Patents by Inventor Keith Dewhirst

Keith Dewhirst 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: 5687755
    Abstract: A condensate trap assembly 12 includes a valve body 28 accommodating a condensate trap element 34 and a valve element 36. The valve element 36 is movable by a positioner 26 to direct flow in a condensate line 10 either through the condensate trap afforded by the trap element, or through the valve bypassing the condensate trap, or to shut off the condensate line 10. The positioner rotates the valve element 36 under the control of control means 54 which responds to signals from a sensor 24 detecting the presence or absence of condensate in a monitoring chamber 16 and the temperature within the chamber 16. The control means 54 is also responsive to the temperature sensed by a temperature sensor 22 upstream of a process 2 utilizing steam or other fluid which is applied to the condensate trap assembly 12.
    Type: Grant
    Filed: June 28, 1996
    Date of Patent: November 18, 1997
    Assignee: Spirax-Sarco Limited
    Inventors: Keith Robert Farquhar, Keith Dewhirst
  • Patent number: 4792090
    Abstract: There is provided, in a thermostatic steam trap that can operate in either of two modes merely dependent upon which way round the trap is connected in a steam flow line, a temperature-responsive element (9) in which there is a valve member (23) that projects from a housing (16) of the element (10) to an extent dependent upon movement of a diaphragm (19) within the housing (16). Movement of the valve member (23) out of the housing (16) to close on a seat (6) is opposed by a spring clip (8), arms (14) of which embrace the outside of the housing (16), so that if the diaphragm (19) fails the trap as a whole fails with the valve (23/6) open. Conveniently the spring clip (8) serves a further function in that lugs (15) of the clip locate on a wall of the valve seat (6) to locate the element (9) in the trap.
    Type: Grant
    Filed: July 8, 1987
    Date of Patent: December 20, 1988
    Assignee: Spirax Sarco Limited
    Inventor: Keith Dewhirst
  • Patent number: 4681256
    Abstract: There is provided, in a thermostatic steam trap that can operate in either of two modes merely dependent upon which way round the trap is connected in a steam flow line, a temperature-responsive element (9) in which there is a valve member (23) that projects from a housing (16) of the element (10) to an extent dependent upon movement of a diaphragm (19) within the housing (16). Movement of the valve member (23) out of the housing (16) to close on a seat (6) is opposed by a spring clip (8), arms (14) of which embrace the outside of the housing (16), so that if the diaphragm (19) fails the trap as a whole fails with the valve (23/6) open. Conveniently the spring clip (8) serves a further function in that lugs (15) of the clip locate on a wall of the valve seat (6) to locate the element (9) in the trap.
    Type: Grant
    Filed: April 24, 1986
    Date of Patent: July 21, 1987
    Assignee: Spirax Sarco Limited
    Inventor: Keith Dewhirst