Patent ID: 9726196
Date: 2017-08-08
CPC Classifications: F04D,F05D

Claim:
1. A motor-compressor system, comprising: a compressor configured to receive a process gas at a suction pressure and to discharge the process gas via an outlet; a motor coupled to the compressor via a rotatable shaft to drive the compressor; a housing having a motor compartment in which the motor is disposed and a compressor compartment in which the compressor is disposed; a bearing coupled to the housing and configured to support the shaft; a shaft seal arranged between the compressor and the bearing; a seal gas system fluidly communicating with the motor compartment via a motor pressurization line, with the outlet of the compressor, and with the shaft seal, the seal gas system being configured to receive the process gas from the outlet of the compressor, and to supply seal gas at a seal gas supply pressure to the shaft seal; a motor pressurization valve coupled to the motor pressurization line; and a controller configured to open the motor pressurization valve at start-up to supply seal gas to the motor compartment, to open the motor pressurization valve during a compressor surge to supply the seal gas to the motor compartment, and to pressurize the motor compartment when a difference between the seal gas supply pressure and the suction pressure is indicative of the seal gas supply pressure being insufficient.