Fluid filter assemblies with integral fluid seals

Details Fluid filter assemblies with integral fluid seals Fluid filter assemblies with integral fluid seals

1999-11-02

2001-10-09

Simmons, David A. (Department: 1724)

Liquid purification or separation

Particulate material type separator, e.g., ion exchange or...

Removable cartridge or hand-manipulated container

C210S321830, C210S450000, C264SDIG004, C206S497000

Reexamination Certificate

active

06299772

ABSTRACT:

FIELD OF THE INVENTION
The present invention concerns fluid filter assemblies and assembly components including a filter element, a housing and a fluid seal. More particularly, the present invention concerns improved fluid filter assemblies and components in which the fluid seal is an integral part of either the filter element or the housing.
BACKGROUND OF THE INVENTION
Fluid filter assemblies are used in a wide variety of applications ranging in scale from the industrial processing of liquids and gases to the residential purification of drinking water. In general, such fluid filtration devices are comprised of a filter element, a housing and a fluid seal. The purpose of the fluid seal is to ensure that fluid entering the housing is directed through the filter assembly in a predetermined path, viz., through the filter element.
Traditionally, fluid seals are discrete parts, such as skirted gaskets, which engage the outer surface of the filter element and the inner surface of the housing. These seals are usually secured to the filter element with an adhesive tape or an adhesive; see, for example, U.S. Pat. No. 5,389,260. The process for applying these seals tends to be very labor intensive and suffers from the associated ergonomic, quality and training implications. With the skirted gasket, fluid pressure between the skirt and the filter element tends to force the seal away from the element, thus threatening the integrity of the seal. This is particularly troublesome if the seal is secured to the filter element by taping. Furthermore, the typically narrow width of a skirted gasket leaves the integrity of the seal susceptible to disruption by surface imperfections and particulate contamination. Yet another disadvantage of the taped-on seal is the tendency to fold back when inserted into the housing, once again threatening the integrity of the seal and the overall performance of the filter assembly. When the integrity of the fluid seal is compromised, the feed stream can bypass the filter element and weaken the performance of the element. With reverse osmosis elements, such leakage results in ion rejection rates and permeate flow rates being less than optimal.
It would be desirable to have a fluid filter assembly whose production more easily lends itself to automation, particularly with respect to the incorporation of the fluid seal. It would also be desirable to have a fluid filter assembly in which the integrity of the fluid seal was more reliable and less susceptible to damage or deformation during installation and operation.
SUMMARY OF THE INVENTION
It has now been found that a filter assembly in which the fluid seal becomes an integral part of the filter element or the housing reduces the risk of the fluid seal folding back during installation and concomitantly increases the reliability of the seal. In reverse osmosis systems, because of the increased performance and reliability of the seal, ion rejection is significantly improved. Furthermore, by incorporating the fluid seal as an integral part of the filter element or the housing, the manufacturing process for the filter assembly and its constituent elements is more easily automated. Thus, the present invention concerns an improved fluid filter assembly of (a) a filter element having an outer surface, (b) a housing having an inner surface spaced from the outer surface of the filter element and (c) a seal between the outer surface of the filter element and the inner surface of the housing which directs fluid through the filter element, wherein the improvement comprises the seal being an integral part of the outer surface of the filter element or the inner surface of the housing. More particularly, the present invention concerns an improved fluid filter assembly of (a) a filter element, consisting of a cartridge filter of granular adsorbents or a hollow fiber or spiral wound membrane element, having an outer surface, (b) a housing having an inner surface spaced from the outer surface of the filter element and (c) a seal between the outer surface of the filter element and the inner surface of the housing which directs fluid through the filter element, wherein the improvement comprises the seal being a material incorporated as an integral part of the outer surface of the filter element or the inner surface of the housing.
Another aspect of the invention is a filter element in which a fluid seal is incorporated as an integral part of its outer surface. Yet another aspect of the invention is a filter assembly housing in which a fluid seal is incorporated as an integral part of its inner surface. When the fluid seal is incorporated into the housing, a seal is not required on the filter element and the cost of replacing the element is reduced. The fluid seal may also be incorporated as an integral part of both the inner surface of the housing and the outer surface of the filter element. In this case, the entire filter assembly could be disposable.


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