Patents by Inventor Robert H. Duncan

Robert H. Duncan 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: 7879771
    Abstract: A non-aqueous, non-flammable Group IVB metal alkoxide crosslinker composition includes a non-aqueous, non-flammable Group IVB metal alkoxide, wherein the metal is chemically bonded to a glycol containing 4 or more carbons, to an alkoxy group containing 6 or more carbons, or a mixture of both. A fracturing fluid employed in the hydraulic fracturing of subterranean formations is formulated through mixture of the non-aqueous, non-flammable Group IVB metal alkoxide crosslinker composition with a polymer solution.
    Type: Grant
    Filed: May 20, 2008
    Date of Patent: February 1, 2011
    Assignee: Benchmark Performance Group, Inc.
    Inventors: Derek E. Vaughn, Robert H. Duncan, David N. Harry, Dennis A. Williams
  • Publication number: 20090288828
    Abstract: A non-aqueous, non-flammable Group IVB metal alkoxide crosslinker composition includes a non-aqueous, non-flammable Group IVB metal alkoxide, wherein the metal is chemically bonded to a glycol containing 4 or more carbons, to an alkoxy group containing 6 or more carbons, or a mixture of both. A fracturing fluid employed in the hydraulic fracturing of subterranean formations is formulated through mixture of the non-aqueous, non-flammable Group IVB metal alkoxide crosslinker composition with a polymer solution.
    Type: Application
    Filed: May 20, 2008
    Publication date: November 26, 2009
    Inventors: Derek E. Vaughn, Robert H. Duncan, David N. Harry, Dennis A. Williams
  • Patent number: 4496799
    Abstract: Circuit for controlling the operation of a handsfree or loudspeaking telephone instrument. The circuit includes an integrated circuit dual tone multifrequency (DTMF) generator. When a button of the generator is depressed, and the instrument is in its handsfree mode, power feed to the generator and the speech network is activated. The tone generation circuitry and speech network are thereby connected in parallel with the handsfree hybrid. When the DTMF button is released, power to the speech network is discontinued. Further, when the instrument is in the handsfree mode, and in the non-dialing condition, the confidence tone muting resistance is shunted so that no voice signal attenuation to the handsfree hybrid can occur. The switching is protected against surges both in the handsfree and hookswitch on and off hook conditions and is protected against leakage at the start of the DTMF output.
    Type: Grant
    Filed: December 13, 1982
    Date of Patent: January 29, 1985
    Assignee: International Telephone and Telegraph Corporation
    Inventors: Rickey W. Kingen, Robert H. Duncan
  • Patent number: 4406926
    Abstract: A telephone instrument station circuit using a digital tone generator for generating dual tone multifrequency (DTMF) signals. The circuit employs both series and shunt muting of the receiver during the intervals occurring during the depressive and release movements of the tone generating key or button of the keyblock. The receiver is doubly muted during these intervals to prevent inductively derived spikes from causing audible clicks in the receiver. During the period of tone generation on full depression of the button, the shunt muting is released to allow the full generated tone to be sent to the line, the series muting remaining in effect.
    Type: Grant
    Filed: December 19, 1980
    Date of Patent: September 27, 1983
    Assignee: International Telephone and Telegraph Corporation
    Inventor: Robert H. Duncan