Liquid purification or separation – With repair or assembling means
Patent
1993-04-13
1995-02-28
Dawson, Robert A.
Liquid purification or separation
With repair or assembling means
210282, 210489, 2104935, B01D 2706
Patent
active
053934229
DESCRIPTION:
BRIEF SUMMARY
This invention relates to filters and is more particularly concerned with disposable filters.
Various types of filters are known. However, regardless of the size of the filter, there may be problems associated with storing filters prior to use and also with their disposal after use.
According to one aspect of the present invention, there is provided a disposable filter characterized by a flexible casing having an inlet into which the material to be filtered is introduced, and at least one filter element sealed to the inside of the flexible casing and positioned across the direction of flow of the material to be filtered, the flexible casing being expandable from a substantially flat form for use and collapsible to a substantially flat form after use for disposal.
By this arrangement, the filter can be flat-packed for storage and shipping, expanded for use, and then collapsed again for ease of disposal. Advantageously, such an arrangement minimizes solution loss on removal of the filter as it can be squeezed to remove excess solution prior to disposal.
The flexible casing is open at one end to provide an outlet for the filtered material.
Advantageously, at least one ion-exchange resin bed may be retained by the or each filter element.
In a preferred embodiment of the present invention, a plurality of filter elements is provided, each element having a different pore size. This has the advantage that progressive filtration can be achieved.
For a better understanding of the present invention, reference will now be made, by way of example only, to the accompanying drawings in which:
FIG. 1 is a side elevation of a filter according to the present invention;
FIG. 2 is a sectioned view taken along lines II--II of FIG. 1;
FIG. 3 is an enlarged sectioned view similar to FIG. 2, but showing an alternative configuration of a filter element constructed in accordance with the present invention.
Referring to FIGS. 1 and 2, a disposable filter 10 is shown. The filter 10 comprises a pair of walls 12, 14 between which three filter elements 16, 18, 20 are arranged. The filter elements 16, 18, 20 can be seen more clearly in FIG. 2. The walls 12, 14 are made from polymeric sheet and are joined to one another, trapping each filter member 16, 18, 20 between them, by respective welds 22, 24. Each filter element 16, 18, 20 is folded so that the fold lies downstream in the filter 10 as shown. The filter media could be supported by perforated or porous polymeric materials depending on the fineness of the filtration required.
An inlet 26 is formed in one end 28 of the filter 10, the walls 12, 14 being joined by a further weld (not shown) across that end 28 but which allows fluid to enter the filter through the inlet 26. End 30 of the filter 10 remote from the inlet 26 is open (as is more clearly seen in FIG. 2). In the particular embodiment described, the inlet 26 comprises a polymeric insert which has a circular cross-section. Alternatively, the insert may be of elliptical cross-section. In, other embodiments of the invention, the inlet 26 may simply be an opening which can be attached, by known means, to the supply of solution to be filtered.
The filter 10 is supplied in flat-pack form, and is expanded in use by connecting the inlet 26 to a supply (not shown) of solution to be filtered. The filter 10 expands under the pressure of solution being pumped into it.
The filter elements 16,. 18, 20 shown in FIG. 2 initially lie flat between the walls 12, 14 before solution is pumped into the filter 10. As solution is pumped into the filter 10, the walls 12, 14 are forced apart and the filter elements 16, 18, 20 take up configurations approximately as shown in FIG. 2.
After the filter 10 has been used for a predetermined length of time or for filtering a predetermined amount of solution, the solution supply is disconnected from the inlet 26 and the filter 10 is squeezed to remove any excess solution and to compress it back into a generally flat configuration ready for disposal.
FIG. 3 illustrates a filter element configuration which could
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Dawson Robert A.
Eastman Kodak Company
Walker W. L.
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