SU786430A1 - Automatic safety device of turbomachine - Google Patents

Description

(54) AUTOMATIC SAFETY AUTOMATIC GURBOMASHINS

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The invention relates to the field of turbo-compressor engineering and, in particular, to systems for the protection of a turbomachine against an increase in the permissible shaft speed.

Such protection systems are called security machines.

A punch-type safety automat is known to contain a firing pin that is capable of being driven by centrifugal forces in a guide bushing installed in the radial drilling of the shaft of the turbomachine 1.

The disadvantage of this automaton of safety is the weakening of the turbo polishing shaft at the place of installation of the automaton, as well as the dynamic imbalance of the shaft at the moment of actuation and exit of the striker from the guide sleeve.

Safety automats are also known that contain a cup spring mounted on the shaft of the turbo-masonry, a stop valve control mechanism with a control cavity, and a nozzle 2.

However, the use of an oil system in such an automatic machine reduces the reliability of its operation, since in the event of an oil pump failure, the turbo masks will stop and, in addition, an increased fire hazard is created.

The purpose of the invention is to increase the reliability of the machine and the danger of knife-cutting.

The goal is achieved by the fact that the automaton additionally contains an ejector, the ejector and the nozzle being connected to the control cavity of the check valve. In order to increase speed, the automaton additionally contains two adjustable throttles, 10 which are stopped in the communication lines of the ejector and the nozzle with the control cavity of the valve.

The drawing shows a schematic diagram of a security machine.

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The trawl spring 1 with weights 2 is fastened with a nut 3 on the hub 4, screwed onto the turbine shaft 5. The steam or gas ejector 6, the working fluid into which enters through the nozzle 7, is connected

20 through a throttle 8 using lines 9, 10 with a check valve control mechanism. In particular, it is connected to the cavity 1 of the membrane 12, which is connected through the brush 13 to the latch 14 of the valve 15 covering the

25, a nozzle 16 connected via a valve 17 to a line 18 controlling a stop valve (not shown in the drawing). Line 10 through the throttle 19 and the line 20 is connected with a fixed nozzle 21. Between the nozzle 16

30 and the valve 15, as well as in the cavity 11, return springs 22 and 23 are located, and the cavity 24 of the membrane 12 is connected to the atmosphere.

Automatic security works as follows.

During normal operation of the turbine of the pullet spring 1 is curved to the right, the nozzle 21 is open. Into the line x 9, 10., 20, due to the suction of air, a vapor ejector 6 creates a vacuum, the value of which depends on the opening 21. through which air is sucked from the atmosphere. When the pulley spring 1 is in the right position, the coil 21 is open to its maximum value, as a result of which the discharge in cavity 11 will be minimal, the force of the spring 23 acting on the membrane 12 will be greater than the force arising from the pressure difference across the membrane and acting on it . In this case, the latch 14 is engaged with the valve 15 and does not allow it to move to the right under the action of the spring 22 and open the nozzle 16.

With an increase in the turbine rotation frequency above the allowable trailer, the spring 1 under the action of the moment from the loads 2 sharply flips to the left (see the dashed line) and covers the nozzle 21 without touching it. As a consequence, the discharge in the cavity 11 increases dramatically and the membrane 12 under the action. the differential pressure, overcoming the force of spring 23, abruptly moves upwards. The latch 14 then disengages from the valve 15 and, due to the action of the spring 23, it nets to the right and opens the drain from the control valve of the stop valve, which causes it to close and stop the turbine.

After the turbine rotates by a certain amount, the spring 1 is re-clicked to the right again, which leads to opening the nozzle 21 and reducing the discharge in the cavity 11 to a value at which the force of the spring 23 becomes greater than the force from the pressure difference upwards acting on the membrane 12. After

when the valve 15 is moved to the left, the latch 14 engages with it again, the nozzle 16 closes and the stop valve opens, which allows the turbine to operate normally. The determination of the safety machine performance without stopping the turbine is made by increasing its rotational speed until the automatic machine operates with the valve 17 closed.

The use of an automatic safety device of this design improves the reliability and accuracy of the protection system and significantly reduces the fire hazard of the unit.

In addition, the use of an ejector as a device that forms a pneumatic impulse reduces the laboriousness of manufacturing an automatic safety device.

Claims (2)

1.Automatic safety turbomachine containing a cup spring mounted on the turbomachine shaft, mechanism controlling a stop valve with a control cavity and a nozzle, characterized in that, in order to increase the reliability of the automatic machine and reduce fire danger, the machine further comprises an ejector, the ejector and the nozzle being connected to the control cavity of the stop valve. 2. An automaton according to claim 1, characterized in that, in order to increase speed, the automatic machine further comprises two adjustable throttles installed in the communication lines of the ejector and the nozzle with the control cavity of the valve. Sources of information taken in attention during examination: 1. "Turbo and compressor engineering. Under ed. V.A. Eliseeva, L., “Mechanical Engineering, 1970, p. 329, fig. 6, pos. 26-28. 2. US patent No. 2973771, cl. 137-57, 1964.