EP0208515A2
Expired / Lapsed
EP
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Filter process and filters therefor
Assignee: Pall Corp
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Filing: 1986-07-03
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Granted: —
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Expires: 2006-07-03
Abstract
Abstract processes for the high efficiency removal of liquid aerosols from gaseous streams and coalescing filters useful for carrying out such processes are provided. The filter comprises a porous medium having a critical surface energy less than the surface tension of the liquid to be removed and the dynamic film thickness of the liquid to be removed is from 0.5 Dto 0.8 D, where D is the mean pore diameter of the porous medium, whereby, in operation, the correlation of the pore size with the dynamic film thickness of the liquid coupled with the relationship between the surface tension of the liquid and the critical surface energy of the porous medium provide high efficiency removal of the liquid aerosol with a minimum resistance to flow. The effluent typically contains 0.05 ppm or less, by weight, of aerosol.
Inventors
- 👤 John David Miller
- 👤 Even Ernest Koslow
- 👤 Kenneth M. Williamson
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-03 21:09
CPC Classifications
B; B01; B01D; B01D39/00; B01D39/14; B01D39/16; B01D39/1607; B01D39/1623; B01D39/20; B01D39/2003; B01D39/2017; B01D46/00; B01D46/24; B01D46/2403; B01D46/2411; Y; Y10; Y10S; Y10S55/00; Y10S55/25
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
122 words
A process for filtering liquid aerosol from a gaseous stream which comprises passing the liquid aerosol-containing gaseous stream through a coalescing filter, said filter comprising a porous medium having a critical surface energy less than the surface tension of the liquid to be removed and the dynamic film thickness (t) of the liquid to be removed is from 0.5 D to 0.8 D, where D is the pore size of said porous medium, whereby, in operation, the correlation of the pore size of said porous medium with the dynamic film thickness of said liquid coupled with the relationship between the surface tension of said liquid and the critical surface energy of said porous medium provide high efficiency removal of said liquid aerosol.
Claim 2
Dependent Claim
122 words
A process for filtering liquid aerosol from a gaseous stream which comprises passing the liquid aerosol-containing gaseous stream through a coalescing filter, said filter comprising a porous medium having a critical surface energy less than the surface tension of the liquid to be removed and the dynamic film thickness (t) of the liquid to be removed is from 0.5 D to 0.8 D, where D is the pore size of said porous medium, whereby, in operation, the correlation of the pore size of said porous medium with the dynamic film thickness of said liquid coupled with the relationship between the surface tension of said liquid and the critical surface energy of said porous medium provide high efficiency removal of said liquid aerosol.
Claim 3
Dependent Claim
14 words
The process of claim 1 wherein said porous medium is a porous, fibrous medium.
Claim 4
Dependent Claim
12 words
The process of claim 2 wherein said aerosol is an oil aerosol.
Claim 5
Dependent Claim
42 words
The process of claim 2 or 3 wherein said porous, fibrous medium has a pore size of from 1 to 5 micrometers and a critical surface energy such that the contact angle (three-phase) is between 100 and 145 degrees with mineral oil.
Claim 6
Dependent Claim
54 words
The process of any one of claims 1-4 wherein said coalescing filter comprises three layers, (a) said porous medium as an intermediate fibrous layer, (b) an upstream fibrous layer having a pore size greater than said intermediate fibrous layer, and (c) a downstream fibrous layer having a pore size greater than said intermediate layer.
Claim 7
Dependent Claim
12 words
The process of claim 2 wherein said aerosol is a water aerosol.
Claim 8
Dependent Claim
40 words
The process of claims 2 or 6 wherein said porous fibrous medium has a pore size of from 1 to 20 micrometers and a critical surface energy such that the contact angle (three-phase) is at least 100 0 with water.
Claim 9
Dependent Claim
58 words
The process of any one of claims 1-7 wherein said porous medium comprises fibers and said fibers are glass, polyolefin, polyester, polyamide fibers, or mixtures thereof and wherein said fibers have been modified with a fluorochemical to reduce the critical surface energy thereof to a value less than the critical surface energy of the liquid to be removed.
Claim 10
Dependent Claim
38 words
The process of any one of claims 1-8 wherein the resistance to flow of said stream through said filter is from 7.0 to 140 grams per square centimeter (0.1 to 2.0 pounds per square inch) (differential) or less.
Claim 11
Dependent Claim
124 words
A coalescing filter for the high efficiency removal of water aerosol from a gaseous stream, said filter comprising three layers, (a) an intermediate fibrous layer having a pore size such that the dynamic film thickness (t) of water is from 0.5 D to 0.8 D, where D is the pore size of the intermediate fibrous layer, the fibers of said intermediate fibrous layer have diameters ranging from 0.1 to 20 micrometers, (b) a fibrous layer upstream of said intermediate layer having a pore size greater than said intermediate layer, and (c) a downstream fibrous layer having a pore size greater than said intermediate layer and wherein the critical surface energy of each layer of said filter is less than the surface tension of water.
Claim 12
Dependent Claim
124 words
A coalescing filter for the high efficiency removal of water aerosol from a gaseous stream, said filter comprising three layers, (a) an intermediate fibrous layer having a pore size such that the dynamic film thickness (t) of water is from 0.5 D to 0.8 D, where D is the pore size of the intermediate fibrous layer, the fibers of said intermediate fibrous layer have diameters ranging from 0.1 to 20 micrometers, (b) a fibrous layer upstream of said intermediate layer having a pore size greater than said intermediate layer, and (c) a downstream fibrous layer having a pore size greater than said intermediate layer and wherein the critical surface energy of each layer of said filter is less than the surface tension of water.
Claim 13
Dependent Claim
125 words
ll. A coalescing filter for the high efficiency removal of oil aerosol from a gaseous stream, said filter comprising three layers, (a) an intermediate fibrous layer having a pore size such that the dynamic film thickness (t) of oil is from 0.5 D to 0.8 D, where D is the pore size of the intermediate fibrous layer, the fibers of said intermediate fibrous layer have diameters ranging from 0.1 to 20 micrometers, (b) a fibrous layer upstream of said intermediate layer having a pore size greater than said intermediate layer, and (c) a downstream fibrous layer having a pore size greater than said intermediate layer and wherein the critical surface energy of each layer of said filter is less than the surface tension of oil.
Claim 14
Dependent Claim
125 words
ll. A coalescing filter for the high efficiency removal of oil aerosol from a gaseous stream, said filter comprising three layers, (a) an intermediate fibrous layer having a pore size such that the dynamic film thickness (t) of oil is from 0.5 D to 0.8 D, where D is the pore size of the intermediate fibrous layer, the fibers of said intermediate fibrous layer have diameters ranging from 0.1 to 20 micrometers, (b) a fibrous layer upstream of said intermediate layer having a pore size greater than said intermediate layer, and (c) a downstream fibrous layer having a pore size greater than said intermediate layer and wherein the critical surface energy of each layer of said filter is less than the surface tension of oil.
Claim 15
Dependent Claim
22 words
A filter cartridge comprising the coalescing filter of claim 10 or 11 and further including a core, support cage, and end caps.
Claim 16
Dependent Claim
23 words
The filter cartridge of claim 12 wherein all parts of said cartridge have critical surface energies less than the surface tension of oil.
References Cited (Backward Citations)
No citation records indexed.
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