Patent Application
20070170101
This invention pertains to a fluid filter assembly having a filter housing with first valve disposed between an annular filter media/core assembly and an end plate at one end of the filter housing and a second valve disposed between the annular filter media/core assembly and a spring at the second end of the filter housing.
Prior art filter devices such as that described in United States Patent Application Publication US 2005-0103692 describe a filter housing with an annular filter media/core assembly disposed therein. The filter described therein contains a combination valve with a first portion that permits fluid flow through a first inlet opening, the filter media/core assembly, and then is discharged through the outlet opening. When the filter media/core assembly begins to clog, pressure upstream builds until a predetermined pressure is attained, opening a second portion of the valve that permits fluid flow directly out a second bypass opening and out the outlet opening, bypassing the filter media/core assembly.
Some valve filters in the prior art accomplish the function of the inlet valve and bypass valve using two separate valves. These valve filters require several component parts to accomplish the anti-drainback and bypass functions and are complicated. The present invention improves on this and other deficiencies as described herein.
An object of the present invention is to provide an improved filter assembly with a simpler design and a less complex bypass valve. In addition to reducing inventory of valve component parts, the bypass valve element of the present invention can be used more universally in a variety of different filter diameters.
The invention pertains to a fluid filter assembly having a cup shaped filter housing open at one end, with an annular filter media/core assembly disposed in the housing. An end plate including an inlet opening and an outlet opening is secured to and closes the open end of the housing. A first valve is disposed between the one end of annular filter media/core assembly and the end plate for controlling fluid flow through the inlet opening. A spring with a bypass opening is disposed between the other end of the annular filter media/core assembly and the top of the housing for biasing the annular filter media/core assembly towards the end plate. A second valve, which is disposed between the annular filter media/core assembly and the spring, controls fluid flow through the bypass opening in the spring. The second valve further has a higher resistance to fluid flow than the first valve.
In normal operation, the first valve yields and permits fluid flow through the inlet opening, the annular filter media/core assembly, and is discharged through the outlet opening. As the filter media/core assembly begins to clog, fluid pressure builds. When a predetermined fluid pressure is attained, the second valve opens to permit fluid flow through the bypass opening, bypassing the annular filter media/core assembly and out the outlet opening.
There is shown in the attached drawings a presently preferred embodiment of the present invention wherein like numerals in the various views refer to like elements and wherein:
There is shown in
An end plate 18 is secured to the housing 12 and closes the open end of housing 12. The end plate 18 has inlet opening means 20 for permitting fluid flow into filter assembly 10 and outlet opening means 22 for permitting fluid flow out of the filter assembly 10. The inlet opening means 20 comprises one or more discrete openings. In like fashion, the outlet opening means may comprise one or more discrete openings. The inlet opening means are preferably a plurality of discrete openings arranged concentrically about a central axis of the filter (or concentrically arranged about the outlet opening). A lid 23 is secured to end plate 18. An annular resilient gasket 25 is received and retained in a recess in lid 23 for providing a seal between the filter assembly 10 and the engine block (not shown) to which the filter assembly 10 is secured in normal use.
Disposed near the open end of housing 12 between the annular filter media 14 and the end plate 18 is an anti-drainback or first valve 24. First valve 24, which is generally annular and is fabricated from a synthetic rubber material, for example, butadiene rubber, is disposed to control fluid flow through inlet opening means 20 to the annular filter media 14. The first valve 24 has an opening 29 adapted to receive the central portion 27 of the end plate 18. On the closed end of housing 12, resilient means, such as a spring 26, is disposed between the closed end of housing 12 and the annular filter media 14. Spring 26 biases annular filter media 14 towards the end plate 18. Spring 26 further has bypass opening means 28 for permitting fluid flow to the central opening in core 16. Bypass opening means 28 comprises one or more discrete openings. In the presently preferred embodiment of the invention, the bypass opening means includes eight bypass openings 28 arranged around the center of spring 26. Persons skilled in the art will understand that the configurations and numbers of openings can be varied. Disposed between the spring 26 and the annular filter media 14 is a second valve 30. Second valve 30, which is generally annular and is fabricated from a synthetic rubber material, for example, butadiene rubber, is disposed to control fluid flow through bypass openings 28.
The resilient gasket 25 will be retained in the recess or groove 32 during handling of the filter assembly 10 and the projections 34 define cooperative engaging means for holding the gasket in place. Persons skilled in the art will understand that gasket 25 can be similarly retained in place in the recess 32 if the projections 34 on the lid 23 were eliminated and projections were provided on the outside or inside surfaces of the gasket 25 for engaging with the walls of recess 32. Such arrangement would function in an equivalent manner.
The first valve 24 is shown in
The spring 26 disposed between the annular filter media 14 and the housing 12 is better shown in
The bypass valve or second valve 30 is shown in
The material qualities of first valve 24 and second valve 30 are chosen such that first valve 24 is more resilient than the second valve 30. In this way, the first valve 24 will open under a lesser pressure, whereas the second valve 30 is stiffer and requires a higher pressure to open. In a presently preferred embodiment, the first valve 24 will open to permit fluid flow through the inlet openings 20 at a minimum pressure, for example on the order of 1 psi. By comparison, the second valve 30 will open to permit fluid flow through the bypass openings 28 at a higher predetermined pressure, for example on the order of 8-10 psi.
The assembly of the filter assembly 10 will now be described. The annular filter media 14 is positioned on the core 16 and the plastisol material 52 and 54 and the end caps 64 and 66 are positioned over the ends of the filter media and secured together in assembled relationship to form the filter media/core assembly. Top end cap enclosure 64 has an annular depending portion 65 for engaging the cylindrical wall portion 50 of second valve 30. The bottom end cap enclosure 66 likewise has an annular depending portion 67 that has an abutment 69 at the lower end as seen in
The end plate 18 and the lid 23 are secured together, for example, by welding, and the gasket 25 is positioned and retained in the recess 32 of the lid. The spring 26 is first inserted into the open end of the housing 12 until it seats against the closed end of the housing 12. Second valve 30 is positioned in sealing engagement with the openings 28 in spring 26.
The filter media/core assembly is inserted into the housing 12 abutting the second valve 30. The top end cap enclosure 64 secures the top end of the filter media/core assembly and firmly seats the second valve 30 against the spring 26 to create a fluid-tight seal between the filter media/core assembly and the bypass valve or second valve 30. The anti-drain back or first valve 24 is positioned between the end cap 66 and the end plate 18, with the abutment 69 engaging the shoulder 38 to help seal fluid flow between the first valve 24 and the filter media/core assembly. The end plate 18 closes the open end of housing 12 and the outer rim of the lid 23 is rolled with the open end of the housing 12 to form a seal 62.
Positioning of the end plate 18 in the housing 12 partially compresses the spring 26, whereby, when the parts are assembled a biasing force is applied by the spring 26 to the top of the filter media/core assembly urging the filter media/core assembly towards the end plate 18. The spring force will help to pin the first valve 24 between the filter media/core assembly and the end plate 18 and to seal flow from between the filter media/core assembly and the end plate 18. The abutment 69 of the end cap 66 will firmly engage the shoulder 38 of the first valve 24. The top end cap 64 will firmly engage the second valve 30 to seal fluid flow between the upper end of the filter media/core assembly and the second valve 30. Stated somewhat differently, the biasing force of the spring 26 will pin the bypass valve 30 in sealing engagement between the spring 26 and the annular filter/media core assembly and will pin the anti-drain back valve 24 in sealing engagement between the filter media/core assembly and the end plate 18.
In operation, the filter assembly 10 is spun onto a threaded stud on the engine block which engages the threads in the outlet opening 22 in the end plate 18 and is secured in place. The flutes or recesses 13 in the housing 12 may be engaged by a tool to help to rotate the housing 12 firmly onto the threaded stud on the engine block in a conventional manner. The gasket 25 will engage the engine block and preclude fluid flow from between the engine block and the filter assembly 10. When the engine is started, fluid, usually oil, will enter the filter assembly 10 through inlet openings 20. Slight pressure will move the first valve 24 open from the inlet openings 20 and oil will flow through inlet openings 20, the filter media 14 and be discharged through the outlet opening means 22 for return to the engine. When the engine is turned off, the first valve 24 will close the inlet openings 20 and prevent return of oil in the filter assembly 10 to the engine. As the filter media 14 clogs during normal operation, pressure will build within the housing 12 of the filter assembly 10. Upon attainment of a predetermined pressure, the second valve 30 will flex downwardly as viewed in
The present invention reduces bypass valve complexity in applications where separate anti-drainback valves and bypass valves are employed in a filter. The bypass valve in the present invention is formed using one additional part. This permits a reduction of inventory of valve component parts, as one bypass valve can be used with a variety of different filter diameters.
In the preferred embodiment of the invention, most of the biasing force to retain the components in assembled relationship within the housing 12 is provided by the spring 26. Some biasing force would be supplied by the inherent resiliency of the anti-drain back valve 24 and the bypass valve 30. In an alternative embodiment, the spring 26 may be a retainer member that does not supply a biasing force and the biasing forces for urging the filter media/core assembly toward the end plate 18 and retaining the components within the housing engaged and in sealing relationship may be supplied by the resiliency of the anti-drain back valve 24 or the bypass valve 30 or the combined resiliency of the two valves 24 and 30. The resiliency may be varied by selection of the material of the two valves, as well as by varying the thickness of one or both of the two valves, as would be apparent to a person of ordinary skill in the art.
While a presently preferred embodiment of the present invention has been shown and described, it will be apparent to persons skilled in the art that the invention may be otherwise embodied within the scope of the following claims.
