| 摘要 |
PURPOSE:To enable to operate a back-pressure turbine at a low back pressure and to in crease the electric power generated per unit quantity of steam, by controlling a control valve disposed on the steam discharge side of the back- pressure turbine on the basis of the flow rate of main steam or the pressure difference at one stage of the back- pressure turbine. CONSTITUTION:In a back-pressure turbine shown in the drawing, the flow rate of main steam is controlled to keep the back pressure constant by detecting change in the back pressure of steam having performed work in the body 1 of the back-pressure turbine by means of a back-pressure controller 6, and controlling a governing valve 4 according to the output signal of said back-pressure controller 6. The back-pressure turbine comprises a stage pressure difference detector 11 which measures the presure difference at the stage of the turbine body 1 requiring a highest strength. Further, a back pressure control valve 12 is provided at the steam discharge side of the turbine body 1. With such an arrangeement, a differential-pressure signal corresponding to the differential pressure at the stage that is measured by the detector 11 is compared with a reference differential-pressure value. Here, a controller 13 functions to close the back- pressure control valve 12 in case that the actually measured value is greater than the reference value and to open the valve 12 in the contrary case. |
