Abstract: A valve apparatus for a fluid transmission line. The valve apparatus comprising a housing; a drive mechanism; a leadscrew selectively rotatable in a first or second rotational leadscrew direction by the drive mechanism; a drive gear mounted to the housing, the drive gear configured to be selectively driven in a first or second drive gear direction during rotation of said leadscrew in the first or second leadscrew direction to operate an iris mechanism.

Abstract: A valve apparatus for a fluid transmission line. The valve apparatus comprising a housing; a drive mechanism; a leadscrew selectively rotatable in a first or second rotational leadscrew direction by the drive mechanism; a drive gear mounted to the housing, the drive gear configured to be selectively driven in a first or second drive gear direction during rotation of said leadscrew in the first or second leadscrew direction to operate an iris mechanism.

Abstract: A control system for a gas generator is disclosed. The control system includes an automotive type oxygen sensor that produces a signal responsive to the oxygen content of a product gas. The automotive type oxygen sensor is connected to a controller and is installed in the gas generator so that the sensor tip is in the product gas, downstream of a first heat exchanger. Preferably, the installation of the automotive sensor is at a point where the product gas has been cooled to at least 1500.degree. F. at a rate of at least 4000.degree. F. The controller produces an output signal responsive to the oxygen sensor signal. A trim valve receives the controller output signal and responsively varies an input gas to vary the composition of the product gas.