JPS54153902A - Steam temperature controlling apparatus - Google Patents

Abstract

PURPOSE: To improve the control performance of an S/H spray valve and to stably perform steam temperature control by keeping constant the differential pressure before and behind the S/H superheater spray valve by means of a pressure transmitter, using programme signals due to a load.

CONSTITUTION: An S/H spray pressure regulating valve 5 is arranged at the front stage of an S/H spray valve 4. The inlet pressure 15 of the S/H spray valve is controlled by controlling the exit pressure of the S/H spray pressure regulating valve at the pressure value which is obtained by adding an arbitrary pressure to a temperature reducer pressure corresponding to each load. To a function generator 16, load instruction 10 is supplied, and the generator generates the value which is obtained by adding a differential pressure set value to the pressure of the temperature reducer in loading, then the resulted value is the target value 17 of the S/H spray valve inlet pressure. An adder 18 reduces the S/H spray valve inlet pressure 9 from the target value 17, and generates the deviation signal 19. To a PI regulator 20, the deviation signal is supplied, and the PI regulator generates the operation amount 12 of the S/H spray pressure regulating valve 5.

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