Patents Assigned to Northern Natural Gas Company
  • Patent number: 4304104
    Abstract: A pitot heat pump is described wherein a multi-stage pitot pump is employed as the compression means in a heat pump thermodynamic cycle. The heat pump is comprised of a multi-stage vapor pitot pump, liquid pitot pump, turbine, vaporizer, evaporator, condenser and expansion valve. The turbine is used to rotate a shaft to which the impellers of the pitot pump are attached. Refrigerant gas from the evaporator enters the first stage of the pitot pump and the impeller therein forces the refrigerant gas outwardly where it enters the narrow end of a pitot tube provided therein. The discharge end of the pitot tube is in communication with the next stage of the pitot pump. In passing through the pitot tube, the refrigerant gas expands and the centrifugal force and the kinetic energy of the gas provide the energy whereby the refrigerant gas is compressed. After the last stage, the compressed gas is transmitted to the condenser of the heat pump.
    Type: Grant
    Filed: May 2, 1980
    Date of Patent: December 8, 1981
    Assignee: Northern Natural Gas Company
    Inventor: Ronald D. Grose
  • Patent number: 4282894
    Abstract: An apparatus for removing concentrations of liquid from a natural gas pipeline comprising a tap valve mounted on the pipeline at the upper portion thereof so as to be in communication with the interior of the pipeline. A siphon apparatus is removably mounted on the tap valve and includes a siphon pipe which is vertically movably mounted with respect to the tap valve. The siphon pipe is vertically movable from an upper position wherein the lower end of the siphon pipe is positioned above the tap valve to a lower position wherein the siphon pipe extends through the tap valve so that the lower end of the siphon pipe is positioned at the bottom interior of the pipeline. A discharge pipe extends from the siphon pipe and is in communication with a liquid holding tank. A siphon valve is imposed in the discharge pipe to permit the selective removal of the liquid from the pipeline. A portion of the siphon pipe is enclosed by an operating cylinder barrel.
    Type: Grant
    Filed: May 21, 1979
    Date of Patent: August 11, 1981
    Assignee: Northern Natural Gas Company
    Inventors: Walter C. Mills, James W. Patterson
  • Patent number: 4155372
    Abstract: An apparatus for removing concentrations of liquid from a natural gas pipeline comprising a tap valve mounted on the pipeline at the upper portion thereof so as to be in communication with the interior of the pipeline. A siphon apparatus is removably mounted on the tap valve and includes a siphon pipe which is vertically movably mounted with respect to the tap valve. The siphon pipe is vertically movable from an upper position wherein the lower end of the siphon pipe is positioned above the tap valve to a lower position wherein the siphon pipe extends through the tap valve so that the lower end of the siphon pipe is positioned at the bottom interior of the pipeline. A discharge pipe extends from the siphon pipe and is in communication with a liquid holding tank. A siphon valve is imposed in the discharge pipe to permit the selective removal of the liquid from the pipeline.
    Type: Grant
    Filed: September 12, 1977
    Date of Patent: May 22, 1979
    Assignee: Northern Natural Gas Company
    Inventors: Walter C. Mills, James W. Patterson
  • Patent number: 4065964
    Abstract: A portable machine for testing protective coatings which have been applied to pipes or the like comprising a portable frame adapted to be hand-held by testing personnel. A pair of elongated arms extend from the portable frame and have pipe shoes on one end thereof adapted to embrace the pipe so that the portable frame will be maintained at a predetermined distance from the pipe during the testing operation. A cutting blade is provided for severing the protective coating from the pipe and has an elongated flexible member connected thereto. A power assembly is secured to the frame and is operatively connected to the elongated flexible member to cause the elongated flexible member and the cutting blade to be moved towards the support to sever the protective coating from the pipe. A force read-out device is connected to the power assembly for indicating the amount of force required to sever the protective coating from the pipe.
    Type: Grant
    Filed: January 24, 1977
    Date of Patent: January 3, 1978
    Assignee: Northern Natural Gas Company
    Inventor: Richard D. Cunningham
  • Patent number: 3948744
    Abstract: An electrode useful in measuring rate of corrosion at the inside surface of a conduit containing a corrosive atmosphere is designed to be inserted in the wall of the conduit and mounted flush with its inside surface. The electrode is formed of three pieces: an elongated cylindrical metallic conductor, a cylindrical metallic tip, and a threaded screw. The tip is shaped such that when the electrode is inserted within the wall of the conduit, the shaped surface of the tip can be positioned exactly flush with the inside surface thereof.An electrode holder is inserted into a hole cut in the conduit and held in place by a welded reinforcing plate on the outside surface of the conduit. An electrode is inserted within the holder and held in place by a retainer cap. When the electrode is to be removed, the retainer cap is taken off and the electrode stays in place by virtue of the frictional forces between it and an elastomeric sleeve which is in place between the electrode and the electrode holder.
    Type: Grant
    Filed: January 2, 1975
    Date of Patent: April 6, 1976
    Assignee: Northern Natural Gas Company
    Inventor: Ralph H. Cushing