Oil Canning of Mesh Screen for Filter

Abstract

A method of reducing if not eliminating the possibility of tearing or ripping of a mesh screen of a filter during the manufacturing process includes the step of intentionally deforming the mesh screen. With this technique, as the plastic material that forms the frame of the filter begins to expand or change shape, as a result of the heating and squeezing steps involved with the molding process, the deformed mesh screen will be able to accommodate the relative changes in shape without tearing or ripping of the mesh screen. With the invention, numerous shapes and configurations of tools may be used to provide the intentional deformation of the mesh screen during the manufacturing process as well as to provide for control over the amount and degree of mesh screen deformation. Also, the resulting filter will have a mesh screen that has improved retention capabilities which will enhance the performance of the filter.

1  A filter comprising:
 a molded frame defining a frame section, the frame section including an open area;   the frame being formed of molded material having a shape altering characteristic such that the open area is of a first size when cool and of a second larger size when subjected to an elevated temperature;   a mesh screen within the frame section; and   the mesh screen having a portion in the frame section defining a non-planar profile selected to accommodate a relative difference in the changes in shape of the frame and the mesh screen at the elevated temperature without tearing the mesh screen.   
   
   
       2 . The filter of  claim 1  wherein the frame defines a plurality of frame sections with the mesh screen molded within each of the plurality of frame sections. 
   
   
       3 . The filter of  claim 2  wherein the non-planar portion of the mesh screen is dome-shaped. 
   
   
       4 . The filter of  claim 3  wherein the mesh screen includes squeezed portions thinner than the domed-shaped portion. 
   
   
       5 . The filter of  claim 1  wherein the frame defines a channel formed around the mesh screen. 
   
   
       6 . The filter of  claim 5  wherein the channel includes a rubber material configured within the channel. 
   
   
       7 . The filter of  claim 1  wherein the non-planar portion of the mesh screen is dome-shaped. 
   
   
       8 . The filter of  claim 7  wherein the mesh screen includes squeezed portions thinner than the domed-shaped portion. 
   
   
       9 . A filter comprising:
 a molded frame defining a frame section, the frame section including an open area;   a mesh screen shaped as a dome in the open area;   a heat-applied seal in a channel in the frame;   the frame being formed of molded material having a shape altering characteristic such that the frame expands when subjected to an elevated temperature for application of the seal; and   the mesh screen dome being of sufficient size to accommodate a relative difference in the changes in shape of the frame and the mesh screen at an elevated temperature required for installation of the heat-applied seal.   
   
   
       10 . The filter of  claim 9  wherein the molded frame defines a plurality of frame sections with the mesh screen molded within each of the plurality of frame sections. 
   
   
       11 . The filter of  claim 10  wherein the mesh screen forms a dome in each of the plurality of frame sections. 
   
   
       12 . The filter of  claim 11  wherein the mesh screen includes squeezed portions in each of the plurality of frame sections, the squeezed portions being thinner than the domes of the frame sections. 
   
   
       13 . The filter of  claim 9  wherein the mesh screen includes a squeezed portion thinner than the dome. 
   
   
       14 . A method of manufacturing a filter comprising the steps of:
 molding a frame defining a plurality of frame sections having open areas;   capturing a mesh screen in at least one of the plurality of frame sections within the open area of the section;   deforming the mesh screen to create a dome in the open area; and   heating the frame to apply a seal around at least one of the plurality of frame sections;   said heating causing said frame to expand and said dome to flatten.   
   
   
       15 . The method of  claim 14  further comprising the step of molding the mesh screen across the plurality of frame sections. 
   
   
       16 . The method of  claim 15  further comprising deforming the mesh screen in each of the plurality of frame sections. 
   
   
       17 . The method of  claim 16  wherein the step of deforming the mesh screen includes squeezing the mesh screen and causing the mesh screen to bulge. 
   
   
       18 . The method of  claim 16  wherein the step of deforming the mesh screen includes deforming the mesh screen between a recess surface and a corresponding boss surface. 
   
   
       19 . The method of  claim 14  wherein the step of deforming the mesh screen includes squeezing the mesh screen and causing the mesh screen to bulge. 
   
   
       20 . The method of  claim 14  wherein the step of deforming the mesh screen includes deforming the mesh screen between a recess surface and a corresponding boss surface.