Abstract: A fluid flow or liquid level switch providing a high level of reliability. Dual reference sensors in a single thermowell operates with two active, independent sensors, which operate with independent electronics having dual signal outputs, to provide constant and continuous redundancy in operation.

Abstract: A fluid flow or liquid level switch providing a high level of reliability. Dual reference sensors in a single thermowell operates with two active, independent sensors, which operate with independent electronics having dual signal outputs, to provide constant and continuous redundancy in operation.

Abstract: A compressor system according to the present invention utilizes direct rotational input from a permanent magnet motor to generate compressed air. The permanent magnet motor is mounted directly to an air screw compressor. The rotational input is provided by the permanent magnet motor to the air screw compressor without a gear train. The permanent magnet motor and associated variable speed drive controls the rotational speed of the permanent magnet motor and hence the screw compressor. Differing motors may selectively mount, and provide rotational input to, the air screw compressor.

Abstract: A two-stage oil free compressor assembly includes a pressure modulation mechanism, which enhances the ambient temperature and altitude capability of the compressor. A selected amount of pressurized fluid is drawn from an output side of a second stage compressor portion and reintroduced into the lower pressure interstage circuit of the assembly, thus raising the interstage pressure. The fluid that flows through the pressure modulation mechanism can be further cooled using the interstage heat exchanger, depending on the needs of a particular situation. A valve in the pressure modulation mechanism is adjusted to control the amount of fluid utilized for pressure modulation. The inventive arrangement permits modulating the pressure ratio of each stage to achieve reasonably balanced discharge temperatures of the first and second stage.

Abstract: A two-stage oil free compressor assembly includes a pressure modulation mechanism, which enhances the ambient temperature and altitude capability of the compressor. A selected amount of pressurized fluid is drawn from an output side of a second stage compressor portion and reintroduced into the lower pressure interstage circuit of the assembly, thus raising the interstage pressure. The fluid that flows through the pressure modulation mechanism can be further cooled using the interstage heat exchanger, depending on the needs of a particular situation. A valve in the pressure modulation mechanism is adjusted to control the amount of fluid utilized for pressure modulation. The inventive arrangement permits modulating the pressure ratio of each stage to achieve reasonably balanced discharge temperatures of the first and second stage.