Patents Examined by David W. Schevermann
  • Pump with speed controller responsive to temperature
    Patent number: 5158436
    Abstract: The pump unit is provided, in particular for heating and cooling installations. The speed of the pump unit may be altered by changing the operating frequency of a frequency converter feeding the electric motor and which forms a structural unit with the pump unit. As soon as the pump unit has reached a parameter characterizing the thermal overload of the same, the frequency converter is controlled in a manner so as to reduce the speed, the reduced speed n' being greater or equal to half the normal speed n.
    Type: Grant
    Filed: March 12, 1991
    Date of Patent: October 27, 1992
    Assignee: Grundfos International a/s
    Inventors: Niels D. Jensen, Ivan Knudsen, Bjarne D. Pedersen