ApplicationNo. 693918 filed on 04/29/1991
US Classes:5/713, Variably pressurizable chambers (e.g., with pump)417/12, Having timer or delay means417/44.2Responsive to pump fluid pressure
ExaminersPrimary: Grosz, Alexander
Attorney, Agent or Firm
Foreign Patent References
International ClassA61G 007/057
AbstractA method for controlling the blower that supplies gas to the gas sacks of a patient support system uses a blower control circuit, a microprocessor, and a pressure sensor. The blower control circuit controls the power that is supplied to operate the blower. The microprocessor activates the blower control circuit with a control signal that causes the control circuit to supply power to the blower. A pressure sensor measures the pressure of the gas exiting the blower and supplies a signal indicative of this pressure, to the microprocessor. The microprocessor stores the measured pressure signal and calculates a reference pressure for the blower. The microprocessor compares the reference pressure to the measured pressure and determines any discrepancy resulting from this comparison. The microprocessor sends a signal to the blower control circuit, wherein the signal is indicative of the discrepancy from the compared pressure and the reference pressure of the blower. The second control signal is such as to enable the blower circuit to reduce the discrepancy calculated by the microprocessor between the reference pressure and the measured pressure. Only discrepencies of a certain magnitude will cause the microprocessor to send the second control signal to the blower control circuit. The time interval over which the microprocessor maintains storage of the measured pressure is chosen so as to reduce the possiblity of pressure instability in the gas sack.
Field of SearchHaving timer or delay means