JPS56106009A - Water induction detecting apparatus - Google Patents

Abstract

PURPOSE: To ensure safe operation of a steam turbine, by detecting back flow fluid extracted from a steam turbine or the like and passed through an extraction pipe by use of the change in the refractive index of a monochromatic light transmitted through the extracted fluid, and controlling various sections of a steam turbine plant on the basis of the results of the above detection.

CONSTITUTION: An extraction pipe 5 connected to the turbine casing is connected at its lower end to a feed water heater (not shown). In case that extraction steam is flowing normally through the pipe 5, a monochromatic light emitted from a laser oscillator 8 is passed through an optical fiber 9, condenser lens 10 and light transmitting window 6 and reaches a light receiving lens 11a through the extraction steam in the pipe 5 since the extraction steam is a colorless, transparent fluid. Therefore, the light received by the lens 11a is passed through a photoelectric converter 13a and a higher-value preceding circuit 14 and actuates a normal-signal generating means 15a. On the other hand, if water is flowing abnormally in the extraction pipe 5, the light is received by either of other light receiving lenses 11bW11d depending on the change of the refractive index, so that either one of other control means 15bW15d is set into operation.

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