Patents by Inventor Keith W. Gustafson

Keith W. Gustafson 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: 6128908
    Abstract: An improved cryogenic liquid storage tank features a main tank containing a ullage tank. The top portion of the main tank communicates with the bottom portion of the ullage tank through a pipe segment and an opening in the ullage tank. The pipe segment is dimensioned and positioned so that the main tank fills with incoming cryogenic liquid while the ullage tank remains primarily empty. The restricted flow into the ullage tank causes the flow of cryogen into the main tank to decrease when the main tank is nearly full. This decrease in flow is utilized to terminate the filling of the tank. Removal of product from the main tank decreases the pressure and the liquid level therein so that liquid flows out of the ullage tank and is unable to return.
    Type: Grant
    Filed: October 15, 1998
    Date of Patent: October 10, 2000
    Assignee: MVE, Inc.
    Inventor: Keith W. Gustafson
  • Patent number: 5572875
    Abstract: A combined second relief valve and restricted orifice is located downstream of the relief valve stack on a vent line. The second relief valve opens at a pressure greater than that of the relief stack. When the second relief valve is closed, vapor is vented through the restricted orifice at high velocity, and when the second relief valve is open, the vapor vents from the unrestricted end of the vent line at high volume.
    Type: Grant
    Filed: April 28, 1994
    Date of Patent: November 12, 1996
    Assignee: Minnesota Valley Engineering, Inc.
    Inventor: Keith W. Gustafson
  • Patent number: 5537824
    Abstract: The fueling station consists of a vacuum insulated storage vessel for storing a large quantity of LNG at low pressure. The LNG is delivered to one of two relatively small volume fuel conditioning tanks where the pressure and temperature of the LNG can be raised or lowered as dictated by the needs of the system. The pressure and temperature in the fuel conditioning tanks are raised by delivering high pressure natural gas vapor thereto from a high pressure bank. The temperature and pressure can be lowered by venting natural gas from the fuel conditioning tanks and/or delivering LNG thereto. The fuel conditioning tanks are connectable to a vehicle's fuel tank via a fill line to deliver natural gas and LNG to the vehicle and to vent natural gas from the vehicle to the fueling station.
    Type: Grant
    Filed: January 31, 1994
    Date of Patent: July 23, 1996
    Assignee: Minnesota Valley Engineering
    Inventors: Keith W. Gustafson, George W. Kalet
  • Patent number: 5421161
    Abstract: A relief valve is provided in the dip tube line that provides a fixed back pressure of 2-3 psi. When the economizer valve on the economizer circuit opens, the back pressure in the dip tube is the head pressure plus the 2-3 psi created by the relief valve. This pressure creates a path of least resistance through the economizer circuit such that the demand of product will draw gas from the gas head via the economizer line until the pressure falls below the valve set at the regulator. Once the pressure falls below the valve set at the regulator, the regulator closes the economizer circuit and liquid will be drawn through the dip tube. Because the relief valve prevents flow back into the tank, an orifice is provided to allow back flow of the cryogen from the withdrawal line to the tank once delivery of product is stopped.
    Type: Grant
    Filed: September 27, 1993
    Date of Patent: June 6, 1995
    Assignee: Minnesota Valley Engineering, Inc.
    Inventor: Keith W. Gustafson
  • Patent number: 5365692
    Abstract: Disclosed is a method for killing animal pests infesting a water-bearing product and including placing the product in a chamber having at least some oxygen therewithin and reducing the pressure in the chamber below atmospheric pressure. The improvement comprises the steps of reducing the pressure in the chamber at least to the boiling point of the water in the product so that oxygen in the chamber is displaced by water vapor until the chamber is substantially oxygen depleted. The oxygen depleted condition is maintained for the "time of lethality," i.e. for a time at least equal to the time required for a pest to be killed in an oxygen-depleted environment. Specific aspects of the new method also involve using inert gas and a poison gas fumigant.
    Type: Grant
    Filed: May 7, 1993
    Date of Patent: November 22, 1994
    Assignee: KGK Ecosystems, Inc.
    Inventor: Keith W. Gustafson
  • Patent number: 5228585
    Abstract: A vehicle-mounted double-walled ellipsoidal cryogenic storage vessel includes an inner vessel enclosed by an outer shell to form an insulation chamber therebetween. Both the inner vessel and the outer shell are formed in the same manner. An elliptical pressure head of circular cross-section is cut along a diameter to form two end halves. An end wall is secured between the two end halves to form an end, which is secured to an end of a wall like cross-section. This process is repeated with another pressure head to form the other end of the storage vessel. Storage vessels may be constructed of any size desired to allow sufficient ground clearance when mounted under a vehicle.
    Type: Grant
    Filed: December 11, 1992
    Date of Patent: July 20, 1993
    Assignee: Minnesota Valley Engineering, Inc.
    Inventors: H. Michael Lutgen, Keith W. Gustafson
  • Patent number: 5011700
    Abstract: There is disclosed a syrup delivery system for carbonated beverages which provides delivery of beverage syrup from a syrup container to a beverage mixer. The syrup delivery system comprises a source of pressurized gas, conveniently the CO.sub.2 gas source which is also used to carbonate the water used to mix the carbonated beverage, and a syrup container. The syrup container comprises a rigid drum having an opening with a closure and a pressurizing fitting for connection to the source of presurized gas. A collapsible bag for holding the syrup is fitted inside of the rigid drum and is connected by means of a double ended connector through the closure to the beverage mixer. In operation, the CO.sub.2 pressurized gas is introduced into the rigid tank between the inside of the tank and the outside of the collapsible bag thereby forcing the syrup out of the bag and to the beverage mixer at a constant pressure.
    Type: Grant
    Filed: August 11, 1989
    Date of Patent: April 30, 1991
    Inventors: Keith W. Gustafson, George W. Kalet, Martin S. Taylor
  • Patent number: 4956975
    Abstract: There is disclosed an improved internal pressure relief valve for filling a cryogenic liquid storage tank. The internal pressure relief valve consists of a housing with a sealing seat at one end, an inlet hole at the other end, and a ball enclosed therein. The internal pressure relief valve is constructed of materials which can withstand the heat encountered during fabrication without melting. Consequently, the material for the ball is more dense than the cryogenic liquid in the tank so that the ball will not float in the cryogenic liquid. Consequently, the ball and the housing are dimensioned so that the momentum of the cryogenic liquid as it flows into the housing toward a vent port during the filling operation is sufficient to drive the ball into engagement with the sealing seat, closing the vent port, and assuring the termination of the filling process when the pressure in the cryogenic tank builds up to that of the delivery pressure.
    Type: Grant
    Filed: August 17, 1989
    Date of Patent: September 18, 1990
    Inventor: Keith W. Gustafson
  • Patent number: 4925060
    Abstract: There is disclosed an atmospheric pressure dewar with an improved closure for the neck opening. The improvement comprises a cork positioned in the neck opening with a fibrous material occupying the peripheral space between the neck opening and the cork to inhibit convection flow of gases in the peripheral space when the dewar is oriented other than in the upright position.
    Type: Grant
    Filed: August 17, 1989
    Date of Patent: May 15, 1990
    Inventor: Keith W. Gustafson
  • Patent number: 4625753
    Abstract: A cryogenic liquid storage tank has an automatic pressure relief means which vents vapor while the tank is being filled so that the tank may be completely filled. The pressure relief means includes a float which, when the cryogenic tank is filled, automatically closes the pressure relief means. In an alternative embodiment, the pressure relief means is combined with an eductor attached to the tank's inlet. The eductor entrains and condenses vapor within the tank to minimize the amount of vapor vented by the pressure relief means.
    Type: Grant
    Filed: July 10, 1985
    Date of Patent: December 2, 1986
    Inventor: Keith W. Gustafson
  • Patent number: 4608831
    Abstract: There is disclosed a self-pressurizing container for liquid helium which comprises an inner and outer vessel with an insulating space between. A heating element is disposed within an insulating barrier tube which extends between the liquid and vapor phases of the helium. The barrier tube insures that the liquid helium is heated and vaporized in the barrier tube without substantially heating the bulk of the liquid helium. The heating element in the preferred embodiment includes a vapor heat exchanger.
    Type: Grant
    Filed: October 24, 1984
    Date of Patent: September 2, 1986
    Inventor: Keith W. Gustafson
  • Patent number: 4491347
    Abstract: A cryogenic connector which embodies interfitting male and female metal members, each having a portion in sliding engagement in the assembled relation with said portion of the female member having a coefficient of expansion greater than the corresponding portion of the male member to provide a mechanical shrink seal therebetween at cryogen temperature.
    Type: Grant
    Filed: January 4, 1982
    Date of Patent: January 1, 1985
    Assignee: Minnesota Valley Engineering, Inc.
    Inventor: Keith W. Gustafson