Dry gas seal contamination prevention system

In combination, a turbomachine having a rotor therein, said rotor having a dry gas seal associated therewith, and a primary seal gas supply system adapted to supply a flow of seal gas to said dry gas seal when a sufficient pressure differential exists as to maintain that flow, said primary seal gas supply system having an upstream section adapted to be connected to a primary source of said gas and a downstream section connected to said dry gas seal, one-way valve between said upstream and downstream sections preventing a back flow of gas from the downstream section into said upstream section;

• and a seal gas pressure booster system including a booster compressor having a gas inlet line connected to said upstream section of the primary seal gas supply system and a gas outlet line connected to said downstream section of said primary seal gas supply system for boosting the pressure of the gas using said primary seal gas supply in said downstream section sufficiently to ensure a continuing flow of primary seal supply gas to said dry gas seal during periods when there is an insufficient seal gas pressure differential associated with said primary system as to maintain the desired flow of seal gas therein, means for producing a signal indicative of insufficient seal gas pressure differential, and means associated with said booster compressor for driving the latter to boost the gas pressure in said downstream section in response to said signal.