EP0212082A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Thermally formed gradient density filter
Assignee: Honeywell International Inc
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Filing: 1986-05-22
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Granted: —
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Expires: 2006-05-22
Abstract
Abstract A fluid filter (88) is formed by producing an air laid nonwoven batt comprising a randomly arranged mixture of thermoplastic fibers and fibers which are not thermoplastic. The batt is then cut into sections, and portions of the batt are heated to a temperature sufficient to partially fuse the fibers, thereby increasing the density of the portion of the batt which is heated. Accordingly, a gradient density filter (88) may be produced having a progressively greater density from the fluid receiving side to the fluid expressing side, so that larger particles are trapped at the fluid receiving side and progressively smaller particles are trapped as the fluid flows through the media, with the finest particles being trapped at the fluid expressing side.
Inventors
- 👤 Donald Irving C/O Allied Corporation Thornton
- 👤 Clarke Alden C/O Allied Corporation Rodman
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 02:53
CPC Classifications
B; B01; B01D; B01D39/00; B01D39/14; B01D39/16; B01D39/1607; B01D39/1623; B01D39/163; D; D04; D04H; D04H1/00; D04H1/40; D04H1/54; D04H1/541; D04H1/5418; D04H1/558; D04H1/70; D04H1/72; D04H1/732; D04H1/76; B01D2239/00; B01D2239/04; B01D2239/0464; B01D2239/06; B01D2239/065; B01D2239/069; B01D2239/0695; B01D2239/10; Y; Y10; Y10S; Y10S264/00; Y10S264/48
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
121 words
Fluid filter including a batt (80) of a nonwoven mixture of a thermoplastic material and fibers that are not thermoplastic, said fibers crossing one another randomly, said filtering media having inner and outer circumferential surfaces, characterized in that the density and stiffness of said media increases from one of said surfaces to the other surface in the direction of fluid flow through the media wherein the media at said one surface is readily permeable to the fluid being filtered and the media at said other surface is substantially less permeable to the fluid being filtered than is the media at said one surface, and the stiffness of the media between said surfaces increases between said one surface and the other surface.
Claim 2
Dependent Claim
121 words
Fluid filter including a batt (80) of a nonwoven mixture of a thermoplastic material and fibers that are not thermoplastic, said fibers crossing one another randomly, said filtering media having inner and outer circumferential surfaces, characterized in that the density and stiffness of said media increases from one of said surfaces to the other surface in the direction of fluid flow through the media wherein the media at said one surface is readily permeable to the fluid being filtered and the media at said other surface is substantially less permeable to the fluid being filtered than is the media at said one surface, and the stiffness of the media between said surfaces increases between said one surface and the other surface.
Claim 3
Dependent Claim
39 words
Fluid filter element as claimed in claim 1, further characterized in that said filtering media is sufficiently stiff at said other surface such that said media is structurally self-supporting, said media being substantially less stiff at said one surface.
Claim 4
Dependent Claim
106 words
Fluid filter as claimed in claim 1, further characterized in that said surfaces include inner and outer circumferential surfaces, said batt (80) being wound in layers in a spiral pattern around said inner circumferential surface with the most dense portion of the batt adjacent the inner circumferential surface, the depth of each layer of the batt wound around the inner circumferential surface increasing as the batt is wound so that the depth of the layer of the batt at the inner circumferential surface is smallest and the depth of the layer of batt at the outer circumferential surface is greatest with the layers therebetween increasing proportionally.
Claim 5
Dependent Claim
39 words
Fluid filter as claimed in claim 1, further characterized in that said batt (80) is formed into discs (102) having a central aperture (104) therethrough and said discs (102) are stacked upon one another to define said fluid filter.
Claim 6
Dependent Claim
35 words
Fluid filter as claimed in claim 4, further characterized in that said discs (102) have a greater density and stiffness adjacent said aperture (104) and a lesser density and stiffness away from said aperture (104).
Claim 7
Dependent Claim
49 words
Fluid filter as claimed in claim 1, further characterized in that said filter is molded into a shape retaining structure (132) having an inner side (130) and an outer side (134), the density and stiffness of one of said sides being greater than the density of the other side.
Claim 8
Dependent Claim
67 words
Fluid filter as claimed in claim 1, further characterized in that said filter is molded into a shape retaining structure (132) having pleats (136) extending circumferentially across said filter, said pleats (136) having fluid receiving and fluid expressing sides, the density and stiffness of the fluid expressing sides of said pleats (136) being greater than the density and stiffness of the fluid receiving side of said pleats.
Claim 9
Dependent Claim
23 words
Fluid filter as claimed in claim 7, further characterized in that a perforated centertube (140) supports at least one of said pleats (136).
Claim 10
Dependent Claim
123 words
Method of forming a fluid filter as claimed in any of the claims 1-8, comprising the steps of forming a nonwoven batt (80) comprising a randomly arrayed mixture of a thermoplastic material and fibers which are not thermoplastic, forming said batt into the desired shape of a fluid filter, characterized in that said heating only a selected portion of said batt (80) while molding the latter into said desired filter shape and while maintaining the rest of said batt (80) other than the selected portion at a temperature less than the temperature of said selected portion to thereby permit softening and fusing of the thermoplastic fibers at said selected portion to thereby increase the stiffness and decrease the permeability of said selected portion.
Claim 11
Dependent Claim
28 words
Method as claimed in claim 9, further characterized in that said method includes the step of simultaneously applying pressure to said selected portion while heating said selected portion.
Claim 12
Dependent Claim
24 words
Method as claimed in claim 9, further characterized in that said selected portion is heated by wrapping said batt around a heated mandrel (84).
Claim 13
Dependent Claim
45 words
Method as claimed in claim 9, further characterized in that said batt is maintained under tension as it is wrapped around said mandrel (84) and the tension on the batt is progressively reduced as successive layers of said batt are wrapped around the mandrel (84).
Claim 14
Dependent Claim
97 words
Method as claimed in claim 9, further characterized in that said method includes the steps of cutting said batt (80) into discs (102) having a concentric aperture (104) extending axially therethrough, passing a heated mandrel (108) through said aperture (104) to increase the stiffness and decrease the permeability of the portion of each disc (102) adjacent said aperture (104), said portion of each disc (102) adjacent said aperture (104) being said selected portion, and stacking said discs (102) upon one another with their central aperture (104) aligned to form an elongated filter with a central passage therethrough.
Claim 15
Dependent Claim
46 words
Method as claimed in claim 13, further characterized in that said portion of each disc (102) adjacent said aperture (104) is stiffened sufficiently so that said discs (102) are structurally self-supporting when stacked upon one another while maintaining sufficient permeability to permit fluid to pass therethrough.
Claim 16
Dependent Claim
64 words
Method as claimed in claim 9, including the step of forcing said batt (80) into a mold member (124) by another member (126) and heating one of said members (126) to a higher temperature while maintaining the other member (124) at a temperature less than the heated member (126), said selected portion of the batt (80) being that portion adjacent the heated member (126).
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