JPS55164708A - Steam control for mixed-pressure steam turbine and its steam controlling apparatus - Google Patents

Abstract

PURPOSE: To minimize the influence of heat exerted to the turbine, by automatically controlling the temperature of mixed steam on the basis of the temperature of steam in an exhaust chamber of a high-pressure turbine by means of a bypass valve disposed between a high-pressure steam supply passage and a low-pressure steam supply passage, in the manner that difference of the state of the above two kinds of steam is minimized.

CONSTITUTION: The high-pressure steam is supplied from the high-pressure steam supply passage 4 to the high-pressure turbine 1 via a high-pressure steam stop valve 5 and a high-pressure steam control valve 6. The low-pressure steam, on the other hand, is supplied via a low-pressure steam stop valve 8, mixed with the high-pressure steam supplied from a bypass passage 10 via the bypass valve 11, and carried to an exhaust chamber 16 via a mixed-steam supply passage 7. Temperatures detected by means 14, 13 for detecting the temperature of high-pressure exhaust steam and that of mixed steam respectively are afforded to a comparator 15, in which they are compared with the temperature of high-pressure exhaust steam. In response to the deviation signal produced by the comparator 15, the bypass valve 11 is opened or closed to control the temperature of mixed steam. By thus minimizing difference in the state of high-pressure exhaust steam in the exhaust chamber 16 and that of mixed steam introduced into the exhaust chamber 16, it is enabled to minimize the influence of heat exerted to the turbine.

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