Gregory Imblum

60929928, Jul 25, 2000

Oct 24, 1996

8/736466

Gregory G. Imblum - Monroeville PA
Charles H. Etheridge - Pittsburgh PA
William R. Frank - Pittsburgh PA

F04B 4900

417 42

The present invention provides a system and a method for controlling and detecting faults in a pump system for use in a gas detection device. The system comprises a power source and a switch in operative or electrical connection with the power source. The system further comprises a pump motor in operative connection with the switch such that the pump motor receives energy from the power source when the switch in a first state, and the pump motor does not receive energy from the power source when the switch in a second state. The system preferably also comprises regeneration circuitry in operative connection with the pump motor. The regeneration circuitry operates to redirect energy produced from momentum of the pump motor while the switch is in the second state back to the pump motor. Transmitting circuitry is preferably provided to transmit a motor signal proportional to the speed of the pump motor during the second state of the switch. Preferably, the switch is modulated between the first state and the second state using a processing or control unit such as a microprocessor.

57807159, Jul 14, 1998

Oct 23, 1996

8/735631

Gregory G. Imblum - Monroeville PA

Mine Safety Appliances Company - Pittsburgh PA

G01N 2704

73 2321

The present invention relates to a programmable current or voltage sensing circuit for use in measuring concentration levels of combustible gases. Generally, the present invention provides an electrical apparatus for detecting the concentration level of a combustible gas comprising a pair of sensor elements each having an electrical output which is compared to the other for measuring the amount of the gas undergoing combustion. The apparatus also generally comprises a first pair of electrical circuits each connected to one sensor element for controlling the amount of electrical current or voltage at that element, a second electrical circuit connected to both elements for comparing the electrical outputs of the sensor elements to measure the amount of gas undergoing combustion, and a third electrical circuit having a reference output signal for individually controlling the amount of electrical current or voltage generated by each of the first electrical circuits. Preferably, the sensor elements are comprised of electrical resistors coated with a heat conducting material wherein one of the elements is further coated with a chemical substance for catalyzing combustion of the gas, such that the combustion will cause the resistance of the catalytically coated sensor element to increase relative to the resistance of the other sensor element.