Patent Application
20060102549
This invention relates to a filter cartridge for use in a fluid filter and to a method of manufacturing the same.
Filter cartridges are used in filter housings for filtering fluids such as oil and fuel. A filter cartridge typically includes spaced apart metal end discs with a filter media or element arranged between the end discs. Edges of the filter element, which may be a pleated paper element, are bonded to the end discs with an adhesive such as plastisol.
The surfaces of the end disc opposite of the filter element seal against the filter housing to prevent fluid from bypassing the filter element. The filter housing is typically constructed of metal so that there is a metal-to-metal seal between the filter cartridge end discs and the filter housing. This type of seal requires high control of the mating surfaces and preload to ensure a good seal. To improve the seal between the filter cartridge and filter housing, gaskets are sometimes bonded to the surfaces of the end discs opposite the filter element. Separately bonding a gasket to the metal end discs adds cost and time to the manufacture filter cartridge.
Integrated plastisol end discs and gaskets have been proposed in the prior art for other applications in which the end disc and gasket are made out of differing plastisols. However, the plastisol providing the flexible gasket is arranged radially inward of a central opening in the end discs. The end disc plastisol and gasket plastisol may well run together during the manufacturing process. This is not an issue in the prior art since a sealing load is applied in a radial direction. However, for filter cartridges configured, like those using metal end discs described above, the sealing load is applied axially. An axial sealing load requires a rigid end disc across the width of the filter element.
What is needed is a filter cartridge having improved, integrated end discs and gaskets and a method for making the same.
One example of a filter cartridge of the present invention includes a filter media having an edge. An annular end disc includes first and second surfaces defined by spaced apart planes. An end disc and integrated gasket includes first and second plastisol materials that are different from one another and have different durometers. The durometer of the second plastisol material makes it more rigid than the first plastisol material. The first plastisol material provides a flexible gasket.
In one embodiment, the edge of the filter media is embedded into the second plastisol material. The second plastisol material is arranged between the planes, and the first plastisol material extends axially away from the second surface. This arrangement of the first and second plastisol materials better ensures that the materials do not mix with one another during dispensing and curing. The arrangement of the first and second plastisol materials provides a generally uniform rigidity across the width of the end disc ensuring better support of the filter media.
Accordingly, the present invention provides a filter cartridge having improved, integrated end discs and gaskets and a method making the same.
These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description.
To better ensure that the filter cartridge seals against the filter structure 14, gaskets 22 are bonded to sides of the end disc 16 opposite the edges 21. The arrangement shown in
An example inventive method of producing an inventive end disc uses the mold 24 depicted in
Referring to
The formulations of the first and second plastisol materials 32 and 36 are such to minimize wet blending, which is a condition during which the materials intermix with one another. It is desirable to retain the first and second plastisol materials 32 and 36 within the volumes provided by the respective first and second cavities 26 and 28. It is also desirable that the rigid second plastisol material 36 extends from the inner peripheral surface 27 to the outer peripheral surface 29 to provide sufficient support for the edge 21 of the filter media 18 (see
A filter media 38 having an edge 21 is embedded into the second plastisol material 36 (as shown in
Subsequent to completing the curing process shown in
The inventive method provides integrated end discs 42 and gaskets 44. The end discs 42, which are provided by the second plastisol material 36, have inner and outer circumferential surfaces 48 and 50. The inner circumferential surfaces 48 provide the opening 49 that is aligned with an opening provided by the filter media 38. The end discs 42 include first and second surfaces 52 and 54 that are respectively defined by first and second planes P1 and P2. The edges 21 of the filter media 38 extend through the first surfaces 52 into the second plastisol material 36. The gaskets 44 extend axially away from the second surfaces 54 in a direction opposite the edge 21. In the embodiment shown in
Although a preferred embodiment of this invention has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.
