Patents by Inventor Barbara C. Gilstad

Barbara C. Gilstad 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).

  • Publication number: 20140034862
    Abstract: Tunable fluid end embodiments comprise a family, each family member comprising a pump housing with at least one installed tunable component chosen from: tunable valve assemblies, tunable valve seats, tunable radial arrays and/or tunable plunger seals. For example, a tunable valve assembly or tunable radial array selectively attenuates valve-generated vibration at its source, thus reducing the likelihood of fluid end failures associated with fatigue cracking and/or corrosion fatigue. Adding tunable valve seats and/or tunable plunger seals to a fluid end facilitates optimal damping and/or selective attenuation of vibration at one or more predetermined (and frequently localized) fluid end resonant frequencies. Thus, the likelihood of exciting destructive resonances in a pump's fluid end housing is further reduced.
    Type: Application
    Filed: October 7, 2013
    Publication date: February 6, 2014
    Inventors: Dennis W. Gilstad, Barbara C. Gilstad
  • Publication number: 20140034863
    Abstract: Tunable fluid end embodiments comprise a family, each family member comprising a pump housing with at least one installed tunable component chosen from: tunable valve assemblies, tunable valve seats, tunable radial arrays and/or tunable plunger seals. For example, a tunable valve assembly or tunable radial array selectively attenuates valve-generated vibration at its source, thus reducing the likelihood of fluid end failures associated with fatigue cracking and/or corrosion fatigue. Adding tunable valve seats and/or tunable plunger seals to a fluid end facilitates optimal damping and/or selective attenuation of vibration at one or more predetermined (and frequently localized) fluid end resonant frequencies. Thus, the likelihood of exciting destructive resonances in a pump's fluid end housing is further reduced.
    Type: Application
    Filed: October 7, 2013
    Publication date: February 6, 2014
    Inventors: Dennis W. Gilstad, Barbara C. Gilstad
  • Publication number: 20140021398
    Abstract: A tunable valve assembly reduces valve-generated vibration. One embodiment comprises a valve body and valve seat having substantially collinear longitudinal axes. A rebound characteristic frequency is associated with rebound of the elastic valve body base plate from forceful contact with the valve seat. A central cavity in the valve body encloses a spring-mass damper optionally immersed in a dilatant liquid and having a damper resonant frequency approximating a pump housing resonance. A lateral support assembly adjustably secured to the valve seat has a support resonant frequency designed in conjunction with the rebound characteristic frequency and the damper resonant frequency. Combined hysteresis heat loss associated with the above three vibration frequencies is reflected in lower closing energy impulse amplitude and damping of associated vibrations.
    Type: Application
    Filed: September 27, 2013
    Publication date: January 23, 2014
    Inventors: Barbara C. Gilstad, Dennis W. Gilstad
  • Publication number: 20130291982
    Abstract: Tunable valve assemblies attenuate valve-generated vibration at one or more predetermined assembly resonant frequencies which are typically altered to correspond to specific pump housing resonant frequencies. Each tunable valve assembly comprises a valve body having a peripheral groove spaced radially apart from a central reservoir. An adjustable flange may be coupled to the valve body for imposing a predetermined shear preload by partially constraining a viscoelastic element in the reservoir. One or more valve assembly resonant frequencies are thus predictably altered. Further, the associated valve-generated vibration spectrum is narrowed, and its amplitude is reduced through hysteresis loss of closing impulse energy at each predetermined assembly resonant frequency. Assembly resonant frequencies are additionally or alternatively altered through choice of viscoelastic elements and inclusions (e.g., shear-thickening materials) in the reservoir and/or peripheral groove.
    Type: Application
    Filed: July 9, 2013
    Publication date: November 7, 2013
    Inventors: Dennis W. Gilstad, Barbara C. Gilstad
  • Patent number: 8567754
    Abstract: Tunable valve assemblies attenuate valve-generated vibration at one or more predetermined assembly resonant frequencies which are typically altered to correspond to specific pump housing resonant frequencies. Each tunable valve assembly comprises a valve body having a peripheral groove spaced radially apart from a central reservoir. An adjustable flange may be coupled to the valve body for imposing a predetermined shear preload by partially constraining a viscoelastic element in the reservoir. One or more valve assembly resonant frequencies are thus predictably altered. Further, the associated valve-generated vibration spectrum is narrowed, and its amplitude is reduced through hysteresis loss of closing impulse energy at each predetermined assembly resonant frequency. Assembly resonant frequencies are additionally or alternatively altered through choice of viscoelastic elements and inclusions (e.g., shear-thickening materials) in the reservoir and/or peripheral groove.
    Type: Grant
    Filed: July 9, 2013
    Date of Patent: October 29, 2013
    Inventors: Dennis W. Gilstad, Barbara C. Gilstad
  • Patent number: 8567753
    Abstract: A tunable valve assembly comprises a valve body, an adjustable preload flange centrally coupled to the valve body, and a viscoelastic element; the assembly attenuates valve-generated vibration transmitted to a pump housing. The vibration spectrum is narrowed and its amplitude reduced through hysteresis loss of closing impulse energy. The viscoelastic element comprises a peripheral groove portion coupled to a central reservoir portion via a plurality of fenestration portions. At least a first predetermined assembly resonant frequency is achieved by changing valve assembly compliance (with associated hysteresis loss) through adjustment of annular shear preload applied by the flange to the viscoelastic element reservoir portion. Such preload adjustment effectively maximizes hysteresis loss at the resonant frequency. At least a second predetermined assembly resonant frequency is achieved through choice of a circumferential shear-thickening material within the viscoelastic element groove portion.
    Type: Grant
    Filed: December 12, 2012
    Date of Patent: October 29, 2013
    Inventors: Dennis W. Gilstad, Barbara C. Gilstad
  • Patent number: 8550425
    Abstract: An impulse tolerant valve assembly comprises a valve body having a longitudinal axis and a central internal cavity, the cavity enclosing a nonlinear spring-mass damper optionally immersed in a dilatant liquid. The central internal cavity is enclosed by a proximal valve body portion and a distal elastic valve body base plate, the base plate having a peripheral valve seat interface. Impulse tolerance results in part from hysteresis heat loss due to compliance of the elastic valve body base plate, as well as from heat loss associated with operation of the nonlinear spring-mass damper. The combined heat loss is reflected in reduction of closing energy impulse amplitude and damping of induced valve body vibrations. Compliance of the elastic valve body base plate increases closing energy impulse duration and narrows the corresponding induced vibration spectrum. The valve body has at least one guide and at least one peripheral seal-retention groove.
    Type: Grant
    Filed: June 18, 2012
    Date of Patent: October 8, 2013
    Inventors: Dennis W. Gilstad, Barbara C. Gilstad
  • Patent number: 8496224
    Abstract: A tunable valve assembly attenuates valve-generated vibration at one or more predetermined assembly resonant frequencies. The assembly comprises a valve body having a peripheral groove spaced radially apart from a central reservoir. An adjustable preload flange is centrally coupled to the valve body for changing assembly compliance and for imposing a shear preload by partially constraining a viscoelastic element in the reservoir. Assembly resonant frequencies are thus predictably altered. Further, the vibration spectrum is narrowed and its amplitude reduced through hysteresis loss of closing impulse energy at each such altered resonant frequency. At least a first predetermined assembly resonant frequency is achieved through adjustment of shear preload, and at least a second predetermined assembly resonant frequency is achieved through choice of a viscoelastic or composite element in the peripheral groove.
    Type: Grant
    Filed: December 29, 2012
    Date of Patent: July 30, 2013
    Inventors: Dennis W. Gilstad, Barbara C. Gilstad
  • Patent number: 8403337
    Abstract: A multifunction ring symmetrical about a longitudinal axis has an elastomeric body, first and second ends, and inner and outer surfaces. The elastomeric body totally encloses at least one pair of longitudinally-spaced circumferential tubular cavities, each pair of cavities being mutually connected via a fluid flow restrictor and substantially filled with at least one fluid medium. Each fluid flow restrictor is responsive to longitudinal compression of the elastomeric body, and the fluid medium facilitates heat conduction, vibration damping, extrusion blocking and/or fluid pressure transmission. Longitudinal compression of a multifunction ring on a pump pressure stroke increases tubular cavity fluid pressure and causes substantially symmetrical radial ring expansion. Radial ring expansion is both inward and outward, thus reducing fluid flow resistance in the fluid flow restrictor.
    Type: Grant
    Filed: September 14, 2012
    Date of Patent: March 26, 2013
    Inventors: Barbara C. Gilstad, Dennis W. Gilstad
  • Patent number: 8292301
    Abstract: A multifunction ring comprises an elastomeric body which totally encloses at least one circumferential tubular cavity filled with at least one liquid medium. In various ring embodiments the liquid medium conducts heat, damps vibration, blocks extrusion and/or transmits hydraulic pressure. When one or more rings are used in a plunger packing, longitudinal compression of the ring(s) secondary to increased pumped fluid pressure occurs during a pressure stroke. Such compression, acting through the compliance of each ring, increases tubular cavity hydraulic pressure and causes radial ring expansion. Ring expansion is both inward toward a plunger and, simultaneously, outward toward its packing box. Inward expansion tends to seal the extrusion gap, while outward expansion increases coupling from plunger to packing box to increase vibration damping and/or heat scavenging. Periodic reduction of pumped fluid pressure tends to reverse radial ring expansion, thus reducing both frictional ring wear and heat generation.
    Type: Grant
    Filed: June 18, 2012
    Date of Patent: October 23, 2012
    Inventors: Dennis W. Gilstad, Barbara C. Gilstad
  • Patent number: 8276918
    Abstract: One or more multifunction elastomeric plunger seal rings augment a plunger packing assembly within a plunger pump packing box. Each such ring comprises a totally-enclosed circumferential tubular cavity. The cavity is filled with a dilatant liquid which transmits hydraulic pressure throughout the tubular cavity and simultaneously damps pump vibration transmitted via the packing box. Pump pressure strokes increase tubular cavity hydraulic pressure, resulting in radial ring expansion forces both inwardly toward a plunger and outwardly toward its packing box. Inward ring expansion tends to close the extrusion gap, while outward expansion force improves heat transfer from plunger to packing box. Outward expansion force also increases coupling of packing box vibration to hysteresis loss in the dilatant liquid.
    Type: Grant
    Filed: April 26, 2012
    Date of Patent: October 2, 2012
    Inventors: Barbara C. Gilstad, Dennis W. Gilstad
  • Patent number: 7716761
    Abstract: An adaptive positioning system embodiment comprises a plurality of longitudinal elements. At least one frame member has an adjustably fixed spatial relationship with a plurality of longitudinal elements, thus forming a conforming assembly capable of supporting a person. The conforming assembly is supported by support means comprising at least one bearing and facilitating rotation (by rotation means) of the conforming assembly (and a supported person) about a longitudinal axis. Control means generate at least one control signal for controlling the rotation means to adapt the positioning system to an individual person, at least one control signal encoding at least one set point and a function of weight distribution on the conforming assembly. The function of weight distribution may be nonlinear. At least one optional multiuse port and/or one or two multiuse optional lateral reverse-foldable longitudinal assemblies may be added to the conforming assembly.
    Type: Grant
    Filed: March 30, 2007
    Date of Patent: May 18, 2010
    Inventors: Dennis W. Gilstad, Barbara C. Gilstad, Elizabeth A. McGuigan, John R. H. Gilstad