FI101997B - Hydraulic release valves - Google Patents

Description

101997

Hydraulic release valves

The present invention relates to test hydraulic release valves for use in hydraulic safety and trip systems for steam turbines and gas turbines.

Steam turbines and gas turbines are monitored during operation by safety and trip systems, which are normally controlled both electrically and hydraulically. This system, hereinafter referred to as the safety system alone, is intended in part to adjust the running conditions of the turbine, in part to trigger a controlled turbine in the event of disturbances or faults. The faults that can occur can be 15 different. A few examples of fault situations are, for example, that the turbine may go overspeed, the condenser in the turbine may lose its vacuum, or the turbine bearings may: '· A pressure drop may occur in the lubrication system. In all such situations, it is important that the safety system • j · 20 trips quickly to initiate a stop.

..... The safety system is triggered by hydraulics. . valves controlled by electrical or hydraulic impulses, whereby the valves move between different spaces 25 and thus cause changes or adjustments to the fluid pressure in the various circuits of the safety system.

To ensure that the hydraulic valves work:: they must be tested correctly at regular intervals. The problem that then arises is, among other things, that ... the turbine may malfunction if the test is carried out while driving. As a result, driveability is impaired if valve testing is performed during turbine operation. 1

It is desirable that the valves of the foregoing be tested under operating conditions. The development of valve equipment has also moved in this direction. Swedish patent 2 101997 7304099-0 discloses a method of using valves in a tripping device, in which the valves can be tested without causing significant pressure changes in the safety system and the resulting driving disturbances. In said patent 5 and other known devices for triggering a safety system, the principle of "1 of many" operation is utilized. By this term is meant the principle that activation of a single valve in a larger system is sufficient to trigger the safety system. 10 Adverse or unnecessary triggering of the safety system In the case of turbines in a nuclear power plant, for example, the unnecessary tripping of a signal system that controls and monitors the tripping of the safety system can lead to very costly interruptions, for example in nuclear power plants. the tested valve does not return to normal mode properly, or control signal the signal does not acknowledge the return of the valve to normal after testing under driving conditions.

25 During operation, the pressure is set by a large number of servos in the hydraulic system. These servos control turbine vapors to quickly close the gas valves. Trigger systems used in the past *: **, such as: V in the above-mentioned Swedish patent, have a certain inability to maintain the required number of servos in excess of the required pressure when testing hydraulic valves while driving. This shortcoming is due to the presence of a throttle in the hydraulic system, which restricts the flow during the test. The desire is thus a trigger system-35 which does not create a throttle in the hydraulic system.

3 101997

In the following, the method is explained that the device for hydraulic valves causes a rapid tripping of the hydraulic safety system. The tripping of this hydraulic safety system is caused by at least two vent-5 bricks being controlled simultaneously from the first to the second stage, whereby the safety system empties and loses its fluid pressure and thus acts on the turbine by a predetermined action. Furthermore, the operation is such that a change from the corresponding first to a second stage state 10 in a single valve, which change occurred during testing of this valve, or which change is due to a fault function in the trigger control system, does not affect the hydraulic safety system. In addition, an implementation in which the number of 15 valves is increased to increase operational reliability, for example in a turbine plant, by reducing the risk that an error signal to the valve:: · triggers the system and causes a costly interruption. The device described uses the so-called "2 of many" -20 function, which means that the valves of at least two tripping devices must act to change the position ____ in order for the safety system to trip.

In the described embodiment, the invention includes a device 25 in which at least two of the optional number of hydraulic valves are connected in series in a line which, from the supply, leads the pressure system to a pressure medium. This pressure medium can be freely selected, but oil will be required in the future. The two valves are identical and preferably consist of 5-way 2-position »« «* ... valves. These valves can vary between the two ‘V, positions. In the first of these two positions, which is the normal mode of operation, two parallel:. channels are open at the same time. the oil is fed from 35 feeds through the open parallel ducts of the first valve further through the corresponding ducts of the second valve connected in series and then further passed along a line supplying a pressure-dependent member to a plurality of quick-closing servo control devices in this application. Alongside said oil line to the quick shut-off servo is a second oil line, which is also supplied from said supply. This oil line passes through two valves connected in series and maintains the oil pressure in the pressure monitor. In both valves, the oil passes to the pressure guard through the second open channel of the corresponding valve.

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As mentioned earlier, the hydraulic valves switch between the two positions. The phase spaces are controlled by some form of movable means inside the hydraulic valve. When a control pressure is applied to this movable means 15 at the end provided with a pressure piston in the pressure range arranged in the pressure piston, the hydraulic valve enters the driving space described above. If no control pressure no longer affects the moving means, the hydraulic valve switches to another phase mode by the force of the return spring, which changes the valve to a discharge state, provided that no control pressure is applied to the valve moving means.

The control of the hydraulic valves described can be achieved in several different ways. Among other things, pressure can be mechanically applied to the pressure range of the moving device, whereby manual control is possible. The electric control is * ί ”fully usable by acting with an electromagnet • · :: on the said pressure range.

'' 30 • · «· ... In order to otherwise provide the required ♦ *** ', a control pressure that allows the control of hydraulic valves, the hydraulic valve can be equipped with a corresponding: \ control valve. These control valves can be «35 different. For example, they can be controlled electromagnetically, hydraulically, pneumatically, mechanically or electrohydraulically. The control is activated, for example, by signals from pressure guards.

When any of the hydraulic valves enters the phase 5 of the other 5, the flow of pressure medium into the pressure guard is plugged in this valve, while in the valve one channel opens a connection due to the pressure guard to empty this line into the tank. The pressure monitor registers the pressure drop. In this second phase space of the hydraulic valve 10, the line through which the pressure control medium was previously fed to the quick-locking servo is also plugged. However, the second channel opens, so that the line through which the pressure medium is applied to the pressure guard in the first phase state now instead opens to the quick-lock servo, so that the quick-lock servo control means is not subjected to pressure drop in the hydraulic valve changed state. Each hydraulic valve shall be such that the changes in the two internal channels open in the driving mode do not change when the second phase mode is started <; 20 simultaneously. Instead, the valves are designed so that the channel connected to the pressure guard is emptied and the second channel connected to the quick-closing servo is switched to another supply line without the quick-closing servo control means then causing significant pressure fluctuations.

25

What now happens if two valves go into the second phase state at the same time is that both oil supply ** 'lines to the pressure guard and the quick-closing servo <· · i /, respectively, are plugged due to the interaction of both valves. The weight guard oil supply line is emptied ... due to a change in the first valve while the quick-closing servo control means is emptied in the second valve. the pressure oil supply is completely closed. 1

With the hydraulic valves connected as described above, it is achieved that the valves can be tested at once without the safety system tripping. Pressure guards can be provided to automate valve testing. In an emergency or otherwise when there is a need to trigger the safety system, this is accomplished by simultaneously imparting two or more valves to trigger the safety system. One advantage of this method is that it is possible to switch to electrical trip signals given by two separate electrical systems, whereby two separate trip signals control a different trip valve. Use as an example 10, it may be mentioned that one of the trip valves may be quiescent-connected and the other trip valve may be working-flow-switched. Such a connection eliminates the problem of, for example, a fuse blowing or a voltage drop in one of the separate electrical systems, and only one hydraulic valve trips, but in contrast the pressure monitor registers by detecting a pressure drop that there is a fault in the safety system.

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Once this is done, security can continue

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20 raises by installing more than two valves in the safety system. It is possible to connect one more valve, but it is advantageous to use four with each other,. a hydraulic valve connected in series. These four I * valves can be monitored by a pressure monitor during the test as 25 independent trip valves operating as described above. An additional advantage is overcome that when the monitoring units require the system to be triggered, V ”can, for example, one of the four valves in the valve system be subject to a fault function so that it does not trip without affecting operational or operational safety.

· «·· ... The intended effect is achieved with the remaining faultless valves. This creates a very high level of reliability for the trigger. 1

Hydraulic valves also have a design that increases their reliability. Normally, during operation, the hydraulic oil passes through said two 101 101997 parallel channels corresponding to the valve. The same oil pressure prevails in these two channels, thus eliminating the risk of leakage from one channel to another. It is intended that no pressure difference or pressure gradient be formed between the two adjacent passages. There are no pressure differences in the valve anywhere except for the tank connection, which is supplemented with a seat. This prevents leakage flows into clearances and the accumulation of dirt and the consequent deterioration of operational reliability. One of the tanks, for the next emptying of the line connected to the tank 10 for emptying, is also specially sealed with a seat valve. The risk of leakage from the duct next to the tank connection, which is under pressure during operation, is thus small.

15 Figure 1 illustrates a double pair of 5-way 2-way hydraulic valves and associated control valves, the control devices of which have not been sketched. The figure also shows the oil supply and pressure monitoring only diagrammatically.

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With the support of Figure 1, the proposed invention is explained. tu embodiment. In this proposed embodiment, a system of hydraulic release valves is described, in which a double system is built with a number of valves. However, it is noted that two valves 25 are sufficient to achieve the required purpose.

The system of 5-way 2-way valves 1, 2, 3, 4, extended ·. · * Sa refers to hydraulic valves, is connected to • Y series of the fluid supply 5 and the pressure guard 6 corresponding to * * 30 corresponding to the pressure-dependent members 7, in this case · · · · Between quick-closing servo controls,. Each of the hydraulic valves 1, 2, 3, 4 in the embodiment shown here is controlled by a control valve 1 ', 2', 3 ', 4', which in turn. *. may be an optional control system. The pressure medium, which is usually oil, is conveyed along a line which branches into two lines before passing through the hydraulic valve, the oil lines passing in parallel alternately through all four valves because the parallel channels of the hydraulic valves are open. After passing through all the valves, the two lines continue to the pressure guard 6, respectively, to pressure-dependent members 7, which in this application of the invention consist of quick-closing servos.

The control means of the hydraulic valves 1, 2, 3, 4 are controlled by the oil pressure of the oil line, which line passes through the open passage belonging to the control valve 1 ', 2', 3 ', 4' in the driving space. These oil lines are also supplied with oil pressure from the pressure medium source 5.

When replacing a hydraulic valve with an associated control valve 15, an impulse is given to the control valve control means to change the state. For example, if such a pulse is given to the control valve 4 ', the pressure supply line 10 to this control valve is plugged, while the line 11 transmitting pressure to the control means of the hydraulic valve 20 becomes unpressurized, then the line 11 empties into the tank 12 in the control valve 4'.

When the control means of the hydraulic valve 4 is depressurized, this spring returns to the second phase state. The line 25 9, which transmits pressure to the quick-closing servo 7, is plugged in this second phase state in the valve 4. The pressure guard 6 becomes depressurized, then the line is emptied into the tank V * 13 in the valve 4. However, the quick-closing servo 7 remains in a constant: Y pressure state. 30 The pressure medium is now fed from line 8. The channel of the valve 4, • II · ... which led the pressure medium to the quick-closing servo from line 9, has • changed to join line 8 and is supplied with it: Y instead of oil now through it.

4 · • · 4 35 It is clear from the above explanation that hydraulic valves can be made to change state and thus either 9 101997 test their operation or without a malicious intent to trip without affecting the safety system.

If the two hydraulic valves are given the signals of the monitoring system 5, the signals change state by means of manual or electrical control or, under the control of the control valves, the safety system is triggered. For example, it is assumed that the control valves 3 'and 4' have both received switching pulses. In this case, the lines 3 'and 4', respectively, of the control valve 10 plug the lines which maintain the pressure of the control means of each of the hydraulic valves 3 and 4. The lines to both valves 3 and the control means become depressurized, whereby each valve 3 and 4 changes state to one of the two possible phase-15 states. In this case, the line 9 is plugged in the valve 3, while the line 8 is connected to the connection 14 in the valve 3 via a change of state. Thus, the line 8 is plugged in the valve 4. The quick-closing servo 7 becomes depressurized because the line to the quick-closing servo 7 is emptied into the tank 15 via the connections 16 and 17 i · <20. The pressure guard empties into the tank 13.

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As can be seen, it is sufficient for the valve system to have two of the valves described in order to achieve the required operation. However, from a safety point of view, a double valve system with four separately controlled valves is preferred. There is nothing to prevent the use of three valves. Operation with more than two valves V "in a valve system is similar to that described above • Y. To trigger the safety system, it is sufficient that t * '30 dual valves receive change signals. These change ... then the space and produce the operation described above * · 1' regardless of which valves have changed space.

, i I t 35 The above-mentioned valve testing can be activated by automated equipment to test the operation of the valves on a regular basis. This automatic testing can be controlled and monitored by pressure guards 6, which includes the fact that a malfunction, for example a valve gets stuck in the test space and the next valve gives a trip is completely eliminated. The test stops if any valve 5 does not return.

In the described embodiment, the control valves 1 ', 2', 3 ', 4' control the control means of the hydraulic valves 1, 2, 3, 4. It is natural that the hydraulic valves 10 be controlled directly by electric control or manual control.

In the described tripping device, a quick shut-off is activated by one or more associated servos. The triggering device described as inventor-15 can, of course, be activated by any type of pressure member acting by a pressure drop. 1 ♦ • · · · • ♦ ·

Claims (7)

11 101997 A valve system connected to a hydraulic safety system for a steam or gas turbine. that the system comprises at least two hydraulic valves (3,4), in which system the hydraulic valves (3,4) are connected so that these hydraulic valves normally maintain pressure with each individual valve in the first stage in both the line and the line of the 10 pressure guards (6) pressure-dependent member (7), and in which system one of the valves (3,4) can switch to the second stage, whereby only the pressure guard (6) becomes depressurized, while simultaneously switching at least two hydraulic valves (3,4) to the second stage triggers the safety system and thereby activates the pressure-dependent member (7) in the depressurized state and when the system of hydraulic valves is adapted to comprise more than two such valves, which at least two hydraulic valves are irrelevant in order to trigger the safety system; go to another I »· '... · phase state during some common time. ml · Valve system according to Claim 1, characterized in that the hydraulic valves (3, 4) consist of 5-way 2-way valves. fr ". Valve system according to Claims 1 and 2, characterized in that the valves are changed manually. 30 electrically, hydraulically, electromagnetically or otherwise. Valve system according to Claim 1, characterized in that the control valves (1 ', 2', 3 ', 4') are adapted to control the hydraulic valves (1,2,3,4). exchange electrically, electromagnetically, hydraulically, electrohydraulically, pneumatically or otherwise. 12 101997 5. A system for a valve according to claim 1, comprising a hydraulic valve (1, 2, 3, 4) adapted to provide a hydraulic system (1, 2, 3, 4) with a hydraulic valve (1, 2, 3, 4) for use with a valve. en automatic utilization and calibration of the tryckni-10 is considered to be tracer (6). Valve system according to Claim 1, characterized in that the actuation of the hydraulic valves (1,2,3,4) of the safety system and the individual testing of each individual hydraulic valve (1,2,3,4) can be provided by an automatic triggering and testing equipment. where the pressure levels are monitored by a pressure guard (6). Valve system according to claims 1 and 2, characterized in that the valves (1,2,3,4) are provided with double channels which are open and under the same pressure during operation in order to avoid a pressure gradient between the pressure means of the individual channels and thus saving from leakage and accumulation of dirt between the channels 15, and that the valves (1,2,3,4) have a tank connection made as a seat valve to achieve a good seal against the adjacent channel through which the pressurized medium flows. Valve system according to claim 1, * !! '. characterized in that the safety system is triggered by at least two valves of this valve system which go into a second phase state under the influence of a trip signal, the trigger signals preferably having a different origin or origin from separate electrical systems, and in which different valves affect different valves. · 1 · · 4 101997 13 l. The system of the valve is connected to a hydraulic head system for a diesel or gasturbiner, the rotating system of which is equipped with 5 hydraulic valves (3, 4), with a hydraulic valve (3, 4) If a hydraulic valve is normally fitted with a shield for the individual valve and then the mains upstream of the hydraulic valve (6) and the LED account 10 of the three-way body (7) and the end of the hydraulic valve ( 3, 4) kan växla account ett andra växlingsläge, varv the self-sustaining account of the triccactors (6) is set up in the tricycle, the median and velcro of the traction unit (3, 4) the account and the traction device of the triccylinder (3, 4) tryckberoende organ (7) i trycklöst tillstdnd och när systemet av hydrau-Liska ventiler är anordnat innefattande fler än tvd sddana ventiler det är utan betydelse vilka ätminstone tvd hydrau-'I 20 Liska ventiler som under ndgon gemensam tid int; Växlingsläge för att dstadkomma en utlösning av säkerhets- «systemet. • 4 f II «(• II« (IV '2. The system of the valve according to claim 1, the transverse of 25 of the hydraulic valve (3, 4) extending from the 5-pin 2-source fan. • · · • · «•» 4. 3. System with valve according to patent 1 and 2, cover • • 44 * 1 !, 1 nat av att ventilerna (3, 4) open manually, electrically, • · **; · 1 30 hydrauliskt , electromagnetic or pd annat setting • · • · · • · · • · · ·; ··: 4. System of the valve according to patent 1, kännetecknat av att styrventiler (! ', 2', 3 ', 4') anordnade att maneuvera de 14 101997 hydrauliska ventilerna (1, 2, 3, 4) växlas exempelvis electrically risk, electromagnetic, hydraulic, electrohydraulic, pneumatic or head set. 6. A system for a valve according to claims 1 and 2, which is connected to a valve (1, 2, 3, 4) and is provided with a double dipper and under the drift of the tricycle to a value of 15 or more in the tricycle gradient. in the case of a dietary apparatus with a dehumidifier and a dehumidifier, the ducts of the ducts diet of the dampers and the exhaust ducts (1, 2, 3, 4) are also subject to the same conditions, channel • I 20 genomströmmad av trycksatt medium. «« «« «I I (• I '•" I 7. A system for a ventilator according to a patent, a signal system for which a valve is used, and a signal system, for which the signaling signal is less than 25. ursprung eller härrör frän separe-Rade elektriska system och där de ätskilda utlösningssigna-.lerna päverkar separata ventiler. • · t ··· 1 • · · • · • · «·· ♦ • · · • 1 1