METHOD TO CONTROL VALVE OF PERIODICAL BLOWDOWN OF DRUM BOILER AND DEVICE FOR ITS REALISATION Russian patent published in 2014 - IPC F22B35/02 

FIELD: power engineering.

SUBSTANCE: in the method to control a valve of periodical blowdown of a drum boiler they additionally measure flow rate of reheated steam, generate signals of current and set quantity of steam, generated in the blowdown-to-blowdown period of time, generate commands of zeroing and start of count of the current quantity of steam generated within the blowdown-to-blowdown period of time, measure position of the actuation mechanism and by sign of position variation speed signal define condition of the valve and generate signals "open" or "close". Definition of the blowdown-to-blowdown interval of time is carried out by comparison of the current quantity of steam produced in the blowdown to blowdown period of time with the set one, which, when achieved, triggers supply of the valve opening signal, by the "open" signal they generate a command to zero the current quantity of steam produced in the blowdown-to-blowdown period of time, at the "open" signal they stop supplying the signal to control valve opening, besides, retaining the valve in the open condition is done by setting time delay, afterwards they start supplying control signal to control valve closing, at the "close" signal they generate the command to start count of the current quantity of steam, generated in the blowdown-to-blowdown period of time, and at the "close" signal they stop supplying control signal to control the valve closing. The device to control the valve of periodical blowdown of the drum boiler comprises a valve with an actuator, a generator of a signal to start an actuator, a timer, a sensor of reheated steam flow rate, a sensor of actuator position, a sensor of open valve position and a sensor of closed valve position, an integrator, a differentiator, three RS-triggers, a zero organ and a setter of steam quantity generated within the blowdown to blowdown period of time.

EFFECT: provision of accurate control of a periodical blowdown valve in a regulating mode of drum boiler operation.

2 cl, 1 dwg, 1 tbl