Electric heating – Metal heating – For bonding with pressure
Reexamination Certificate
1999-09-30
2001-01-30
Jeffery, John A. (Department: 3742)
Electric heating
Metal heating
For bonding with pressure
C392S416000, C392S411000, C228S124600, C210S493200, C055SDIG005
Reexamination Certificate
active
06180909
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to the filtering of a fluid and more particularly to an apparatus and method for sealing a filter element to a support member by infrared energy.
2. Background of the Invention
In a typical fluid filter, a porous filter media is secured to a support member or the like for mounting or suspending the filter media. In the case of a cylindrical filter, the filter media is formed into a cylindrical configuration and a first and a second cylindrical end of the filter media is bonded to a first and a second support member such as a first and a second end cap. The first and second end caps mount the filter media relative to a fluid input source and a fluid output source. In many cases, a braze material is used for affixing the first and second cylindrical ends of the filter media to the first and second end caps.
In one example of the construction of the fluid filter, the first end cap was placed on the horizontal surface facing upwardly and filled with a braze material. The first end of the filter material was inserted into the braze material contained within the first end cap and the assembly was heated for melting the braze material to bond the first end of the cylindrical filter media to the first end cap. A second end cap was placed on a horizontal surface facing upwardly and was filled with a braze material. The second end of the filter material was inserted within the braze material contained within the second end cap and the assembly was heated for melting the braze material to bond the second end of the cylindrical filter media to the first end cap. A distinct disadvantage of the aforementioned process was that the bonding of both the first and second cylindrical ends of the filter media required two separate and distinct heating processes.
Some in the prior art have used a combination of a powdered first braze material having a first melting point, a powdered second braze material having a second melting point, and a binder material for controlling the position and migration of the powdered braze material during the heating process. The use of the binder material enabled the powdered braze materials to be positioned within an inverted end cap to allow both the first and the second ends of the cylindrical filter media to be bonded to the first and second end caps during a single heating process. The binder material prevented the powder braze materials from being discharged from the inverted end cap. In addition, the binder material inhibited the migration or wicking of the braze material into the filter media during the heating process. The binder material was burnt away leaving only the braze material to bond the first and second ends of the cylindrical filter media to the first and second end caps.
Others in the prior art have used other methods for creating a bond between metallic filter media and another metal component of a filter assembly.
U.S. Pat. No. 2,642,187 to Bell discloses a replaceable filter unit of the character described comprising a pleated filter body of resin-impregnated paper arranged in tubular form and with the pleats extending substantially radially, end discs of the same material as the filter body closing off opposite ends of the body, said discs being bonded by a thermosetting resin adhesive to opposite end edges of said pleats, said adhesive lying between under faces of said discs and corresponding end edges of said pleats in contact therewith, and having turned down rims bonded adhesively by thermosetting resin adhesive to folds of the pleats, said adhesive lying between inner faces of the turned down rims and the folds of the pleats in contact therewith.
U.S. Pat. No. 2,877,903 to Veres discloses a unit for filtering particulate matter from a fluid flowing therethrough, a hollow filter body comprising a screen equipped with a screen closure at one end thereof, a cap substantially closing the other end of said screen body and defining connecting means for communicating the interior of said filter body with a fluid flow line, and a mass of pellets defining a substantially continuous coating along the outer surface of the screen end closure and screen body and being bonded to each other and to the screen body and end closure to form an integrated structure therewith, whereby both said screen body and screen end closure define filtering areas through which fluid may pass to the interior of the screen body.
U.S. Pat. No. 2,957,235 to Steinberg discloses a method of assembling first and second elements composed of a mixture of powdered metal and resinous binder comprising placing said first element on a support, heating said first element until said resin binder therein becomes pliable without the element losing shape, placing said second element against said first element, applying pressure to said second element until a bond is formed by the resinous binder between said first and second elements, removing the elements from said support, cooling the assembly of said elements, supporting said assembly with sinter material in a sintering zone, and sintering said assembly into a unitary sintered structure.
U.S. Pat. No. 3,379,000 to Webber et al discloses a tow of metal filaments each having a maximum cross-section of less than approximately 10 microns and a length of approximately 50 feet and having a trace amount of a different material diffused in the outer surface thereof.
U.S. Pat. No. 3,490,902 to Fisher discloses a method for forming porous structures useful, for example, as filters, diffusion membranes, sound absorbers, and the like. The structures contain a sintered metal portion at least one surface of which having embedded and bonded thereto a reinforcing member. Some of the fibers in the fiber metal portion are bonded to each other and to the reinforcing member.
U.S. Pat. No. 3,505,038 to Luksch et al. discloses a mass comprising a plurality of randomly disposed hair-like substantially solid metal fibers, wherein said fibers are substantially free from particles of degradation and air transportable, and wherein said mass has resilient loft, substantial uniformity of density and distribution of voids, handlable green strength, and a density range of from one percent to eighty-five percent.
U.S. Pat. No. 3,716,347 to Bergstrom et al. discloses metal parts joined together with sintered powdered metal by applying a mixture of powdered metal and an organic heat-fugitive binder to the parts at the locus of the joint to be formed therebetween, assembling the parts in their desired joined configuration, and heating the assembly to volatilize or burn-off the binder and sinter the powdered metal.
U.S. Pat. No. 4,114,794 to Storms discloses an autogenous or sinter bond between metallic filter media and other metal components of a filter assembly is produced by joining the parts through a diffusion bonding membrane. The membrane comprises a web of small diameter metal fibrils which will sinter bond to both the filter media and the other filter parts to form a physically strong and leak-free seal.
U.S. Pat. No. 4,169,059 to Storms discloses an autogenous or sinter bond between metallic filter media and other metal components of a filter assembly is produced by joining the parts through a diffusion bonding membrane. The membrane comprises a web of small diameter metal fibrils which will sinter bond to both the filter media and the other filter parts to form a physically strong and leak-free seal.
U.S. Pat. No. 4,290,889 to Erickson discloses a new and unique means for preventing the crowns of a backflushable filter element unit from splitting which has heretofore been caused by the cyclic action of the cleaning and backflushing. A layer of staple material is positioned adjacent the outer layer of filter media to prevent bellowing or ballooning. An additional staple layer may be positioned adjacent the inner layer of filtered media to provide additional support. With both staple layers in position on both sides of the filter media, the media is firmly captured and the crowns will
Blue Craig A.
Li Tao
Malanga Robert
Quick Nathaniel R.
Sikka Vinod K.
Frijouf Rust & Pyle P.A.
Jeffery John A.
USF Filtration and Separations Group Inc.
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