Patents by Inventor Ray F. Stewart

Ray F. Stewart has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 4957612
    Abstract: Electrodes for electrochemical processes, especially anodes for the cathodic protection of metal substrates, e.g. reinforcing bars in concrete, comprise a conductive core which acts as a current-distributing member, an outer member which provides an electrochemically active outer surface, and an intermediate member composed of a material which is of higher resistivity, and/or which is less electrochemically active, than the material of the outer member. The higher the resistivity of the intermediate member, the more regular the current distribution along the length of the electrode. When the intermediate member is less electrochemically active, this protects the core from corrosion if the outer member is damaged by physical means or through electrochemical erosion. Preferably at least one of the intermediate member and the outer member is composed of a conductive polymer, especially one comprising carbon black or graphite as conductive filler.
    Type: Grant
    Filed: February 9, 1987
    Date of Patent: September 18, 1990
    Assignee: Raychem Corporation
    Inventors: Ray F. Stewart, James C. Thompson
  • Patent number: 4926165
    Abstract: Devices for detecting and obtaining information about an event, for example the presence of a liquid, which comprise (1) a swellable member which swells upon occurrence of the event and (2) a restraining member which, when the swellable member swells, restricts movement of the swellable member and thus causes the impedance of the device to change. In a preferred embodiment the device comprises two elongate conductors helically wrapped around a support core, a swellable, conductive polymer member surrounding the conductors. Occurrence of an event causes the swellable material to swell and form a conductive bridge between the conductors.
    Type: Grant
    Filed: March 11, 1986
    Date of Patent: May 15, 1990
    Assignee: Raychem Corporation
    Inventors: John Lahlouh, Ray F. Stewart, Robert S. Wasley, Paul D. Hauptly, Laurence M. Welsh
  • Patent number: 4888098
    Abstract: An electrode, preferably of a conductive polymer, has on its surface, preferably over all of its surface, an ion exchange material, preferably of significant thickness. Such a coated electrode may be used for sensing the presence or measuring the concentration of an ionic species, or for removal from or release of an ionic species into an electrode.
    Type: Grant
    Filed: February 20, 1987
    Date of Patent: December 19, 1989
    Assignee: Raychem Corporation
    Inventors: Eric D. Nyberg, Ken A. Klingman, Jeff Curtis, Ray F. Stewart
  • Patent number: 4830855
    Abstract: Temperature-controlled diffusional active agent dispensers that use a side-chain crystallizable polymer in a form that is not free to flow above its melt temperature as a rate-controlling matrix are disclosed. The polymer may be crosslinked to render it nonflowable, be supported, or grafted to a permeable support. Elements that facilitate or permit heating by radiation or electrical conductance/inductance may be included in the dispenser. At temperatures below the melt temperature of the polymer, the polymer is substantially impermeable to the agent. At tempertures at or above the melt temperature the polymer is substantially permeable to the agent.
    Type: Grant
    Filed: November 13, 1987
    Date of Patent: May 16, 1989
    Assignee: Landec Labs, Inc.
    Inventor: Ray F. Stewart
  • Patent number: 4826685
    Abstract: A molluscicidal device in the form of a chemophysical barrier which is placed in the path of molluscs (e.g., between their habitat and an area to be protected from infestation). The device comprises a solid body, typically in the form of a sheet or continuous length strip made of a thermoplastic water-insoluble polymer in which is dispersed a molluscicidal agent. The dimensions of the body, the nature of the agent, and the concentration of the agent on the surface of the body are such as to cause any mollusc that attempts to cross the body to be immobilized, whereby it remains on the body and receives a lethal dose of the agent.
    Type: Grant
    Filed: November 17, 1986
    Date of Patent: May 2, 1989
    Assignee: Landec Labs, Inc.
    Inventor: Ray F. Stewart
  • Patent number: 4502929
    Abstract: Methods of preventing corrosion in which current flows between the to-be-protected substrate and a distributed electrode whose electrochemically active surface is provided by an element which is composed of a conductive polymer and which is at least 500 microns thick. In one embodiment, the electrode is a flexible strip comprising a highly conductive core, e.g. of copper, and a conductive polymer element surrounding the core. In another embodiment, the electrode is a conductive polymer layer which conforms to the surface of the substrate but is separated from it by a layer of insulation.
    Type: Grant
    Filed: July 29, 1982
    Date of Patent: March 5, 1985
    Assignee: Raychem Corporation
    Inventors: Ray F. Stewart, Michael Masia, Albert B. Macknick
  • Patent number: D287856
    Type: Grant
    Filed: September 19, 1983
    Date of Patent: January 20, 1987
    Inventor: Ray F. Stewart