Down cycle cleaning device with self-cleaning filter screen

Abstract

This invention relates to the field of down processing technology and provides a down circulation cleaning device with a self-cleaning filter. The device includes a body, a washing assembly, a filter element, and a circulation pump. The filter element is cylindrical with a filter screen on its sides. The circulation cleaning device also includes a drive assembly for rotating the filter element and a backwashing assembly for backwashing the sides of the filter element from the inside out. Centrifugal force combined with backwashing removes impurities adhering to the sides of the filter element. The circulation cleaning device also includes a cleaning assembly for removing the impurities detached from the sides of the filter element. The drive assembly drives the filter element to rotate, while the backwashing assembly backwashes the sides of the filter element from the inside out. The rotation of the filter element subjectes the adhering impurities to centrifugal force, which, combined with the backwashing action, removes the impurities adhering to the sides of the filter element, thus achieving self-cleaning of the filter element.

Description

Technical Field

[0001] This invention relates to the field of down processing technology, specifically a down circulation cleaning device with a self-cleaning filter. Background Technology

[0002] Down raw materials are collected from the surface of waterfowl and contain a large amount of dust, sand, dander, grease and other organic or inorganic impurities. They must undergo a cleaning process to meet the cleanliness requirements specified in the relevant product standards.

[0003] In existing down cleaning processes, to achieve efficient water resource utilization and maintain the cleanliness of the solvent within the cleaning system, a circulating filtration cleaning method is typically employed. Specifically, a washing liquid containing cleaning aids is injected into the cleaning drum. The down is tumbled and kneaded within the drum under mechanical agitation or water flow impact, causing impurities adhering to the fiber surface and inside the down clusters to gradually detach and disperse in the washing liquid. The outlet of the cleaning drum is equipped with a filter screen connected to a circulating pump. The filter screen performs solid-liquid separation of the washing liquid, trapping suspended particulate impurities. The purified liquid is then pumped back into the cleaning drum for subsequent cleaning operations. This circulating filtration process effectively reduces the cumulative concentration of impurities in the washing liquid, preventing secondary contamination of the down fibers due to continuously increasing impurity levels. To ensure a continuous and stable cleaning effect under limited water volume conditions, the fixed filter structure commonly used in existing devices lacks an active cleaning mechanism. As the filtration process progresses, impurities trapped on the filter's inflow surface (i.e., the filter surface) accumulate and gradually form a dense pollution layer, causing filter clogging and affecting filtration efficiency. To address this issue, some existing technologies attempt to set up a reciprocating brushing mechanism on the filter surface. However, this type of mechanical brushing method has inherent defects: when the brushing element reciprocates on the filter surface, it easily presses some impurities into the filter pores, causing a wedging or clogging effect (this phenomenon is more obvious when the size of the impurity particles is similar to the filter pore diameter). This not only fails to effectively restore the filter's filtration flux but also exacerbates the irreversible clogging, making it difficult to achieve the expected cleaning effect.

[0004] Therefore, the present invention proposes a down circulation cleaning device with a self-cleaning filter to solve the above problems. Summary of the Invention

[0005] The purpose of embodiments of the present invention is to provide a down circulation cleaning device with a self-cleaning filter to solve the above-mentioned problems.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A down circulating cleaning device with a self-cleaning filter includes a body, a washing component disposed on the body for washing down, a filter element for filtering the cleaning liquid, and a circulating pump for circulating the cleaning liquid. The filter element is cylindrical with a filter screen on its side. The cleaning liquid flows from the outside of the filter element to the inside for filtration. The circulating cleaning device also includes a drive component for driving the filter element to rotate and a backwashing component for backwashing the side of the filter element from the inside to the outside. The impurities adhering to the side of the filter element are removed by centrifugal force combined with the backwashing action. The circulating cleaning device also includes a cleaning component for cleaning the impurities that have been removed from the side of the filter element.

[0007] In one alternative embodiment: the cleaning assembly includes a partition in the body and a first annular plate, a second annular plate, a cylindrical plate, and a support plate located below the partition. The partition has an openable and closable liquid outlet. The filter element is rotatably mounted on the support plate. The first annular plate, the second annular plate, the cylindrical plate, and the side wall of the body together form a collection chamber for collecting impurities. The cleaning assembly also includes several telescopic components for driving the cylindrical plate to rise and fall. In the closed state of the collection chamber, the cylindrical plate is in sealed compression contact with the first annular plate, the second annular plate, and the support plate. During cleaning, the liquid outlet on the partition is closed, and the cylindrical plate is driven to fall a set distance by the several telescopic components, so that the collection chamber opens towards the filter element. The outward-facing side of the collection chamber also has several drain outlets.

[0008] In one alternative: the cleaning assembly further includes a partition plate disposed between the partition plate and the first annular plate, and a plurality of rods are provided between the partition plate and the bearing plate to achieve fixed setting of the bearing plate.

[0009] In one alternative: the second annular plate is positioned at a height lower than the support plate, and the bottom side of the collection chamber is sloped towards the drain outlet.

[0010] In one alternative embodiment: the bottom of the machine body is further provided with a liquid receiving chamber for holding cleaning fluid, the drive assembly includes a bottom plate located below the support plate and in sealed compression contact with the cylindrical plate on its side, the cylindrical plate and the bottom plate form an accumulation chamber for accumulating the filtered cleaning fluid, a liquid discharge channel is provided between the accumulation chamber and the liquid receiving chamber, the accumulation chamber is provided with a plurality of liquid discharge ports, and a shut-off valve is provided at each liquid discharge port, a shaft coaxial with the filter element is rotatably passed through the liquid discharge channel, the upper end of the shaft is fixedly connected to the filter element, and blades are provided on the shaft section located in the liquid discharge channel.

[0011] In one alternative embodiment: the backwashing assembly includes an inner cylinder disposed within a filter element, a liquid outlet pipe slidably extending through the wall of the inner cylinder, a limiting boss being provided on the section of the liquid outlet pipe located within the inner cylinder, a rod being provided within the inner cylinder, an elastic element being provided between the liquid outlet pipe and the rod, a hollow shaft with its upper end connected to the inner cylinder, a circulation guide pipe and a flushing guide pipe being provided at the output end of the circulation pump, wherein the end of the flushing guide pipe away from the circulation pump is rotatably connected to and communicates with the lower end of the shaft, a first shut-off valve being provided on the circulation guide pipe, a second shut-off valve being provided on the flushing guide pipe, and a one-way valve being provided in the liquid outlet pipe that only allows the cleaning liquid in the liquid outlet pipe to be discharged.

[0012] In one alternative: the end of the outlet pipe away from the rod is provided with a spray head that causes the cleaning fluid to be discharged in a cone shape.

[0013] In one alternative: the circulating cleaning device further includes a level gauge for monitoring the remaining amount of cleaning fluid in the liquid chamber and a replenishment pipe for adding supplementary cleaning fluid to the liquid chamber to maintain a set remaining amount range.

[0014] Compared with the prior art, the beneficial effects of the embodiments of the present invention are as follows: The filter element is driven to rotate by the drive component, while the backwash component backwashes the sides of the filter element from the inside out. The rotation of the filter element causes the adhering impurities to be subjected to centrifugal force, which, together with the backwashing action, causes the impurities adhering to the sides of the filter element to detach, thus achieving self-cleaning of the filter element. The cleaning component removes the impurities that have detached from the sides of the filter element. The technical purpose is not only to remove impurities from the filter element, but also to continuously clean the impurities that have been filtered, solve the problem of impurity accumulation near the filter element, and ensure the filtration efficiency of the cleaning solution.

[0015] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0016] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. Furthermore, these drawings and textual descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concepts of this application to those skilled in the art through reference to specific embodiments.

[0017] Figure 1 This is a schematic diagram of the structure of an embodiment of the present invention.

[0018] Figure 2 for Figure 1 Enlarged view of point A in the middle.

[0019] Figure 3 This is a schematic diagram (partial cross-section) showing the arrangement of the filter element, the first annular plate, the second annular plate, and the support plate in accordance with the present invention.

[0020] Figure 4 This is a schematic diagram (partial cross-section) showing another angle arrangement between the filter element, the first annular plate, the second annular plate, and the support plate in the present invention.

[0021] Figure 5 for Figure 1 Enlarged view of section B in the middle.

[0022] Figure 6 This is a schematic diagram illustrating the arrangement between the liquid outlet pipe and the elastic element in an embodiment of the present invention.

[0023] Figure 7 for Figure 1 Enlarged view of point C.

[0024] Figure reference numerals: 1-body, 2-filter element, 3-drive assembly, 301-accumulation chamber, 302-base plate, 303-liquid discharge channel, 304-shaft, 305-blade, 306-discharge port, 307-on / off valve, 4-cleaning assembly, 401-partition plate, 402-crossbeam, 403-first annular plate, 404-second annular plate, 405-cylindrical plate, 406-drainage port, 407 - Telescopic component, 408-Bearing plate, 5-Liquid chamber, 6-Circulating pump, 7-Level gauge, 8-Replenishment pipe, 9-Backwash assembly, 901-Inner cylinder, 902-Outlet pipe, 903-Spray head, 904-Check valve, 905-Rod, 906-Limiting boss, 907-Elastic component, 908-Circulating guide pipe, 909-First shut-off valve, 910-Flush guide pipe, 911-Second shut-off valve. Detailed Implementation

[0025] The present application will now be described in further detail with reference to the accompanying drawings. It should be noted that the following specific embodiments are only used to further illustrate the present application and should not be construed as limiting the scope of protection of the present application. Those skilled in the art can make some non-essential improvements and adjustments to the present application based on the above application content.

[0026] Please see Figure 1 and Figure 2A down circulating cleaning device with a self-cleaning filter screen includes a body 1, a washing component disposed on the body 1 for washing down, a filter element 2 for filtering the cleaning liquid, and a circulating pump 6 for circulating the cleaning liquid. The filter element 2 is cylindrical, with a filter screen on its side. The cleaning liquid flows from the outside of the filter element 2 to the inside for filtration (i.e., the side of the filter element 2 facing outward is the filter surface, and its upper end is closed). The circulating cleaning device also includes a driving component 3 for driving the filter element 2 to rotate and a backwashing component 9 for backwashing the side of the filter element 2 from the inside out. Through centrifugal force combined with the backwashing action, impurities adhering to the side of the filter element 2 are removed. The circulating cleaning device also includes a cleaning component 4 for cleaning the impurities that have been removed from the side of the filter element 2.

[0027] It should be noted that the washing assembly includes an inner washing tub (with perforated side walls for easy circulation of the washing liquid) for containing down and washing liquid, an agitator (mechanical agitation or water / air flow disturbance) for agitating the down, a piping system for the input / output of the washing liquid (such as drain outlet, inlet, etc.), and corresponding auxiliary components (such as pressure plates (used to push down the down floating on the liquid surface during the washing process to fully submerge it), and down agitation structures (periodically agitating the down or water flow to change its motion state and break any static accumulation that may form)). These are existing technologies, and the specific component composition of the washing assembly and the connections and linkages between the components will not be described in detail here.

[0028] The cleaning solution is filtered through filter element 2. The cleaning action of filter element 2 is initiated periodically (i.e., the cleaning action is initiated once at a certain time interval according to the set schedule). Specifically, the filter element 2 is driven to rotate by drive component 3. At the same time, the backwash component 9 backwashes the sides of filter element 2 from the inside to the outside. The rotation of filter element 2 causes the adhering impurities to be subjected to centrifugal force. Combined with the backwashing action (liquid flow impacts from the inside to the outside of filter element 2), the impurities adhering to the sides of filter element 2 are detached, realizing the self-cleaning of filter element 2. The cleaning component 4 cleans the impurities that have detached from the sides of filter element 2. The technical purpose is not only to remove impurities from filter element 2 (this method leaves impurities still near filter element 2, which can easily cause blockage), but to continuously clean the filtered impurities, solve the problem of impurity accumulation near filter element 2, and ensure the filtration efficiency of cleaning solution.

[0029] Please see Figures 1-4In one embodiment of the present invention, the cleaning component 4 includes a partition 401 disposed in the body 1 and a first annular plate 403, a second annular plate 404, a cylindrical plate 405 and a support plate 408 disposed below the partition 401. The partition 401 is provided with an openable and closable liquid outlet (such as a gate at the liquid outlet to achieve intermittent opening and closing). The filter element 2 is rotatably disposed on the support plate 408. The first annular plate 403, the second annular plate 404, the cylindrical plate 405 and the side wall of the body 1 together constitute a collection chamber for collecting impurities. The cleaning component 4 also includes a plurality of telescopic members 407 for driving the cylindrical plate 405 to rise and fall (the telescopic members 407 are electric telescopic rods, telescopic cylinders, etc. in the prior art). In the closed state of the collection chamber, the cylindrical plate 405 and the first annular plate 403, the second annular plate 404 and the support plate 408 are in a sealed compression contact (the sealing effect is achieved by setting a sealing strip on the contact edge, such as setting a sealing strip on the upper edge of the cylindrical plate 405 to seal when it is in compression contact with the first annular plate 403, or setting a sealing strip on the edge of the support plate 408 to seal when it is in compression contact with the cylindrical plate 405). During cleaning, the liquid outlet on the partition plate 401 is closed, and the cylindrical plate 405 is driven to descend a set distance by several telescopic members 407 so that the collection chamber is open towards the filter element 2. Several drain ports 406 are also provided on the outward side of the collection chamber. Under the action of centrifugal force and backwashing, impurities will move away from the filter element 2 and enter the collection chamber, and then be discharged to the designated position through the drain ports 406.

[0030] Furthermore, in this embodiment, the cleaning component 4 also includes a partition 402 disposed between the partition 401 and the first annular plate 403, and a plurality of rods are provided between the partition 402 and the support plate 408 to achieve the fixed setting of the support plate 408.

[0031] Furthermore, in this embodiment, the second annular plate 404 is set at a height lower than the support plate 408, and the bottom side of the inside of the collection chamber is inclined to the drain port 406 to avoid backflow of impurities entering the collection chamber.

[0032] Please see Figure 1 and Figure 5In one embodiment of the present invention, the bottom of the body 1 is further provided with a liquid receiving chamber 5 for holding cleaning liquid. The drive assembly 3 includes a bottom plate 302 located below the support plate 408 and in sealed compression contact with the cylindrical plate 405 on its side. The cylindrical plate 405 and the bottom plate 302 form an accumulation chamber 301 for accumulating the filtered cleaning liquid. A liquid discharge channel 303 is provided between the accumulation chamber 301 and the liquid receiving chamber 5. The accumulation chamber 301 is provided with a plurality of liquid discharge ports 306, and a shut-off valve 307 (electric valve) is provided at the liquid discharge ports 306. A shaft 304 coaxial with the filter element 2 is rotatably passed through the liquid discharge channel 303. The upper end of the shaft 304 is fixedly connected to the filter element 2, and a blade 305 is provided on the shaft section located in the liquid discharge channel 303.

[0033] In this embodiment, the liquid-containing chamber 5 can be used to contain all the cleaning liquid. After a batch of down is cleaned, the cleaning liquid flows into the solution chamber 5. After the cleaned down of that batch is taken out, the next batch of down is put in. The cleaning liquid in the liquid-containing chamber 5 can still be used if the requirements (i.e., the concentration of effective ingredients) are met. The on-off valve 307 is opened and closed intermittently (i.e., it is opened for a set time after a set time interval). During the closing period, the cleaning liquid falling into the accumulation chamber 301 continues to accumulate. After opening, the accumulated cleaning liquid flows in large volume through the liquid-falling channel 303. The blade 305 drives the shaft 304 to rotate at high speed under the impact of the high flow rate and high falling speed of the cleaning liquid, that is, drives the filter element 2 to rotate at high speed, so that the impurities are thrown away from the filter element 2 under the action of centrifugal force.

[0034] Please see Figure 1 , Figure 2 , Figure 6 and Figure 7 In one embodiment of the present invention, the backwashing assembly 9 includes an inner cylinder 901 disposed in the filter element 2. A liquid outlet pipe 902 is slidably arranged through the cylinder wall of the inner cylinder 901. The section of the liquid outlet pipe 902 located in the inner cylinder 901 is provided with a limiting boss 906. A rod 905 is also provided in the inner cylinder 901. An elastic element 907 (preferably, the elastic element 907 is a spring rope) is provided between the liquid outlet pipe 902 and the rod 905. The shaft 304 is hollow inside and its upper end is connected to the inner cylinder 901. The output end of the circulation pump 6 is provided with a circulation guide pipe 908 and a flushing guide pipe 910. The end of the flushing guide pipe 910 away from the circulation pump 6 is rotatably connected to and communicates with the lower end of the shaft 304. A first shut-off valve 909 is provided on the circulation guide pipe 908 and a second shut-off valve 911 is provided on the flushing guide pipe 910. A one-way valve 904 is also provided in the liquid outlet pipe 902, which only allows the cleaning liquid in the liquid outlet pipe 902 to be discharged.

[0035] It should be noted that before cleaning the filter element 2, the drain outlet on the partition 401 is first closed to prevent the cleaning liquid from flowing down. After closing, the cleaning action is started after a set delay. During this period, the existing cleaning liquid is filtered and enters the accumulation chamber 301. After the set delay, the on / off valve 307 at the drain outlet 306 is opened. At the same time, the cylindrical plate 405 is lowered by a set distance through several telescopic components 407, so that the collection chamber opens towards the filter element 2 and the backwashing component 9 performs a backwashing action. After the cleaning action is completed, the cylindrical plate 405 is moved upward and reset by several telescopic components 407. Finally, the drain outlet on the partition 401 is reopened, and this cycle is repeated.

[0036] In this embodiment, during backwashing, the first shut-off valve 909 is closed and the cleaning fluid circulation is stopped (the drain port on the partition 401 is closed and the cleaning fluid is no longer discharged, maintaining the balance of the cleaning fluid volume for washing and avoiding excessive cleaning fluid), while the second shut-off valve 911 is open (it is closed during non-cleaning periods). Clean (filtered) cleaning fluid is pumped into the inner cylinder 901 by the circulation pump 6. Under the action of centrifugal force, the outlet pipe 902 is also thrown out, so that the end away from the rod 905 (i.e., the outlet end) approaches the side of the filter element 2 (approaching the spray, reducing the sprayed cleaning fluid flushing stroke, thereby reducing pressure attenuation and ensuring the backwashing effect). The cleaning fluid entering the inner cylinder 901 is diverted into the outlet pipe 902 and accelerated under the action of centrifugal force to ensure the backwashing pressure requirement. After cleaning is completed, the outlet pipe 902 is reset under the action of the elastic element 907, making room for the space between the inner cylinder 901 and the side of the filter element 2, avoiding obstruction of the cleaning fluid filtration efficiency.

[0037] Furthermore, in this embodiment, the end of the liquid outlet pipe 902 away from the rod 905 is provided with a spray head 903 that discharges the cleaning liquid in a cone shape, thereby increasing the backwashing range and fully covering the entire side of the filter element 2, avoiding backwashing dead corners.

[0038] Furthermore, in this embodiment, the circulating cleaning device also includes a level gauge 7 for monitoring the remaining amount of cleaning fluid in the liquid chamber 5 and a replenishment pipe 8 (supplying cleaning fluid from the outside) for adding supplementary cleaning fluid to the liquid chamber 5 to maintain the set remaining amount range. Since backwashing consumes a certain amount of cleaning fluid, in order to avoid insufficient cleaning fluid, the level gauge 7 monitors the remaining amount of cleaning fluid in the liquid chamber 5. When the remaining amount is lower than the set threshold, the replenishment pipe 8 replenishes the cleaning fluid to the liquid chamber 5 to ensure the normal operation of the down cleaning work.

[0039] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A down circulating cleaning device with a self-cleaning filter, comprising a body (1), a washing assembly disposed on the body (1) for washing down, a filter element (2) for filtering the cleaning liquid, and a circulating pump (6) for circulating the cleaning liquid, characterized in that, The filter element (2) is cylindrical with a filter screen on its side. The cleaning liquid flows from the outside of the filter element (2) to the inside for filtration. The circulating cleaning device also includes a drive assembly (3) for driving the filter element (2) to rotate and a backwashing assembly (9) for backwashing the side of the filter element (2) from the inside to the outside. The impurities adhering to the side of the filter element (2) are removed by the centrifugal force combined with the backwashing action. The circulating cleaning device also includes a cleaning assembly (4) for cleaning the impurities that have been removed from the side of the filter element (2).

2. The down circulation cleaning device with a self-cleaning filter according to claim 1, characterized in that, The cleaning assembly (4) includes a partition (401) disposed in the body (1) and a first annular plate (403), a second annular plate (404), a cylindrical plate (405), and a support plate (408) disposed below the partition (401). The partition (401) is provided with an openable liquid outlet. The filter element (2) is rotatably disposed on the support plate (408). The first annular plate (403), the second annular plate (404), the cylindrical plate (405), and the side wall of the body (1) together constitute a collection chamber for collecting impurities. The component (4) also includes several telescopic components (407) for driving the cylindrical plate (405) to rise and fall. When the collection chamber is closed, the cylindrical plate (405) is in sealed compression contact with the first annular plate (403), the second annular plate (404) and the support plate (408). During cleaning, the liquid outlet on the partition plate (401) is closed, and the cylindrical plate (405) is driven to fall a set distance by several telescopic components (407) so that the collection chamber is open to the side facing the filter (2). The side of the collection chamber facing outward is also provided with several sewage outlets (406).

3. The down circulation cleaning device with a self-cleaning filter according to claim 2, characterized in that, The cleaning component (4) also includes a partition (402) disposed between the partition (401) and the first annular plate (403), and a number of rods are provided between the partition (402) and the bearing plate (408) to achieve the fixed setting of the bearing plate (408).

4. The down circulation cleaning device with a self-cleaning filter according to claim 2, characterized in that, The second annular plate (404) is set at a height lower than the support plate (408), and the bottom side of the inside of the collection chamber is inclined to the drain port (406).

5. The down circulation cleaning device with a self-cleaning filter according to claim 2, characterized in that, The bottom of the body (1) is also provided with a liquid-containing chamber (5) for holding cleaning liquid. The drive assembly (3) includes a bottom plate (302) located below the support plate (408) and in sealed compression contact with the cylindrical plate (405) on the side. The cylindrical plate (405) and the bottom plate (302) form an accumulation chamber (301) for accumulating the filtered cleaning liquid. A liquid-falling channel (303) is provided between the accumulation chamber (301) and the liquid-containing chamber (5). The accumulation chamber (301) is provided with a plurality of liquid outlets (306), and a shut-off valve (307) is provided at the liquid outlets (306). A shaft (304) coaxial with the filter element (2) is also rotatably passed through the liquid-falling channel (303). The upper end of the shaft (304) is fixedly connected to the filter element (2), and blades (305) are provided on the shaft section located in the liquid-falling channel (303).

6. The down circulation cleaning device with a self-cleaning filter according to claim 5, characterized in that, The backwashing assembly (9) includes an inner cylinder (901) disposed in the filter element (2). A liquid outlet pipe (902) is slidably arranged through the cylinder wall of the inner cylinder (901). The section of the liquid outlet pipe (902) located in the inner cylinder (901) is provided with a limiting boss (906). A rod (905) is also provided in the inner cylinder (901). An elastic element (907) is provided between the liquid outlet pipe (902) and the rod (905). The shaft (304) is hollow inside and its upper end is connected to the inner cylinder (901). The output end of the circulating pump (6) is provided with a circulating liquid guide pipe (908) and a flushing liquid guide pipe (910). The end of the flushing liquid guide pipe (910) away from the circulating pump (6) is rotatably connected to the lower end of the shaft (304) and communicates with it. The circulating liquid guide pipe (908) is provided with a first shut-off valve (909), and the flushing liquid guide pipe (910) is provided with a second shut-off valve (911). The outlet pipe (902) is also provided with a one-way valve (904) that only allows the cleaning liquid in the outlet pipe (902) to be discharged.

7. The down circulation cleaning device with a self-cleaning filter according to claim 6, characterized in that, The end of the outlet pipe (902) away from the rod (905) is provided with a spray head (903) that causes the cleaning liquid to be discharged in a cone shape.

8. The down circulation cleaning device with a self-cleaning filter according to claim 6, characterized in that, The circulating cleaning device also includes a level gauge (7) for monitoring the remaining amount of cleaning fluid in the liquid chamber (5) and a replenishment pipe (8) for adding replenishing cleaning fluid to the liquid chamber (5) to maintain the set remaining amount range.

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