RU2174608C1 - Control scheme for automatic flap gate of steam- turbine shutoff valve - Google Patents

Abstract

FIELD: turbine manufacture. SUBSTANCE: control scheme has pulsed and forced oil supply lines running to automatic flap gate through common throttling port of turbine control gear. In case of fire in vicinity of turbine shutoff valve slide valves of turbine automatic safety device provide for oil drain to tank from all oil lines of automatic flap gate and closure of shutoff valve under action of actuating mechanism of turbine protection system. EFFECT: improved fire safety of control scheme. 2 dwg

Description

 The invention relates to power engineering, in particular to turbine engineering.

 In steam turbine plants of power plants, at least one stop valve with an actuator called an automatic shutter (shutter) installed directly on or near the body of the stop valve is installed on the pipeline from the steam generator to the steam turbine.

 The stop valve is designed to stop the steam supply to the turbine in emergency situations, in order to prevent its damage by closing it with the help of an automatic shutter.

 The shutter is usually controlled by a hydraulic system for regulating and protecting the turbine using mineral oil as a working fluid.

 Known hydraulic control circuits for locking the shutoff valve of a steam turbine provide for the supply of oil to the power line of the shutter to open the shutoff valve directly from the pump [1].

 Closest to the invention is a control circuit for shutter valve shutter of a turbine shown in FIG. 12].

 The scheme is used in the regulation systems of OJSC Turbomotor Plant.

 An impulse line 2 from the turbine control mechanism (MUT) 3, connected to the actuator of the emergency turbine emergency protection - the slide valves of the automatic safety device (ZAB) 4, and the oil power line 5 necessary to open the stop valve through the check valve 6 from the pressure head are fed to the shutter 1 line of pumps: starting 7 in the start and stop modes of the turbine and the main oil pump 8 with a drive directly from the turbine shaft - in the modes of operation of the turbine idling and under load.

 Cocking the shutter (opening the stop valve) is carried out by supplying oil from the pressure line of the pumps using the MUT to the ZAB first, which ensures their readiness for operation, then through the throttle window built into the MUT, into the pulse chamber 9 of the autolock, as a result of which the pressure rises in it , the force on the upper end of the spool 10 from the oil pressure overcomes the force of the tension spring 11, and the spool 10 moves down, opening the oil supply from the power line 5 through the windows 12 of the chamber 13 under the piston 14, the flow of which is connected to the rods with a rod stop valve (. Figure 1 is not shown); the force from the pressure of the power oil on the piston overcomes the force of the compression springs 15, and the piston moves upward, opening the stop valve.

 Upon receipt of a signal to the ZAB to shut off the turbine from emergency protection or during an operative shutdown action on the ZAB, the latter are triggered, opening a drain from impulse line 2; the oil pressure in the chamber 9 decreases, the spool 10 under the action of the spring and constant force from the pressure of the power oil moves upward, blocking the access of the power oil through the window 12 under the piston and opens the drain from under it, as a result of which the piston 14 moves downward by the force of the springs 15, closing the stop valve.

 When the shut-off valve is closed by means of the MUT, the access of oil to impulse line 2 is blocked, and the pressure in it, due to the presence of special drainage holes in the ZAB, decreases, which, just as when the ZAB is triggered, closes the stop valve.

 The described control circuit of the shutter valve shutter has the disadvantage that the supply of power oil to the shutter directly from the pressure line of the pumps, in case of a flange of the pipe flange connection to the shutter body or damage to the pipeline and oil ignition due to falling onto the hot parts of the shutoff valve and steam pipelines, and for other reasons, it does not allow to stop the flow of oil through the pipeline until the flow of oil or the main or starting pump stops, which Touches the development of fire.

 The disadvantage of the scheme is the impossibility of closing the retainer with the help of the MUT or ZAB in case of loss of mobility of the spool 10 due to its jamming, since it is impossible to open the oil drain from under the piston through the window 12, which poses a danger of an emergency.

 The problem to which the invention is directed, is to increase the fire safety of the control circuit of the shutter valve auto-shutter and increase the reliability of closing the shut-off valve in case of jamming the shutter valve by changing the oil supply circuit to the shutter.

 The invention is illustrated in FIG. 2.

 An essential feature of the invention is the general supply of oil to the shutter 1 from the pressure line of the pumps through MUT 3 to both pulse 2 and power line 5.

 Cocking the shutter (opening the stop valve) is carried out by supplying oil using the MUT 3 from the pressure line of the pumps, where it is supplied through the check valve 6, either from the start pump 7 in the start and stop modes of the turbine, or from the main oil pump 8 located on the turbine shaft , - at the turbine operating modes at idle and under load. In this case, the oil flows first to ZAB 4, which ensures their readiness for operation, then through the throttle window built into the MUT, to impulse line 2, and power line 5.

 In this case, the pressure in the chambers 9 and 13 rises, the force on the upper end of the spool 10 from the oil pressure overcomes the force of the tension spring 11, the spool moves down, opening the oil supply through the windows 12 under the piston 14, the rod of which is connected by rods to the stop valve rod (in Fig. . 2 not shown); the force from the oil pressure on the piston overcomes the force of the compression springs 15, and the piston moves upward, opening the stop valve.

 Upon receipt of a signal to the ZAB to shut off the turbine from emergency protection or during an operative shutdown action on the ZAB, the latter are triggered, opening the drain of pulse and power oil, i.e. drain from the chambers 9 and 13, the valve 10, under the action of the spring 11, moves upward, opening the oil drain from under the piston 14, as a result of which the piston moves downward by the force of the springs 15, closing the stop valve.

 When the shut-off valve is closed by means of the MUT, the oil supply to the impulse and power line is blocked, which, due to the presence of special drainage holes in the ZAB, is emptied, which, like when the ZAB is triggered, closes the shut-off valve.

 Thus, the invention compares favorably with its counterpart in that when the ZAB is triggered, not only the pulsed oil is drained, but also the power one, and when the turbine is switched off quickly using the MUT, the oil supply to the shutter is completely cut off and the pipeline between the MUT and the shutter is emptied; in both cases, the stop valve closes even when the spool 10 seizes.

 The specified advantage of the invention facilitates the liquidation of an emergency in the event of a fire.

Sources of information
1. Benenson E.I., Ioffe L.S. Heat-producing steam turbines ". - M.: Energy, 1976, S. 202-203, 235-237.

 2. Benenson E.I., Ioffe L.S. Heating steam turbines. - M .: Energoatomizdat, 1986, p. 239-241.

Claims (1)

 The control circuit of the shutter valve shutter of a steam turbine, containing pulse and power lines of oil supplied as a working fluid to the shutter, characterized in that, in order to increase fire safety and reliability of shutter operation, the oil is supplied from the pump through a common throttle window of the mechanism turbine control.

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