Turtback type filter for impurity removal of crude oil

Abstract

The invention relates to a turtleback type filter for impurity removal of crude grease, which is applied to the field of filtration. The turtleback type filter comprises a filter shell, a turtleback type sealing screw cap in rotary sealing connection with the upper end of the filter shell, an oil inlet pipe connected below the turtleback type sealing screw cap, a steam pipe communicated above the oil inlet pipe, and a blow-off pipe communicated with the bottom of the filter shell, the support cylinder and the filter cylinder are firstly used for double filtration of grease, the grease naturally sinks to the bottom of the filter cylinder under the action of impurity precipitation, and then the isolation type blowdown device is regulated and controlled to enable the upper and lower deformation type pipe blocking covers to deform front and back, so that the impurities are isolated and discharged, online cleaning is realized, disturbance to the grease can be effectively avoided, and the service life of the grease is prolonged. The filter cartridge is periodically cleaned by steam purging, the steam is pre-stored by the purging compensator, and the pre-stored steam can be automatically released and blown to the filter cartridge during steam purging, so that the insufficiency of steam purging force is effectively compensated, and the purging effect is effectively improved.

Description

Technical Field

[0001] The present invention relates to a turtle-back filter for removing impurities from crude oil, especially a turtle-back filter for removing impurities from crude oil applied in the filtration field. Background Art

[0002] The main function of the oil impurity removal filter is to remove impurities in the oil to ensure the purity and safety of the oil. In order to maintain an efficient filtration effect, the filters on the current market all have an automatic cleaning function.

[0003] For example, a filtration device for oil production with the publication number of CN221155713U uses a brush to clean the barrel wall, but the bristles on the brush will fall into the oil, affecting the quality of the oil. Therefore, in the prior art, cleaning is carried out by steam purging. For example, a filter with a steam purging device with the publication number of CN219441040U uses the steam purging method to clean the filtration component.

[0004] Although the prior art has disclosed a method for online cleaning of the filter, the oil will be agitated during cleaning, resulting in more thorough mixing of the oil and impurities, which instead reduces the filtration efficiency. Moreover, when steam purging, if the impurities are stuck on the filter mesh and the steam pressure is insufficient, the cleaning effect will not meet the standard. Summary of the Invention

[0005] Aiming at the above-mentioned prior art, the technical problem to be solved by the present invention is to perform online cleaning of the filter mesh while filtering and to compensate for the problem of insufficient pressure during steam purging.

[0006] To solve the above problems, the present invention provides a turtle-back filter for removing impurities from crude oil, which includes a filter shell, a turtle-back sealing rotary cover rotatably and sealingly connected to the upper end of the filter shell, an oil inlet pipe connected below the turtle-back sealing rotary cover, a steam pipe communicated above the oil inlet pipe, a sewage discharge pipe communicated at the bottom of the filter shell, and an oil outlet pipe communicated at the side of the sewage discharge pipe. The inner wall of the turtle-back sealing rotary cover is provided with an oil passage communicated with the oil inlet pipe, and the oil inlet pipe and the oil passage are sealingly connected by a flange. A steam purging device communicated with the steam pipe is further provided outside the filter shell. A support cylinder with a pore size of 0.5 - 1 mm is placed inside the filter shell, and a filter cylinder is placed inside the support cylinder. A plurality of equally spaced and circumferentially distributed ultrasonic vibrators are installed on the inner side wall of the support cylinder, and the vibration surface of the ultrasonic vibrator contacts the filter cylinder. Multiple groups of matching differential pressure sensors are installed on the inner wall of the filter shell and the inner wall of the filter cylinder, and the differential pressure sensors are signal-connected to the steam purging device through a control processor.

[0007] In the above-mentioned turtle-back filter for removing impurities from crude oil, the impurities are allowed to sink by the action of impurity precipitation, and then the precipitated impurities are isolated and discharged through an isolation type sewage discharger, so as to achieve the effect of online cleaning. It is also periodically cleaned in cooperation with the steam purging method, and can also compensate for the insufficient steam pressure, effectively improving the purging effect.

[0008] As a further improvement of the present application, a purging compensator coaxial with the filter cartridge is fixedly connected to the lower end of the turtle-back sealing cap, and an isolation type sewage discharger is fixedly connected to the lower end of the purging compensator. The bottom of the filter cartridge is communicated with a slag discharge pipe extending into the sewage discharge pipe, and a perforation matching the slag discharge pipe is opened at the bottom of the support cylinder. The isolation type sewage discharger penetrates into the interior of the slag discharge pipe.

[0009] As a further improvement of the present application, a solid bottom cylinder is fixedly inlaid at the bottom of the filter cartridge, and the mesh number of the filter cartridge is 500 - 800 meshes.

[0010] As a further improvement of the present application, the isolation type sewage discharger includes upper, middle and lower section deformed push rods, and a deformed pipe blocking cover fixedly connected between adjacent two deformed push rods. The upper deformed pipe blocking cover is arranged close to the upper port of the slag discharge pipe. The middle section deformed push rod is made of magnetic material, and the upper and lower section deformed push rods are made of electromagnetic material. A pressure sensor is installed on the side wall of the middle section deformed push rod close to the lower deformed pipe blocking cover. The pressure sensor is signal-connected to the upper and lower section deformed push rods. A push rod is also slidably connected to the inner wall of the middle section deformed push rod, and the upper and lower ends of the push rod are respectively in contact with the upper and lower section deformed push rods.

[0011] As another improvement of the present application, the deformed pipe blocking cover includes an oval pressure-resistant cover and a plurality of groups of elastic plastic membranes symmetrically distributed up and down and inlaid inside the pressure-resistant cover. A connecting pin is rotatably connected between two elastic plastic membranes in the same group.

[0012] As a supplementary improvement of the present application, the purging compensator includes an elastic air bag in the middle and hard air bag heads connected to the upper and lower ends of the elastic air bag. The inner wall of the upper hard air bag head is provided with a ventilation hole communicated with the elastic air bag. A steam channel communicated with the ventilation hole and the oil passage is opened on the inner wall of the turtle-back sealing cap. An electromagnetic valve is installed inside the steam channel. A plurality of self-opening and closing air release valves are fixedly inlaid on the side wall of the elastic air bag and distributed in an equidistant and circumferential manner. An opening valve belt is connected between two opposite self-opening and closing air release valves.

[0013] As a supplementary improvement of the present application, the self-opening and closing air release valve includes a valve seat fixedly connected to the inner and outer walls of the elastic air bag, a positioning ring fixedly connected between the two valve seats, and a sealing piece hinged to the positioning ring through a damping hinge. The sealing piece is magnetically adsorbed to the positioning ring, and the opening direction of the sealing piece faces the inside of the elastic air bag.

[0014] As yet another improvement of the present application, the valve-opening belt includes an elastic belt and a non-elastic belt inserted inside the elastic belt, and the length of the non-elastic belt is greater than the length of the elastic belt.

[0015] In summary, first, the grease is double-filtered by the support cylinder and the filter cylinder, and the impurities naturally sink to the bottom of the filter cylinder by the sedimentation effect of the impurities. Then, by adjusting the isolation type sewage discharger, the upper and lower deformable pipe blocking covers are deformed before and after, so as to isolate and discharge the impurities, realizing online cleaning, which can effectively avoid disturbing the grease, thereby effectively improving the filtering effect. The filter cylinder is also regularly cleaned by steam purging, and the steam purging compensator is used to pre-store steam. When steam purging, the pre-stored steam can be automatically released and blown towards the filter cylinder, thereby effectively compensating for the deficiency of the steam purging force and further effectively improving the purging effect. Description of the Drawings

[0016] Figure 1 Stereo split view of the filter of the first embodiment of the present application; Figure 2 Front view sectional view of the filter of the second embodiment of the present application; Figure 3 Stereo view of the purge compensator and the isolation type sewage discharger of the third embodiment of the present application; Figure 4 Dynamic change view of the isolation type sewage discharger of the second embodiment of the present application during isolation of sewage discharge; Figure 5 Front view sectional view of the deformable pipe blocking cover of the second embodiment of the present application; Figure 6 Dynamic change view of the purge compensator of the third embodiment of the present application during pre-storing steam; Figure 7 Stereo view of the self-opening and closing air release valve of the third embodiment of the present application; Figure 8 Valve-opening belt diagram of the third embodiment of the present application.

[0017] Explanation of the reference numerals in the drawings: 1. Filter housing, 2. Turtle-back seal cap, 201. Oil passage, 202. Steam passage, 3. Inlet oil pipe, 4. Steam pipe, 5. Drain pipe, 6. Outlet oil pipe, 7. Support cylinder, 8. Filter cartridge, 801. Solid bottom cylinder, 9. Differential pressure sensor, 10. Ultrasonic vibrator, 11. Purge compensator, 1101. Elastic airbag, 1102. Rigid capsule head, 12. Isolated drainer, 1201. Deformable push rod, 1202. Deformable pipe plug cover, 12021. Pressure-resistant cover, 12022. Elastic plastic diaphragm, 12023. Connecting pin, 1203. Thrust rod, 1204. Pressure sensor, 13. Slag discharge pipe, 14. Self-opening and closing air release valve, 1401. Valve seat, 1402. Positioning ring, 1403. Sealing piece, 15. Valve opening belt, 1501. Elastic belt, 1502. Non-elastic belt. Specific embodiments

[0018] The following describes in detail three embodiments of the present application with reference to the accompanying drawings.

[0019] The first embodiment: As Figure 1 , 2 shown, it includes a filter housing 1, a turtle-back seal cap 2 rotatably and sealingly connected to the upper end of the filter housing 1, an inlet oil pipe 3 connected below the turtle-back seal cap 2, a steam pipe 4 communicating above the inlet oil pipe 3, a drain pipe 5 communicating with the bottom of the filter housing 1, and an outlet oil pipe 6 communicating with the side of the drain pipe 5. An oil passage 201 communicating with the inlet oil pipe 3 is provided on the inner wall of the turtle-back seal cap 2, and the inlet oil pipe 3 and the oil passage 201 are sealed and connected by a flange. A steam purging device (which is a prior art, and the specific working principle and structure will not be described in detail here) communicating with the steam pipe 4 is also provided outside the filter housing 1. A support cylinder 7 with a pore size of 0.5 - 1 mm is placed inside the filter housing 1, and a filter cartridge 8 is placed inside the support cylinder 7. A plurality of equally spaced and circumferentially distributed ultrasonic vibrators 10 (the specific model is selected according to actual needs) are installed on the inner side wall of the support cylinder 7, and the vibrating surface of the ultrasonic vibrator 10 contacts the filter cartridge 8. Multiple groups of matching differential pressure sensors 9 (the specific model is selected according to actual needs) are installed on the inner wall of the filter housing 1 and the inner wall of the filter cartridge 8, and the differential pressure sensor 9 is signal-connected to the steam purging device through a control processor (the specific control principle and structure of this part are well-known technologies for those skilled in the relevant fields and will not be described in detail here); As Figure 2As shown in the figure, during specific filtration, the crude oil enters the interior of the filter through the oil inlet pipe 3 and the oil passage 201. The crude oil is filtered through the filter cartridge 8 and the support cylinder 7. Impurities are retained inside the filter cartridge 8, and the filtered oil is discharged through the oil outlet pipe 6. Most of the water and impurities in the oil precipitate at the bottom of the sewage discharge pipe 5 and are discharged through the sewage discharge pipe 5. During filtration, the pressure difference sensor 9 continuously detects the pressure inside and outside the filter cartridge 8. If the internal and external pressure difference exceeds the set threshold, it indicates that the filter cartridge 8 is blocked. Therefore, the pressure difference sensor 9 starts the steam purging device to purge and clean the filter cartridge 8 through the control processor. Additionally, the ultrasonic vibrator 10 is started simultaneously during purging to vibrate the filter cartridge 8, thereby effectively improving the cleaning effect; This embodiment mainly uses the filter cartridge 8 to filter the crude oil and regularly cleans the filter cartridge 8 in cooperation with steam purging, eliminating the trouble of disassembly and cleaning and effectively maintaining the high-efficiency filtration state of the filter cartridge 8.

[0020] The second embodiment: This embodiment further improves the cleaning method of the filter cartridge 8 on the basis of the first embodiment, effectively improving the cleaning efficiency, while other parts remain the same as the first embodiment; As Figure 2 shown, the lower end of the turtle-back type sealing rotary cover 2 is fixedly connected with a purging compensator 11 coaxial with the filter cartridge 8, and the lower end of the purging compensator 11 is fixedly connected with an isolation type sewage discharger 12. The bottom of the filter cartridge 8 is communicated with a slag discharge pipe 13 extending into the sewage discharge pipe 5, and a perforation matching the slag discharge pipe 13 is opened at the bottom of the support cylinder 7. The isolation type sewage discharger 12 penetrates into the interior of the slag discharge pipe 13. A solid bottom cylinder 801 is fixedly embedded at the bottom of the filter cartridge 8, and the mesh number of the filter cartridge 8 is 500 - 800 meshes; As Figure 3 、 4 shown, the isolation type sewage discharger 12 includes upper, middle, and lower deformed push rods 1201 and a deformed pipe blocking cover 1202 fixedly connected between adjacent two deformed push rods 1201. The upper deformed pipe blocking cover 1202 is arranged close to the upper port of the slag discharge pipe 13. The middle deformed push rod 1201 is made of magnetic material, and the upper and lower deformed push rods 1201 are made of electromagnetic material. A pressure sensor 1204 (the specific model is selected according to actual requirements) is installed on the side wall of the middle deformed push rod 1201 close to the lower deformed pipe blocking cover 1202. The pressure sensor 1204 is signal-connected to the upper and lower deformed push rods 1201. A push rod 1203 is also slidably connected to the inner wall of the middle deformed push rod 1201, and the upper and lower ends of the push rod 1203 are respectively in contact with the upper and lower deformed push rods 1201; As Figure 4As shown, the specific operation of the isolation type sewage discharger 12 is as follows: while the filter cartridge 8 is filtering the grease, the water and impurities in the grease are denser than the grease and therefore settle at the bottom of the solid bottom cartridge 801. In the filtering state, the deformable push rod 1201 of the lower section is energized to generate a magnetic attraction force on the deformable push rod 1201 of the middle section. Under the magnetic attraction force, the deformable push rod 1201 of the lower section moves upward, thereby causing the deformable plugging pipe cover 1202 at the lower section to deform and expand. After the deformation of the deformable plugging pipe cover 1202 at the lower section expands, it closely adheres to the inner wall of the slag discharge pipe 13 to form a sealing barrier, while the deformable push rod 1201 of the upper section is moved upward. 1. When no electricity is supplied, the upper deformable plugging pipe cover 1202 naturally sags and contracts, so that the precipitated water and impurities will sink on the lower deformable plugging pipe cover 1202. When in the cleaning state, the upper deformable push rod 1201 is energized, while the lower deformable push rod 1201 is powered off, so that the upper and lower deformable plugging pipe covers 1202 can switch their states. The upper deformable plugging pipe cover 1202 can intercept the grease, and the lower deformable plugging pipe cover 1202 can open the channel to let the water and impurities naturally fall to the bottom of the sewage pipe 5 and be discharged. In this way, the impurities can be cleaned online, and the grease can be effectively avoided. In addition, the role of the push rod 1203 is that when the upper and lower deformable plugging covers 1202 are switched in state, the upper and lower deformable push rods 1201 resist the push rod 1203 to ensure that the upper and lower deformable plugging covers 1202 are in different states, so as to avoid the two deformable plugging covers 1202 being closed at the same time to hinder the discharge of impurities. When steam purging is performed, the upper and lower deformable push rods 1201 are powered off at the same time, so that the upper and lower deformable plugging covers 1202 are in a naturally drooping state, so that the impurities and water blown down can be continuously discharged; In addition, the pressure sensor 1204 is used to detect the pressure of the precipitated impurities and water. When the pressure reaches the set threshold, the pressure sensor 1204 can automatically control the power on and off states of the upper and lower deformable push rods 1201 to discharge the sewage in time, so as to prevent the accumulation of too many impurities and affect the filtering effect. like Figure 5As shown in the figure, the deformable pipe plugging cover 1202 includes an oval pressure-resistant cover 12021 (preferably made of rubber, and other materials can also be selected according to actual needs), and multiple groups of elastic plastic diaphragm sheets 12022 symmetrically distributed up and down and embedded inside the pressure-resistant cover 12021 (preferably made of polyurethane elastic material, and other materials can also be selected according to actual needs). A connecting pin 12023 is rotatably connected between two elastic plastic diaphragm sheets 12022 in the same group. When the deformable pipe plugging cover 1202 is extruded by the deformation pushing rod 1201, the two opposite elastic plastic diaphragm sheets 12022 rotate around the middle connecting pin 12023 relative to each other, so that the deformation of the entire deformable pipe plugging cover 1202 becomes an ellipsoid, thereby blocking the slag discharge pipe 13 with the deformable pipe plugging cover 1202.

[0021] In this embodiment, the isolated sewage discharge is realized by controlling the deformation of the upper and lower deformable pipe plugging covers 1202, effectively avoiding a large amount of oil being carried out when cleaning impurities, thus avoiding waste. And most importantly, online cleaning is realized, effectively maintaining the high filtration efficiency of the filter cartridge 8, and at the same time, the trouble of regularly disassembling the filter cartridge 8 for cleaning can be saved.

[0022] The third embodiment: On the basis of the first embodiment and the second embodiment, this embodiment further improves the steam purging, and uses the purging compensator 11 to compensate for the insufficient blowing force during steam purging, and the rest is the same as the first embodiment.

[0023] As Figure 3 、 6 shown, the purging compensator 11 includes an elastic airbag 1101 in the middle (preferably made of high-temperature resistant rubber, and other materials can also be selected according to actual needs), and hard capsule heads 1102 connected to the upper and lower ends of the elastic airbag 1101. The inner wall of the upper hard capsule head 1102 is provided with a ventilation hole communicating with the elastic airbag 1101. The inner wall of the turtle-back type sealing rotary cover 2 is provided with a steam channel 202 communicating with the ventilation hole and the oil passage 201 at the same time, and a solenoid valve (the specific model is selected according to actual needs) is installed inside the steam channel 202. A plurality of self-opening and closing air release valves 14 are fixedly embedded in the side wall of the elastic airbag 1101 and distributed in an equidistant and circumferential manner, and an opening valve belt 15 is connected between two opposite self-opening and closing air release valves 14; As Figure 7 shown, the self-opening and closing air release valve 14 includes a valve seat 1401 fixedly connected to the inner and outer walls of the elastic airbag 1101, a positioning ring 1402 fixedly connected between the two valve seats 1401, and a sealing piece 1403 hinged to the positioning ring 1402 through a damping hinge. The sealing piece 1403 is magnetically adsorbed to the positioning ring 1402, and the opening direction of the sealing piece 1403 faces the inside of the elastic airbag 1101; As Figure 6 shown, the working process of the purge compensator 11 is as follows: during the regular cleaning by steam purging, first open the solenoid valve inside the steam passage 202, so that the steam entering from the steam pipe 4 and the oil passage 201 flows along the steam passage 202 into the inside of the purge compensator 11. In the initial state, the sealing piece 1403 is magnetically adsorbed on the positioning ring 1402 to achieve the sealing of the purge compensator 11. When the steam enters the inside of the purge compensator 11, the purge compensator 11 continuously expands and becomes larger. As the purge compensator 11 expands, the distance between the two self-opening and closing air release valves 14 increases, and then the valve opening belt 15 is gradually straightened. When the distance between the two opposite sealing pieces 1403 increases to exceed the length of the non-elastic belt 1502, the pulling effect of the valve opening belt 15 causes the sealing piece 1403 to be pulled open, thereby releasing the steam. Since the elastic airbag 1101 has elasticity, when releasing the steam, the elasticity of the elastic airbag 1101 acts on the steam, thereby increasing the purging force of the steam on the filter cartridge 8 and effectively improving the steam purging effect.

[0024] As Figure 8 shown, the valve opening belt 15 includes an elastic belt 1501 and a non-elastic belt 1502 inserted inside the elastic belt 1501, and the length of the non-elastic belt 1502 is greater than the length of the elastic belt 1501. The elastic belt 1501 serves to wrap and protect the non-elastic belt 1502, and when the distance between the two opposite sealing pieces 1403 exceeds its own length, the non-elastic belt 1502 can pull the sealing piece 1403 away from the positioning ring 1402, thereby releasing the steam.

[0025] This embodiment mainly considers that there may be a situation of insufficient steam pressure during steam purging, so as to use the purge compensator 11 to compensate the steam purging force, thereby effectively improving the purging effect on the filter cartridge 8. Especially when the filter cartridge 8 is severely blocked, the cleaning effect can be effectively improved.

[0026] Combined with the current actual requirements, the above-mentioned embodiment adopted in this application, the protection scope is not limited to this. Within the knowledge scope of those skilled in the art, various changes made without departing from the concept of this application still fall within the protection scope of the present invention.

Claims

1. A turtle-back filter for removing impurities from crude grease, characterized in that: It includes a filter housing (1), a turtle-back type sealing rotary cover (2) rotatably and sealingly connected to the upper end of the filter housing (1), an oil inlet pipe (3) connected below the turtle-back type sealing rotary cover (2), a steam pipe (4) communicated above the oil inlet pipe (3), a sewage discharge pipe (5) communicated at the bottom of the filter housing (1), and an oil outlet pipe (6) communicated on the side of the sewage discharge pipe (5). A through-oil channel (201) communicated with the oil inlet pipe (3) is provided on the inner wall of the turtle-back type sealing rotary cover (2), and the oil inlet pipe (3) and the through-oil channel (201) are sealingly connected by a flange. A steam purging device communicated with the steam pipe (4) is further provided outside the filter housing (1). A support cylinder (7) with a pore size of 0.5 - 1 mm is placed inside the filter housing (1), and a filter cartridge (8) is placed inside the support cylinder (7). A plurality of equally spaced and circumferentially distributed ultrasonic vibrators (10) are installed on the inner side wall of the support cylinder (7), and the vibrating surface of the ultrasonic vibrator (10) contacts the filter cartridge (8). A plurality of groups of matching differential pressure sensors (9) are installed on the inner wall of the filter housing (1) and the inner wall of the filter cartridge (8), and the differential pressure sensor (9) is signal-connected to the steam purging device through a control processor; A purging compensator (11) coaxial with the filter cartridge (8) is fixedly connected to the lower end of the turtle-back type sealing rotary cover (2), and an isolation type sewage discharger (12) is fixedly connected to the lower end of the purging compensator (11). A slag discharge pipe (13) extending into the sewage discharge pipe (5) is communicated at the bottom of the filter cartridge (8), and a perforation matching the slag discharge pipe (13) is provided at the bottom of the support cylinder (7). The isolation type sewage discharger (12) penetrates into the interior of the slag discharge pipe (13); The isolation type sewage discharger (12) includes upper, middle, and lower deformed push rods (1201), and a deformed pipe blocking cover (1202) fixedly connected between adjacent two deformed push rods (1201). The upper deformed pipe blocking cover (1202) is arranged close to the upper port of the slag discharge pipe (13). The middle deformed push rod (1201) is made of a magnetic material, and the upper and lower deformed push rods (1201) are made of an electromagnetic material. A pressure sensor (1204) is installed on the side wall of the middle deformed push rod (1201) close to the lower deformed pipe blocking cover (1202). The pressure sensor (1204) is signal-connected to the upper and lower deformed push rods (1201). A push rod (1203) is also slidably connected to the inner wall of the middle deformed push rod (1201), and the upper and lower ends of the push rod (1203) are respectively in contact with the upper and lower deformed push rods (1201); The deformed pipe blocking cover (1202) includes an oval pressure-resistant cover (12021) and a plurality of groups of symmetrically distributed upper and lower elastic plastic diaphragms (12022) embedded inside the pressure-resistant cover (12021), and a connecting pin (12023) is rotatably connected between two elastic plastic diaphragms (12022) in the same group.

2. The turtle-back filter for crude grease impurity removal according to claim 1, characterized in that: A solid bottom cylinder (801) is fixedly embedded at the bottom of the filter cartridge (8), and the mesh number of the filter cartridge (8) is 500 - 800 meshes.

3. The turtle-back filter for crude grease impurity removal according to claim 1, wherein: The purging compensator (11) includes an intermediate elastic airbag (1101) and rigid capsule heads (1102) connected to the upper and lower ends of the elastic airbag (1101). An air vent communicating with the elastic airbag (1101) is provided on the inner wall of the upper rigid capsule head (1102). A steam channel (202) communicating with the air vent and the oil passage (201) is provided on the inner wall of the turtle-back type sealing rotary cover (2). A solenoid valve is installed inside the steam channel (202). A plurality of self-opening and closing air release valves (14) are fixedly embedded in the side wall of the elastic airbag (1101) and are evenly distributed in a circumferential manner. An opening valve belt (15) is connected between two opposite self-opening and closing air release valves (14).

4. The turtle-back filter for crude grease impurity removal according to claim 3, characterized in that: The self-opening and closing air release valve (14) includes a valve seat (1401) fixedly connected to the inner and outer walls of the elastic airbag (1101), a positioning ring (1402) fixedly connected between the two valve seats (1401), and a sealing piece (1403) hinged to the positioning ring (1402) through a damping hinge. The sealing piece (1403) is magnetically adsorbed to the positioning ring (1402), and the opening direction of the sealing piece (1403) faces the inside of the elastic airbag (1101).

5. The turtle-back filter for crude grease impurity removal according to claim 3, characterized in that: The opening valve belt (15) includes an elastic belt (1501) and a non-elastic belt (1502) inserted inside the elastic belt (1501), and the length of the non-elastic belt (1502) is greater than the length of the elastic belt (1501).

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