CONTROL SYSTEM FOR BLEED AIR TEMPERATURE LOWERING DEVICE OF MIXED PRESSURE BLEEDER TURBINE

PURPOSE:To obtain the control system for cutting off a temperature lowering spray immediately after the transition from the air bleed operation to the mixed gas operation by detecting the signal at the point where each flow rate of a turbine high pressure reducing valve and a low pressure reducing valve becomes equal and operating a lowered temperature water introduction cut-off system. CONSTITUTION:When a turbine is in the air bleed operation, a portion of the exhaust of a high pressure turbine 4 is bleeded, and in order to lower the bleed air temperature to a prescribed temperature in a process, the signal of a controller 13 is input to an adjusting valve 14, and control for setting the temperature to a constant value by adjusting the introduction quantity of the lowered temperature water by a temperature lowering device 11 is carried out. In order to stop the introduction of the lowered temperature water immediately after the transition from the air bleed operation to the mixed gas operation of the turbine, the signal at the point where each steam quantity which flows in a high pressure reducing valve 3 and a low pressure reducing valve 6 becomes equal (nonbleed and nonmixed gas operation) is detected by a controller 17, and a temperature lowered water introduction cut-off valve 15 is compulsorily closed. Further, when the temperature becomes below a set value by a temperature switch 18 as back-up (completion of the bleed air operation), the lowered temperature water introduction cut-off valve 15 is compulsorily closed.