Patents Represented by Attorney J. S. Campbell
  • Patent number: 4110392
    Abstract: The present invention provides porous polytetrafluoroethylene ("PTFE") products having fine pores and high porosity, the pore diameter being less than about 1,500A, generally ranging from about 100A to 1,000A. The process for the manufacture of these products comprises: (a) shaping of a lubricated PTFE mixture, by extrusion and/or rolling; (b) a first stretching of the shaped mass while in an unsintered state; (c) free sintering of the stretched mass at a temperature above 327.degree. C; and (d) a second stretching of the sintered mass. These porous PTFE products are suitable for use as gas separators, diaphragms, filters, and other applications.
    Type: Grant
    Filed: December 17, 1976
    Date of Patent: August 29, 1978
    Assignee: W. L. Gore & Associates, Inc.
    Inventor: Etsuo Yamazaki
  • Patent number: 4051230
    Abstract: In this process metal ions such as Ag.sup.+, Pb.sup.2+, Co.sup.2+, Cu.sup. 2+, Fe.sup.3+, etc., are extracted through a porous membrane impregnated with the first extractant containing chelating agents. The membrane contacts with an extraction feed on one side, and with the second extractant on the other side, and the objective metal ions are transferred from the feed to the second extractant. Throughout the extraction process, the pH values of the extraction feed, the impregnated extractant solution, and the second extractant are kept in decreasing order.An apparatus used for the above objective is also provided by this invention.
    Type: Grant
    Filed: December 17, 1974
    Date of Patent: September 27, 1977
    Assignee: W. L. Gore & Associates, Inc.
    Inventor: Terukatsu Miyauchi
  • Patent number: 4051011
    Abstract: The present invention provides an effective process for an enzymatic reaction which utilizes the enzyme membrane of the invention. The enzyme membrane consists of an enzyme strongly entrapped in a membrane base, said base being porous, fibrous, or roughened material which is permanently self-polarized or maintained polarized under an electric field. This enzyme membrane catalytically reacts with a substrate solution without loss of enzyme. The most preferred material for the membrane substrate is expanded porous polytetrafluoroethylene.
    Type: Grant
    Filed: October 22, 1975
    Date of Patent: September 27, 1977
    Assignee: W. L. Gore & Associates, Inc.
    Inventors: Terukatsu Miyauchi, Shintaro Furusaki
  • Patent number: 4025679
    Abstract: The product of the present invention is a fabric woven from oriented polytetrafluoroethylene (PTFE) strands, in which the strands of the weave are interconnected by a multiplicity of fine PTFE fibrils. To produce this fabric, consisting entirely of PTFE, a woven PTFE fabric is heated substantially unrestrained to a temperature above the crystalline melt point of PTFE and stretched. Alternatively, a woven PTFE fabric may be impregnated with other fluorocarbon polymers, heated substantially unrestrained to a temperature above the crystalline melt point of PTFE, and subsequently stretched, thereby generating a multiplicity of fine fibrils interconnecting the weave.
    Type: Grant
    Filed: August 6, 1976
    Date of Patent: May 24, 1977
    Assignee: W. L. Gore & Associates, Inc.
    Inventor: Thomas E. Denny