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Screw compressor slide valve engine RPM tracking system

  • US 4,342,199 A
  • Filed: 10/03/1980
  • Issued: 08/03/1982
  • Est. Priority Date: 10/03/1980
  • Status: Expired due to Term
First Claim
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1. A helical screw compressor slide valve engine RPM tracking system for an engine driven compressed gas refrigeration system, said refrigeration system including:

  • an engine driven helical screw rotary compressor having a low side, suction pressure inlet, and a high side, discharge pressure outlet, and a longitudinally shiftable slide valve for loading and unloading the compressor,a fluid pressure operated slide valve actuator operatively coupled to said slide valve for shifting said slide valve between full load and full unload positions,first control valve means for selectively connecting said slide valve actuator to the compressor high side discharge pressure outlet to effect compressor loading, andsecond control valve means for selectively connecting said slide valve actuator to the compressor low side suction pressure inlet to effect unloading of the compressor,the improvement wherein said tracking system comprises;

    tracking means responsive to engine acceleration and deceleration for immediately connecting said slide valve actuator to the low side compressor suction pressure inlet during engine acceleration to immediately unload the compressor and for connecting the slide valve actuator to the refrigeration high side discharge pressure outlet during engine deceleration to immediately load the compressor, thereby preventing refrigeration system temperature fluctuation due to engine acceleration or deceleration, and wherein said tracking means includes means for sensing a change in compressor suction pressure responsive to engine acceleration or engine deceleration, and means for operating said second control valve means and said first control valve means, respectively, to effect immediate unloading of the compressor or loading of the compressor as required to meet engine acceleration or deceleration conditions.

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