초록 ▼

Method and apparatus for operating compressors to avoid surges. The compressor is controlled by direct measurement of the rate of volumetric flow, Q, of gas through the compressor via the use of an acoustic flow meter, or other sonic velocity measuring device in combination with a standard flow mete

Method and apparatus for operating compressors to avoid surges. The compressor is controlled by direct measurement of the rate of volumetric flow, Q, of gas through the compressor via the use of an acoustic flow meter, or other sonic velocity measuring device in combination with a standard flow meter and the measurement of the speed, N, of the compressor. The Q/N ratio is calculated electronically and output to a controller which, through a control circuit, operates a recycle valve in a by pass line leading from the discharge side to the suction side of the compressor. The Q/N ratio measured by the controller at compressor operating conditions is compared with a Q/N ratio at which surge will occur. When the measured Q/N ratio is less than the Q/N ratio at surge, the recycle valve will open and flow gas from the discharge side to the suction side of the compressor to avoid surge flow in the compressor.

대표청구항 ▼

In a method for controlling a compressor in which a control valve is employed in an electronic circuit to control the recycle of gas from the discharge outlet to the suction inlet to the compressor, the steps of: measuring the sonic velocity, that is the speed of sound in the gas, and the rate of vo

In a method for controlling a compressor in which a control valve is employed in an electronic circuit to control the recycle of gas from the discharge outlet to the suction inlet to the compressor, the steps of: measuring the sonic velocity, that is the speed of sound in the gas, and the rate of volumetric flow, Q, of gas through said operating compressor, measuring the rate of speed, N, of said operating compressor, establishing a Q/N ratio from the values Q and N generated by the operating compressor, establishing a set point Q/N ratio based on a rate of gas flow above which compressor surge can occur, and comparing the Q/N ratio of the operating compressor with the Q/N set point ratio such that a measured Q/N ratio in the direction of a lower gas flow will open the control valve and permit the flow of recycle gas from the discharge outlet of the compressor to the suction inlet of the compressor, and return of the Q/N ratio of the operating compressor to the set point Q/N ratio will close the control valve to cut off the flow of recycle gas, wherein the Q/N set point ratio is constantly redefined based on measured gas sonic velocity during operation of the compressor.