Liquid purification or separation – Plural distinct separators – Filters
Reexamination Certificate
2000-05-09
2001-10-23
Savage, Matthew O. (Department: 1723)
Liquid purification or separation
Plural distinct separators
Filters
C210S486000, C210S492000
Reexamination Certificate
active
06306300
ABSTRACT:
This invention relates to filter cartridges of the type having a plurality of filter cells, and to the filter cells themselves.
Filter cartridges of the type with which the present invention is concerned, i.e. for the filtration of fluids such as wines, other alcoholic beverages such as beer, soft drinks, fruit juices, and other beverages, and for use in the chemical and pharmaceutical industries, comprise a plurality of individual filter cells which are connected together and which together form the cartridge, the cartridge being located in an outer vessel or container. Each of the individual cells is formed with upper and lower filtration medium layer(s) disposed about and in relation to an inner separator disc, and each has a central aperture which, when a plurality of cells are placed in contiguous and stacked relationship, form a continuous elongate central aperture down the centre of the cartridge. The elongate central aperture communicates with the interiors of the cells such that a fluid to be filtered—fed into the vessel or container—flows from the exterior of the individual cells, through the layer(s) of filtration medium of the cells, into the cells themselves, and thence into the elongate central aperture. The filtered fluid leaves the vessel or container through a suitable outlet in said vessel or container.
Such filter cartridges as described above may contain one or up to sixteen or even more individual filter cells in which, about the elongate central aperture, the filtration medium layer(s) of adjacent cells are in mutual contact. Because of this mutual contact, the height of the cartridge—which is desirably pre-set to an optimum height—has a tendency to reduce during use of the filtration apparatus, with the result that the individual cells become unstable, and compression must be applied to the cartridge in order to take up and compensate for the aforesaid reduction in height.
In addition, when the individual filter cells become unstable, they have a tendency to move laterally relative to each other, which may cause gaps to appear between adjacent cells, this resulting in the fluid to be filtered—or some at least of said fluid to be filtered—passing directly to the elongate central aperture instead of firstly passing through the filter cells.
The above described conditions-can result in failure of the filtration apparatus in that the fluid is not filtered sufficiently, and also in a shortened life expectancy of the individual cells. In addition due to the necessity of providing adjustment means in order to attempt to compensate for the above, the cost of the apparatus is increased.
There have been many proposals for improving the construction of and the performance of filter cartridges. For example, prior cases such as WO 91/04089, GB 2185196, and U.S. Pat. No. 4,704,207 disclose filter cartridges, but the disclosures in these prior cases retain the disadvantages referred to above and do not overcome the problems set forth herein.
The present invention therefore seeks to provide an improved form of filter cartridge which will obviate the disadvantages of known filter cartridges.
According to the present invention, there is provided a filter cartridge including a plurality of filter cells arranged in contiguous and stacked relationship, each filter cell including an inner separator disc having a central aperture and a plurality of upstanding members arranged about said aperture, adjacent filter cells being spaced from each other by spacer means, means being provided to hold said filter cells and said spacer means in position to form said cartridge, said plurality of upstanding members being in the form of pins or teeth and said spacer means being in the form of spacer rings or gaskets having lands or grooves which are engaged by the pins or teeth of adjacent cells.
Preferably, said rings or gaskets will be double-sided in that they are each provided with a land or groove at each side thereof.
Said spacer rings or gaskets will preferably be composed of plastics material and of the same material as the inner separator discs.
Preferably, said spacer rings or gaskets will be coated to make them chemically resistant.
The means to hold said filter cells and said spacer rings or gaskets in position will preferably be a plurality of straps which engage with end caps provided on said cartridge. Alternatively, said means will be thermal welding, adhesive, or a central core.
Said straps will preferably be composed of metal, alloy, or of plastics material.
Said end caps will preferably be annular and will each have three equispaced recesses in the upper surfaces thereof, said recesses being adapted to receive shaped ends of said straps so as to hold the integers of the filter cartridge in the desired positions.
REFERENCES:
patent: 2444147 (1948-06-01), Walton
patent: 4704207 (1987-11-01), Chu
patent: 4783262 (1988-11-01), Ostreicher et al.
patent: 5055192 (1991-10-01), Artinyan et al.
patent: 1096331 (1961-01-01), None
patent: 2185196 (1987-07-01), None
patent: WO9104089 (1991-04-01), None
Brown Philip John
Green Steven Mark
Hallewell John
Harding William Henry
Klauber & Jackson
Savage Matthew O.
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