阅读说明：本技术 一种双疏水结构的燃油滤清器 (Fuel filter with double hydrophobic structures ) 是由 简鹏真 窦武 张文明 李印乐 于 2020-07-09 设计创作，主要内容包括：本发明提供了一种双疏水结构的燃油滤清器,属于汽车发动机预滤器技术领域。它解决了现有燃油滤清器水分离效率低的问题。本双疏水结构的燃油滤清器包括壳体和安装在壳体内的燃油滤芯,所述燃油滤芯包括上端盖、下端盖、疏水网和中心网,还包括安装在壳体上的集水结构和能够对待过滤燃油的杂质和水分进行过滤的滤纸,所述滤纸外侧与壳体内侧壁之间形成有用于置放上述待过滤燃油的脏油腔,所述脏油腔与上述集水结构连通。本双疏水结构的燃油滤清器具有水分离效率好、可单独更换滤纸及中心网结构以降低使用成本以及提高滤纸使用寿命的优点。(The invention provides a fuel filter with a double-hydrophobic structure, and belongs to the technical field of automobile engine prefilters. It has solved the problem that current fuel filter separation of water is inefficient. This fuel filter of two hydrophobic structures includes the casing and installs the fuel filter core in the casing, the fuel filter core includes upper end cover, bottom end cover, hydrophobic net and central net, still including installing the water collection structure on the casing and can treating impurity and the moisture of filtering the fuel and carry out filterable filter paper, be formed with between filter paper outside and the casing inside wall and be used for placeeing the above-mentioned dirty oil chamber of waiting to filter the fuel, dirty oil chamber and above-mentioned water collection structure intercommunication. This fuel filter of two hydrophobic structures has that water separating efficiency is good, can change filter paper and central net structure alone in order to reduce use cost and improve filter paper life's advantage.)

1. The utility model provides a two hydrophobic structure's fuel filter, includes casing (1) and installs the fuel filter core in casing (1), the fuel filter core includes upper end cover (5), lower end cover (6), hydrophobic net (10) and well core net (8), its characterized in that: still including installing water collecting structure on casing (1) and can treating the filter paper (7) that filter the impurity and the moisture of filtering the fuel, be formed with between filter paper (7) outside and casing (1) inside wall and be used for placeeing above-mentioned dirty oil chamber (2) of treating the fuel that filters, dirty oil chamber (2) and above-mentioned water collecting structure intercommunication.

2. The fuel filter of claim 1, wherein the fuel filter has a double hydrophobic structure, the fuel filter element is arranged at the upper end part of the shell (1), the lower end part of the shell (1) is provided with an outer side cavity (1a) and an inner side cavity (1b), the water collecting structure is a water collecting cup (3) with an outer water collecting cavity (31) and an inner water collecting cavity (32), the water collecting cup (3) is hermetically connected with the lower end of the shell (1) through a sealing connection structure, the dirty oil chamber (2) is communicated with the outer water collecting chamber (31) through the outer side chamber (1a), an oil purifying cavity is formed between the hydrophobic net (10) and the central net (8), the oil purifying cavity is communicated with the inner side cavity (1b) of the shell (1) and is communicated with the inner water collecting cavity (32) through the inner side cavity (1b) of the shell (1), and the bottoms of the outer water collecting cavity (31) and the inner water collecting cavity (32) are both provided with a water drain valve (33).

3. The fuel filter of a double hydrophobic structure according to claim 2, wherein a first gap (21) is formed between the outer peripheral wall of the lower end cap (6) and the inner side wall of the housing (1), and the dirty oil chamber (2) communicates with the outer chamber (1a) through the first gap (21).

4. The fuel filter with the double hydrophobic structures as claimed in claim 3, wherein the sealing connection structure comprises an external thread arranged on the outer peripheral wall of the lower end of the housing (1), a first convex edge (34) and a lock nut (4) arranged on the outer cavity wall of the outer water collecting cavity (31) of the water collecting cup (3), an internal thread matched with the external thread is arranged on the inner side wall of the lock nut (4), a second convex edge (41) is formed by the lower end of the lock nut (4) protruding inwards, a connecting part (35) is formed between the first convex edge (34) and the upper end face of the outer cavity wall of the outer water collecting cavity (31) of the water collecting cup (3), after assembly, the connecting part (35) is connected with the inner side wall of the lower end of the housing (1) in an attaching manner and is connected in a sealing manner through a sealing ring, and the external thread is connected with the internal thread in a threaded manner, the lower end of the shell (1) abuts against the upper end face of the first convex edge (34), and the lower end face of the first convex edge (34) abuts against the upper end face of the second convex edge (41).

5. The fuel filter of the double hydrophobic structure of claim 2 or 3 or 4, characterized in that the aperture of the water collecting cup (3) is big end down and the peripheral wall of the outer water collecting cavity (31) is an arc surface.

6. The fuel filter of claim 5, wherein the fuel filter element further comprises a base (9), the respective upper end and lower end of the filter paper (7) and the central net (8) are respectively and fixedly mounted on the upper end cover (5) and the lower end cover (6), a mounting through hole (63) which is opposite to and communicated with the inner through hole of the central net (8) is formed in the middle of the lower end cover (6), the lower end of the hydrophobic net (10) is fixedly mounted on the base (9), and the base (9) is detachably connected with the lower end cover (6) after the upper end of the hydrophobic net (10) is inserted into the inner through hole of the central net (8) from the mounting through hole (63).

7. The fuel filter with the double hydrophobic structures as claimed in claim 6, wherein the outer edge of the upper end cover (5) protrudes towards the inner side of the upper end cover (5) to form a first reinforcing rib (51), the inner side of the upper end cover (5) is further provided with a second reinforcing rib (52), and the first reinforcing rib (51) and the second reinforcing rib (52) are perpendicular to the inner side of the upper end cover (5); the outer edge of the lower end cover (6) protrudes towards the inner side face of the lower end cover (6) to form a third reinforcing rib (61), the edge of the hole wall of the mounting through hole (63) on the lower end cover (6) protrudes towards the inner side face of the lower end cover (6) to form a fourth reinforcing rib (62), and the third reinforcing rib (61) and the fourth reinforcing rib (62) are perpendicular to the inner side face of the lower end cover (6); the filter paper (7) is sleeved on the peripheral wall of the central net (8) and is fixedly arranged between the first reinforcing rib (51) and the second reinforcing rib (52) together with the central net (8), and the lower end of the filter paper is fixedly arranged between the third reinforcing rib (61) and the fourth reinforcing rib (62).

8. The fuel filter with the double hydrophobic structures as claimed in claim 7, wherein one end side of the base (9) is provided with an annular mounting groove (91) and an annular connecting step surface (92), the connecting step surface (92) is located at the peripheral edge of the base (9), the lower end of the hydrophobic net (10) is inserted into the mounting groove (91) to be hermetically and fixedly connected with the base (9), and the peripheral hole wall of the mounting through hole (63) of the lower end cover (6) abuts against the connecting step surface (92) to be detachably connected between the base (9) and the lower end cover (6); a plurality of water guiding through grooves (93) are uniformly formed between the mounting clamping groove (91) and the connecting step surface (92), and the water guiding through grooves (93) are communicated with an oil purifying cavity between the hydrophobic net (10) and the central net (8).

9. The fuel filter of claim 8, wherein the connecting step surface (92) is lower than the groove bottom surface of the mounting groove (91).

10. The fuel filter of claim 8, wherein the upper end of the hydrophobic net (10) is connected with a cover (10a) for separating the inner cavity of the hydrophobic net (10) from the clean oil cavity, and a second gap (11) is formed between the cover (10a) and the inner side surface of the upper end cover (5).

Technical Field

The invention belongs to the technical field of automobile engine prefilters, relates to a fuel filter, and particularly relates to a fuel filter with a double-hydrophobic structure.

Background

At present, vehicle engines are basically internal combustion engines, and mainly use two fuels, namely gasoline and diesel oil. As a fuel, there is a certain requirement for the quality and cleanliness of the oil. For refining processing reasons, the finished fuel oil must contain a certain amount of impurities, moisture and gums. The fuel filter is used for filtering out impurities and moisture in the fuel and providing clean fuel for the engine. Because there are three precision matching parts in the diesel engine supply system, the requirement for the cleanness degree of diesel oil is high, and the colloid content in the diesel oil is high, if these colloid and impurity are not filtered and enter the fuel injection pump, it is easy to accelerate the abrasion of the precision matching parts, and is easy to block, and reduce the service life of the engine, and at the same time, if the moisture and colloid in the fuel oil enter the cylinder, the combustion of the combustible gas mixture is poor, and the power of the engine is reduced. And a key part of the fuel filter for filtering colloid, impurities and the like is a fuel filter element, and the filtering effect of the fuel filter element represents the filtering effect of the whole fuel filter, so that the design of the fuel filter element structure is very important.

The structure of the existing fuel filter element generally comprises an upper end cover, a lower end cover, and filter paper, a central net and a hydrophobic net which are arranged between the upper end cover and the lower end cover, the whole fuel filter element is arranged in a shell of a filter, a dirty oil cavity is formed between the peripheral wall of the filter paper and the shell, and the peripheral wall of the lower end cover is connected with the inner side wall of the shell in a sealing way. The filter paper is used for filtering impurities and the like of fuel oil to be filtered, and the hydrophobic net is used for filtering moisture in the fuel oil filtered by the filter paper, but the filter paper has some problems: it is not high that it filters moisture efficiency mainly to be the hydrophobic net for filtering moisture among the prior art to lead to whole fuel filter's separation of water efficiency to reduce.

Disclosure of Invention

The invention aims to solve the technical problems and provides a fuel filter with a double-hydrophobic structure.

The purpose of the invention can be realized by the following technical scheme: the utility model provides a fuel filter of two hydrophobic structures, includes the casing and installs the fuel filter core in the casing, the fuel filter core includes upper end cover, lower extreme cover, hydrophobic net and central net, its characterized in that: the fuel oil filter is characterized by further comprising a water collecting structure arranged on the shell and filter paper capable of filtering impurities and moisture of fuel oil to be filtered, a dirty oil cavity used for containing the fuel oil to be filtered is formed between the outer side of the filter paper and the inner side wall of the shell, and the dirty oil cavity is communicated with the water collecting structure.

In foretell fuel filter of two hydrophobic structure, the fuel filter core install the upper end at the casing, tip has outside chamber and inboard chamber under the casing, the cup that catchments of water structure for having outer chamber and the interior chamber that catchments just catchments the cup and realize sealing connection through sealing connection structure with the casing lower extreme, above-mentioned dirty oil pocket passes through outside chamber with the chamber intercommunication that catchments outward, be formed with the clean oil chamber between hydrophobic net and the central net, the clean oil chamber just passes through with the inboard chamber intercommunication of above-mentioned casing the inboard chamber of casing with the above-mentioned interior chamber intercommunication that catchments, the bottom in outer chamber and the interior chamber that catchments of catchmenting all is equipped with the outlet valve.

In the fuel filter with the double hydrophobic structures, a first gap is formed between the peripheral wall of the lower end cover and the inner side wall of the shell, and the dirty oil cavity is communicated with the outer side cavity through the first gap.

In the fuel filter with the double hydrophobic structures, the sealing connection structure comprises an external thread arranged on the outer peripheral wall of the lower end of the shell, a first convex edge and a lock nut which are arranged on the outer cavity wall of the water collecting cavity outside the water collecting cup, an internal thread matched with the external thread is arranged on the inner side wall of the lock nut, a second convex edge is formed at the lower end of the lock nut in an inward protruding mode, a connecting part is formed between the first convex edge and the upper end face of the outer cavity wall of the water collecting cavity outside the water collecting cup, after assembly, the connecting part is connected with the inner side wall of the lower end of the shell in a leaning and connecting mode and achieves sealing connection through a sealing ring, the external thread is connected with the internal thread in a threaded mode, the lower end of the shell is leaned on the upper end face of the first convex edge, and the lower end face of the first convex edge.

In the fuel filter with the double hydrophobic structures, the caliber of the water collecting cup is a large-end-up and the peripheral wall of the outer water collecting cavity is an arc-shaped surface.

In the fuel filter with the double-hydrophobic structure, the fuel filter element further comprises a base, the respective upper ends and lower ends of the filter paper and the central net are respectively and fixedly installed on the upper end cover and the lower end cover, the middle part of the lower end cover is provided with an installation through hole which is just opposite to the conduction through hole of the central net, the lower end of the hydrophobic net is fixedly installed on the base, and the base is detachably connected with the lower end cover after the upper end of the hydrophobic net is inserted into the inner through hole of the central net from the installation through hole.

In the fuel filter with the double-hydrophobic structure, the outer edge of the upper end cover protrudes towards the inner side surface of the upper end cover to form a first reinforcing rib, the inner side surface of the upper end cover is also provided with a second reinforcing rib, and the first reinforcing rib and the second reinforcing rib are perpendicular to the inner side surface of the upper end cover; the outer edge of the lower end cover protrudes towards the inner side face of the lower end cover to form a third reinforcing rib, the edge of the hole wall of the mounting through hole in the lower end cover protrudes towards the inner side face of the lower end cover to form a fourth reinforcing rib, and the third reinforcing rib and the fourth reinforcing rib are perpendicular to the inner side face of the lower end cover; the filter paper sleeves the peripheral wall of the central net and is fixedly arranged between the first reinforcing rib and the second reinforcing rib together with the central net at the upper end, and the lower end is fixedly arranged between the third reinforcing rib and the fourth reinforcing rib.

In the fuel filter with the double hydrophobic structures, an annular mounting clamping groove and an annular connecting step surface are formed in one end side of the base, the connecting step surface is located at the peripheral edge of the base, the lower end of the hydrophobic net is inserted into the mounting clamping groove to be hermetically and fixedly connected with the base, and the peripheral hole wall of the mounting through hole of the lower end cover abuts against the connecting step surface to be detachably connected between the base and the lower end cover; and a plurality of water guiding through grooves are uniformly formed between the mounting clamping groove and the connecting step surface, and the water guiding through grooves are communicated with the oil purifying cavity between the drainage net and the central net.

In the fuel filter with the double-hydrophobic structure, the connecting step surface is lower than the groove bottom surface of the mounting clamping groove.

In the fuel filter with the double hydrophobic structures, the upper end of the hydrophobic net is connected with a sealing cover for separating an inner cavity of the hydrophobic net from the clean oil cavity, and a second gap is formed between the sealing cover and the inner side face of the upper end cover.

Compared with the prior art, the core-replaceable fuel filter core has the following advantages:

1. the filter paper can filter impurities and can also filter moisture, so that a double-hydrophobic structure is formed by the filter paper and a hydrophobic net in the existing structure, the first-time moisture filtration is carried out at the filter paper, the second-time moisture filtration is carried out on the hydrophobic net, and compared with the single-time moisture filtration of the hydrophobic net in the existing structure, the twice-water filtration mode greatly improves the efficiency and effect of the moisture filtration, so that the defect that the water separation efficiency of the whole fuel filter element is reduced due to the low efficiency of the single-time moisture filtration of the hydrophobic net in the prior art is overcome;

2. the upper end cover, the lower end cover, the filter paper and the central net form a structural combination, the hydrophobic net and the base form a structural combination, the two structural combinations are very convenient to disassemble and install, when the filter paper needs to be replaced in use, the structural combination formed by the upper end cover, the lower end cover, the filter paper and the central net is only required to be disassembled, and then a new structural combination is replaced, the structures such as the hydrophobic net and the like do not need to be replaced together, so that the cost is saved; meanwhile, the upper end cover, the lower end cover, the filter paper and the central net are made into an integral structure, so that the replacement is very convenient;

3. because the dirty oil cavity is communicated with the outer water collecting cavity of the water collecting cup through the outer side cavity, part of impurities filtered and intercepted by the filter paper in the dirty oil cavity can be precipitated to the lower end of the dirty oil cavity and then discharged into the outer water collecting cavity through the outer side cavity to be discharged together with water, so that the impurities cannot be retained in the dirty oil cavity for a long time to block the outer side wall of the filter paper, and the service life of the filter paper is prolonged;

4. the sealing connection structure between the water collecting cup and the lower end of the shell can facilitate the disassembly of the water collecting cup, and the assembly is convenient.

Drawings

FIG. 1 is a block diagram of the present fuel filter.

Fig. 2 is a cross-sectional view at a-a in fig. 1.

Fig. 3 is an assembly view of a fuel filter cartridge.

Fig. 4 is an exploded view of the fuel cartridge.

Fig. 5 is an exploded view of a fuel filter element.

Fig. 6 is a schematic structural view of the base.

Fig. 7 is a structural view of the water collecting cup.

In the figure, 1, a housing; 1a, a lateral cavity; 1b, an inner cavity; 2. a dirty oil chamber; 21. a first gap; 3. a water collecting cup; 31. an outer water collection cavity; 32. an inner water collection cavity; 33. a water drain valve; 34. a first convex edge; 35. a connecting portion; 4. a lock nut; 41. a second convex edge; 5. an upper end cover; 51. a first reinforcing rib; 52. a second reinforcing rib; 6. a lower end cover; 61. a third reinforcing rib; 62. a fourth reinforcing rib; 63. mounting a through hole; 7. filtering paper; 8. a central network; 9. a base; 91. installing a clamping groove; 92. connecting the step surfaces; 93. a water guiding through groove; 10. a hydrophobic net; 10a, sealing the cover; 11. a second gap; 12. an injection pump.

Detailed Description

The following are specific embodiments of the present invention and are further described with reference to the drawings, but the present invention is not limited to these embodiments.

As shown in fig. 1, 2 and 3, the fuel filter with double hydrophobic structures comprises a housing 1, a water collecting structure and a fuel filter element arranged at the upper end part of an inner cavity of the housing 1, wherein the lower end part of the housing 1 is provided with an outer side cavity 1a and an inner side cavity 1b, the fuel filter also comprises a fuel injection pump 12, and the fuel injection pump 12 is arranged at the lower end part of the housing 1. The fuel filter element comprises an upper end cover 5, a lower end cover 6, a hydrophobic net 10, a central net 8 and filter paper 7, wherein 7 pieces of the filter paper 7 on the filter paper 7 are chrysanthemum-shaped, namely, the filter paper is in a shape of circling back and forth to increase the filtering contact surface, so that the filtering efficiency and the filtering effect are improved; the filter paper 7 can not only filter impurities in the fuel oil to be filtered, but also filter moisture in the fuel oil to be filtered, and the contact surface of the filter paper 7 filter plate is large, so that the efficiency and the effect of moisture filtering are greatly improved; simultaneously, constitute two hydrophobic structure with the hydrophobic net 10 among the current structure, carry out moisture at filter paper 7 and filter for the first time, carry out moisture filtration for the second time on hydrophobic net 10, for the hydrophobic net 10 single filtration moisture of current structure, the two times moisture filtration mode and the powerful filtration moisture effect of filter paper 7 of this application have improved moisture filterable efficiency and effect greatly, thereby the inefficiency that leads to whole fuel filter core water separation efficiency to reduce of hydrophobic net 10 single filtration moisture among the prior art has been compensatied, make whole fuel filter core's filtration efficiency improve greatly.

As shown in fig. 2 and 7, the water collecting structure is a water collecting cup 3 having an outer water collecting cavity 31 and an inner water collecting cavity 32, the water collecting cup 3 is in sealed connection with the lower end of the housing 1 through a sealing connection structure, a dirty oil cavity 2 for placing fuel oil to be filtered is formed between the outer side of the filter paper 7 and the inner side wall of the housing 1, a first gap 21 is formed between the outer peripheral wall of the lower end cover 6 and the inner side wall of the housing 1, the dirty oil cavity 2 sequentially passes through the first gap 21, the outer side cavity 1a is communicated with the outer water collecting cavity 31, and moisture and impurities generated after the fuel oil to be filtered in the dirty oil cavity 2 is filtered by the filter paper 7 sequentially pass through the first gap 21 and the outer side cavity 1a and enter the outer. An oil purification cavity is formed between the hydrophobic net 10 and the central net 8 in the fuel filter element, the oil purification cavity is communicated with the inner side cavity 1b of the shell 1 and is communicated with the inner water collection cavity 32 through the inner side cavity 1b of the shell 1, fuel oil passing through the filter paper 7 enters the oil purification cavity, secondary water filtration is carried out through the hydrophobic net 10, and filtered water enters the inner water collection cavity 32 through the inner side cavity 1 b. The bottoms of the outer water collecting cavity 31 and the inner water collecting cavity 32 are both provided with a water drain valve 33, and when the moisture and the like in the outer water collecting cavity 31 and the inner water collecting cavity 32 reach a certain amount, the corresponding water drain valve 33 is opened to be discharged. It is very convenient and the environmental protection is clean to the moisture and the impurity treatment after filtering, can not pollute filter inner structure.

Specifically, as shown in fig. 2, the sealing connection structure includes an external thread disposed on the outer peripheral wall of the lower end of the housing 1, a first convex edge 34 and a lock nut 4 disposed on the outer cavity wall of the outer water collection cavity 31 of the water collection cup 3 are disposed, an internal thread matched with the external thread is disposed on the inner side wall of the lock nut 4, a second convex edge 41 is formed by inward protruding the lower end of the lock nut 4, a connection portion 35 is formed between the first convex edge 34 and the upper end surface of the outer cavity wall of the outer water collection cavity 31 of the water collection cup 3, after assembly, the connection portion 35 is connected with the inner side wall of the lower end of the housing 1 by being attached, and sealing connection is realized by a seal ring, the external thread is connected with the internal thread by screw threads, the lower end of the housing 1 is attached to the upper end surface of the first convex edge 34. The bore of the water collecting cup 3 is an arc-shaped surface with a large upper end and a small lower end, and the peripheral wall of the outer water collecting cavity 31 is an arc-shaped surface, during assembly, the locking nut 4 is sleeved in from the lower end of the water collecting cup 3 and reaches the upper end of the water collecting cup 3 to enable the lower end surface of the first convex edge 34 to be attached to the upper end surface of the second convex edge 41, then the internal thread of the locking nut 4 is sleeved on the external thread on the peripheral wall of the lower end of the shell 1 and screwed up in a threaded rotating manner, the connecting part 35 of the water collecting cup 3 and the inner side wall of the lower end of the shell 1 are attached to each other to be in sealing connection, and meanwhile the lower end of the shell 1. Similarly, when the locking nut 4 is disassembled, the locking nut is only required to be rotated reversely. Therefore, the water collecting cup 3 is very simple and fast to mount and dismount, and the water collecting cup 3 is convenient to dismount and clean.

As shown in fig. 3, 4, 5 and 6, the fuel filter element further comprises a base 9, the respective upper ends and lower ends of the filter paper 7 and the central net 8 are respectively and fixedly installed on the upper end cover 5 and the lower end cover 6, the middle part of the lower end cover 6 is provided with an installation through hole 63 which is just opposite to and communicated with the inner through hole of the central net 8, the lower end of the hydrophobic net 10 is fixedly installed on the base 9, the base 9 is detachably connected with the lower end cover 6 after the upper end of the hydrophobic net 10 is inserted into the inner through hole of the central net 8 from the installation through hole 63, the upper end of the hydrophobic net 10 is connected with a sealing cover 10a which separates the inner cavity of the hydrophobic net 10 from the clean oil cavity, and a second gap 11 is formed between the sealing. During the use, the fuel filter core is the consumer, need change new fuel filter core after using the certain time, filter effect can be very poor otherwise, filter paper 7 life is lower, change the frequency fast, but hydrophobic net 10 life is very long, can use for a long time, change the frequency very low, and filter paper 7 and hydrophobic net 10 among the prior art make an overall structure, if will change filter paper 7 then can only take hydrophobic net 10 to change whole fuel filter core assembly together, cause the waste to structures such as hydrophobic net 10 like this, use cost is higher. The central net 8 and the base 9 are made into an integral module structure, the upper end cover 5, the lower end cover 6, the central net 8 and the filter paper 7 are made into an integral module structure, the assembly, disassembly and assembly are very convenient, when the filter paper 7 needs to be replaced in use, the structural combination formed by the upper end cover 5, the lower end cover 6, the filter paper 7 and the central net 8 is only required to be disassembled, and then a new structural combination is replaced, the structures such as the hydrophobic net 10 and the like do not need to be replaced together, so that the cost is saved; meanwhile, the upper end cover 5, the lower end cover 6, the filter paper 7 and the central net 8 are made into an integral structure, and the replacement is very convenient.

Further, as shown in fig. 2, a first reinforcing rib 51 is formed at the outer edge of the upper end cap 5 protruding towards the inner side of the upper end cap 5, a second reinforcing rib 52 is further arranged on the inner side of the upper end cap 5, and the first reinforcing rib 51 and the second reinforcing rib 52 are both perpendicular to the inner side of the upper end cap 5; the outer edge of the lower end cover 6 protrudes towards the inner side face of the lower end cover 6 to form a third reinforcing rib 61, the edge of the hole wall of the mounting through hole 63 on the lower end cover 6 protrudes towards the inner side face of the lower end cover 6 to form a fourth reinforcing rib 62, and the third reinforcing rib 61 and the fourth reinforcing rib 62 are perpendicular to the inner side face of the lower end cover 6; the filter paper 7 is sleeved on the peripheral wall of the central net 8, the upper end of the filter paper and the central net 8 are fixedly arranged between the first reinforcing rib 51 and the second reinforcing rib 52 in a glue bonding mode, and the lower end of the filter paper is fixedly arranged between the third reinforcing rib 61 and the fourth reinforcing rib 62 in a glue bonding mode; of course, other fixing means than gluing, such as hot plate welding, may be used.

Further, as shown in fig. 2, an annular mounting groove 91 and an annular connecting step surface 92 are formed on one end side of the base 9, and the connecting step surface 92 is located at the peripheral edge of the base 9 and is lower than the groove bottom surface of the mounting groove 91. The lower end of the hydrophobic net 10 is inserted into the mounting clamping groove 91 to be hermetically and fixedly connected with the base 9, and the peripheral hole walls of the mounting through hole 63 of the lower end cover 6 are abutted against the connecting step surface 92 to realize the detachable connection between the base 9 and the lower end cover 6; a plurality of water guiding through grooves 93 are uniformly formed between the mounting clamping groove 91 and the connecting step surface 92, and the water guiding through grooves 93 are communicated with an oil purifying cavity between the drainage net 10 and the central net 8; the filtered water in the clean oil chamber enters the inside chamber 1b through the water guiding through groove 93.

The specific embodiments described herein are merely illustrative of the spirit of the invention. Various modifications or additions may be made to the described embodiments or alternatives may be employed by those skilled in the art without departing from the spirit or ambit of the invention as defined in the appended claims.