Patents by Inventor Don L. Drinkwater

Don L. Drinkwater 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: 5444360
    Abstract: A method and an apparatus to reduce the maintenance required for equipment which is not operating for relatively long periods of time such as seasonal equipment. The invention turns the equipment on for a brief interval at fixed periods of time. This cycling of the equipment during normally non-operating periods of time helps to prevent problems which occur when equipment is left idle for relatively long periods of time.
    Type: Grant
    Filed: November 4, 1994
    Date of Patent: August 22, 1995
    Inventor: Don L. Drinkwater
  • Patent number: 5240179
    Abstract: A method and an apparatus to aid in the prevention of pipe freezing. This method utilizes fluid in motion to help pipes resist freezing. When initiated by the control circuit, fluid flows through the pipes to prevent freezing. The control system utilizes either a fixed duty cycle, a variable duty cycle, a duty cycle which can be selected or a temperature sensor. Other apparatus of this sort use the heat produced by electrical current to heat a pipe to prevent freezing. The method and apparatus described here utilizes fluid in motion to accomplish a similar task. This method is particularly suited for hot water circulating types of systems.
    Type: Grant
    Filed: November 22, 1991
    Date of Patent: August 31, 1993
    Inventor: Don L. Drinkwater
  • Patent number: 4818891
    Abstract: A method and an apparatus which delay initiation of a shut down procedure in a computer to allow the riding through of variations in a power supply. An interrupter receives and interrupts an asserted shut down signal and outputs an interrupt signal when the shut down signal has been asserted. A gate trigger is coupled to the interrupter and triggers an energy booster to raise the power supplied to the computer when the gate trigger receives the interrupt signal from the interrupter. The amount of energy remaining in the energy booster is monitored by a monitor and a depletion signal is outputted when the amount of energy remaining in the energy booster is below a reference value. An output stage has inputs coupled to the interrupter and the monitor, and receives at these inputs the interrupt signal and the depletion signal and outputs a re-asserted shut down signal to the computer when both the interrupt signal and the depletion signal are present at the inputs of the output stage.
    Type: Grant
    Filed: May 6, 1988
    Date of Patent: April 4, 1989
    Assignee: Digital Equipment Corporation
    Inventor: Don L. Drinkwater