JP2004113979A - Apparatus for washing filter by using supercritical or subcritical fluid - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for washing filter by using a supercritical or subcritical fluid, by which a filter is washed efficiently without being damaged so that the released stain is not stuck to the filter again. <P>SOLUTION: This apparatus is characterized by being provided with a washing tank 50 for washing an air filter 25 by making the supercritical or subcritical fluid pass through there and a main body 41 of the tank 50 and a cap 47 between which the filter 25 is held in the tank 50 so that the supercritical or subcritical fluid is made to pass through the filter medium of the filter 25 and which are arranged for forming flow passages of prescribed lengths on the upstream and downstream sides of the filter 25. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a device for cleaning a fluid purification filter using a supercritical or subcritical fluid, and particularly to a cleaning device suitable for cleaning an air filter.
[0002]
[Prior art]
The performance of an air filter of an air purifying device installed in an air conditioner of a building deteriorates due to a dust load, and therefore, it needs to be periodically replaced. Until now, most of them have been treated as industrial waste and replaced with new ones. However, opportunities for washing and regenerating and reusing mainly so-called medium-performance filters are increasing.
[0003]
FIG. 7 is a partially cutaway perspective view showing an example of a separator type air filter. The separator type air filter has a structure in which a filter medium 1 made of a non-woven fabric such as glass fiber or polypropylene is folded and adhered and fixed to a frame 2 made of aluminum or wood with a urethane resin adhesive or an epoxy resin adhesive. Therefore, the filter medium 1 is sandwiched and held by a separator 3 made of aluminum or the like. That is, by allowing a fluid such as air to flow through the filter medium 1, impurities such as particles in the fluid can be collected and removed. The separator type air filter is used when the processing air volume is large.
[0004]
FIG. 8 is a partially cutaway perspective view showing an example of a mini-pleated air filter. The configuration of the mini-pleated air filter is such that a filter medium 4 made of non-woven fabric such as glass fiber or polypropylene is folded and fixed to a frame 5 made of aluminum or wood with a urethane resin adhesive or an epoxy resin adhesive. Because of its low strength, it is reinforced with beads 6 of ethylene resin or the like. That is, by allowing a fluid such as air to flow through the filter medium 4, impurities such as particles in the fluid can be collected and removed. The mini-pleat type air filter does not have a large processing air volume as the separator type air filter, but is thin and is used in a vertical laminar flow type clean room or the like.
[0005]
As a technique for cleaning and regenerating an air filter, a technique using a liquid solvent containing a detergent such as a surfactant (for example, see Patent Literature 1) and a technique of cavitation due to ultrasonic waves on a filter surface held in a cleaning liquid have been known. What generates it (for example, see Patent Document 2) is known. An air filter suitable for this cleaning method has a filter fiber formed of a water-resistant nonwoven fabric such as polypropylene, and has a fiber density on the order of a medium-performance filter. In this method, regeneration is performed through a number of steps such as a rinsing step, a dehydration step, and a drying step after the washing step.
[0006]
On the other hand, as a method excellent in cleaning fine structures using a cleaning solvent other than a liquid, there is a cleaning method using a fluid in a supercritical state or a subcritical state.
[0007]
As a cleaning method of this kind, for example, a cleaning object is cleaned by circulating and flowing a supercritical fluid (e.g., vaporization, liquefied state by pumping by a vapor pressure difference, and using gravity drop transfer with a level difference set based on the vapor pressure difference). (For example, refer to Patent Documents 3 to 5), and a method for preventing a contaminant from re-adhering by providing a gas filter at a gaseous place in a supercritical fluid circulation path (for example, see Patent Document 6). , The supercritical fluid in the washer quickly flows out of the washer, etc., causing strong disturbance and a large amount of air bubbles on the surface of the contaminant. A method of dissolving and cleaning an object to be cleaned (for example, see Patent Document 7), a method of projecting a supercritical fluid from a nozzle by a jet jet to remove dirt from the object to be cleaned (for example, Patent Documents 3 and 4). See.) It is draft.
[0008]
FIG. 9 is a temperature-pressure characteristic diagram showing a state diagram using carbon dioxide as an example. A fluid having a temperature and pressure exceeding the critical point is a supercritical fluid, and a state near the critical point is a subcritical fluid.
[0009]
The supercritical state is a state where the liquid does not become a liquid even if pressure is applied. Supercritical fluids have viscosity, diffusion coefficient, density, and dissolving power that are intermediate values between gas and liquid.The density is close to that of liquid, and its viscosity behaves like gas. It has the characteristic that it is excellent. Furthermore, it is excellent in mass transfer due to its high diffusivity. The supercritical fluid has a feature that a large change in density can be obtained with a slight change in pressure. In general, since the solubility of a substance is proportional to the density, a supercritical fluid can obtain a large difference in solubility only by a change in pressure, and has an excellent advantage as a cleaning medium.
[0010]
In addition, cleaning using a supercritical fluid is superior to conventional wet cleaning in cleaning effects of fine objects, requires no drying after cleaning, can be processed in a short time, and has no waste liquid due to vaporization. . The advantages are very large, for example, the dissolving power can be freely controlled by adding additives, and the running cost is low.
[0011]
In addition, such a supercritical fluid has been industrially used for a long time in the separation and extraction operation. A target substance is dissolved from a raw material in a supercritical fluid and then taken out, and the target component is extracted by evaporating the supercritical fluid under reduced pressure. This process is very similar to washing raw materials, but the extraction operation on the extracted components is fundamentally different from the cleaning operation where the original material after separation is important . In addition, unlike the extraction operation, supercritical cleaning requires care to prevent damage to the object to be cleaned, and complete cleaning must be performed unless the dirt once removed does not adhere to the object to be cleaned again. It must be noted that cleaning cannot be performed.
[0012]
[Patent Document 1]
JP 2001-17809 A
[Patent Document 2]
JP-A-11-188322
[Patent Document 3]
JP-A-10-94766
[Patent Document 4]
JP-A-10-163152
[Patent Document 5]
JP 2000-153244 A
[Patent Document 6]
JP-A-7-284739
[Patent Document 7]
JP-A-8-290128
[Problems to be solved by the invention]
Conventional filter cleaning and regeneration technology uses detergents and ultrasonic waves with a liquid solvent.Since the filter is immersed in the liquid solvent in the cleaning tank for cleaning, the soil removed once adheres to the fiber of the filter. there is a possibility. Further, when the filter has a fiber structure of several micron to submicron order, such as a high-performance filter, the cleaning solvent does not easily penetrate into the deep layer of the filter, so that the filter cannot be cleaned well.
[0020]
Particularly, in the case of a high-performance filter made of glass fiber, the glass fiber is hydrophobic, so that the cleaning solvent cannot penetrate into the fiber and cannot be effectively cleaned.
[0021]
Further, in the method of cleaning an air filter using a detergent or ultrasonic waves with a liquid solvent, a step of drying the filter immersed in the liquid solvent after the cleaning is required, so that a large amount of energy such as heat or air for drying is required. Required.
[0022]
When the object to be washed is washed by a method of immersing it in a supercritical fluid, there is a problem that the separated contaminants are left floating in the fluid and reattach to the filter fibers. In order to solve this, a rinsing step of immersing in a clean fluid again is necessary, which is uneconomical. Similarly, the method using ultrasonic waves also requires a rinsing step with a clean fluid since reattachment of suspended contaminants cannot be avoided.
[0023]
Filtration of the filter includes filtration of the fiber surface and filtration of the deep part of the fiber, and the fiber surface has the largest amount of dirt collected. Fine dirt that cannot be collected by surface filtration is collected from the upstream side by a mechanism such as inertia, interception, or diffusion in the process of flowing inside the fiber. Therefore, the amount of dirt collected by the filter is the largest on the upstream side. In the case of a high-performance air filter having a collection efficiency exceeding 99.99%, dirt such as particles adheres before reaching the fiber surface on the downstream side.
[0024]
In the method of circulating and circulating a supercritical fluid (see, for example, Patent Documents 3 to 5), the solvent is conveyed by vaporization or liquefaction by a vapor pressure difference, or by gravity drop conveyance with a level difference set based on the vapor pressure difference. With all the advantages that can be achieved. In this method, at first glance, it can be seen that the problem of re-adhesion can be solved by circulation, but in actuality, fluid flows only to the surface layer of the filter fiber, and dirt attached to the surface reduces redeposition while reducing Although it can be washed, it cannot be washed in the deep part because the fluid flow is weak. Further, the surface dirt may re-attach by diffusion to the deep part of the fiber or the lower part of the dirt.
[0025]
When a high-pressure supercritical fluid is applied from a nozzle or the like to a glass fiber filter having an order of several microns to a submicron, the filter may hit the cleaning tank due to the pressure of the fluid and damage the fiber.
[0026]
The supercritical fluid in the washer is rapidly discharged out of the washer, causing strong disturbance and a large amount of air bubbles on the surface of the contaminant. The method of cleaning the object to be cleaned (see, for example, Patent Document 7) is effective for cleaning the object to be cleaned having sufficient strength, but the bubbling of a glass fiber filter that is weak against impacts is effective. There is a risk of collision with the cleaning tank wall due to vibration or the like and breakage. Also in this method, reattachment of dirt is inevitable.
[0027]
In a method in which a supercritical fluid is jetted from a nozzle by a jet jet to remove dirt from an object to be cleaned (see, for example, Patent Documents 3 and 4), a fiber is damaged by contact between a filter and a cleaning tank, and a deep layer of the filter fiber is formed. The cleaning effect of the part is weak.
[0028]
An operation such as forced agitation by a propeller or the like in the cleaning tank is effective for removing dirt on the filter surface, but the effect of cleaning the inside of the glass fiber is low. In addition, surface dirt may adhere to the deep layer and the back surface.
[0029]
As described above, the breakage of the glass fiber at the time of cleaning is caused by the collision between the filter and the inner wall of the cleaning tank caused by the flow. When a plurality of filters are introduced, collision between the filters may cause damage.
[0030]
The present invention has been made in view of the above circumstances, and is necessary for liquid cleaning and the like as an apparatus for cleaning an air filter or the like, which is a low-strength microstructure composed of glass fibers of several micron to submicron order. Eliminates unnecessary process steps such as dry drying, and uses supercritical or subcritical fluids to clean filter media such as fine glass fibers without damaging them. It is an object of the present invention to provide a filter cleaning device using a supercritical or subcritical fluid.
[0031]
[Means for Solving the Problems]
In order to achieve the above object, a filter cleaning apparatus of the present invention includes a filter placed in a cleaning tank, a supercritical or subcritical fluid introduced and circulated in the cleaning tank, and a diffusion coefficient of a supercritical or subcritical fluid. Clean the filter by quickly forcibly peeling and dissolving the contaminants by utilizing the permeability to the microstructure due to the large particle size, and the easy occurrence of interfacial flow and convection due to the extremely small kinematic viscosity. In the filter cleaning device, fix the filter in the cleaning tank, or insert the filter into the holding member and fix the holding member in the cleaning tank so that the filter does not collide with the inner wall of the cleaning tank due to the flow of the fluid and is not damaged. It is characterized by.
[0032]
In the case where supercritical or subcritical fluid is allowed to flow, the filter frame is fixed and the fluid is allowed to flow only through the filter medium, for example, fibers, or the filters are individually introduced into the holding member, and the desorbed contamination It is characterized in that a plurality of filters are arranged in a washing tank and washed so that the objects do not adhere again. And it is characterized in that a unidirectional flow is formed so that a supercritical / subcritical fluid can flow in a direction opposite to the direction in which the filter is used.
[0033]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0034]
FIG. 1 is a configuration explanatory view showing a basic configuration example of a filter purification device according to an embodiment of the present invention. In the figure, 11 is a cylinder for supplying carbon dioxide (carbon dioxide supply means), 12 is a pump (carbon dioxide pressurized liquid sending means), 13 is a temperature controller, 14 is a washing having a washing solvent introducing means and a discharging means. The tank, 15 is a pressure control valve (pressure adjusting means), T is a thermometer, P is a pressure gauge, and FM is a flow meter.
[0035]
That is, a glass fiber air filter to be cleaned is housed in the holding member and introduced into the cleaning tank 14. The carbon dioxide supplied from the cylinder 11 is converted into a 40 to 60 degree gaseous supercritical carbon dioxide gas through a pump 12, a temperature controller 13, and a pressure control valve 15, and is supplied to the cleaning tank 14 at 15 to 20 MPa. Circulates for about one hour to clean the glass fiber air filter and the like to be cleaned.
[0036]
The temperature and pressure in the cleaning tank 14 are appropriately determined depending on the strength of the material of the object to be cleaned and the dirt components, and may be other temperatures and pressures depending on the object to be cleaned. The carbon dioxide at the time of washing may be in a subcritical state below the critical point.
[0037]
FIG. 2A is a longitudinal sectional view showing a holding member for accommodating the air filter according to the embodiment of the present invention, and FIG. 2B is a sectional view taken along line AA of FIG. 2A. A rectangular parallelepiped holding member body 21 made of stainless steel is provided with a filter mounting space portion 22 having an open surface, and a discharge portion (outlet) 23 communicates with the outside at a lower portion on the bottom side of the filter mounting space portion 22. An introduction portion (entrance) 24 is provided at an upper portion on the open surface side of the filter mounting space portion 22 so as to communicate with the outside. An air filter 25 is inserted into the filter mounting space 22 with the upstream side (suction side) on the bottom side and the downstream side (blowing side) on the open side. A plate-like lid 26 made of stainless steel is detachably attached to the open surface side of the filter attachment space 22 by fixing bolts 27 so as to sandwich the frame of the air filter 25. The lid 26 is provided with a communication hole 29 for communicating the introduction portion (entrance) 24 and the filter mounting space 22. In this case, between the lid 26 and the air filter 25 and between the bottom surface of the filter mounting space 22 and the air filter 25 so that the supercritical or subcritical fluid flows through the flow path in the holding member 28 without stagnation. Spaces are respectively formed between the air filters 25 so as to form flow paths of a predetermined length upstream and downstream of the air filter 25 sandwiched therebetween. A holding member 28 is composed of the holding member main body 21 and the lid 26.
[0038]
After the air filter 25 is inserted with the upstream side (suction side) in actual use facing the bottom surface of the holding member main body 21, the air filter 25 is closed with the lid 26 and stored. The holding member main body 21 has a supercritical or subcritical fluid introduction part 24 and a discharge part 23. The supercritical or subcritical fluid flowing from the supercritical or subcritical fluid (carbon dioxide) introduction part 24 is supplied to the air filter. The structure is such that a supercritical or subcritical fluid containing dirt is discharged from the discharge part 23 by flowing between the fibers (filter media) in the opposite direction to the time of use.
[0039]
FIG. 3A is a longitudinal sectional view showing a cleaning tank to which a holding member with an air filter according to an embodiment of the present invention is fixed, and FIG. 3B is a sectional view taken along line BB of FIG. 3A. . That is, a support rod 32 is provided in a bottomed cylindrical cleaning tank main body 31, and a supporting step 33 is provided on an inner peripheral surface of the cleaning tank main body 31. Alternatively, a subcritical fluid (carbon dioxide) discharge unit 34 is provided. A cleaning tank lid 35 is detachably attached to an opening of the cleaning tank main body 31 by a fixing member, for example, a lid fixing bolt 36, and a supercritical or subcritical fluid (carbon dioxide) introduction part 37 is provided in the cleaning tank lid 35. Provided.
[0040]
Two holding members 28 holding the air filters 25 as shown in FIG. 2 are arranged in the washing tank main body 31 so as to be sandwiched in parallel in the horizontal direction, and are provided on the support rod 32 and the support step 33. Will be installed. In this case, the holding member 28 is inserted so that the discharge portion 23 of the holding member 28 faces the discharge portion 34 of the cleaning tank main body 31, and the cleaning tank lid 35 having the supercritical or subcritical fluid introduction portion 37 is closed and sealed. . Upstream between the holding member 28 and the washing tank lid 35 and between the bottom of the washing tank body 31 and the holding member 28 so that the supercritical or subcritical fluid flows through the flow path in the washing tank body 31 without stagnation. A space is formed so as to form a flow path of a predetermined length on the side and the downstream side. In this example, three holding members 28 can be inserted in parallel to perform cleaning at the same time. The supercritical or subcritical fluid flows in the order of the introduction part 37, the introduction part 24 of the holding member 28, the filter medium of the air filter 25, the discharge part 23 of the holding member 28, and the discharge part 34. By forming the unidirectional flow of the supercritical or subcritical fluid in this way, the dirt of the air filter 25 dispersed in the supercritical or subcritical fluid adheres to another air filter 25 when the air filter 25 is washed. It is not structured.
[0041]
In the above-described embodiment, the case where three air filters are simultaneously cleaned using three holding members has been described. However, the present invention is not limited to this, and a plurality of air filters are simultaneously used using a plurality of holding members. You may make it wash | clean.
[0042]
FIG. 4A is a longitudinal sectional view showing a cleaning tank to which an air filter according to an embodiment of the present invention is directly fixed, and FIG. 4B is a sectional view taken along line CC of FIG. 4A. That is, a support step 42 is provided on the inner peripheral surface of the bottomed cylindrical cleaning tank main body 41, and a supercritical or subcritical fluid (carbon dioxide) discharge section 43 is provided at the bottom of the cleaning tank main body 41. Can be A fixing step 44 is provided on the inner peripheral surface near the upper portion of the cleaning tank main body 41. An air filter 25 is disposed on the supporting step 42, and a fixing member 45 is detachably attached to the fixing step 44 by a fixing screw 46, and the air filter 25 is pressed by the fixing member 45 to be pinched. To be installed. The air filter 25 is installed with the upstream side (suction side) on the bottom side and the downstream side (blowing side) on the open side. A plate-shaped lid 47 is detachably attached to the open surface side of the cleaning tank main body 41 with a lid fixing bolt 48, and a supercritical or subcritical fluid (carbon dioxide) introduction portion (inlet) is attached to the lid 47. 49 are provided. An upstream side is provided between the air filter 25 and the cleaning tank lid 47 and between the bottom of the cleaning tank main body 41 and the air filter 25 so that the supercritical or subcritical fluid flows through the flow path in the cleaning tank 50 without stagnation. A space is formed on the downstream side so as to form a flow path of a predetermined length.
[0043]
The supercritical or subcritical fluid introduced from the introduction part 49 into the inside of the cleaning tank 50 in the closed space formed by the cleaning tank body 41 and the lid 47 forms a piston flow and is discharged from the discharge part 43. A fixing member 45 for fixing the air filter 25 is provided inside the cleaning tank, and the frame of the air filter 25 is pressed and fixed by a fixing screw 46. Normally, the outer peripheral portion of the air filter 25 is formed of a frame made of aluminum, wood, or the like, and a packing such as butyl rubber is attached to an upstream portion and / or a downstream portion in order to hermetically attach the air filter 25 to an air conditioning duct or an air purifier. Have been. Using the frame and the packing of the air filter 25, the air filter 25 is pressed and fixed to a shelf (supporting step 42) inside the cleaning tank. The supercritical or subcritical fluid flows only to the filter medium inside the air filter 25. The fouling that is dispersed in the supercritical or subcritical fluid immediately moves downstream. The cleaning effect of the air filter 25 is higher when supercritical or subcritical carbon dioxide is flowed in the opposite direction to the use (at the time of collecting particles). As a method for fixing the air filter 25, the fixing member 45 may be used as shown in FIG. 4, or the lid and the fixing member may be integrally formed and performed together with the closing operation of the lid.
[0044]
FIG. 5 is an explanatory diagram showing a result of performing filter cleaning in one-way flow according to the embodiment of the present invention. Using a polydispersed dioctyl phthalate particle having a central particle diameter of 0.3 μm, the soiled air filter is washed with supercritical carbon dioxide at a temperature of 40 ° C. and a pressure of 20 MPa for 120 minutes until the pressure loss rises to twice that of a new product. went. From the results of the weight change, it can be seen that most of the dirt has been removed by washing with supercritical carbon dioxide. The measurement results of the pressure loss and the collection efficiency show that the collection performance of the air filter has been almost completely recovered by the washing.
[0045]
FIG. 6 is a characteristic diagram in which the transmittance (= 1−collection efficiency) for each particle diameter of the filter is measured using the zinc chloride particles according to the embodiment of the present invention. The transmittance curve for the particle diameter is an index for indirectly evaluating the fiber structure of the filter from the particle diameter at which the maximum transmission occurs and the transmittance at that time.From the transmittance curves before and after washing, the effect on the filter fiber due to washing can be determined. You can see. From the results shown in FIG. 6, it can be seen that the transmittance is hardly affected by any particle size before and after washing. This shows that the filter cleaning device according to the embodiment of the present invention can perform cleaning and regeneration without damaging the filter.
[0046]
In the embodiment of the present invention, an example in which carbon dioxide is used as the cleaning fluid has been described. However, the present invention is not limited to this, and other fluids suitable for cleaning in a supercritical or subcritical state are used. Can do it. In addition, the size of the filter and the size of the cleaning tank or the holding member need not necessarily be the same, and when the size of the filter is smaller than the size of the cleaning tank or the holding member, the filter may be held using a gap material or the like. Is also good.
[0047]
【The invention's effect】
As described above, according to the present invention, a supercritical or subcritical fluid is used as a cleaning solvent, and a filter layer having a fine structure can be cleaned to a deep fiber layer, and a drying step required for liquid cleaning, etc. And the cleaning process can be shortened. By fixing the filter inside the cleaning tank, it is possible to prevent the weak filter from colliding with the cleaning tank during cleaning and being damaged. In addition, by controlling the flow of the fluid in the cleaning tank to a one-way flow, reattachment of the detached dirt is reduced. It is possible to wash a plurality of filters at the same time.
[Brief description of the drawings]
FIG. 1 is a configuration explanatory view showing a basic configuration example of a filter purification device according to an embodiment of the present invention.
2A is a longitudinal sectional view showing a holding member for accommodating an air filter according to an embodiment of the present invention, and FIG. 2B is a sectional view taken along line AA of FIG.
3A is a longitudinal sectional view showing a cleaning tank to which a holding member with an air filter according to an embodiment of the present invention is fixed, and FIG. 3B is a sectional view taken along the line BB of FIG.
4A is a longitudinal sectional view showing a cleaning tank to which an air filter according to an embodiment of the present invention is directly fixed, and FIG. 4B is a sectional view taken along line CC of FIG.
FIG. 5 is an explanatory diagram showing a result of performing filter cleaning with a one-way flow according to the embodiment of the present invention.
FIG. 6 is a characteristic diagram in which transmittance (= 1−collection efficiency) for each particle diameter of a filter is measured using zinc chloride particles according to the embodiment of the present invention.
FIG. 7 is a partially cutaway perspective view showing an example of a separator type air filter.
FIG. 8 is a partially cutaway perspective view showing an example of a mini-pleated air filter.
FIG. 9 is a temperature-pressure characteristic diagram showing a state diagram using carbon dioxide as an example.
[Explanation of symbols]
11 Cylinder for supplying carbon dioxide (carbon dioxide supply means)
12 Pump (Pressurized liquid sending means of carbon dioxide)
13 Temperature controller 14 Cleaning tank having cleaning solvent introduction means and discharge means 15 Pressure control valve (pressure control means)
T Thermometer P Pressure gauge FM Flow meter

Claims (5)

A washing tank for washing the filter by flowing a supercritical or subcritical fluid,
A filter provided so as to sandwich a filter in a washing tank so that a supercritical or subcritical fluid flows through a filter medium, and to form a flow path of a predetermined length upstream and downstream of the sandwiched filter. A filter cleaning apparatus using a supercritical or subcritical fluid, comprising: a holding means. Filter holding means,
A fixing member for holding the filter from the upstream side of the filter,
The filter cleaning device using a supercritical or subcritical fluid according to claim 1, comprising a bottomed cylindrical cleaning device main body that sandwiches the filter from the downstream side of the filter. A washing tank for washing the filter by flowing a supercritical or subcritical fluid,
The filter is detachably provided in the washing tank, holds the filter inside such that a supercritical or subcritical fluid flows through the filter medium, and has a predetermined length on the upstream and downstream sides of the held filter. A filter cleaning apparatus using a supercritical or subcritical fluid, comprising: a filter holding member in which a flow path is formed. The supercritical or subcritical method according to claim 3, wherein a plurality of filter holding members are provided in parallel in the cleaning tank, and the plurality of filters held by the plurality of filter holding members are washed at the same time. Filter cleaning device using fluid. When cleaning the filter, a supercritical fluid or a subcritical fluid is introduced from an air outflow side of the filter, and a supercritical fluid or a subcritical fluid is discharged from an air inflow side of the filter. A filter cleaning device using the supercritical or subcritical fluid according to any one of claims 1 to 4.

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