Compressor startup control

In a control system for a gas compressor including a positive displacement gas compressor, a motor drivably connected to said compressor, an inlet throttling valve operable to be open to admit inlet gas to said compressor upon commencement of starting of said compressor and including a pressure fluid actuator for closing said throttling valve, compressed gas receiver means connected to said compressor, a compressed gas service conduit connected to said receiver means for conducting compressed gas from said receiver means, and a check valve interposed in said service conduit and operable to prevent the back flow of compressed gas from said service conduit to said receiver means, the improvement characterized by:

• first conduit means in communication with said receiver means for conducting a pressure fluid signal to said actuator to close said throttling valve in response to increasing pressure in said receiver means upon starting said compressor;
• a normally open control valve interposed in said first conduit means, said control valve being pressure fluid actuated to interrupt said pressure fluid signal to said throttling valve,
• a pressure fluid timer in communication with said first conduit means for receiving a pressure fluid signal therefrom and for actuating said control valve to interrupt said pressure fluid signal to said actuator at the expiration of a predetermined time period to allow said throttling valve to reopen;
• second conduit means in communication with said service conduit downstream of said check valve in regard to the normal flow of compressed gas;
• and,
• a first shuttle valve connected to said first conduit means and said second conduit means and responsive to the greater of the pressure signals in said respective conduit means to conduct said greater pressure signal to said actuator for closing said inlet throttling valve.