Southern Gas Association

Southwest Research Corporation

Morton E Brown

Carl E Edlund

Cecil R Sparks

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. One embodiment includes a central processing unit that provides for the loading of memories for supplying operational data to the reciprocating compressor simulation circuits and the centrifugal compressor circuits and receives the resulting data measured from these system circuits to compute the acoustic operational parameters for the system for display.

Gas pumping system analog

A self-contained measuring device indicates three parameters necessary to the determination of operating performance of an electrical analog of a reciprocating gas compressor or pump. A first portion of the device provides for measuring any horsepower changes during operation as a percentage of the ideal operating conditions. A second portion of the device measures the discharge current from the analog cylinder. A third portion of the device measures the phase between a sinusoidal reference signal and a non-sinusoidal periodic driving signal. The phase measuring portion of the device is used primarily for initial setup of the analog, while the first and second portions are used both during setup and during normal operation.

Performance indicator for compressor analogs

A relative horsepower indicator is used with an electrical model of a reciprocating gas compressor. A voltage representing the cylinder motion is modified and multiplied with a voltage representing the cylinder pressure. The result is calibrated to indicate one hundred percent cylinder horsepower when the model is operated under ideal conditions. The indicator is then used to indicate deviations from this ideal operating mode when the compressor model is used in a complete pumping system model.

Relative horsepower indicator

An improved phase indicator measures the phase difference between a sinusoidal reference signal and a shaped signal having the same frequency. Means are provided for generating a first pulse which begins when the shaped signal makes a positive going transition past a selected voltage level, and ends when the reference signal makes a positive going transition past the zero reference level. A second pulse begins at the end of the first pulse, and ends when the shaped signal makes a negative transition past the selected level. The relative phase of the two signals are adjusted until the first and second pulses are the same length, which occurs when the two signals are 90 degrees out of phase. An indicator is then calibrated to read 90 degrees, and thereafter indicates the correct phase relationship between the two signals.

Apparatus for phase measurement

An improved driving signal source for an electrical analog of a reciprocating compressor generates a variable frequency sinusoidal output. The ratio between the electrical frequency used by the analog and the mechanical frequency of the modeled compressor is controlled by a ratio set switch. Upper and lower limits of the mechanical speed are operator determined, and the electrical output frequency is varied between the corresponding upper and lower electrical analog frequencies. The instantaneous output frequency of the improved source is displayed in terms of mechanical compressor speed. The ratio of electrical to mechanical frequency can be changed independently of the upper and lower mechanical speed settings.

Growing community of inventors

San Antonio, TX, United States of America

Morton E Brown