Equipment for controlling the extraction pressure of an extraction condensing turbine

Claim 1

Apparatus for controlling the extraction pressure of an extraction condensing turbine having an intermediate-pressure section or high-pressure section and a double-flow low-pressure section, said double-flow low-pressure section having guide vane lattices, said apparatus including means for taking steam off a stage in the blade pasage of said intermediate-pressure section or the high-pressure section of said turbine for heating purposes or chemical process purposes, means for passing the steam remaining in the turbine into said double-flow low-pressure turbine section, pivotable vanes of said guide vane lattices arranged in said double-flow, low-pressure turbine section downstream of the steam extraction point and means for effecting vane pivoting motion by adjusting levers, adjusting rings forming the bearings of the adjusting levers for axial displacement of said adjusting levers, the improvement wherein said double-flow low-pressure turbine section further comprises an annular casing (7, 9, 10) arranged coaxially to and surrounding a rotor shaft (4), annular pistons (11, 12) axially slidably supported in an annular space (6) defined by at least said annular casing (7, 9, 10), adjusting rings (15) slidably connected to said annular pistons (11, 12), said annular pistons (11, 12) being mounted on at least one coaxial rod (13), said annular pistons (11, 12) having radially outer and radially inner peripheral surfaces, seal strips (14) provided on said radially outer and radially inner peripheral surfaces, means defining pressure spaces, respectively, (23a, 23b) for said two annular pistons (11, 12), means including pipes (21, 22) for supplying said pressure spaces (23a, 23b) with turbine steam from said intermediate-pressure section or said high-pressure section at a correspondingly high pressure, means forming low-pressure spaces downstream of the guide vanes (18), means defining at least one suction space, and means for communicating via connections (24, 5, 29), said at least one suction space with the low-pressure spaces downstream of the guide vanes (18), and a pressure setting valve (25) arranged in said control pressure pipe (21), and the actuating and control mechanism for said setting valve and said means for effecting vane pivoting motion constituting the guide vane adjusting apparatus being arranged in the annular space (1) between the two first moving blade lattices (2a, 2b) of the low-pressure turbine section.