LIQUID FILTER

Abstract

A fuel filter device for operation in a position under non-extreme conditions, when there is enough time for replacement of the clogged filter element, or in a reverse position in a fuel bypassing state for non-stop operation under extreme conditions, when there is no time for replacement of the clogged filter element. The device consists of cup-shaped members, which are interconnected through a threaded connection and form a cavity that contains a spring compressed between the bottom of an opening of one of the cup-shaped members and an abutment formed between two openings of another cup-shaped member. The compression force of the spring is applied to a seal ring placed into an annular groove formed in the abutment surface through a flange of the filter element. Another improved sealing feature is provided by a second seal ring, which seals the threaded connection, when the connection is tightened.

Claims

1. A liquid filter comprising: a first cup-shaped member having a first opening and a first connection member on one end and a liquid outlet portion on an end opposite to said one end of the first cup-shaped member; the first cup-shaped member having an abutment surface in the first opening; a second cup-shaped member having a second opening and a second connection member on one end and a liquid inlet portion on an end opposite to said one end of the second cup-shaped member, the second opening having a bottom, the first connection member being engageable with the second connection member; a liquid filter interior cavity formed by the first opening and the second opening when the first connection member is engaged with the second connection member; a first seal member for sealing the first connection member and the second connection member when the first connection member is engaged with the second connection member; a groove, which is formed in the abutment surface and has a depth; a second seal member, which is inserted into the groove and has a thickness greater than the depth of the groove; a filter element for a liquid to be filtered, the filter element having a peripheral surface and a flanged portion, which projects in a radial outward direction from the peripheral surface and abuts the second sealing member; and a coil spring inserted into the liquid filter interior cavity and compressed between the bottom of the second opening and the flanged portion, which is pressed by the spring to the abutment surface.

2. The liquid filter according to claim 1, wherein the liquid filter is a fuel filter.

3. The liquid filter according to claim 2, wherein the first cup-shaped member and the second cup-shaped member have round cross-sections, the filter element is a disk-shaped filter element, the first seal member is a first seal O-ring, and the second seal member is a second seal O-rings.

4. The liquid filter according to claim 3, wherein the first connection member is a first thread and the second connection member is a second thread.

5. The liquid filter according to claim 4, wherein the disk-shaped filter element has a first end face, a second end face, and a plurality of ribs that extend outward from the first end face and the second end face of the disk-shaped filter element.

6. The liquid filter according to claim 5, wherein the disk-shaped filter element is made from a pleated stainless-steel mesh laminate.

7. The liquid filter according to claim 4, wherein the first thread is an internal thread and the second thread is an external thread.

8. The liquid filter according to claim 5, wherein the first thread is an internal thread and the second thread is an external thread.

9. The liquid filter according to claim 2, wherein the first cup-shaped member is a filter body, the second cup-shaped member is a filter body cap, the first connection member is a first thread and the second connection member is a second thread.

10. The liquid filter according to claim 9, wherein the first thread is an internal thread and the second thread is an external thread.

11. The liquid filter according to claim 10, wherein the filter body and the filter body cap have round cross-sections, the filter element is a disk-shaped filter element, the first seal member is a first seal O-ring, and the second seal member is a second seal O-rings.

12. The liquid filter according to claim 11, wherein the disk-shaped filter element has a first end face, a second end face, and a plurality of ribs that extend outward from the first end face and the second end face of the disk-shaped filter element.

13. The liquid filter according to claim 12, wherein the disk-shaped filter element is made from a pleated stainless-steel mesh laminate.

14. The liquid filter according to claim 13, wherein the filter body and the filter body cap are made from with surfaces finished by anodizing, the filter element is made from pleated 304 stainless steel mesh layers having filtering holes of 0.01 mm in diameter.

15. A liquid filter comprising: A first cup-shaped member of a circular cross-section having on one end a first opening that has a bottom surface and a predetermined diameter, a first fitting on the other end for connecting the first cup-shaped member to a liquid receiver device, a second opening having a diameter smaller than said predetermined diameter and deepening from the bottom of the first opening toward the first fitting, and an annular shoulder left on the bottom surface of the first opening after the formation of the second opening, the first cup-shaped member having a first thread; a second cup-shaped member having on one end a third opening that has a bottom surface, a second fitting on the other end for connecting the second-cup shape member to a liquid supplier device, and a second thread engageable with the first thread of the first cup-shaped members, one of the first thread and the second thread having a front end and another one having a rear end; a liquid filter interior cavity defined by the first cup-shaped member and the second cup-shaped member when they are screwed together to form a threaded connection by moving the front end of one of the first thread and the second thread toward the rear end of another of the first thread and the second thread; a first seal O-ring, which is placed between the front end of one of the first thread and the second thread and the a rear end of another one of the first thread and the second thread and which is deformed in a radial outward direction by being squeezed between the front end of one of the threads and the rear end of another one of the threads to seal the threaded connection against penetration of liquid therethrough toward the first fitting, when the threaded connection is tightened to a tightened state at which the front end of one of the first thread and the second thread is moved to a position nearest to the rear end of another of the first thread and the second thread; a disk-shaped filter element having a first end face, a second end face, an outer peripheral surface, and an annular flange projecting in a radial outward direction from the peripheral surface, and a plurality of ribs that extend outward from the first end face and the second end face of the disk-shaped filter element; a second seal O-ring that is placed into the annular groove, the annular groove having a depth and the second seal O-ring has a cross-section diameter that is greater than the depth of the groove ; and a coil spring, which is inserted into the liquid filter interior cavity and which in said tightened state of the threaded connection is compressed between the bottom of the third opening and the second end face of the flange of the disk-shaped filter element, whereby the first end face of the flange is pressed to the second seal O-ring and thus fixes the disk-shaped filter element in place and prevents the liquid from passing around the disk-shaped filter element.

16. The liquid filter according to claim 15, wherein the liquid is fuel, and the liquid filter is a fuel filter.

17. The liquid filter according to claim 16, wherein the first cup-shaped member is a filter body, the second cup-shaped member is a filter body cap, the first thread is an external thread, and the second thread is an internal thread engageable with the external thread.

18. The liquid filter according to claim 17, wherein the disk-shaped filter element is made from a pleated stainless-steel mesh laminate.

19. The liquid filter according to claim 18, wherein the filter body and the filter body cap are made from aluminum with surfaces finished by anodizing, the filter element is made from a pleated stainless steel mesh layers.

20. The liquid filter according to claim 19, wherein the pleated stainless-steel mesh laminate has filtering holes of 0.01 mm in diameter.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] FIG. 1 is a three-dimensional partial sectional view of a liquid filter of the invention with filter components in positions for use under non-extreme conditions when bypassing of the filter element is not necessary.

[0023] FIG. 2 is an encircled area A of FIG. 1 shown on a larger scale.

[0024] FIG. 3 is a diametrical cross-sectional view of a pleated filter element of the liquid filter of the invention

[0025] FIG. 4 is three-dimensional partial sectional view of a liquid filter of the invention with filter components in positions for use under extreme conditions with a possibility of bypassing the filter element in case of clogging.

DETAILED DESCRIPTION OF THE INVENTION

[0026] The invention relates to a liquid filter, in particular to a liquid filter to be selectively preinstalled in one of two installation positions. More specifically, the invention relates to a liquid filter that can be installed in one position for use under non-extreme conditions when there is enough time for replacing a clogged filter element and in a reversed position for use under critical conditions, when there is no time for replacing a clogged filter element.

[0027] Hereinafter, the liquid filter of the invention will be referred to as a fuel filter. It is understood, however, that fuel is mentioned only as an example and that any other liquid, e.g., oil, water, solution, or the like, may constitute a filtration medium.

[0028] The fuel filter of the invention will be further described in detail with reference to the attached drawings, wherein FIG. 1 is a three-dimensional partial sectional view of a liquid filter of the invention with filter components in positions for use under non-extreme conditions when bypassing of the filter element is not necessary FIG. 2 is an encircled area A of FIG. 1 shown on a larger scale, and FIG. 3 is a diametrical cross-sectional view of the filter element used in the liquid filter of FIG. 1.

[0029] In order not to complicate the images in the drawings, the cross-sectional areas are not hatched.

[0030] As can be seen from FIG. 1, where the entire fuel filter is designated by reference numeral 20, the fuel filter consists of a filter body 22 with a filter outlet fitting 24 and a body cap 26 that is connected to the filter body 22, e.g., through a threaded connection 28, and has a filter input fitting 30. In the aforementioned threaded connection, the filter body 22 may have an external thread 28a and the body cap 26 may have an internal thread 28b, or vice versa. In the first case, the cap 26 is screwed onto the filter body 22. Reference numerals 23=1, 23-2, . . . 23-n designate cooling fins formed on the outer surfaces of the filter body 22 and the filter cap 26 (FIG. 1).

[0031] The threaded connection 28 is provided with a first seal O-ring 32 that prevents metal-to-metal contact between the filter body 22 and the cap 26 and seals the threaded connection 28. The seal O-ring 32 is placed between the ends of the external and internal threads 28a and 28b, respectively, at a place where the end face 26a of the body cap 26 meets the end face 22a of the filter body 22. When the threads are strongly tightened, the first seal O-ring 32 is deformed and expands in a radial outward direction thus tightly sealing the connection against penetration of the liquid through the threads.

[0032] The filter body 22 has a cup-shaped configuration with a large-diameter opening 22b (FIG. 1) on an open end of the filter body 22 and a small-diameter opening 22c (FIG. 2) bored in the large-diameter opening 22b deeper into the filter body 22 in the direction of the outlet fitting 24 leaving a flat annular shoulder 22d on the bottom of the large-diameter opening 22b. An annular groove 22e is formed on this flat annular shoulder 22d for placing a second seal O-ring, the purpose of which will be described later. Details of the groove 22e, seal O-ring 34, the large-diameter opening 22b, and the small-diameter opening are shown in FIG. 2, which is an encircled area A of FIG. 1 depicted on a larger scale. The annular groove 22e may have a depth of up to half-diameter of the cross-section of the second O-ring 34.

[0033] The filter body cap 26 also has a cup-shaped configuration with an opening 26b and a bottom surface 26c at the end of the opening 26b. The openings 22b (FIG. 1), 22c (FIGS. 2), and 26b (FIG. 1) define a filter interior cavity 27. Installed inside the filter interior cavity 27 is a filter element 36, which is shown in a diametrical cross section in FIG. 3. The filter element 36 is made in the form of a porous pleated disk-shaped body, provided with a plurality of serrations or ribs 36-1, 36-2, . . . 36-n, which extend outward from the end faces 36a and 36b of the filter element 36 and are intended for increasing the filtering surface areas. On its outer peripheral surface 37, the filter element is provided with an annular flange 36c. This flange is squeezed between the aforementioned second seal O-ring ring 22e and an end of a coil spring 38, which is inserted into the filter interior cavity 27 of the filter and compressed between the mating side of the flange 36c (FIGS. 1 and 3) and the bottom 26c (FIG. 1) of the cap opening. In this case, the shoulder 22d (FIG. 2) functions as an abutment surface for the end 38a of the spring 38. The outer edge 36d of the flange is not in a sealing engagement with the inner wall 22f of the large-diameter opening 22b of the filter body 22 leaving a small gap 22g between them.

[0034] For securing connection of a fuel-supply hose (not shown), the filter input fitting 30 on the cap side may have double O-ring seals 40a and 40b (FIG. 1). Reference numeral 42 designates a seat for a prefiltration element (not shown). In the situation of FIG. 4, the fitting 24 functions as a filter inlet fitting, and the fitting 30 functions as a filter outlet fitting.

[0035] A distinguishing feature of the fuel filter 20 of the invention is that this filter allows pre-installation of the filter 20 for operation under normal, i.e., direct flow conditions, when the fuel passes through the filter element 36 in the direction of arrow B (FIG. 1) from the inlet fitting 30 (which in this case is on the side of the fuel pump [not shown]) and there is enough time for replacing the filter element 36, when it is clogged, and for operation under extreme (racing) conditions, e.g., when the fuel filter is installed on a vehicle that participates in racing and there is no time for replacing the clogged filter element. In that case, the filter 20 is preinstalled in a reversed position shown in FIG. 4. i.e., so that the filter element 36 faces directly to the flow of fuel, which in that case is supplied to the engine through the filter in the direction of arrow C. When in this position of the filter 20 the filter element 36 is clogged to the extent that the supply of fuel to the engine is discontinues, the filter 20 will automatically switch to a bypass mode of operation with the flow of the fuel around the clogged filter.

[0036] More specifically, for use under extreme conditions of racing, when the priority is a victory and the malfunction of the fuel filter is a secondary problem, a racer preinstalls the fuel filter 20 in a backward, e.g., a reversed position, at which the fuel supply line is connected to the fitting 24 on the filter cap side. Until the filter element 36 is not clogged, the filter operates normally and allows the fuel to flow from fuel tank to the carburetor (not shown) or from the fuel pump to the fuel injector (not shown). However, when the filter element 36 is clogged and a pressure of the accumulated fuel increases, the increased pressure acts onto the facing side 36e (FIG. 4) of the filter element 36 as on a piston and shifts the filter element 36 toward the now-outlet side of the filter body cap, i.e., in the direction of arrow C against the coil spring 38 and away from the second seal O-ring 36c. As a result, the spring 38 is biased in the fuel supply direction of arrow C, the second seal O-ring 36c does not work anymore as a seal, and a bypass channel is opened for the flow of the fuel beyond the filter element 36 through the gap 22g between the flange 36d of the filter element 36 and the inner wall 22f of the large-diameter opening 22b of the filter body 22.

[0037] Upon completion of the racing, the cap-body unit can be reinstalled into its original position (FIG. 1) for use under normal conditions and for cleaning the fuel from possible contaminants prior to delivery of the fuel to the engine system.

[0038] Thus, it has been shown that the liquid filter 20 of the invention is a versatile device which is simple in construction, inexpensive to manufacture, and reliable in operation under normal as well as under harsh extreme conditions.

[0039] According to one embodiment of the invention, the fuel sensor has the filter body and the filter body cap made from aluminum, e.g., Aluminum 6061-T6 with surfaces finished by anodizing. The filter element is made from pleated 304 stainless steel mesh laminate having total thickness of 4,318 mm, flange thickness of about 1 mm, and filtering holes of 0.01 mm in diameter. The total effective filtration area is 645.15 mm.sup.2. The element provides a maximum flow of 3.785 liters per minute. The element is washable, reusable indefinitely, and cleaned easily with air or soluble rinse.

[0040] Thus, it has been shown that the liquid filter of the invention is the fuel filter 20 that has a first cup-shaped member, i.e., the filter body 22 that has a first opening 22b and a first connection member, i.e., the external thread 28a on one end and a liquid outlet portion, i.e., the outlet fitting 24, on the end opposite to the threaded end of the filter body 22. The filter 20 has a small-diameter opening 22c (FIG. 2) bored in the large-diameter opening 22b deeper into the filter body 22 in the direction of the outlet nipple 24. An annular shoulder 22d (FIG. 2) that functions as an abutment surface is formed on the bottom of the large-diameter opening 22b, and annular groove 22e for placing a seal O-ring 34. The purpose of this seal ring is to seal the filter element 36 against passage of the fuel around the flange 36c of the filter element to the outlet fitting 24. Another seal ring 32 is placed between the front end of the internal thread 28b formed in the cap 26 and the rear end of the external thread 28a of the filter body 22. The seal ring 32 seals the threaded connection of the filter body 22 with the filter body cap 26 when both threads are strongly tightened.

[0041] Although the invention has been shown and described with reference to specific embodiments, it is understood that these embodiments should not be construed as limiting the areas of application of the invention and that any changes and modifications are possible, provided these changes and modifications do not depart from the scope of the attached patent claims. For example, the body and cap can be made from material other than aluminum, e.g., a light alloy. The filter element may have different shape, made of a material different from the pleated 304 stainless steel mesh. The filters may be different in size and throughput capacity, can be installed on a carburetor-fuel supply systems or on fuel-pump supply systems, on cars, or motorcycles, etc. The fittings on both sides of the filter may be identical or different and intended for connections hoses or pipes. Finally, the liquid filter build on the principle of the invention is applicable for filtering liquids other than fuels, e.g., oils, aqueous solutions, or any other contaminated liquids that need to be cleaned before admission to the destination equipment. The cup-shaped body and cap may have a square cross-section and are interconnected and fixed together through a device other than threads.