Double-stage filtration fuel filter

Abstract

The present invention discloses a two-stage filtering fuel filter. A filter element assembly is inserted into a housing assembly. A water collecting cup assembly is connected to the lower end of the housing assembly. An oil inlet and an oil outlet are provided on the housing body of the housing assembly. The filter element assembly includes a coarse filtering part and a fine filtering part arranged in a stacked manner. The coarse filtering layer of the coarse filtering part and the fine filtering layer of the fine filtering part are connected by a middle end cover. The upper part of the middle end cover covers the bottom of the fine filtering layer, a middle through hole is opened in the lower part of the middle end cover, and a flow-through channel communicating the middle through hole with the dirty side of the fine filter is provided in the middle of the middle end cover. In the present invention, the coarse filtering layer and the fine filtering layer of the filter element assembly are connected by the same middle end cover, reducing the setting of the matching structure, simplifying the structure, and reducing the requirements for the machining accuracy and assembly accuracy of each component. The coarse filtering part combines a dirty side water separation structure and a clean side two-stage water separation structure to achieve water separation and filtration, with high water separation efficiency, more thorough separation and filtration of water, and providing cleaner fuel for the engine.

Description

Technical Field

[0001] The present invention relates to the technical field of engine fuel filters, and particularly to a two-stage filtered fuel filter. Background Art

[0002] The fuel filter is connected in series in the engine fuel system. After filtering out impurities and water in the fuel, it provides clean fuel to the fuel pump and the high-pressure common rail system, avoiding the wear and corrosion of precision components in the engine fuel system by impurities and water, and ensuring the normal operation of the engine.

[0003] In order to meet the requirements of National VI, commercial vehicles usually adopt a two-stage filtered fuel filter, and its filter element assembly includes a coarse filter assembly and a fine filter assembly arranged in series. The existing two-stage filtered fuel filter has the following disadvantages:

[0004] (1) The structures of the coarse filter assembly and the fine filter assembly are basically the same. The filter layer is sleeved on the outer periphery of the central pipe network, and upper end caps and lower end caps are respectively arranged at the upper and lower ends of the filter layer. The coarse filter assembly and the fine filter assembly are connected in series through connecting parts. The filter element assembly contains many components, with a high cost. The overall structure is not compact enough, the volume is relatively large, and it is relatively heavy. Moreover, between the filter layer of the coarse filter assembly and its upper end cap, between the filter layer of the fine filter assembly and its lower end cap, between the upper end cap of the coarse filter assembly and the connecting part, and between the lower end cap of the fine filter assembly and the connecting part, separate matching structures need to be set respectively, and the processing precision of each component and the assembly precision among the three are required to be relatively high.

[0005] (2) The existing coarse filter assembly usually only relies on the water-repellent net to separate water in the fuel, and the water separation efficiency is relatively low.

[0006] (3) The existing filter assembly with a hand pump is usually composed of a hand pump base connected to the fuel filter. When the fuel is flowing, larger particulate impurities in the fuel may adhere to the check valve in the hand pump base, resulting in the failure of the base hand pump and thus unable to pump fuel. Moreover, the structure of the filter assembly with a hand pump base used in the market is complex. When cleaning particulate impurities, it is time-consuming and laborious, and it is impossible to promptly handle the particulate impurities.

[0007] (4) The existing fuel filter's water collection cup usually has only one water collection cavity. The water filtered out from the dirty side and the clean side of the filter element assembly is collected into the same water collection cavity. The oil-water mixture accumulated on the dirty side is likely to cause secondary pollution to the subsequent fuel, thereby increasing the filtering burden of the filter element assembly, reducing the filtering efficiency, and also reducing the service life of the fuel filter. Summary of the Invention

[0008] In view of the above-mentioned disadvantages of the existing double-stage filtration fuel filter, the applicant provides a double-stage filtration fuel filter with a reasonable structure, which reduces the use of components, reduces costs, has a more compact structure, and the water separation function does not decay during the whole life cycle.

[0009] The technical solution adopted by the present invention is as follows:

[0010] A double-stage filtration fuel filter, in which a filter element assembly is inserted into a housing assembly, a water collecting cup assembly is connected to the lower end of the housing assembly, and an oil inlet and an oil outlet are arranged on the housing body of the housing assembly; the filter element assembly includes a coarse filtration part and a fine filtration part arranged in a stacked manner. The outer side of the coarse filtration part is the coarse filtration dirty side, and the center of the coarse filtration part is the coarse filtration clean side; the outer side of the fine filtration part is the fine filtration dirty side, and the center of the fine filtration part is the fine filtration clean side. The coarse filtration dirty side is communicated with the oil inlet, and the fine filtration clean side is communicated with the oil outlet; the coarse filtration layer of the coarse filtration part and the fine filtration layer of the fine filtration part are connected by a middle end cover, and the middle end cover isolates the coarse filtration part and the fine filtration part; the upper part of the middle end cover covers the bottom of the fine filtration layer, a middle through hole communicating with the coarse filtration clean side is opened at the lower part of the middle end cover, and a flow-through channel communicating the middle through hole with the fine filtration dirty side is arranged in the middle of the middle end cover.

[0011] As a further improvement of the above technical solution:

[0012] The coarse filtration part of the filter element assembly includes a coarse filtration layer, a central network tube, and a water collecting cylinder. The coarse filtration layer is sleeved on the outer periphery of the central network tube, a water-repellent net is nested on the central network tube, the water collecting cylinder is inserted between the coarse filtration layer and the central network tube, and the annular cavity between the water collecting cylinder and the water-repellent net forms a hydrophobic cavity; a water-repellent coating is coated on the outer surface of the coarse filtration layer; a lower end cover is arranged at the lower end of the coarse filtration layer, and a lower through hole communicating with the hydrophobic cavity is opened at the center of the lower end cover; the fine filtration part of the filter element assembly includes a fine filtration layer, an upper end cover is adhesively fixed to the upper end of the fine filtration layer, an upper through hole communicating with the fine filtration clean side is opened at the center of the upper end cover; a cover cylinder is sleeved on the outer periphery of the middle and lower parts of the fine filtration layer.

[0013] The middle end cover includes an integrally formed upper cover plate part, a lower cover plate part and a plurality of connecting ribs. The plurality of connecting ribs are vertically arranged between the upper cover plate part and the lower cover plate part, and a flow-through channel is formed between adjacent connecting ribs; the upper cover plate part covers the lower end of the fine filtration layer and has a closed bottom surface; the lower cover plate part covers the upper end of the coarse filtration layer, and a middle through hole is opened at the center of the lower cover plate part.

[0014] The middle end cover includes a separately designed upper cover plate and a lower cover plate. The upper cover plate and the lower cover plate are connected by a clamping structure, a plurality of transverse ribs are arranged between the upper cover plate and the lower cover plate, a flow-through channel is formed between adjacent transverse ribs, and a middle through hole is opened at the center of the lower cover plate; the upper cover plate covers the lower end of the fine filtration layer, and the lower cover plate covers the upper end of the coarse filtration layer.

[0015] An outer cylinder is vertically arranged in the middle of the inner side of the housing body, the outer cylinder extends into the fine filtration clean side and supports on the inner side of the fine filtration layer; an interference fit is formed between the outer cylinder and the upper end cover to form an interference sealing surface.

[0016] An inner cylinder is vertically provided inside the shell main body, and the inner cylinder is located inside the outer cylinder; a hand pump assembly is arranged inside the inner cylinder and the outer cylinder. The valve seat of the hand pump assembly is fixed to the lower end of the outer cylinder, and the valve ball is placed inside the valve seat and can form a one-way valve seal with the valve seat. The push-pull rod is inserted through the center of the inner cylinder, and the valve frame and the valve plate are fixed to the lower end of the push-pull rod. The valve plate covers the upper side of the valve frame; the upper end of the push-pull rod passes through the shell main body, and the hand grip is fixed to the upper end of the push-pull rod.

[0017] The upper end of the inner cylinder is provided with a protruding part, and the protruding part extends into the oil outlet; several guiding ribs are arranged at the lower end of the inner cylinder.

[0018] An insert kit is arranged in the insertion hole of the shell main body. Several reinforcing ribs are arranged on the outer peripheral surface of the lower end of the insert kit. Two upper and lower second sealing rings are arranged between the insert kit and the push-pull rod; a first sealing ring is arranged on the inner side surface of the hand grip, and the first sealing ring is directly opposite to the upper side of the mating surface between the insert kit and the push-pull rod; the lower end of the push-pull rod has a thick-diameter part, the upper end surface of the thick-diameter part is a limiting surface, and the height of the thick-diameter part is equal to or greater than the vertical distance between the upper end surface of the protruding part of the inner cylinder and the lower end surface of the insert kit.

[0019] A partition ring is arranged inside the cup body of the water collecting cup assembly. The partition ring divides the cavity inside the cup body into a clean-side water collecting cavity and a dirty-side water collecting cavity. The clean-side water collecting cavity communicates with the hydrophobic cavity inside the coarse filter part of the filter element assembly, and the dirty-side water collecting cavity communicates with the outside of the coarse filter part of the dirty side of the coarse filter.

[0020] A drain hole is opened on the bottom surface of the cup body. The upper part of the drain hole is divided into a clean-side hole and a dirty-side hole by the partition ring. The lower part of the drain hole is an insertion hole part. A drain screw sleeve is connected inside the insertion hole part. A sealing gasket is sleeved on the upper end of the drain screw sleeve. A drain valve is sleeved on the outer periphery of the drain screw sleeve; a water guide groove is horizontally opened on the inner side of the bottom surface of the cup body corresponding to the clean-side water collecting cavity, and the water guide groove communicates with the clean-side hole; several drain grooves are opened on the drain screw sleeve; an axial sealing surface and a radial sealing ring are arranged on the sealing gasket.

[0021] The beneficial effects of the present invention are as follows:

[0022] The coarse filter layer and the fine filter layer of the filter element assembly of the present invention are connected through the same middle end cover. It only needs to ensure the fitting accuracy between the coarse filter layer and the middle end cover and between the fine filter layer and the middle end cover, reducing the setting of fitting structures, simplifying the structure, and lowering the requirements for the machining accuracy and assembly accuracy of each component. The water-repellent coating on the outer surface of the coarse filter layer constitutes the water separation structure on the dirty side of the coarse filter, intercepting and filtering most of the water particles in the fuel on the dirty side of the coarse filter to achieve water separation and filtration on the dirty side of the coarse filter; the water collecting cylinder and the water-repellent net constitute the double-stage water separation structure on the clean side of the coarse filter. The water collecting cylinder intercepts the water particles passing through the coarse filter layer and coalesces them into large water droplets that slide downward, and the water-repellent net further intercepts and filters a small amount of water particles driven by the inertia of fuel flow to achieve water separation and filtration on the clean side of the coarse filter; the coarse filter part realizes water separation and filtration through the combination of the dirty side water separation structure and the clean side double-stage water separation structure, with high water separation efficiency, more thorough separation and filtration of water, and providing cleaner fuel for the engine. The cover cylinder in the middle and lower part of the fine filter layer can force the fuel liquid level to climb and reach the fine filter layer only after passing over the upper port of the cover cylinder, keeping the fuel liquid level always stably above the upper port of the cover cylinder and ensuring the stability of the liquid level; in addition, corresponding customer information, product information, etc. can be printed on the outer surface of the cover cylinder to achieve the effect of advertising and publicity.

[0023] The outer cylinder of the housing assembly of the present invention is inserted into the center of the fine filter layer, which can support the fine filter layer and prevent the fine filter layer from collapsing. The outer cylinder is integrally formed on the housing body, which replaces the traditional central mesh support member to support the fine filter layer, reduces the use of support members, lowers the cost of parts, and simplifies the structure of the fine filter part, making the overall structure of the filter element assembly more compact, smaller in size, and lighter. The outer wall surface of the outer cylinder and the upper end cover are sealed through an interference sealing surface, and the interference sealing surface replaces the traditional seal to conduct sealing, reducing the use of seals and lowering the cost of parts. The protruding part of the inner cylinder vertically extends into the oil outlet, which can reasonably and effectively utilize the space of the oil outlet. Within the limited design space, the effective stroke cavity of the push rod is increased as much as possible, improving the oil pumping efficiency of the hand pump assembly. The guiding ribs at the lower end of the inner cylinder enable the valve holder to always move along the central axis of the inner cylinder, preventing the valve holder from shaking and causing abnormal wear of the push rod. There are two second sealing rings, upper and lower, between the insert kit and the push rod, improving the sealing reliability and product stability. Half of the first sealing ring on the inner side of the hand grip contacts the housing body and the other half contacts the insert kit, which can seal the mating surface between the housing body and the insert kit, preventing product leakage caused by fatigue loosening between the insert kit and the housing body during their service life, and improving the sealing reliability and stability of the product. The limiting surface of the thick diameter part of the push rod limits the maximum stroke of the push rod, preventing the valve plate from directly colliding with the insert kit and causing abnormal wear of the valve plate, ensuring that after the push rod is lifted to the highest position, the valve holder and the valve plate still remain within the inner cylinder, preventing the valve plate from sliding out of the inner cylinder and causing abnormal wear of the valve plate. The ribbed plate of the valve holder can improve the support strength of the valve holder and prevent the valve holder from collapsing. The outer hexagonal mounting post of the valve seat facilitates the installation of the valve seat onto the housing body with the aid of auxiliary tools.

[0024] The cup body of the water collecting cup assembly of the present invention is separated into two water collecting cavities by a separating ring. The clean-side water collecting cavity only collects the water on the clean side, and the dirty-side water collecting cavity only collects the water on the dirty side. The water in the two water collecting cavities does not interfere with each other, preventing the oil-water mixture on the dirty side from causing secondary pollution to the subsequent fuel, reducing the filtration burden of the filter element assembly, and improving the filtration efficiency and the service life of the fuel filter. The water in the clean-side water collecting cavity and the dirty-side water collecting cavity converges to the lower part of the drain hole and is discharged through the same drain screw sleeve and drain valve, realizing the discharge of the water in the two water collecting cavities using one drain valve, reducing the use of components, lowering the component cost, and simplifying the structure of the water collecting cup assembly, making the overall structure more compact and lightweight. The water guide groove can guide the water in the clean-side water collecting cavity to the clean-side hole, facilitating the complete drainage of the water in the clean-side water collecting cavity. The drain screw sleeve realizes axial sealing and radial sealing simultaneously through a sealing gasket, with more reliable sealing and lower product leakage risk. The lower end cover of the filter element assembly and the separating ring are sealed through an interference sealing surface. The interference sealing surface replaces the traditional sealing parts for sealing, reducing the use of sealing parts and lowering the component cost. The convex ribs and concave ribs of the cup body can improve the strength of the cup body. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a perspective view of the present invention.

[0026] Figure 2 is a cross-sectional view of the present invention.

[0027] Figure 3 is a perspective view of the filter element assembly.

[0028] Figure 4 is a cross-sectional view of the filter element assembly.

[0029] Figure 5 is a perspective view of an embodiment of the middle end cover.

[0030] Figure 6 is an exploded view of another embodiment of the middle end cover.

[0031] Figure 7 is a three-dimensional sectional view of another embodiment of the middle end cover.

[0032] Figure 8 is a three-dimensional sectional view of the housing assembly.

[0033] Figure 9 is a perspective view of the valve seat.

[0034] Figure 10 is a perspective view of the valve frame.

[0035] Figure 11 is a perspective view of the inlay kit.

[0036] Figure 12It is a three-dimensional view of the water collecting cup assembly.

[0037] Figure 13 It is a sectional view of the water collecting cup assembly.

[0038] Figure 14 It is Figure 13 an enlarged view of part A in

[0039] Figure 15 It is a three-dimensional view of the drain screw sleeve.

[0040] Figure 16 It is a schematic diagram of the fuel working principle of the present invention.

[0041] Figure 17 It is a schematic diagram of the exhaust working principle of the present invention. At this time, the push-pull rod of the hand pump assembly is pulled up.

[0042] Figure 18 It is a schematic diagram of the exhaust working principle of the present invention. At this time, the push-pull rod of the hand pump assembly is pushed down.

[0043] In the figure: 1. Housing assembly; 11. Housing main body; 12. Oil inlet; 13. Oil outlet; 14. Inner cylinder; 141. Protruding part; 142. Guide rib; 15. Outer cylinder; 151. Oil passage; 16. Hand pump assembly; 161. Valve seat; 1611. Mounting post; 162. Valve ball; 163. Push-pull rod; 1631. Thick diameter part; 1632. Limiting surface; 164. Valve frame; 1641. Oil passage hole; 1642. Rib plate; 165. Valve plate; 166. Hand grip; 167. First sealing ring; 17. Insertion kit; 171. Reinforcing rib; 172. Second sealing ring; 18. Limiting rib; 19. Exhaust valve;

[0044] 2. Filter element assembly; 10. Coarse filter part; 20. Fine filter part; 21. Coarse filter layer; 22. Fine filter layer; 23. Upper end cover; 231. Upper through hole; 232. First convex ring; 24. Middle end cover; 241. Upper cover plate part; 242. Lower cover plate part; 2421. Middle through hole; 243. Connecting rib; 244. Flow-through channel; 245. Upper cover plate; 2451. Hook; 2452. Cross rib; 246. Lower cover plate; 2461. Middle through hole; 2462. Axial convex ring; 25. Lower end cover; 251. Lower through hole; 252. Second convex ring; 26. Central network tube; 261. Water passage hole; 27. Water repellent net; 28. Water collecting cylinder; 29. Covering cylinder;

[0045] 3. Water collecting cup assembly; 31. Cup body; 311. Convex rib; 312. Concave rib; 32. Partition ring; 33. Clean side water collecting cavity; 34. Dirty side water collecting cavity; 35. Drain hole; 351. Clean side hole; 352. Dirty side hole; 353. Insertion hole part; 354. Step surface; 36. Water guide groove; 37. Drainage screw sleeve; 371. Drainage groove; 38. Sealing gasket; 381. Axial sealing surface; 382. Radial sealing ring; 39. Drain valve;

[0046] 100. Coarse filter dirty side; 200. Coarse filter clean side; 300. Fine filter dirty side; 400. Fine filter clean side; 500. Hydrophobic cavity. Detailed implementation mode

[0047] The following combines with the attached drawings to illustrate the detailed implementation mode of the present invention.

[0048] As Figure 1 、 Figure 2 shown, the double-stage filtering fuel filter of the present invention includes a housing assembly 1, a filter element assembly 2 and a water collecting cup assembly 3. The filter element assembly 2 is inserted into the inner cavity of the housing assembly 1, and the water collecting cup assembly 3 is fixedly connected to the lower end of the housing assembly 1 by thread connection.

[0049] As Figure 3 、 Figure 4 shown, the filter element assembly 2 is a double-stage filtering filter element, including a coarse filter part 10 and a fine filter part 20 arranged in layers from bottom to top; the outside of the coarse filter layer 21 of the coarse filter part 10 is the coarse filter dirty side 100, and the center of the coarse filter layer 21 is the coarse filter clean side 200; the outside of the fine filter layer 22 of the fine filter part 20 is the fine filter dirty side 300, and the center of the fine filter layer 22 is the fine filter clean side 400.

[0050] As Figure 4As shown, the coarse filtration part 10 of the filter element assembly 2 includes a coarse filtration layer 21, a central network tube 26, and a water collecting cylinder 28; the coarse filtration layer 21 is sleeved on the outer periphery of the central network tube 26, a water repellent net 27 is nested on the circumferential surface of the central network tube 26, the water collecting cylinder 28 is inserted between the coarse filtration layer 21 and the central network tube 26, the water collecting cylinder 28 is a cylindrical cotton cylinder, and the annular cavity between the water collecting cylinder 28 and the water repellent net 27 forms a hydrophobic cavity 500; a layer of water repellent coating is applied on the outer surface of the coarse filtration layer 21; the water repellent coating on the outer surface of the coarse filtration layer 21 constitutes a water separation structure on the dirty side 100 of the coarse filter, intercepts and filters most of the water particles in the fuel on the dirty side 100 of the coarse filter, and realizes water separation and filtration on the dirty side 100 of the coarse filter; the water collecting cylinder 28 and the water repellent net 27 constitute a two-stage water separation structure on the clean side 200 of the coarse filter. The water collecting cylinder 28 intercepts the water particles passing through the coarse filtration layer 21 and coalesces them into large particle water droplets that slide downward, and the water repellent net 27 further intercepts and filters a small amount of water particles driven by the inertia of fuel flow, realizing water separation and filtration on the clean side 200 of the coarse filter; the coarse filtration part 10 realizes water separation and filtration through the combination of the dirty side water separation structure and the clean side two-stage water separation structure, with high water separation efficiency, more thorough separation and filtration of water, and providing cleaner fuel for the engine. The top surface of the central network tube 26 is open, and the middle part of the bottom surface is blocked at the bottom of the clean side 200 of the coarse filter. A number of water passing holes 261 communicating with the hydrophobic cavity 500 are provided on the outer side of the bottom surface of the central network tube 26. The lower end of the coarse filtration layer 21 is adhesively fixed with a lower end cover 25, a lower through hole 251 is provided in the center of the lower end cover 25, and the lower through hole 251 communicates with the hydrophobic cavity 500; a number of second convex rings 252 protrude radially outward along the outer circumferential surface of the lower part of the lower end cover 25.

[0051] As Figure 4 shown, the fine filtration part 20 of the filter element assembly 2 includes a fine filtration layer 22, the upper end of the fine filtration layer 22 is adhesively fixed with an upper end cover 23, an upper through hole 231 is provided in the center of the upper end cover 23, and the upper through hole 231 communicates with the clean side 400 of the fine filter; a number of first convex rings 232 protrude radially inward along the inner circumferential surface of the upper through hole 231. As Figure 3 , Figure 4 shown, a cover cylinder 29 is sleeved on the outer periphery of the middle and lower part of the fine filtration layer 22. The cover cylinder 29 is a paper sleeve. The cover cylinder 29 can force the fuel liquid level to climb, and the fuel can only reach the fine filtration layer 22 after passing over the upper port of the cover cylinder 29, so that the fuel liquid level is always stably maintained above the upper port of the cover cylinder 29, ensuring the stability of the liquid level; in addition, corresponding customer information, product information, etc. can also be printed on the outer surface of the cover cylinder 29 to achieve the effect of advertising and publicity.

[0052] As Figure 3 , Figure 4As shown in the figure, the upper end of the coarse filter layer 21 of the coarse filter part 10 of the filter element assembly 2 is connected to the lower end of the fine filter layer 22 of the fine filter part 20 through the middle end cover 24. The coarse filter layer 21, the fine filter layer 22 and the middle end cover 24 are respectively fixed by bonding; the coarse filter layer 21 and the fine filter layer 22 are connected by the same middle end cover 24. Only the matching accuracy between the coarse filter layer 21 and the middle end cover 24 and between the fine filter layer 22 and the middle end cover 24 needs to be ensured, reducing the setting of the matching structure, simplifying the structure, and reducing the requirements for the machining accuracy and assembly accuracy of each component. As Figure 2 As shown in the figure, after the filter element assembly 2 is inserted into the housing assembly 1, a sealing member is provided between the outer peripheral surface of the middle end cover 24 and the inner peripheral surface of the housing body 11 to seal and isolate the coarse filter dirty side 100 of the coarse filter part 10 from the fine filter dirty side 300 of the fine filter part 20, preventing the fuel in the coarse filter dirty side 100 from leaking into the fine filter dirty side 300 and affecting the filtration efficiency.

[0053] As Figure 5 As shown in the figure, it is a schematic diagram of an embodiment of the middle end cover 24. The middle end cover 24 includes an integrally formed upper cover plate part 241, a lower cover plate part 242 and a plurality of connecting ribs 243. The plurality of connecting ribs 243 are vertically arranged between the upper cover plate part 241 and the lower cover plate part 242, and an over-flow channel 244 for fuel flow is formed between adjacent connecting ribs 243. The upper cover plate part 241 has a closed bottom surface, and a middle through hole 2421 is opened in the center of the lower cover plate part 242. The middle through hole 2421 communicates with the over-flow channel 244. As Figure 4 As shown in the figure, the upper cover plate part 241 of the middle end cover 24 covers the lower end of the fine filter layer 22 to seal the bottom of the fine filter clean side 400 in the center of the fine filter layer 22; the lower cover plate part 242 of the middle end cover 24 covers the upper end of the coarse filter layer 21, and the middle through hole 2421 of the lower cover plate part 242 communicates with the coarse filter clean side 200 in the center of the coarse filter layer 21; the over-flow channel 244 of the middle end cover 24 communicates with the fine filter dirty side 300 outside the fine filter layer 22.

[0054] As Figure 6 、 Figure 7 As shown in the figure, it is a schematic diagram of another embodiment of the middle end cover 24. The middle end cover 24 includes a separately designed upper cover plate 245 and a lower cover plate 246. The upper cover plate 245 covers the lower end of the fine filter layer 22, and the lower cover plate 246 covers the upper end of the coarse filter layer 21; the upper cover plate 245 and the lower cover plate 246 are connected by a clamping structure. A plurality of hooks 2451 and a plurality of transverse ribs 2452 are vertically extended downward on the bottom surface of the upper cover plate 245; a middle through hole 2461 is opened in the center of the lower cover plate 246, and an axial convex ring 2462 is vertically extended downward from the lower cover plate 246; a plurality of hooks 2451 of the upper cover plate 245 are clamped on the axial convex ring 2462 of the lower cover plate 246, and the transverse ribs 2452 abut against the lower cover plate 246, and an over-flow channel 244 is formed between adjacent transverse ribs 2452. In other embodiments, the transverse ribs 2452 can also be integrally formed on the lower cover plate 246.

[0055] As Figure 8 shown, an oil inlet 12 is provided in the middle and lower part of the shell main body 11 of the shell assembly 1, and an oil outlet 13 is provided at the top of the shell main body 11. As Figure 2 、 Figure 16 shown, the oil inlet 12 communicates with the dirty side 100 of the coarse filter, and the oil outlet 13 communicates with the clean side 400 of the fine filter. As Figure 8 shown, in the middle of the inner side of the top surface of the shell main body 11, an inner cylinder 14 and an outer cylinder 15 extend vertically downward. The inner cylinder 14 and the outer cylinder 15 are coaxially arranged, and there is an annular space between them. The height of the outer cylinder 15 is greater than the height of the inner cylinder 14. As Figure 2 shown, the outer cylinder 15 and the inner cylinder 14 pass through the upper through hole 231 of the upper end cover 23 of the filter element assembly 2 and extend into the clean side 400 of the fine filter. There is a space between the lower port of the outer cylinder 15 and the upper surface of the middle end cover 24 of the filter element assembly 2 to form an oil passage 151; the outer cylinder 15 is inserted inside the fine filter layer 22, which can support the fine filter layer 22 and prevent the fine filter layer 22 from collapsing. The outer cylinder 15 is integrally formed on the shell main body 11, which replaces the traditional central net support to support the fine filter layer 22, reduces the use of support parts, reduces the cost of parts, and simplifies the structure of the fine filter part 20, making the overall structure of the filter element assembly 2 more compact, smaller in volume and lighter. The outer wall surface of the outer cylinder 15 is in interference fit with several first convex rings 232 of the upper end cover 23 to form an interference sealing surface to seal the mating surface between the outer cylinder 15 and the upper end cover 23. The interference sealing surface replaces the traditional seal to seal, reduces the use of seals, and reduces the cost of parts. Several limiting ribs 18 are provided on the inner side of the top surface of the shell main body 11 and outside the outer cylinder 15. The limiting ribs 18 are pressed against the upper end cover 23 of the filter element assembly 2 to axially limit the filter element assembly 2 and improve the strength of the shell main body 11 at the same time. An exhaust valve 19 is provided on the top surface of the shell main body 11.

[0056] As Figure 8 shown, a hand pump assembly 16 is provided inside the inner cylinder 14 and the outer cylinder 15. The hand pump assembly 16 includes a valve seat 161, a valve ball 162, a push-pull rod 163, a valve frame 164, a valve piece 165 and a hand grip 166. The valve seat 161 is fixed at the lower end opening of the outer cylinder 15 by screwing tightly. As Figure 2 shown, there is a space between the lower surface of the valve seat 161 and the upper surface of the middle end cover 24 of the filter element assembly 2 to ensure that the fuel has enough flow space. As Figure 8As shown, the valve ball 162 is placed inside the valve seat 161. Under the action of its own weight, the valve ball 162 is pressed against the inner surface of the valve seat 161, forming a one-way valve seal with the valve seat 161. It can cooperate with the push-pull rod 163 to achieve the fuel pumping function, and can also prevent fuel from flowing back during the shutdown state. The push-pull rod 163 vertically penetrates through the center of the inner cylinder 14. The valve frame 164 and the valve plate 165 are fixed to the lower end of the push-pull rod 163. The valve plate 165 covers the upper side of the valve frame 164. The upper end of the push-pull rod 163 passes through the top surface of the housing body 11. The hand grip 166 is fixed to the upper end of the push-pull rod 163. The hand grip 166 and the housing body 11 can be fixed tightly by screwing. As Figure 17 、 Figure 18 As shown, after the hand grip 166 is loosened from the housing body 11, by pulling and pressing the hand grip 166, the valve frame 164 and the valve plate 165 can be driven to move up and down along the inner cylinder 14 through the push-pull rod 163. As Figure 2 、 Figure 8 As shown, at the upper end of the inner cylinder 14, at the part communicating with the oil outlet 13, a convex part 141 is formed by extending upward toward the oil outlet 13. The convex part 141 vertically protrudes into the oil outlet 13, which can reasonably and effectively utilize the space of the oil outlet 13. Within the limited design space, the effective stroke cavity of the push-pull rod 163 is increased as much as possible, improving the fuel pumping efficiency of the hand pump assembly 16. A number of guide ribs 142 are circumferentially arranged at the lower end of the inner cylinder 14. As Figure 2 As shown, when the push-pull rod 163 is pressed to the lowest position and in the locked state, the valve frame 164 still remains within the range of the guide ribs 142, that is, the guide ribs 142 enable the valve frame 164 to always move along the central axis of the inner cylinder 14, avoiding the valve frame 164 from shaking and causing abnormal wear of the push-pull rod 163. Inside the insertion hole on the top surface of the housing body 11 through which the push-pull rod 163 is inserted, a cylindrical insert kit 17 is embedded. As Figure 11 As shown, a number of reinforcing ribs 171 are convexly arranged on the outer peripheral surface of the lower end of the insert kit 17. The reinforcing ribs 171 can make the connection between the insert kit 17 and the housing body 11 tighter, making it difficult for the insert kit 17 to be peeled off from the housing body 11 and cause failure. Two upper and lower second sealing rings 172 are arranged between the inner peripheral surface of the insert kit 17 and the outer surface of the push-pull rod 163 to perform two seals between the insert kit 17 and the push-pull rod 163, improving the sealing reliability and the stability of the product. A first sealing ring 167 is arranged on the inner side surface of the hand grip 166. The first sealing ring 167 is directly opposite to the upper side of the mating surface between the insert kit 17 and the push-pull rod 163. After the hand grip 166 is tightened to the housing body 11, half of the first sealing ring 167 contacts the housing body 11 and the other half contacts the insert kit 17, which can seal the mating surface between the housing body 11 and the insert kit 17, preventing product leakage caused by fatigue loosening within the service life of the insert kit 17 and the housing body 11, and improving the sealing reliability and stability of the product.

[0057] AsFigure 9 As shown, an externally hexagonal mounting post 1611 is provided at the lower part of the valve seat 161, facilitating the installation of the valve seat 161 onto the housing main body 11 with the aid of auxiliary tools.

[0058] As Figure 8 shown, at the lower end of the push-pull rod 163 and above the valve disc 165, there is a thickened portion 1631 with a larger rod diameter. The lower end face of the thickened portion 1631 presses the valve disc 165 onto the valve holder 164. The upper end face of the thickened portion 1631 is a limiting surface 1632. As Figure 18 shown, when the push-pull rod 163 is lifted to the highest position, the limiting surface 1632 of the thickened portion 1631 abuts against the lower end face of the inlay kit 17, limiting the maximum stroke of the push-pull rod 163 and preventing the valve disc 165 from directly colliding with the inlay kit 17, which may cause abnormal wear of the valve disc 165. The height of the thickened portion 1631 is equal to or greater than the vertical distance between the upper end face of the protruding portion 141 of the inner cylinder 14 and the lower end face of the inlay kit 17, ensuring that after the push-pull rod 163 is lifted to the highest position, the valve holder 164 and the valve disc 165 still remain within the inner cylinder 14, preventing the valve disc 165 from sliding out of the inner cylinder 14 and causing abnormal wear of the valve disc 165.

[0059] As Figure 10 shown, a plurality of oil passing holes 1641 are circumferentially formed on the valve holder 164. Vertically arranged triangular rib plates 1642 are provided on the bottom surface of the valve holder 164 between adjacent two oil passing holes 1641. The rib plates 1642 can improve the support strength of the valve holder 164 and prevent the valve holder 164 from collapsing.

[0060] As Figure 12 、 Figure 13 shown, in the middle of the inner side of the bottom surface of the cup body 31 of the water collecting cup assembly 3, a partition ring 32 vertically protrudes upward. The partition ring 32 divides the cavity inside the cup body 31 into a clean-side water collecting cavity 33 and a dirty-side water collecting cavity 34 on the inner and outer sides. As Figure 2 shown, the clean-side water collecting cavity 33 communicates with the hydrophobic cavity 500 inside the coarse filter part 10 of the filter element assembly 2. The water separated and filtered by the coarse filter clean side 200 slides downward and converges into the clean-side water collecting cavity 33; the dirty-side water collecting cavity 34 communicates with the coarse filter dirty side 100 outside the coarse filter part 10. The water separated and filtered by the coarse filter dirty side 100 slides downward and converges into the dirty-side water collecting cavity 34. As Figure 2 shown, the lower part of the lower end cover 25 of the filter element assembly 2 is inserted into the inner side of the partition ring 32. The second convex ring 252 of the lower end cover 25 is in interference fit with the partition ring 32 to form an interference sealing surface, sealing the mating surface between the lower end cover 25 and the partition ring 32. The interference sealing surface replaces the traditional sealing element for sealing, reducing the use of sealing elements and lowering the cost of components.

[0061] As Figure 12 、 Figure 13As shown in the figure, a drain hole 35 is vertically opened on the bottom surface of the cup body 31. The upper part of the drain hole 35 is separated by a separating ring 32 into a clean-side hole 351 communicating with the clean-side water collecting cavity 33 and a dirty-side hole 352 communicating with the dirty-side water collecting cavity 34. The lower part of the drain hole 35 is an insertion hole part 353, and there is a stepped surface 354 between the insertion hole part 353, the clean-side hole 351 and the dirty-side hole 352. As Figure 13 shown, a drain screw sleeve 37 is fixedly connected by threads in the insertion hole part 353. A sealing gasket 38 is sleeved on the upper end part of the drain screw sleeve 37, and a drain valve 39 is sleeved on the outer periphery of the drain screw sleeve 37. The water collecting cup assembly 3 is separated into two water collecting cavities by the separating ring 32. The clean-side water collecting cavity 33 only collects the water on the clean side, and the dirty-side water collecting cavity 34 only collects the water on the dirty side. The water in the two water collecting cavities does not interfere with each other, preventing the oil-water mixture on the dirty side from causing secondary pollution to the subsequent fuel, reducing the filtration burden of the filter element assembly 2, and improving the filtration efficiency and the service life of the fuel filter. After the water in the clean-side water collecting cavity 33 and the dirty-side water collecting cavity 34 is discharged separately from the upper part of the drain hole 35, they are gathered together at the lower part of the drain hole 35 and discharged through the same drain screw sleeve 37 and drain valve 39, realizing the discharge of the water in the two water collecting cavities, namely the clean-side water collecting cavity 33 and the dirty-side water collecting cavity 34, by using one drain valve 39, reducing the use of the drain screw sleeve 37 and the drain valve 39, lowering the cost of parts, and simplifying the structure of the water collecting cup assembly 3, making the overall structure more compact and lightweight.

[0062] As Figure 12 、 Figure 13 shown, a water guide groove 36 is horizontally opened on the inner side of the bottom surface of the cup body 31 corresponding to the clean-side water collecting cavity 33. The water guide groove 36 communicates with the clean-side hole 351, and can guide the water in the clean-side water collecting cavity 33 to the clean-side hole 351, which is beneficial to completely drain the water in the clean-side water collecting cavity 33. As Figure 15 shown, a plurality of drain grooves 371 are vertically and evenly opened on the upper part of the drain screw sleeve 37 along the circumferential direction. In this embodiment, three drain grooves 371 are opened along the circumferential direction, which is convenient for discharging the water collected in the cup body 31. As Figure 13 、 Figure 14 shown, the top surface of the sealing gasket 38 is an axial sealing surface 381, and the axial sealing surface 381 is pressed against the stepped surface 354 of the drain hole 35 to achieve axial sealing; there is a raised ring on the outer peripheral surface of the sealing gasket 38, and this raised ring forms a radial sealing ring 382. The radial sealing ring 382 is pressed against the inner peripheral surface of the insertion hole part 353 to achieve radial sealing; the drain screw sleeve 37 realizes both axial sealing and radial sealing through the sealing gasket 38, the sealing is more reliable, and the product leakage risk is lower.

[0063] As Figure 12 shown, a plurality of outwardly protruding ribs 311 and a plurality of inwardly concave ribs 312 are provided on the circumferential wall surface of the cup body 31. The ribs 311 and the ribs 312 can improve the strength of the cup body 31.

[0064] In actual use of the present invention:

[0065] (1) As shown in Figure 16 , when filtering fuel, as shown by the arrow in the figure, the fuel enters the dirty side 100 of the coarse filter from the fuel inlet 12 of the housing assembly 1, enters the clean side 200 of the coarse filter after being filtered by the coarse filter layer 21 of the coarse filter section 10, flows to the dirty side 300 of the fine filter through the flow-through channel 244, enters the clean side 400 of the fine filter after being filtered by the fine filter layer 22 of the fine filter section 20, the fuel overcomes the gravity of the valve ball 162 and pushes the valve ball 162 open to enter the interior of the inner cylinder 14, and flows out from the fuel outlet 13. When the fuel flows through the coarse filter layer 21, the water-repellent coating on the outer surface of the coarse filter layer 21 intercepts and filters most of the water particles in the fuel, and the filtered dirty-side water slides downward and converges into the dirty-side water collection cavity 34 of the water collection cup assembly 3; when the fuel flows through the water-collecting cylinder 28 and the water-repellent net 27, the water-collecting cylinder 28 and the water-repellent net 27 further intercept and filter the water particles in the fuel, and the filtered clean-side water slides downward and converges into the clean-side water collection cavity 33 of the water collection cup assembly 3.

[0066] (2) After the fuel filter assembly is installed for the first time or after periodic maintenance, it is necessary to evacuate the gas inside the fuel filter assembly and pump the fuel. As shown in Figure 17 and Figure 18 , when exhausting gas: First, disconnect the fuel pipe connection at the fuel outlet 13, then loosen the handgrip 166 of the hand pump assembly 16 from the housing body 11, hold the handgrip 166 with your hand and pull it upward, the valve plate 165 tightly adheres to block the oil passage hole 1641 of the valve holder 164, a negative pressure is formed in the lower space of the valve plate 165, thereby sucking the valve ball 162 open to draw air, and the air in the upper space of the valve plate 165 is discharged along the fuel outlet 13; after the push rod 163 is pulled up to the maximum stroke, hold the handgrip 166 with your hand and press it downward, the valve ball 162 falls back to the valve seat 161 under its own weight to form a check valve seal, and air or fuel cannot flow back, and the air or fuel in the lower space of the valve plate 165 passes through the oil passage hole 1641 of the valve holder 164 to push the valve plate 165 open to reach the internal cavity of the inner cylinder 14. Repeat this reciprocating motion until fuel can be seen flowing out from the fuel outlet 13, then stop pumping fuel, reconnect the fuel pipe at the fuel outlet 13, and tighten the handgrip 166 back to the housing body 11 to complete pumping fuel and exhausting gas.

[0067] (3) Regular drainage: The water separated by the filter element assembly 2 will deposit in the water collection cup assembly 3. When the water in the water collection cup assembly 3 is full, open the drain valve 39 to drain the water. After draining is completed, tighten the drain valve 39.

[0068] The above description is an explanation of the present invention, not a limitation of the present invention. Without departing from the spirit of the present invention, the present invention can be modified in any form.

Claims

1. A two-stage filtering fuel filter, in which a filter element assembly (2) is inserted into a housing assembly (1), a water collecting cup assembly (3) is connected to the lower end of the housing assembly (1), and an oil inlet (12) and an oil outlet (13) are provided on a housing body (11) of the housing assembly (1); characterized in that: The filter element assembly (2) includes a coarse filter part (10) and a fine filter part (20) arranged in a stacked manner. The outer side of the coarse filter part (10) is the coarse filter dirty side (100), and the center of the coarse filter part (10) is the coarse filter clean side (200); the outer side of the fine filter part (20) is the fine filter dirty side (300), and the center of the fine filter part (20) is the fine filter clean side (400). The coarse filter dirty side (100) is connected to the oil inlet (12), and the fine filter clean side (400) is connected to the oil outlet (13); The coarse filter layer (21) of the coarse filter part (10) is connected to the fine filter layer (22) of the fine filter part (20) through a middle end cover (24). The middle end cover (24) isolates the coarse filter part (10) and the fine filter part (20); the upper part of the middle end cover (24) covers the bottom of the fine filter layer (22), and a middle through hole communicating with the coarse filter clean side (200) is opened in the lower part of the middle end cover (24). An overflow channel (244) communicating the middle through hole and the fine filter dirty side (300) is provided in the middle of the middle end cover (24); An outer cylinder (15) is vertically provided in the middle of the inner side of the shell body (11). The outer cylinder (15) extends into the fine filter clean side (400) and is supported inside the fine filter layer (22); an inner cylinder (14) is also vertically provided on the inner side of the shell body (11). The inner cylinder (14) is located inside the outer cylinder (15); a hand pump assembly (16) is arranged inside the inner cylinder (14) and the outer cylinder (15). The valve seat (161) of the hand pump assembly (16) is fixed at the lower end of the outer cylinder (15). The valve ball (162) is placed in the valve seat (161) and can form a one-way valve seal with the valve seat (161). The push-pull rod (163) is inserted through the center of the inner cylinder (14). The valve frame (164) and the valve piece (165) are fixed at the lower end of the push-pull rod (163). The valve piece (165) covers the upper side of the valve frame (164); the upper end of the push-pull rod (163) passes through the shell body (11), and a hand grip (166) is fixed at the upper end of the push-pull rod (163).

2. The two-stage filtering fuel filter according to claim 1, characterized in that: The coarse filter part (10) of the filter element assembly (2) includes a coarse filter layer (21), a central network tube (26), and a water collecting cylinder (28). The coarse filter layer (21) is sleeved on the outer periphery of the central network tube (26). A water repellent net (27) is nested on the central network tube (26). The water collecting cylinder (28) is inserted between the coarse filter layer (21) and the central network tube (26). The annular cavity between the water collecting cylinder (28) and the water repellent net (27) forms a hydrophobic cavity (500); the outer surface of the coarse filter layer (21) is coated with a water repellent coating; a lower end cover (25) is provided at the lower end of the coarse filter layer (21). A lower through hole (251) is opened in the center of the lower end cover (25), and the lower through hole (251) communicates with the hydrophobic cavity (500); the fine filter part (20) of the filter element assembly (2) includes a fine filter layer (22). An upper end cover (23) is adhesively fixed at the upper end of the fine filter layer (22). An upper through hole (231) is opened in the center of the upper end cover (23), and the upper through hole (231) communicates with the fine filter clean side (400); a cover cylinder (29) is sleeved on the outer periphery of the middle and lower part of the fine filter layer (22).

3. The two-stage filtering fuel filter according to claim 1, characterized in that: The middle end cover (24) includes an integrally formed upper cover plate portion (241), a lower cover plate portion (242), and a plurality of connecting ribs (243). The plurality of connecting ribs (243) are vertically arranged between the upper cover plate portion (241) and the lower cover plate portion (242), and an over-flow channel (244) is formed between adjacent connecting ribs (243). The upper cover plate portion (241) covers the lower end portion of the fine filter layer (22) and has a closed bottom surface. The lower cover plate portion (242) covers the upper end portion of the coarse filter layer (21), and a middle through hole (2421) is formed in the center of the lower cover plate portion (242).

4. The two-stage filtering fuel filter according to claim 1, characterized in that: The middle end cover (24) includes a separately designed upper cover plate (245) and a lower cover plate (246). The upper cover plate (245) and the lower cover plate (246) are connected by a clamping structure. A plurality of horizontal ribs (2452) are arranged between the upper cover plate (245) and the lower cover plate (246), and an over-flow channel (244) is formed between adjacent horizontal ribs (2452). A middle through hole (2461) is formed in the center of the lower cover plate (246). The upper cover plate (245) covers the lower end portion of the fine filter layer (22), and the lower cover plate (246) covers the upper end portion of the coarse filter layer (21).

5. The two-stage filtering fuel filter according to claim 2, characterized in that: An interference fit is formed between the outer cylinder (15) and the upper end cover (23) to form an interference sealing surface.

6. The two-stage filtering fuel filter according to claim 1, characterized in that: A protruding portion (141) is provided at the upper end portion of the inner cylinder (14), and the protruding portion (141) extends into the oil outlet (13). A plurality of guiding ribs (142) are provided at the lower end portion of the inner cylinder (14).

7. The two-stage filtering fuel filter according to claim 1, characterized in that: An insert fitting (17) is provided in the insertion hole of the housing main body (11). A plurality of reinforcing ribs (171) are provided on the outer peripheral surface of the lower end portion of the insert fitting (17). Two upper and lower second sealing rings (172) are provided between the insert fitting (17) and the push rod (163). A first sealing ring (167) is provided on the inner side surface of the hand grip (166), and the first sealing ring (167) is directly opposite to the upper side of the mating surface between the insert fitting (17) and the push rod (163). The lower end portion of the push rod (163) has a thick diameter portion (1631), the upper end surface of the thick diameter portion (1631) is a limiting surface (1632), and the height of the thick diameter portion (1631) is equal to or greater than the vertical distance between the upper end surface of the protruding portion (141) of the inner cylinder (14) and the lower end surface of the insert fitting (17).

8. The two-stage filtering fuel filter according to claim 1, characterized in that: A partition ring (32) is provided in the cup body (31) of the water collecting cup assembly (3). The partition ring (32) divides the cavity in the cup body (31) into a clean side water collecting cavity (33) and a dirty side water collecting cavity (34). The clean side water collecting cavity (33) communicates with the hydrophobic cavity (500) in the coarse filter portion (10) of the filter element assembly (2), and the dirty side water collecting cavity (34) communicates with the coarse filter dirty side (100) outside the coarse filter portion (10).

9. The two-stage filtering fuel filter according to claim 8, characterized in that: A drain hole (35) is formed on the bottom surface of the cup body (31). The upper part of the drain hole (35) is separated into a clean side hole (351) and a dirty side hole (352) by a separating ring (32). The lower part of the drain hole (35) is an insertion hole part (353). A water discharge screw sleeve (37) is connected in the insertion hole part (353). A sealing gasket (38) is sleeved on the upper end part of the water discharge screw sleeve (37). A drain valve (39) is sleeved on the outer periphery of the water discharge screw sleeve (37). A water guide groove (36) is horizontally formed on the inner side of the bottom surface of the cup body (31) corresponding to the clean side water collecting cavity (33). The water guide groove (36) communicates with the clean side hole (351). A plurality of water discharge grooves (371) are formed on the water discharge screw sleeve (37). An axial sealing surface (381) and a radial sealing ring (382) are provided on the sealing gasket (38).

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