Method and apparatus for draining liquid working fluid from turbine

Abstract

Liquid working fluid is drained from the sump of the cannister of a power plant of the type described by transferring the working fluid to the condenser rather than to the boiler. In one embodiment of the invention, liquid in the sump is drained by gravity into an auxiliary boiler which heats the drained liquid producing vapor at substantially the pressure of the condenser; and the resultant vapor is piped directly into the condenser where it condenses and joins the main condensate produced from vapor that has been exhausted from the turbine. In a second embodiment of the invention, the exhaust conduit carrying exhaust vapor from the cannister to the condenser is provided with a loop or elbow that extends below the level of the cannister, and a conduit connects the sump in the cannister to the loop. As a consequence, liquid working fluid in the cannister drains by gravity into the bottom of the loop where it is vaporized or swept by extracting superheat from the exhaust vapor and then returned to the condenser. This arrangement is advantageous in that no additional fuel is utilized to vaporize the drained liquid. Furthermore, the work required of the condenser is reduced because of the reduction in superheat of the vapor entering the condenser.