Method of producing a fluorocarbon filter element

• US 4,588,464 A
• Filed: 05/08/1984
• Issued: 05/13/1986
• Est. Priority Date: 09/09/1983
• Status: Expired due to Term

• Current Assignee: Pall Corporation (Danaher Corporation), Kurashiki Boseki Kabushiki Kaisha 7-1 Hommachi Kurashiki-Shi Okayama Japan
• Original Assignee: Kurashiki Boseki Kabushiki Kaisha
• Inventors: Inoue, Akihisa, Hori, Yoshihiro, Miyagi, Tokuya, Fujimori, Shoichi, Hamada, Katushi
• Primary Examiner(s): Fisher, Richard V.
• Assistant Examiner(s): Millard, Wanda L.
• Application Number:
  US06/608,309
• Time in Patent Office: 735 Days
• Field of Search: 210/493.1, 210/493.2, 210/493.5, 210/500.2, 156/218, 156/69, 156/306.6, 156/309.6, 29/163.5 F, 55/DIG. 5, 264/162, 264/249
• US Class Current: 156/218
• CPC Class Codes: B01D 2201/0407 Perforated supports on both sides of the filtering element
• CPC Class Codes: B01D 29/111 Making filtering elements
• CPC Class Codes: B01D 29/21 with corrugated, folded or wound sheets
• CPC Class Codes: B01D 39/1692 Other shaped material, e.g. perforated or porous sheets
• CPC Class Codes: B01D 63/061 Manufacturing thereof
• CPC Class Codes: B01D 63/067 with pleated membranes
• CPC Class Codes: B29C 65/02 by heating, with or without pressure
• CPC Class Codes: B29C 65/0672 Spin welding
• CPC Class Codes: B29C 65/4815 Hot melt adhesives, e.g. thermoplastic adhesives
• CPC Class Codes: B29C 65/5021 being multi-layered
• CPC Class Codes: B29C 65/5042 covering both elements to be joined
• CPC Class Codes: B29C 65/5057 positioned between the surfaces to be joined B29C65/5035 takes precedence
• CPC Class Codes: B29C 65/5071 and being composed by one single element
• CPC Class Codes: B29C 65/5078 and being composed by several elements
• CPC Class Codes: B29C 65/5085 and comprising grooves, e.g. being E-shaped, H-shaped
• CPC Class Codes: B29C 66/112 Single lapped joints
• CPC Class Codes: B29C 66/1122 Single lap to lap joints, i.e. overlap joints B29C66/45, B29C66/472, B29C66/52272 take precedence
• CPC Class Codes: B29C 66/135 Single hemmed joints, i.e. one of the parts to be joined being hemmed in the joint area
• CPC Class Codes: B29C 66/4322 by joining a single sheet to itself B29C66/4332 takes precedence
• CPC Class Codes: B29C 66/5344 said single elements being substantially annular, i.e. of finite length, e.g. joining flanges to tube ends B29C66/5346 takes precedence
• CPC Class Codes: B29C 66/612 : Making circumferential joints
• CPC Class Codes: B29C 66/71 : characterised by the composition of the plastics material of the parts to be joined welding bar compositions B29C65/125
• CPC Class Codes: B29C 66/723 : being multi-layered B29C66/7292, B29C66/72941 take precedence
• CPC Class Codes: B29C 66/727 : being porous, e.g. foam
• CPC Class Codes: B29C 66/729 : Textile or other fibrous material made from plastics
• CPC Class Codes: B29C 66/7294 : Non woven mats, e.g. felt
• CPC Class Codes: B29K 2027/12 : containing fluorine
• CPC Class Codes: B29K 2027/18 : PTFE, i.e. polytetrafluorethene , e.g. ePTFE, i.e. expanded polytetrafluorethene
• CPC Class Codes: B29L 2031/14 : Filters optical filters B29L2011/0066, sieves or screens B29L2031/737
• CPC Class Codes: Y10S 55/05 : Methods of making filter
• CPC Class Codes: Y10T 156/1038 : Hollow cylinder article

Abstract

The present invention provides a filter element made wholly of fluorocarbons resin, comprising as essential elements a filter material produced by folding a sandwich-form sheet comprising a filter membrane made of a fluorocarbon resin and net supporters made of a thermoplastic fluorocarbon resin superimposed on the both surfaces thereof into a pleat form and liquid-tightly welding the edge parts of the both sides of the pleated sheet, sealed end parts produced by embedding the both end parts of said filter material except the central openings into a thermoplastic fluorocarbon resin to force the resin into the pleats, whereby the both end parts are each integrally and tightly welded, and fluorocarbon resin caps welded liquid-tightly with said sealed end parts, and production thereof.

Claims

1. A method for producing a filter element made wholly of a fluorocarbon resin characterized by forming sheet comprising a filter membrane made of a fluorocarbon resin and net supporters made of thermoplastic fluorocarbon resin superimposed on the both surfaces thereof into a pleat form, bending the pleated sheet into a cylindrical form liquid-tightly welding the edge parts of the adjacent both sides, pre-welding the pleats by heating the both end parts of the cylindrical pleat-form filter to a temperature higher than the melting point of the net supporter, cooling the pre-welded filter, melting a thermoplastic fluorocarbon resin in a circular mold having means defining a central opening, inserting the end parts of the cooled pre-welded pleat into the molten thermoplastic fluorocarbon resin in the circular mold having a central opening to force the resin into the pleats, whereby the end part and the molten resin are integrally welded together, and fitting fluorocarbon resin caps having a prescribed shape in the ends parts of the resulting filter material.

2. A method as described in claim 1, wherein the edge parts of the both sides of the pleat-form filter are welded together by inserting a welding tape made of a thermoplastic fluorocarbon resin between the edge parts.

3. A method as described in claim 1, wherein the filter membrane is made of PTFE.

4. A method as described in claim 1, wherein the net supporter is made of PFA, FEP or EPE.

5. A method as described in claim 1, wherein the resin for welding the end parts is PFA, FEP or EPE.

6. A method as described in claim 1, wherein the cap is made of PTFE, FEP, PFA or EPE.

7. A method as described in claim 1, wherein at least one of the caps has a central opening.

8. A method as described in claim 1, wherein the element is provided with an additional fluorocarbon resin core material for supporting the filter membrane material, inside the central opening of the filter element, and then integrally welding two or three of the assembly thus obtained.