WO2014173320A1 - Air filter - Google Patents

Abstract

An air filter, comprising: a vent pipe (110); a filtering element (130) disposed in an airtight manner external to the vent pipe (110) and used for air filtration; a first one-way valve used to open and close the vent pipe (110); and a second one-way valve (120) used to allow the air to pass through the filtering element (130) when open, and to prevent the air from passing through the filtering element (130) when closed; during the operation of the filter, the second one-way valve (120) is closed when the first one-way valve is open, and the second one-way valve (120) is open when the first one-way valve is closed.

Description

 Gas filter technology

 The present invention relates to a gas filter, and more particularly to a built-in nasal filter that can be used to filter air to protect human health before it enters the human respiratory system, and can also be used as a drug delivery system for medical or health purposes. .

Background technique

 At present, air pollution has caused health threats to people in many parts of the world, and people urgently need to be able to breathe clean air in their daily lives and work. To this end, some people wear masks to filter contaminated air, but wearing a mask can make people feel uncomfortable, and the mask and face are often not tightly attached, resulting in poor filtering; Some jobs that require air filtration but are inconvenient to wear masks, such as traffic police on duty on the road, need to use their mouths to blow the whistle, but the masks obviously hinder their work.

 Various built-in nasal filters have been proposed, such as the applicant's patent in China.

A built-in nasal filter is disclosed in CN1819857B, which has a large filtration area and low cost, and can be placed in the nose instead of a mask.

 However, existing built-in nasal filters still have drawbacks. For example, in use, the exhaled gas of the human body contacts the filter element of the existing nasal filter and is partially filtered through the filter element, causing the filter element to be re-contaminated by the exhaled gas of the human body (which contains moisture and hundreds of bacteria). As a result, the service life of the filter element is reduced; and in the case of a drug on the filter element, the drug component is blown out by the exhaled gas into the external environment, resulting in a decrease in the efficacy. Also for example, the filter element is often fixedly attached to its holding device and is not replaceable, and the retaining device is also discarded at the end of the life of the filter element, resulting in an increase in the cost of use of the filter.

Summary of the invention In view of the above problems in the prior art, the present invention provides a gas filter comprising: a vent pipe; a filter element airtightly disposed outside the vent pipe for filtering gas; a first check valve for opening And closing the vent tube; and a second one-way valve for allowing gas to pass through the filter element when opened, and blocking gas from passing through the filter element when closed, wherein, during operation of the filter, when the first check valve The second check valve is closed when opened, and the second check valve is opened when the first check valve is closed.

 Preferably, the first one-way valve comprises: a first valve flap for closing and opening the vent pipe, and a first valve seat for fixing the first one-way valve on the vent pipe and supporting the first valve flap .

 Preferably, the second one-way valve comprises: a second valve flap distributed outside the vent pipe; and a second valve seat for fixing the second one-way valve to the vent pipe and supporting the second valve flap.

 Preferably, the second valve seat comprises an inner ring member, an outer ring member and a spoke connecting the inner and outer ring members, the second valve seat is airtightly sleeved on the vent pipe through the inner ring member, and is passed through the outer ring member The filter element is hermetically connected, and the second valve flap is coupled to one of the inner ring member, the outer ring member and the spoke.

 Preferably, the second valve seat has an air vent, the filter element covers the air vent, and the second valve lobes are used to open and close the air vent. The vent is hermetically sealed by the filter element so that the second flap opens or closes the vent to allow or prevent gas from passing through the filter element.

 Preferably, the first and second flaps are flexible. The first and second flaps can be made of silicone. Preferably, the gas filter further comprises a fixing sleeve for being sleeved on the vent tube or inserted into the vent tube to hermetically clamp the filter element and the second one-way valve to the fixing sleeve and Between the snorkels.

 Preferably, the filtering surface of the filter element has wrinkles that increase the filtration area. More preferably, the filter element includes an inner cylinder and an outer cylinder that are nested with each other, and a gap exists between the inner and outer cylinders for supplying the gas, and one end of the outer cylinder is connected to one end of the inner cylinder.

Preferably, the vent pipe, the filter element, the first check valve and the second check valve constitute a filter package The gas filter comprises two of the filtering device and a holding device, the holding device is for fixedly connecting the two filtering devices; preferably, the holding device is connected to the vent pipe of the two filtering devices And having a clamping portion for fixing and holding the two filtering devices.

 In the gas filter of the present invention, two completely isolated gas passages (for example, a passage for a human inhaled gas and a passage for a human exhaled gas) are formed by using a one-way valve for respectively filtering the gas for entering the filter. And the exhaust gas discharged after use, to avoid secondary pollution of the filter element by the exhaust gas, thereby prolonging the service life of the filter element. Moreover, the filter element is detachably mounted in the filter, allowing the user to easily replace the filter element, greatly reducing the cost of use of the filter.

DRAWINGS

 1 and 2 are perspective views of a gas filter according to a first embodiment of the present invention.

 3 and 4 are respectively a longitudinal sectional view and an exploded view of a gas filter according to a first embodiment of the present invention.

 5-9 are respectively a front view, a bottom perspective view, a top perspective view, a longitudinal cross-sectional view, and an exploded view of a modification of the gas filter according to the first embodiment of the present invention.

 10-13 are a side view, a bottom view, a longitudinal cross-sectional view, and an exploded view, respectively, of a gas filter according to a second embodiment of the present invention.

 14 and 15 are a bottom view and a plan view, respectively, of a vent pipe and a holding device of a gas filter according to a second embodiment of the present invention.

 16 and 17 are a bottom view and a plan view, respectively, of a filter element of a gas filter according to a second embodiment of the present invention.

 18 and 19 are a longitudinal cross-sectional view and a plan view, respectively, of a second check valve of a gas filter according to a second embodiment of the present invention.

20 and 21 are gas filtration states of a gas filter according to a second embodiment of the present invention, respectively Figure and exhaust gas discharge state diagram.

 Fig. 22 shows a modification of the gas filter according to the second embodiment of the present invention, in which filter elements having different forms of wrinkles are used.

Concrete implementation

 The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

 1-2 are perspective views showing a gas filter according to a first embodiment of the present invention, and Figs. 3-4 are respectively a longitudinal sectional view and an exploded view of the gas filter. The gas filter includes: a vent pipe 110, a filter element 130 that is gas-tightly disposed outside the vent pipe 110 for filtering gas, and a gas for allowing gas to permeate through the filter element 130 when opened and blocking gas from passing when closed The second one-way valve 120 of the filter element 130, and one end of the vent pipe 110 is provided with a first one-way valve composed of a first valve seat 114 and a first valve flap 112 for opening and closing the vent pipe 110. In operation of the filter, the second one-way valve 120 is closed when the first one-way valve is open, and the second one-way valve 120 is open when the first one-way valve is closed.

 The gas filter of the present invention can be used in various cases where it is necessary to filter the inflowing gas and exhaust the exhaust gas. For example, the gas filter of the present invention can be placed in the nostrils in the direction indicated by the arrow in Fig. 3 (i.e., the longitudinal direction). . As used herein, the term "exhaust gas" means a gas that is filtered by a filter to be discharged through the filter after use (eg, human exhaled gas), and the term "proximal" means that the filter is in use, the filtration The front end of the device itself or its components in the inflow direction of the gas to be filtered (ie, in the opposite direction of the exhaust gas discharge direction), and the term "distal" means the inflow of the filter to be filtered by the filter itself or its components. The back end in the direction. For example, when the filter is used in a nostril, "proximal" means one end closer to the human body, and "distal" means an end farther from the human body. The term "longitudinal" direction is the direction from the proximal end to the distal end.

As shown in Figures 1-4, the vent tube 110 is generally cylindrical and has an internal passage 111 for exhaust gas discharge. The first valve seat 114 of the first one-way valve is disposed at the distal end of the vent pipe 110, and is connected to the first valve flap 112. The first flap 112 is joined and supported. The first valve seat 114 has an air hole communicating with the internal passage 111 of the vent pipe 110, and the first valve flap 112 is movable to open or close the first valve seat 114 (specifically, open or close the first valve seat 114) The air vents open or close the vent tube 110, and the first valve flap 112 is in airtight engagement with the valve seat when the first valve seat 114 is closed. Preferably, the first flap 112 is flexible and is susceptible to elastic deformation by the differential pressure of the two sides thereof, and may of course be rigid. When the exhaust gas flows from the proximal end to the distal end of the vent pipe 110, the free end 113 of the first flap 112 is easily blown by the exhaust gas, thereby opening the vent pipe 110; conversely, when a negative pressure is formed in the vent pipe 110, the free end 113 is easily adsorbed on the first valve seat 114 to close the vent pipe 110. The first valve seat 114 may be hermetically connected or integrally formed with the vent tube 110. The first valve seat 114 can also be part of the vent tube 110. At this time, the first flap 112 is directly coupled to the vent tube 110 for opening and closing the vent tube 110.

As shown in FIG. 1-4, the second check valve 120 includes: a second valve flap 121, and a second valve seat 123 connected to the second valve flap 121 and supporting the second valve flap 121. The second check valve 120 The second valve seat 123 is in airtight engagement with the vent pipe 110. The second valve seat 123 further includes a fixing hole 126 for allowing the vent pipe 110 to pass through and the second valve seat 123 to be sleeved on the vent pipe 110. The second valve seat 123 further includes a sealing lip 124 for airtight engagement with a wall of the chamber containing the filter, such as a wall of a nostril, the sealing lip 124 preferably being flexible to facilitate formation of the Airtight joint. The second valve seat 123 has air holes distributed outside the vent pipe 110, and the air holes are hermetically covered by the filter element 130, so that the filter element 130 can filter the gas flowing in through the air holes. The second flap 121 is movable to open or close the second valve seat 123, specifically to open or close the air vent of the second valve seat 123, thereby allowing gas to pass through the second one-way valve and further through the filter element 130. Or the exhaust gas is prevented from passing through the filter element 130 and further discharged from the second check valve. The second flap 121 is in airtight engagement with the valve seat when the second valve seat 123 is closed. Preferably, the second flap 121 is flexible and elastically deformed by the difference in air pressure between the two sides thereof, for example, the air pressure in the chamber accommodating the filter when the filter discharges the exhaust gas (that is, the snorkel) In 110 The air pressure is slightly higher than the ambient air pressure, thereby pressing the second valve flap 121 against the second valve seat 123 to close the second valve seat 123; conversely, when a negative pressure is formed in the chamber accommodating the filter, the free end 122 is lifted to open the second valve seat 123. The second valve seat 123 may be hermetically connected or integrally formed with the vent tube 110 and/or the first valve seat 114.

 In the present embodiment, the second valve seat 123 includes an inner ring member 127, an outer ring member 128, and spokes 129 connecting the inner and outer ring members, as shown in Figs. The inner ring member 127 includes a fixing hole 126. The second valve seat 123 is fixedly sleeved on the vent pipe 110 through the fixing hole 126 in the middle of the inner ring member 127, and is airtightly connected to the filter element 130 through the outer ring member, as shown in FIG. The two flaps 122 can be coupled to any one of the inner ring member 127, the outer ring member 128 and the spokes 129, or a combination thereof, as long as the second flap 122 can be opened by the difference in air pressure between the two sides thereof or The second valve seat 123 can be closed.

 The filter element 130 is hemispherical by embedding the edge 132 of the opening 131 on the hemisphere (ie, the distal end of the filter element 130) into the annular groove 125 on the proximal side of the outer annulus 128 of the second valve seat 123, The filter element 130 is connected to the second valve seat 123, preferably in a gastight connection. The filter element 130 is also sleeved over the vent tube 110 by a mounting aperture 133 therein. In the present embodiment, the first valve seat 114 constitutes a flange of the vent pipe 110, the proximal end of the vent pipe 110 passes through the fixing holes 126 and 133, and the fixing sleeve 140 is sleeved from the proximal end of the vent pipe 110. The air tube 110 is placed such that the edges of the fixing holes 126 and 133 are sandwiched between the vent tube 110 and the fixed sleeve 140, thereby forming a gas-tight connection between the vent tube 110, the second valve seat 123, and the filter element 130.

 Preferably, the first check valve and the second check valve are made of silicone resin.

In order to facilitate assembly and improve the stability of the connection, the vent tube 110 may be made of a hard material. The following is a description of how the filter works when it is used in the nostrils. When the filter is placed in the nostril in the direction of the arrow in Figure 3, the sealing lip 124 forms a gas-tight engagement with the inner wall of the nostril. Inhale in the human body At this time, a negative pressure is formed in the nostrils, so that the first flap 112 is adsorbed to close the vent 110, but the second flap 121 is opened, thereby allowing air to pass through the vent of the second valve seat 123 to reach the filter element 130, after filtering The element 130 is filtered and then enters the human body; when the human body exhales, the air pressure in the nostrils is slightly higher than the ambient air pressure, so that the first valve flap 112 is opened to open the vent pipe 110 for exhaust gas discharge, but the second valve flap 121 is closed, thereby preventing the exhaust gas. The filter element 130 is discharged from the air hole of the second valve seat 123. It can be seen that the filter of the present invention completely isolates the passage of the filtered gas from the passage of the exhaust gas, avoids secondary contamination of the filter element 130, and prolongs the service life of the filter element 130. And the filter element 130 is detachably clamped to the second valve seat 123 and the vent pipe 110, and can be replaced as needed.

 In the present invention, various modifications can be made to the filter. For example, the shape of the vent pipe 110 is not limited to a cylindrical shape, and may have other shapes such as a polyhedral shape, a frustum shape, and the like. The first one-way valve is not necessarily disposed at the distal end of the vent pipe, and may be disposed at any position between the proximal end of the vent pipe and even between the distal end and the proximal end, as long as the exhaust gas can be smoothly discharged through the vent pipe 110 but prevented from being The filtered gas enters the vent pipe 110. The second one-way valve is not necessarily provided at the distal end of the filter as shown in the first embodiment, but may be disposed at the proximal end of the filter as shown in the second embodiment. The filter element 130 can also have other shapes, such as a frustum shape, a parabolic shape, a cylindrical shape, and the like. The airtight engagement between the filter element 130 and the second check valve 120 can also be achieved in other ways, or the relative position of the filter element 130 and the second check valve 120 in the longitudinal direction of the filter can also be changed, as long as the filter element is guaranteed 130 can be used to cover the air vent of the second one-way valve 120, thereby enabling the second valve flap 121 to allow and block the passage of gas through the filter element 130 when opening and closing the air vent.

A modification of the gas filter according to the first embodiment of the present invention will now be described with reference to Figs. 5-9. This variant differs from the gas filter described above in that both the first check valve and the second check valve are integrated on the vent tube, and the fixed sleeve is inserted into the vent tube for fixing the filter element. The area is specifically described below do not.

 As illustrated, the gas filter of this variation includes: a vent tube 110, a filter element 130 that is gas tightly disposed outside the vent tube 110 for filtering gas, and for allowing gas to pass through the filter element 130 when opened And blocking the gas to pass through the second one-way valve 120 of the filter element 130 when closed, and is formed integrally with the vent tube 110, and one end of the vent tube 110 is provided with the first valve flap 112 to constitute the first one-way valve. Used to open and close the snorkel 110. In operation of the filter, the second one-way valve 120 is closed when the first one-way valve is open, and the second one-way valve 120 is open when the first one-way valve is closed.

 The second check valve 120 includes: a second valve flap 121, and a second valve seat 123 connected to the second valve flap 121 and supporting the second valve flap 121. The second valve seat 123 includes an outer ring member 128 and a spoke 129. The outer ring member 128 is coupled to the vent tube 110 by the spokes 129. The second valve seat 123 has air holes distributed outside the vent pipe 110, and the air holes are hermetically sealed by the filter member 130, so that the filter member 130 can filter the gas flowing in through the air holes.

 The filter element 130 is hemispherical by embedding the edge 132 of the opening 131 on the hemisphere (ie, the distal end of the filter element 130) into the annular groove 125 on the proximal side of the outer annulus 128 of the second valve seat 123, The filter element 130 is connected to the second valve seat 123, preferably in a gastight connection. The filter element 130 further has a fixing hole 133 through which the fixing sleeve 140 is inserted and inserted into the vent pipe 110, thereby clamping the edge of the fixing hole 133 between the vent pipe 110 and the fixing sleeve 140, thereby forming A gas-tight connection between the vent tube 110 and the filter element 130.

 The gas filter in this modification is identical to the gas filter in the first embodiment, and therefore will not be described again.

The gas filter in the first embodiment described above or the gas filter in the modification of the first embodiment may be used in combination, and the plurality of gas filters are fixed by the holding means to hold the gas filter in, for example, the nostrils . A gas filter according to a second embodiment of the present invention will now be described with reference to Figs. As shown in Figures 10-13, the gas filter of the second embodiment includes two identical filtering devices 501 and 502 and a holding device 215 that fixedly connects the two filtering devices. Each of the filtering devices 501 or 502 is similar to the filter of the first embodiment, the main difference being that the second one-way valve 220 of the filtering device is located at the proximal end of the vent tube 210, the filter element 230 and the second one-way valve 220 The relative position in the longitudinal direction of the filter is opposite to the relative position of the filter element 130 and the second check valve 120 in the first embodiment, and the filter element 230 has wrinkles for increasing the filtration area.

 In particular, the filtering device 501 or 502 comprises: a vent tube 210, a filter element 230 that is gas-tightly disposed outside the vent tube 210 for filtering gas, and for allowing gas to pass through the filter element 230 when opened and when closed The gas is blocked from passing through the second one-way valve 220 of the filter element 230. One end (e.g., the distal end) of the vent tube 210 is provided with a first one-way valve 503 composed of a first valve seat 214 and a first valve flap 212 for opening and closing the vent tube 210. In operation of the filter, the second one-way valve 220 is closed when the first one-way valve 503 is open, and the second one-way valve 220 is open when the first one-way valve 503 is closed.

 The retaining device 215 is coupled to both the first valve seats 214 of the filter devices 501 and 502, and in turn to the vent tubes 210 of the filter devices 501 and 502 to securely connect the two filter devices 501 and 502. Of course, the retaining device 215 can also be fixedly coupled to the filtering devices 501 and 502 by fixed attachment to other components of the filtering devices 501 and 502. Preferably, the retaining device 215 has a gripping portion 216 for gripping the nasal cap, for example, when the filter is used in the nostril, thereby holding the filtering devices 501 and 502 in the nostrils and preventing the filtering devices 501 and 502 from being Inhaled into the nasal cavity.

As shown in Figures 10-15, the vent tube 210 is generally cylindrical and has an internal passage 211 for exhaust gas discharge. A first valve seat 214 of the first one-way valve 503 is disposed at a distal end of the vent tube 210, coupled to the first valve flap 212 and supporting the first valve flap 212. The first valve seat 214 has an air hole communicating with the internal passage 211 of the vent pipe 210, and the first valve flap 212 is movable to open or close the first valve seat (specifically, The air vent of the first valve seat is opened or closed to open or close the vent tube 210, and the first valve flap 212 is in airtight engagement with the valve seat when the first valve seat is closed. Preferably, the first flap 212 is flexible and susceptible to elastic deformation by the differential pressure on both sides thereof, for example, the free end 213 of the first flap 212 when the exhaust gas flows from the proximal end to the distal end of the vent tube 210. It is easily blown by the exhaust gas to open the vent pipe 210; conversely, when a negative pressure is formed in the vent pipe 210, the free end 213 is easily attracted to the first valve seat 214 to close the vent pipe 210.

 The first valve seat 214 can be hermetically connected or integrally formed with the vent tube 210. The first valve seat 214 can also be part of the vent tube 210, in which case the first flap 212 is directly coupled to the vent tube 210 for opening and closing the vent tube 210.

As shown in FIGS. 10-13 and 18-19, the second check valve 220 includes: a second valve flap 221, and a second valve seat 223 connected to the second valve flap 221 and supporting the second valve flap 221, second The one-way valve 220 is hermetically engaged with the vent tube 210 through the second valve seat 223. The second valve seat 223 includes a sealing lip 224 for airtight engagement with a wall of the chamber containing the filter, such as a wall of a nostril, the sealing lip 224 preferably being flexible to facilitate formation of the gas Close joint. The second valve seat 223 has air holes distributed outside the vent pipe 210, and the air holes are hermetically sealed by the filter element 230, so that the filter element 230 can filter the gas flowing in through the air holes. The second flap 221 is movable to open or close the second valve seat 223, specifically to open or close the air vent of the second valve seat 223, thereby allowing gas to pass through the filter element 230 and pass through the second check valve. The air holes or the exhaust gas are prevented from being discharged from the air holes of the second check valve to contaminate the filter element 230. The second flap 221 is in airtight engagement with the valve seat when the second valve seat 223 is closed. Preferably, the second flap 221 is flexible and is elastically deformed by the difference in air pressure between the two sides thereof, for example, the air pressure in the chamber accommodating the filter when the filter discharges the exhaust gas (that is, the snorkel) The air pressure in 210 is slightly higher than the ambient air pressure, thereby pressing the second valve flap 221 against the second valve seat 223 to close the second valve seat 223; conversely, when a negative pressure is formed in the chamber accommodating the filter, Free end of the second flap 221 122 is lifted to open the second valve seat 223. The second valve seat 223 can be hermetically connected to the vent tube 210. For example, in the present embodiment, the second valve seat 223 includes an inner annular member 227, an outer annular member 228, and spokes 229 that connect the inner and outer annular members, as shown in Figs. The inner ring member 227 includes a fixing hole 226 for the fixing sleeve 240 to pass through, and when the fixing sleeve 240 passes through the fixing hole 226 and is fixed by inserting the vent tube 210 from the proximal end of the vent tube 210, the fixing The edge of the aperture 226 is clamped between the flange at the proximal end of the fixed sleeve 240 and the proximal end of the vent tube 210, as shown in Figure 12, such that the second valve seat 223 is hermetically connected to the vent tube 210. The second flap 222 can be coupled to any one of the inner ring member 227, the outer ring member 228, and the spoke 229, or a combination thereof, as long as the second flap 222 can be opened by the air pressure difference on both sides thereof. Or the second valve seat 223 can be closed.

 The filter element 240 includes an outer cylinder 234 and an inner cylinder 235 that is sleeved inside the outer cylinder 234. There is a gap between the inner and outer cylinders 235 and 234 for gas circulation, and the distal end of the outer cylinder 234 and the inner cylinder 235 The distal end of the outer cylinder 234 is hermetically inserted into the annular groove 235 of the outer ring member 228 of the second valve seat 234. The proximal end of the inner cylinder 235 has a fixing hole 233, the fixing sleeve The fixing hole 233 can also pass through the fixing hole 233, so that when the fixing sleeve 240 is inserted into the vent pipe 210 from the proximal end of the vent pipe 210, the edge of the fixing hole 233 is also clamped at the flange of the proximal end of the fixing sleeve. Between the proximal end of the vent tube 210 and the edge of the fixing hole 226, as shown in FIG. 12, the filter element 230 is hermetically connected to the second one-way valve 220, and covers the second one-way valve 220. Stomata. Filter element 230 can have many wrinkles. Specifically, the inner and outer cylinders 234, 235 have a plurality of pleats on the wall of the cylinder, such as straight pleats, a filter element 230' annular pleats as shown in Fig. 22, etc., to increase filtration of the filter element. area.

 Of course, the filter element 230 can have three or more cylinders nested one behind the other and in turn, rather than just two cylinders. The principle is similar and will not be described here.

Here, the fixation sleeve 240 can be rigid for insertion through the proximal end of the vent tube 210. When the air tube 210 is fixed, a hermetic joint is formed between the second valve seat 223 of the second check valve, the vent tube 210 and the filter element 230, and when the fixed sleeve 240 is detached from the vent tube 210, The filter element 230 is easily replaced.

 Each of the check valves of the present invention can be made of silica gel to achieve a sensitive one-way filtering function, but can also be made of other materials such as rubber or plastic. The filtration unit of the present invention can be made of various materials such as polyester fibers to effect gas filtration; and can be provided with drugs for therapeutic and health care purposes for therapeutic and health purposes.

 The working principle of the filter of this embodiment will be described below when it is used in the nostrils. When the filter is placed in the nostril in the direction of the arrow in Figure 10, the sealing lip 224 forms a gas-tight engagement with the inner wall of the nostril. When the human body inhales, a negative pressure is created in the nostrils, so that the first flap 212 closes the vent 210, but the second flap 221 opens, allowing air to pass through the filter element 230 and then from the vent of the second valve seat 223. Entering the human body, as shown in FIG. 20, the arrow indicates the flow direction of the airflow; when the human body exhales, the air pressure in the nostrils is slightly higher than the ambient air pressure, so that the first valve flap 212 is opened to open the vent pipe 210 for the exhaust gas to be smoothly discharged. However, the second flap 221 is closed, thereby preventing exhaust gas from being discharged from the air holes of the second valve seat 223 to contaminate the filter element 230, as shown in Fig. 21, wherein the arrows indicate the flow direction of the air flow. It can be seen that the filter of the present invention completely isolates the passage of the filtered gas from the passage of the exhaust gas, avoids secondary contamination of the filter element 230, and prolongs the service life of the filter element 230.

The filter element 230 is clamped in the recess 225 of the second valve seat 223 and clamped between the flange of the fixed sleeve 240 and the proximal end of the vent tube 210 by passing the fixed sleeve 240 from the snorkel When the 210 is pulled out, the filter element 230 can be easily detached from the recess 225, so that the new filter element 230 can be replaced. When assembling the new filter element 230, the proximal end of the outer cylinder 234 of the filter element 230 is caught in the recess 225, and the fixed sleeve 240 is passed through the fixing hole of the second valve seat 223 of the second check valve. 226 and a fixing hole 233 of the inner cylinder 235 of the filter element 230, and inserted into the vent pipe 210, thereby being fixed The edges of the holes 226 and 233 are held between the flange at the proximal end of the fixed sleeve 240 and the proximal end of the vent tube 210, so that the filter element 230 is replaced.

 Fig. 22 shows a modification of the gas filter according to the second embodiment of the present invention, which differs from the gas filter of the second embodiment in that a filter element 230 having a different form of wrinkles is used.

 The technical solution of the present invention has been exemplified above by a plurality of embodiments. Of course, the invention is not limited to the embodiment. A person skilled in the art will recognize that various modifications and substitutions may be made to the various embodiments based on the principles of the invention, and all such modifications and substitutions are also within the scope of the invention.

Claims

Claim  1. A gas filter comprising:  Snorkel  a filter element that is gas-tightly disposed outside the vent tube for filtering gas;  a first check valve for opening and closing the vent pipe;  a second check valve for allowing gas to pass through the filter element when opened, and blocking gas from passing through the filter element when closed  Wherein, in the operation of the filter, the second one-way valve is closed when the first one-way valve is open, and the second one-way valve is open when the first one-way valve is closed.  2. The gas filter according to claim 1, wherein: the first one-way valve comprises: a first valve flap for closing and opening the vent pipe, and  a first valve seat for securing the first one-way valve to the vent tube and supporting the first valve flap. The gas filter according to claim 1 or 2, wherein the second one-way valve comprises: a second valve flap distributed outside the vent pipe;  a second valve seat for securing the second one-way valve to the vent tube and supporting the second valve flap. 4. The gas filter according to claim 3, wherein the second valve seat comprises an inner annular member, an outer annular member, and spokes connecting the inner and outer annular members, the second valve seat being ventilated by the inner annular member a sleeve is disposed on the vent tube and is hermetically connected to the filter element by an outer ring member, and the second valve flap is coupled to one of the inner ring member, the outer ring member and the spoke.  The gas filter according to claim 3 or 4, wherein the second valve seat has an air hole, the filter element covers the air hole, and the second valve flap is used to open and close the air hole .  6. The gas filter of any of claims 1-5, wherein the first and second flaps are flexible. 7. The gas filter according to any one of claims 1 to 5, further comprising a fixing sleeve for arranging The vent tube is inserted into the vent tube to hermetically clamp the filter element and the second one-way valve between the fixed sleeve and the vent tube.  The gas filter according to any one of claims 1 to 7, wherein the filter surface of the filter element has a wrinkle that increases the filtration area.  The gas filter according to any one of claims 1 to 8, wherein the filter element comprises an inner cylinder and an outer cylinder which are nested with each other, and a gap exists between the inner and outer cylinders, the outer cylinder One end is connected to one end of the inner cylinder.  The gas filter according to any one of claims 1 to 9, wherein the vent pipe, the filter element, the first check valve, and the second check valve constitute a filtering device, and the gas filter includes two a filter device and a holding device, wherein the holding device is for fixedly connecting the two filter devices; preferably, the holding device is connected to a vent pipe of the two filter devices, and has a clamping portion, the clamping device The portion is used to securely hold the two filtering devices.