An apparatus is disclosed that includes a fluid inlet in fluid communication with a valve assembly, the valve assembly structured to selectively permit the flow of a motive fluid from the fluid inlet to a fluid driven motor, wherein the valve assembly further includes a first plunger including a plurality of axially extending fluid channels, wherein the plunger is selectively movable by an actuator in a manner such that as the plunger is displaced farther away from a closed position, the number of axially extending fluid channels placed in fluid communication with the fluid inlet increases, and wherein the axially extending fluid channels permit the flow of the motive fluid from the fluid inlet to the fluid driven motor.

An apparatus is disclosed that includes a fluid inlet in fluid communication with a valve assembly, the valve assembly structured to selectively permit the flow of a motive fluid from the fluid inlet to a fluid driven motor, wherein the valve assembly further includes a first plunger including a plurality of axially extending fluid channels, wherein the plunger is selectively movable by an actuator in a manner such that as the plunger is displaced farther away from a closed position, the number of axially extending fluid channels placed in fluid communication with the fluid inlet increases, and wherein the axially extending fluid channels permit the flow of the motive fluid from the fluid inlet to the fluid driven motor.

A multi-stage expansion device having bypass capabilities and a variable speed drive is disclosed. In one example, the multi-stage expansion device has a housing within which a first stage, a second stage, and a third stage are housed. The housing may also be configured with internal working fluid passageways to direct a working fluid from the first stage to the second stage and/or from the second stage to the third stage. Each of the stages may include a pair of non-contacting rotors that are mechanically connected to each other and to a power output device such that energy extracted from the working fluid is converted to mechanical work at the output device. In one example, a bypass line is provided to bypass working fluid around the first stage and a bypass line is provided to bypass working fluid around the second stage.

A method for expanding a gas flow between an inlet for the supply of the gas flow at certain inlet conditions of inlet pressure and inlet temperature and an outlet for the delivery of expanded gas at certain desired outlet conditions of outlet pressure and outlet temperature, whereby this method at least comprises the step of at least partly expanding the gas flow between the inlet and the outlet through a pressure reducing valve and at least partly expanding it through a pressure reducing unit with a rotor driven by the gas for converting the energy contained in the gas into mechanical energy on this shaft.

A method for expanding a gas flow between an inlet for the supply of the gas flow at certain inlet conditions of inlet pressure and inlet temperature and an outlet for the delivery of expanded gas at certain desired outlet conditions of outlet pressure and outlet temperature, whereby this method at least comprises the step of at least partly expanding the gas flow between the inlet and the outlet through a pressure reducing valve and at least partly expanding it through a pressure reducing unit with a rotor driven by the gas for converting the energy contained in the gas into mechanical energy on this shaft.