Abstract: An apparatus and method for monitoring a reciprocating member of a reciprocating piston compressor is presented. The apparatus and method provide a means for measuring parameters of the reciprocating member, such as road load or cross-head temperature and the like, and wirelessly transmitting the data to a receiver. A mobile assembly is attached to a reciprocating member of the compressor, the mobile assembly having a sensor assembly, a wireless transmitter and a power generation assembly. The sensor assembly measures a parameter of the reciprocating member and generates a representative sensor signal. The wireless transmitter wirelessly transmits a corresponding data signal to a stationary assembly mounted nearby. The power assembly powers the transmitter and sensor assembly. The measured data is used, in conjunction with other measurements, such as a crankshaft encoder, to calculate the work performed by the compressor, the power used by the compressor and other information.

Abstract: A method and apparatus for detecting the occurrence of surge or incipient surge in a centrifugal compressor is supplied. The centrifugal compressor has an inlet passage, an inlet passage wall and an impeller. When flowing a fluid through the centrifugal compressor thereby establishing a fluid flow in the inlet passage, the fluid flow is measured in the inlet passage proximate the inlet passage wall and proximate the impeller. The measurements may include detecting a reverse in the fluid flow direction, measuring a tangential component to the fluid flow, measuring a substantial decrease in the axial fluid flow, and/or measuring the fluid temperature. Fluid flow in the compressor can then be modified or controlled to prevent surge.

Abstract: An apparatus and method for monitoring a reciprocating member of a reciprocating piston compressor is presented. The apparatus and method provide a means for measuring parameters of the reciprocating member, such as road load or cross-head temperature and the like, and wirelessly transmitting the data to a receiver. A mobile assembly is attached to a reciprocating member of the compressor, the mobile assembly having a sensor assembly, a wireless transmitter and a power generation assembly. The sensor assembly measures a parameter of the reciprocating member and generates a representative sensor signal. The wireless transmitter wirelessly transmits a corresponding data signal to a stationary assembly mounted nearby. The power assembly powers the transmitter and sensor assembly. The measured data is used, in conjunction with other measurements, such as a crankshaft encoder, to calculate the work performed by the compressor, the power used by the compressor and other information.

Abstract: A method and apparatus for detecting the occurrence of surge or incipient surge in a centrifugal compressor is supplied. The centrifugal compressor has an inlet passage, an inlet passage wall and an impeller. When flowing a fluid through the centrifugal compressor thereby establishing a fluid flow in the inlet passage, the fluid flow is measured in the inlet passage proximate the inlet passage wall and proximate the impeller. The measurements may include detecting a reverse in the fluid flow direction, measuring a tangential component to the fluid flow, measuring a substantial decrease in the axial fluid flow, and/or measuring the fluid temperature. Fluid flow in the compressor can then be modified or controlled to prevent surge.

Abstract: An apparatus for determining a square root averaging error for a differential pressure orifice meter while measuring volumetric fluid flow in a closed medium including input circuitry that provides an input signal corresponding to the instantaneous differential pressure measured at the orifice plate and logic circuitry connected to receive the signals from the input circuitry for computing the square root averaging error for the orifice meter over a selected time interval. Also disclosed is an apparatus for measuring volumetric fluid flow in a closed medium that includes input circuitry for providing an input signal corresponding to a differential pressure at an orifice located within the closed medium and logic circuitry connected to receive the input signal, compute a square root of the corresponding differential pressure and provide an output signal corresponding to this square root.

Abstract: A system for electrically simulating the acoustical properties of a fluid transfer system including an electrical circuit for simulating the acoustic properties of fluid piping and an electrical circuit coupled to the fluid piping circuit for electrically simulating the acoustical properties of fluid transfer through at least one cylinder of a reciprocating compressor wherein the reciprocating compressor simulation circuitry includes a variable capacitor that simulates a change of volume and pressure within the compressor by varying the magnitude of capacitance. The system also includes the means for electrically simulating the acoustic properties of a centrifugal compressor including a variable capacitor for simulating flow through the compressor. This system further includes an output circuit for displaying the operational parameters of the system.

Abstract: An apparatus for electrically simulating a reciprocating gas pump or compressor includes unidirectional devices for simulating intake and discharge valves. The volume of the reciprocating cylinder is modeled by a fixed capacitor coupled in a feedback arrangement with a variable gain amplifier. The gain of the amplifier is preferably controlled by the contents of a digital memory device, which varies the gain to simulate the pumping action of a compressor. The device provides voltage outputs representing the pressure and volume readings obtained in the compressor being simulated.

Abstract: A device suitable for use as an electrical analog of a unidirectional mechanical valve includes a three-terminal MOSFET. A sensing comparator has inputs coupled to the drain and source terminals of the FET, and an output coupled to the gate of the FET. A floating power supply allows the analog to operate independently of the circuit in which it is used. The FET will conduct current whenever the voltage from the drain to the source exceeds a threshold value, and will effectively act as an open circuit whenever the drain to source voltage is less than this threshold.

Abstract: Disclosed is an analog apparatus for simulating the low frequency pulsations and surge characteristics of centrifugal compressors and pumps and their interaction with piping systems. The apparatus includes a capacitor pump for simulating the pumping action of a centrifugal compressor. Voltages are applied to the input and output of the capacitor pump that are proportional to the section and discharge pressures of the compressor. The capacitor pump is driven electrically to simulate the action of the centrifugal compressor in a piping network.