Patents by Inventor Mark D. Lehmann

Mark D. Lehmann 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: 7548170
    Abstract: A method for controlling operation of a heat exchanger system comprises providing a heat exchanger system mountable to a rear door of a rack mounted computer system, circulating a heat transport medium through the heat exchanger system, detecting leaks in the heat exchanger system by comparing a first flow rate in an inflow line to a second flow rate in a return flow line, emitting a leakage alert and ceasing further circulation of the heat transport medium through the heat exchanger system when the first flow rate exceeds the second flow rate by a predetermined flow amount, optimizing operation of the rack mounted computer system by monitoring an interior temperature of the rack mounted computer system in a plurality of vertical zones, and optimizing operation of the heat exchanger system by comparing a second temperature measured by a second temperature sensor in the return flow line with a predetermined maximum return flow temperature value.
    Type: Grant
    Filed: June 4, 2008
    Date of Patent: June 16, 2009
    Assignee: International Business Machines Corporation
    Inventors: Marc Griffel, Mark D. Lehmann, Michael Schaefer, Karl H. Uhl
  • Patent number: 6027605
    Abstract: Wafer verifying apparatus for receiving a wafer thereagainst and for verifying the wafer, wafer verifying apparatus comprising a fixture including a stage for receiving thereagainst a surface of the wafer, a vacuum assembly for effecting a vacuum coupling of the surface of the wafer to the stage, and sensor apparatus for accepting the wafer in the presence of a vacuum couple of the surface of the wafer against the stage and for rejecting the wafer absent a vacuum couple of the surface of the wafer against the stage.
    Type: Grant
    Filed: May 22, 1998
    Date of Patent: February 22, 2000
    Assignee: Raines Technologies, Inc.
    Inventors: Mark D. Lehmann, Dorman Raines, Charles A. Stamps