller proportion of the suction flow flows through a second duct. Preferably, the second duct is formed as a bypass duct, wherein the second duct is in particular specified to bypass the piston chamber of the suction device or to avoid the piston chamber.

[0027] Preferably, the suction flow during the suction operation of the suction device flows through the first and through a second duct, wherein a larger proportion of the suction flow flows through the wider, i.e. larger, first duct, while a smaller portion of the suction flow flows through the second duct, which preferably has a smaller cross section than the first duct. Thus, the suction operation of the suction device differs from the per-formance of filter cleaning (“filter cleaning procedure”) preferably in that in the suction operation the suction flow flows through the suction duct and the bypass duct, while in the course of a filter cleaning procedure the suction flow flows only through the second duct, i.e. the bypass duct. This switching off of the first duct, i.e. the suction duct, is caused in particular by the movement of the one piston which can move back and forth in a piston chamber of the suction device. Depending on the design of the piston chamber, this can be an up-and-down (i.e. an upward-downward) or a sideways movement of the piston. The piston is preferably designed to carry out a linear motion for starting or carrying out a filter cleaning procedure. The movement of the piston allows the first duct to be closed so that there is no longer any fluidic connection between the motor of the suction device and the filter. To do this, the piston can stroke over the motor opening of the piston chamber, thereby closing the motor opening and thus the first duct. In this way, there is no longer any suction flow flowing through the first duct. The suction operation of the suction device during a filter cleaning procedure, i.e. during the filter cleaning phase, is maintained by the second duct, which preferably bypasses the piston chamber. The second duct is a bypass or a targeted bypass of the suction device piston chamber. This is advantageously made possible by the fact that the second duct, for example, is guided past the outside of the piston chamber.

[0028] The wording that suction operation is maintained through the bypass duct is not contradictory to the statement that suction flow flows through the first duct and through a second duct during suction operation of the suction device, while during a filter cleaning procedure the suction flow flows only through the second duct, i.e. the bypass duct. The suction operation, or the suction phase, of the suction device is preferably characterized in that the suction device only suctions, but the filter is not being cleaned. The filter cleaning phase of the suction device is preferably characterized in that the filter of the suction device is cleaned, while the suction operation of the suction device is maintained by the second or bypass duct—quasi in a special operation. This maintenance of the suction operation during the performance of a filter cleaning procedure represents a particular advantage of the invention.

[0029] It is preferred within the context of the invention that the piston is returned pneumatically and / or mechanically to an initial position. The piston is conveyed back to its initial position particularly after the filter cleaning procedure has been completed. The initial position preferably corresponds to the suction operation position of the piston. The return of the piston can be performed in different ways. For example, the piston can be returned mechanically. In an alternative design embodiment of the invention, the piston can be conveyed back to its initial position in a pneumatic manner. The return of the piston to its initial position represents in particular a movement counter to the movement by which the piston is conveyed from the suction operation position to the filter cleaning position. In other words, the piston is conveyed back from the filter cleaning position to the suction operation position by the returning action, wherein the suction operation position represents the initial position of the piston.

[0030] Further advantages can be found in the description of the figures hereunder. The figures, the description and the claims contain numerous features in combination. The person skilled in the art will expediently also consider the features individually and com-bine them into useful further combinations.BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In the figures, identical and equivalent components are provided with the same reference signs. In the figures:

[0032] FIG. 1 shows a view of a preferred design embodiment of the suction device during the suction operation;

[0033] FIG. 2 shows a view of a preferred design embodiment of the suction device at the beginning of filter cleaning; and

[0034] FIG. 3 shows a view of a preferred design embodiment of the suction device during filter cleaning.DETAILED DESCRIPTION

[0035] FIG. 1 shows a preferred design embodiment of the suction device 10 during the suction operation. The suction device 10 can be designed as a vacuum cleaner or as an industrial vacuum cleaner and comprises a motor 16, which generates an air or suction flow 18. The suction device 10 can consist of an upper part (suction head) and a lower part, wherein the lower part of the suction device 10 can comprise a collection container 12 for suction material 14, such as dust. In the suction device 10 an opening which can be connected to a suction hose can be provided. The suction hose can be connected to a floor nozzle or a machine tool, so that a floor can be cleaned or dust created when working with the machine tool can be suctioned with the suction device 10. The dust 14 is inducted into the suction device 10 by means of the suction flow 18, wherein a large part of the dust 14 can be deposited in the collection container 12. The suction flow 18 is furthermore fed through a filter 20 within the suction device 10, wherein the suction flow 18 is further cleaned through the filter 20. When the suction flow 18 passes through the filter 20, individual dust particles 14 can be trapped in the filter so that these dust particles 14 are filtered out of the air flow 18. In the case of heavy dust load, the filter 20 of the suction device 10 may become clogged, whereby the performance of the suction device 10 or its suction strength may be reduced. In the field of industrial vacuum cleaners, it is therefore known to regularly clean the filter or filters 20 of the suction device 10. In the context of the present invention, it is provided that a piston 22 is moved in the direction of the filter 20. This movement of the piston 22 is indicated in FIG. 2 by an arrow with the letter “v”. The piston 22 can move in particular linearly in a piston chamber 26 and have a piston face 42 with a specific cross-sectional area on its lower side. If the piston 22 moves from top to bottom in the piston chamber 26 during implementation, for example, the air in a compression zone (see FIG. 2) can be compressed in the compression zone 38. This in particular owing to the fact that the filter 20 initially represents a resistance for the air in the compression zone 38, but this resistance can be overcome by the downward movement of the piston 22 and the increase in the pressure on the air. The continued movement of the piston 22 allows the compressed air to be pushed abruptly through the filter 20. This advantageously achieves two effects: on the one hand, there is so-called backwashing of the filter 20, i.e. air is passed through the filter 20 in the reverse suction direction. On the other hand, mechanical agitating of the filter 20 occurs as a result of the surge of compressed air passing through. Both effects of the piston movement lead to effective cleaning of the filter 20, wherein any adhering filter cake can be released from the filter 20 and falls into the collection container 12.

[0036] However, the invention not only provides effective filter cleaning. As a result of an arrangement of a first duct 24 and a second duct 28 described below, the suction operation of the suction device 10 can also be maintained while carrying out filter cleaning. The first duct 24, which is preferably also referred to as “suction duct” in the context of the invention, is specified to receive a larger proportion 18a of the suction flow 18. The second duct 28, which is preferably also referred to as “bypass duct” in the context of the invention, is specified to receive a smaller proportion 18b of the suction flow 18. The larger portion 18a of the suction flow 18 is shown in FIG. 1 with a stronger dashed line than the smaller portion 18b of the suction flow 18. The smaller portion 18b and the larger portion 18a conjointly form the suction flow 18, as is represented by the curly bracket in FIG. 1. The larger portion 18a of the suction flow 18 is guided in the first duct 24 from the filter 20 in the direction of the motor 16 or the turbine (not shown) of the suction device 10. In the process, the suction flow 18a passes through the piston chamber 26 in the suction operation and leaves the piston chamber 26 through a motor opening 40, wherein the motor opening 40 has a diameter d. An intermediate portion 44 of the first duct 24 through which the larger part 18a of the suction flow 18 is guided can be disposed between the piston chamber 26 and the motor 16. At the end of the intermediate portion 44 is a motor inlet 34 which has a cross-sectional area 32. In other words, the intermediate portion 44 on the turbine side can be delimited by the motor inlet 34, while the intermediate portion 44 on the piston chamber 26 side is delimited by the motor opening 40. Thus, the intermediate portion 44 extends between the motor opening 40 on one side and the motor inlet 34 on the other side. The intermediate portion 44 can have a tapered profile, wherein a cross section 32 of the motor inlet 34 can be larger than a cross-sectional area of the motor opening 40, wherein the motor opening 40 has a diameter d. This preferably means in the context of the invention that the cross section of the first duct 24, or its intermediate portion 44, in the region of the motor inlet 34 is greater than a cross section of the first duct 24, or its intermediate portion 44, in the region of the motor opening 40, wherein the motor opening 40 marks or forms the transition between the intermediate portion 44 or the motor 16 on one side and the piston chamber 26 on the other side. It has proven to be particularly advantageous if the cross-sectional area 30 of the second duct 28 is significantly smaller than the cross-sectional area 32 of the motor inlet 34. Preferably, the size of the cross-sectional area 30 of the second duct 28 can be in a range of 3-10% of a cross-sectional area 32 of the motor inlet 34. For example, if the cross-sectional area 32 of the motor inlet 34 is 100 cm2, the cross-sectional area 30 of the second duct 28 can, for example, lie in a range between 3 and 10 cm2. It has been demonstrated that a good split between the larger part 18a and the smaller part 18b of the suction flow 18 can be achieved by such a ratio of the cross-sectional areas. Thus, on the one hand, effective backwashing of the filter 20 for the purpose of filter cleaning can be achieved and, on the other hand, the suction operation of the suction device 10 via the second duct 28 can be maintained to such an extent that further suction material 14 can be inducted into the suction device 10 with a sufficient suction force.

[0037] The suction device 10 can have in addition to the first duct 24 a second duct 28, which extends, for example, between the intermediate portion 44 and the filter 20. The second duct 28 is designed in particular as a bypass duct in order to bypass the piston chamber 26 and to direct a smaller part of the suction flow 18b past the piston chamber 26 from the filter 20 to the turbine or to the motor 16 of the suction device 10. By providing the second duct 28, the suction operation can be maintained even when the filter 20 of the suction device 10 is being cleaned. The first duct 24 is preferably closed during the filter cleaning, specifically by the piston 22, which in order to start filter cleaning moves from a suction operation position to a filter cleaning position in the piston chamber 26. In other words, the piston 22 is specified to start filter cleaning by moving the piston 22 from a suction operation position to a filter cleaning position. For this purpose, the piston 22 can reliably move, for example, from a higher suction operation position to a lower filter cleaning position, i.e. carry out a movement from top to bottom, following gravity. FIG. 1 shows in particular a suction device 10, in which the piston 22 in the piston chamber 26 is present in the suction operation position. This means in the exemplary embodiment of the invention shown in FIG. 1 that the piston 22 in the suction operation is disposed in an upper region of the piston chamber 26. The larger part 18a of the suction flow 18 can flow only in the suction operation position of the piston 22, while the smaller part 18b of the suction flow 18 can flow both in the suction operation position (FIG. 1), as well as in the intermediate position (FIG. 2), and in the filter cleaning position (FIG. 3) of the piston 22. The flow of the larger part 18a of the suction flow 18 through the first duct 24 is interrupted in particular by the downward movement of the piston 22 by way of which filter cleaning is initiated. Preferably, in the context of the present invention, only a much smaller suction flow 18 flows during filter cleaning compared to the suction operation.

[0038] When the piston 22 moves from the suction operation position to the filter cleaning position, the piston 22 preferably sweeps across the motor opening40 of the piston chamber 26 and thus closes the motor opening 40. In this way, the suction flow 18a through the first duct 24 comes to a standstill, while the suction flow 18b can continue to flow through the second duct 28. The second duct 28 has a substantially constant diameter over its length in the exemplary embodiments of the invention shown in the figures. Thus, the cross-sectional area 30 of the second duct 28 is also substantially constant over its length.

[0039] The situation in which the piston 22 moves downward and closes the motor opening 40 of the piston chamber 26 is shown in FIG. 2. The (downward) movement of the piston 22 is symbolized in particular by the downward pointing arrow, which is marked with the letter “v”. FIG. 2 thus shows an intermediate position of the piston 22, which is located between the suction operation position and the filter cleaning position. In this intermediate position, the compression zone 38 is located below the piston 22, or the piston face 42, which comprises a compression volume. The compression volume is formed by the air located in this lower region of the piston chamber 26. In other words, a lower region of the piston chamber 26, which extends between the filter 20 and the piston 22 or the piston face 42, can form the compression zone 38 which comprises a certain amount of air, the latter being able to be compressed by the ongoing movement of the piston 22—in the exemplary embodiment shown in FIG. 2: in a spatial direction downward. The air in the compression zone 38 is compressed as a result. The spatial direc-tions O (upward) and U (downward) are symbolized in FIG. 2 by the double arrow, with the tips of the double arrow pointing in the spatial direction upward (O) or downward (U).

[0040] The compression zone 38 has a height h, wherein the height h can correspond, for example, to the spacing between the at least one contact face 36 and the lower edge of the motor opening 40. In other words, the compression zone 38 can extend in the top-to-bottom orientation between the motor opening 40 (top) and the at least one contact face 36 (bottom). It is preferred in the context of the invention that the height h of the compression zone 38 is in a range of less than 1 / 1500·mm of a cross-sectional area 42 of the piston 22. The height h of the compression zone 38 is expressed in millimeters [mm], while the cross-sectional area 42 of the piston 22 is expressed in square-millime-ters [mm2]. The optimum height h of the compression zone 38 in units of mm can thus be determined by multiplying the area of the piston (in units of mm2) by the factor ( 1 / 1500 mm). The movement of the piston 22, for example, has a length L, which is shown in FIG. 1. The length L of the movement of the piston 22 can correspond to the sum of the height h of the compression zone 38 and the diameter d of the motor opening 40, i.e. L=h+d.

[0041] If the piston 22 moves further down in the piston chamber 26, in the direction of the filter 20, the piston 22 pushes the compressed air in front of itself. The compressed air forms a surge of compressed air which can move through the filter 20 and thus clean the filter 20. The surge of compressed air, or compressed air pulse, acts in two ways: on the one hand, the surge of compressed air leads to backwashing of the filter 20, so that any filter cake is released and can fall into the collection container 12 of the suction device 10. On the other hand, the surge of compressed air can cause a mechanical vibration of the filter 20, which can also lead to the possibly adhering filter cake coming off the filter 20.

[0042] The movement of the piston 22 ends when the piston 22 impacts the at least one contact face 36 and thus comes to a stop. The piston 22 has then reached its filter cleaning position. The filter cleaning position of the piston 22 is shown in FIG. 3.

[0043] The second duct 28 is advantageously not closed by the downward movement of the piston 22. This is ensured by the contact faces 36, which can be provided, for example, above the filter 20 in the piston chamber 26. The contact faces 36 decelerate the movement of the piston 22 so that the piston 22 comes to rest on the contact faces 36. In this filter cleaning position of the piston 22, only the smaller part 18b of the suction flow 18 can flow, wherein the suction operation of the suction device 10 can be maintained via this smaller part 18b of the suction flow 18, and the suction device 10 can also continue to be used for inducting suction material 14 during the filter cleaning. After completion of filter cleaning, the piston 22 can be returned pneumatically and / or mechanically to its initial position, the initial position preferably corresponding to the suction operation position of the piston 22.

[0044] FIG. 2 shows a potential design embodiment of the suction device 10 at the beginning of the filter cleaning, wherein the piston 22 is in an intermediate position, while FIG. 3 shows a potential design embodiment of the suction device 10 during the filter cleaning, wherein the piston 22 is in a filter cleaning position.LIST OF REFERENCE SIGNS10 Suction device

[0046] 12 Collection container

[0047] 14 Suction material

[0048] 16 Motor

[0049] 18 Suction flow

[0050] 18a Larger part of the suction flow

[0051] 18b Smaller part of the suction flow

[0052] 20 Filter

[0053] 22 Piston

[0054] 24 First duct

[0055] 26 Piston chamber

[0056] 28 Second duct

[0057] 30 Cross-sectional area of the second duct

[0058] 32 Cross-sectional area of the motor inlet

[0059] 34 Motor inlet

[0060] 36 Contact face

[0061] 38 Compression zone

[0062] 40 Motor opening of the piston chamber

[0063] 42 Cross-sectional area of the piston

[0064] 44 Intermediate portion

[0065] h Height of the compression zone

[0066] d Diameter of the motor opening

[0067] L Length of the movement of the piston

[0068] V Movement of the piston

[0069] O Upward spatial direction

[0070] U Downward spatial direction

Examples

Embodiment Construction

[0035]FIG. 1 shows a preferred design embodiment of the suction device 10 during the suction operation. The suction device 10 can be designed as a vacuum cleaner or as an industrial vacuum cleaner and comprises a motor 16, which generates an air or suction flow 18. The suction device 10 can consist of an upper part (suction head) and a lower part, wherein the lower part of the suction device 10 can comprise a collection container 12 for suction material 14, such as dust. In the suction device 10 an opening which can be connected to a suction hose can be provided. The suction hose can be connected to a floor nozzle or a machine tool, so that a floor can be cleaned or dust created when working with the machine tool can be suctioned with the suction device 10. The dust 14 is inducted into the suction device 10 by means of the suction flow 18, wherein a large part of the dust 14 can be deposited in the collection container 12. The suction flow 18 is furthermore fed through a filter 20 w...

Claims

1-15. (canceled)16: A suction device comprising:a collection container for receiving suction material;a filter for cleaning the suction flow;a motor for driving a turbine, the turbine being specified to generate a vacuum and thus a suction flow for inducting the suction material; anda piston designed to be movable for carrying out filter cleaning and releases a first duct in a suction operation position and closes the first duct by moving into a filter cleaning position, air between the piston and the filter being compressed in such a way that a surge of compressed air is forced through the filter and the filter is cleaned in this way.17: The suction device as recited in claim 16 wherein the first duct is disposed between the motor and the filter, wherein the first duct is formed as a suction duct and runs at least in portions through a piston chamber of the suction device.18: The suction device as recited in claim 17 further comprising a second duct formed as a bypass duct, the second duct being specified to bypass the piston or the piston chamber.19: The suction device as recited in claim 17 wherein the suction operation is maintained by the second duct during filter cleaning.20: The suction device as recited in claim 18 wherein a size of a cross-sectional area of the second duct is in a range of 1-25% of a cross-sectional area of a motor inlet.21: The suction device as recited in claim 18 wherein a size of a cross-sectional area of the second duct is in a range 2-15% of a cross-sectional area of a motor inlet.22: The suction device as recited in claim 18 wherein a size of a cross-sectional area of the second duct is in a range of 3-10% of a cross-sectional area of a motor inlet.23: The suction device as recited in claim 20 wherein the motor inlet delimits the first duct on a turbine side.24: The suction device as recited in claim 16 wherein at least one contact face delimiting movement of the piston from the suction operation position to the filter cleaning position is provided in the piston chamber.25: The suction device as recited in claim 24 wherein the piston chamber has a compression zone extending between the at least one contact face and a motor opening of the piston chamber.26: The suction device as recited in claim 25 wherein a height of the compression zone is less than 1 / 1500 mm multiplied by a cross-sectional area of the piston in mm2.27: The suction device as recited in claim 16 wherein a length of movement of the piston is greater than or equal to a sum of the height of the compression zone and a diameter of the motor opening.28: The suction device as recited in claim 16 further comprising an intermediate portion disposed between the motor and the piston chamber, the intermediate portion forming a sub-portion of the first duct.29: A method for operating a suction device as recited in claim 16, the method comprising the following steps:a) providing the suction device and operating the suction device in a suction operation;b) carrying out a filter cleaning procedure by moving a piston from a suction operation position to a filter cleaning position, by this movement closing a first duct so that air between the piston and the filter is compressed in such a way that a surge of compressed air is forced through the filter and the filter is cleaned in this way.30: The method as recited in claim 29 wherein in the suction operation a larger proportion of a suction flow flows through the first duct and a smaller proportion of the suction flow flows through a second duct.31: The method as claimed in claim 30 wherein the suction operation is maintained by the second duct during the filter cleaning procedure.32: The method as recited in claim 30 wherein the piston is returned pneumatically or mechanically to an initial position.

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