JPH0322491Y2 - - Google Patents

Description

[Detailed description of the invention] [Technical field of the invention] The invention is a system that is installed in the middle of a steam turbine system that pumps high-temperature, high-pressure steam from a steam generation source to a steam turbine, and that controls the supply and stop of steam to the steam turbine. The present invention relates to a steam valve mechanism to be regulated, and particularly to a steam valve mechanism installed in a mixed pressure steam line.

[Technical background of the invention]

Mixed-pressure steam turbines are mainly used in chemical factories, paper mills, etc., in order to effectively utilize surplus steam generated and discharged from various manufacturing processes, and to generate new power sources such as in-house power generation. It is commonly used.

FIG. 2 is a schematic configuration diagram showing a mixed pressure steam turbine system L using a mixed pressure steam turbine, and shows the main process 1.
The steam generated passes through the steam stop valve 2 and the steam control valve 3 and is injected into the steam turbine 4, causing the rotor blades of the turbine 4 to rotate at high speed, and at the same time causing the generator 5 connected to the turbine 4 to rotate. It is activated to generate electricity, and the discharged steam flows into the condenser 6, where it is cooled and condensed. On the other hand, the mixed pressure steam turbine 4 also utilizes surplus steam generated in other processes, and as shown in the figure, for example, the auxiliary process 7
The steam generated in a, 7b, and 7c also flows into the stages of the steam turbine 4 at the same pressure as the steam pressure on each process side as mixed pressure steam, mixes with the steam from the main process 1 side, and reaches the condenser 6. By the way, these auxiliary steps 7a to 7
In the middle of the steam turbine system L from c to the steam turbine 4, depending on the load state of the steam turbine 4, etc.
Usually, a steam valve mechanism M is provided to regulate the inflow of steam.

FIG. 3 shows a conventional steam valve mechanism M installed in the middle of a steam turbine system L, and this mechanism M has a main control valve 14 that extends into the main cylinder 8. and hydraulic output side O and hydraulic input side i
A piston 9 sliding inside the main cylinder 8 while defining a valve chamber 1 is connected to the piston 9 via a rod 10.
1, the auxiliary process 7a flows in from the right side in the figure.
7c is provided with a valve body 13 that opens and closes the opening 12 as the piston 9 moves, so as to prevent the steam generated in the valve chamber 11 from flowing out to the steam turbine side. A biasing spring 15 is interposed on the output chamber side O of the piston 9, and biases the piston 9 toward the input chamber side i. Further, the input chamber side i is connected to a relay cylinder 16 that relays hydraulic input. Then, by supplying hydraulic oil to the hydraulic input chamber i side via the relay cylinder 16, the main control valve 14 is opened, and when the hydraulic oil supply is stopped, the valve is closed by the biasing force of the biasing spring 15.

[Problems with background technology]

By the way, in such a conventional steam valve, the turbine is operated with the amount of steam generated only in the main process 1,
When steam is not used in the auxiliary processes 7a to 7c and the steam valves interposed between these processes are fully closed to block the inflow of steam, the steam pressure of the turbine is controlled from below the valve chamber 11 in FIG. acts, causing the main control valve 14 to move slightly in the opening direction against the biasing force of the biasing spring 15, causing a backflow of steam and causing a loss of steam energy. For this reason, attempts are made to increase the diameter of the piston 9 to strengthen the force acting in the closing direction of the main control valve 14, but in such a case, for example, the steam supply to the turbine may be stopped to cut off the load on the turbine. When the main control valve 14 needs to be closed rapidly to prevent overrunning of the turbine rotor blades, or when a turbine failure occurs, the main control valve 14 cannot be closed quickly. The aforementioned issues had no choice but to be left unresolved.

Further, when the load applied to the biasing spring 15 is increased, the opening 12 is rapidly closed, which causes a problem in that the load on the turbine changes rapidly, causing a problem in the turbine.

[Purpose of invention]

The purpose of the present invention is to eliminate the above-mentioned drawbacks and provide a steam valve mechanism that can select any valve opening/closing function in order to supply or stop steam to a steam turbine depending on the load condition of the steam turbine, etc. shall be.

[Summary of the idea]

The purpose of this valve is to be located in a valve chamber that has an opening provided in the middle of the steam turbine system, and to move forward and backward with respect to this opening, opening and closing the opening to regulate the flow of steam into the steam turbine. The main control valve has a main control valve with a main control valve at one end, and a main cylinder having a hydraulic output chamber and a hydraulic input chamber at the other end, and defining a hydraulic input/output chamber. A piston that slides within the main cylinder is provided, and a biasing spring that normally biases the main control valve in the closing direction with respect to the opening is provided on the output chamber side of the main cylinder. In a steam valve mechanism in which a relay valve is interposed in each passage connected to the relay valve, a hydraulic directional control valve is provided between an oil passage connected to the relay valve and an oil passage connected to the output chamber of the main cylinder, and this hydraulic directional control valve is provided. The valve balances the hydraulic pressure in both chambers by communicating the hydraulic pressure in only one direction of the input chamber and the output chamber, and by communicating the circuit connecting the input/output chamber with the hydraulic directional control valve. This is achieved by comprising three-way switching means.

[Example of idea]

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows an embodiment of the present invention, and the figure shows a schematic overall configuration diagram of a steam valve mechanism M.

In the figure, for example, the auxiliary process 7 is shown at the upper right end.
An opening 17 opened in the middle of the steam turbine system L connected to a is shown, and this opening 17 opens and closes the valve chamber RV for regulating the inflow of steam, and connects the auxiliary process 7a and the steam turbine 4. It's communicating.

The steam valve mechanism M includes a main control valve 18, a biasing spring 20, and a hydraulic directional control valve 21. A main cylinder 23 is formed near the valve chamber RV, separated by a partition wall 22, and the main control valve 18 moves in the left-right direction across the valve chamber RV and the main cylinder 23. That is, the main control valve 18 is operated by a piston 24 whose one end extends into the main cylinder 23 and slides inside the main cylinder 23 while defining the main cylinder 23 into an output chamber O and an input chamber i. The other end is connected via a rod 25 penetrating the partition wall 22, and the piston 24
As the main cylinder 23 moves, the opening 17
It is formed from a valve body 26 that moves forward and backward relative to the valve body 26.

One end of the input chamber i of the main cylinder 23 is connected via a through hole 27 to an input relay cylinder 29 having a valve seat 28 expanded in diameter from the through hole 27 at one end. In this input relay cylinder 29, a relay valve 19 is slid in order to supply hydraulic oil to the input chamber i of the main cylinder 23 and open the main control valve 18 by moving the piston 24 to the left side. One end of this relay valve 19 forms a truncated conical portion 19a and engages with the enlarged diameter portion of the valve seat 28, and the other end is connected via a small diameter portion 19b. It forms a flange portion 19c and is slidably formed on the inner surface of the relay cylinder 29. A valve spring 31 is compressed around the small diameter portion 19b of the relay valve 19, and applies a biasing force to move the relay valve 19 away from the valve seat 28. In addition, a thin hole 32 is bored through the axial center of this relay valve 19, and the hydraulic pressure from the hydraulic directional control valve 21 connected below the relay cylinder 29 passes through this thin hole 32. It is buffered and sent to the input chamber i of the main cylinder 23. Further, a drain hole 33 is formed in the enlarged diameter portion of the valve seat 28, and is connected to a tank (not shown).

On the other hand, a biasing spring 20 is compressed in the output chamber O of the main cylinder 23, and presses against the piston 24 of the main control valve 18 to push the valve body 26 connected to the other end of the piston 24. A spring is biased in a direction that always closes the opening 17.

A characteristic feature of the present invention is that a hydraulic directional control valve 21 that can switch the oil path direction in three directions is provided in the steam valve mechanism. 3 switchable positions 21 as 3-way switching means of 21
a, 21b, and 21c are shown. This directional control valve 21 has four ports P, A, B, and T, and port P is connected to an oil path to a pump (not shown) and also functions exclusively as an inlet for hydraulic oil supplied from the pump. do. Ports A and B function as outlets for the hydraulic oil sucked in from port P, and port T functions exclusively as a discharge port, and its extension is connected to a tank (not shown). Port A is connected to the relay cylinder 29 through an oil path, and port B is connected to the main cylinder 23.
The oil passage is connected to the output chamber O of the oil passage with an orifice means 34 interposed therebetween to prevent oil pressure fluctuations during oil passage switching. This hydraulic directional control valve 21 is 21a
In the position shown in , port P communicates only with port A, and port B communicates only with port T. Next, in the position shown in 21b, while port T is in a blocked state,
Each of the ports P communicates with the ports A and B at the contact point Pc, so that the oil passage connected to the input relay cylinder 29 and the oil passage connected to the output chamber O are also in communication. Further, in the position 21c, the port P communicates only with the port B which is connected to the output chamber O, and the port A communicates only with the port T serving as a drain outlet.

[Effect]

The steam valve mechanism operates as follows.

In the state shown in FIG. 1, the hydraulic directional control valve 21 is
1a, the hydraulic oil supplied from the pump passes through ports P and A to the input relay cylinder 29, is further hydraulically buffered by a thin hole 32, passes through this, and enters the input chamber of the main cylinder 23. i and inputting hydraulic pressure to the piston 24, the piston 24 resists the urging force of the urging spring 20.
is about to be moved to the output chamber O side and the valve body 26 is about to be opened. In this state, it performs the same function as the conventional mechanism shown in FIG. The control valve 18 will be fully opened, and the steam generated in the auxiliary process 7a will flow into the steam turbine 4.

In this state, when hydraulic oil is not supplied to the input relay cylinder 29, the relay valve 1 is
9 is returned and the valve seat 28 is opened, all the hydraulic oil in the input chamber i becomes drain and is discharged from the drain hole 33 and stored in the tank, and the valve body 26 is pressed by the biasing spring. and becomes fully closed.

Next, when the valve body 26 is to be fully closed from the fully open state due to some process-related circumstances, the hydraulic directional control valve 21 is first switched to the position 21b. At this time, the hydraulic oil supplied to port P is simultaneously supplied to ports A and B via contact Pc, while port T, which was connected to the drain, is blocked inside the control valve 21. Then, the hydraulic oil that has passed through the A port is continuously supplied to the input relay cylinder 29 connected to the input chamber i, and at the same time, the B
The hydraulic oil that has passed through the port passes through the orifice means 34 and flows into the output chamber O of the cylinder 23.
Here, at the contact point Pc of the directional control valve 21, the oil passage leading to the input chamber i of the main cylinder 23 and the oil passage leading to the output chamber O communicate with each other, and as a result, the oil pressure difference before and after the piston 24 disappears. The piston 24 moves toward the input chamber i side by the load of the biasing force of the biasing spring 20.
The force that presses the piston 24 is stronger than the valve body 26 .
begins to move in the direction of closure. At the same time, the hydraulic oil that had been flowing into the input chamber i side of the piston 24 flows backward through the thin hole 32 drilled along the axis of the input relay cylinder 29, returns to the port A, and further flows through the directional control valve. 21 contact point Pc and orifice means 34
, and then flows backward into the output chamber O of the main cylinder 23. Finally, after the valve body 26 is fully closed, the directional control valve 21 is switched to the position 21c. In this position 21c, port P is connected only to port B, and hydraulic oil is continuously supplied only to output chamber O of main cylinder 23. On the other hand, port A, which had previously been supplied with hydraulic oil, is connected only to port T, and the hydraulic oil is drained into the tank. Therefore, the relay valve 1 in the input relay cylinder 29
As a result of 9 being pushed back downward by the valve spring 31,
The relay valve 19 is separated from the valve seat 28. The hydraulic oil remaining in the input chamber i also flows out from the drain hole 33 to the tank. At this point, no hydraulic pressure acts on the input chamber i of the main cylinder, and the valve body 2
6, the opening 17 is completely closed due to the load of both the biasing load of the biasing spring 20 and the hydraulic pressure acting on the input chamber i.
The main control valve 18 is placed in a fully closed state. Here, the steam from the steam turbine cannot move the main control valve 18 in the opening direction due to a reverse force in the valve chamber RV, and it is possible to maintain a completely closed state. If it is desired to open the valve again and utilize the steam generated in the auxiliary step 7a, the above operation may be performed in reverse.

In addition, when switching the direction control valve 21 from the open position to the position 21b, the input relay cylinder 29
The closing speed of the valve body 26 can be arbitrarily adjusted by adjusting the diameter of the small hole 32 formed in the relay valve 19, so that, for example, the load increase rate (or decrease rate) of the turbine can be determined. If so, it is possible to choose a slow closing speed that is above this rate of change, so that the turbine does not experience sudden load changes and fail.

Further, according to the above embodiment, when the main control valve 18 is closed, the hydraulic pressure does not act on the input chamber i at all, but acts only on the output chamber O side, so that the biasing spring 2
As a result of being able to set the zero design load to be the same as the conventional one, there is no need to increase the diameter of the piston 24.

Further, although this embodiment shows a case where it is used in a mixed pressure steam turbine system, the steam valve mechanism according to the present invention can also be applied to a steam turbine in which only the main process is the steam generation source.

[Effect of idea]

By using the steam valve mechanism based on the present invention, it is possible to prevent backflow of steam from the turbine during turbine operation and maintain a completely closed state without increasing the piston diameter of the main control valve. In addition, it is possible to obtain slow and fast valve opening and closing actions in response to the steam generation source process and the load condition of the steam turbine, which not only improves the durability of the steam valve mechanism itself, but also improves the original nature of the steam valve mechanism. It is possible to reliably achieve this function.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a steam valve mechanism according to the present invention, FIG. 2 is a schematic diagram of a mixed pressure steam turbine system, and FIG. 3 is a schematic diagram of a conventional steam valve mechanism. L... Steam turbine system, M... Steam valve mechanism, i... Input chamber, O... Output chamber, 17... Opening, 18... Main control valve, 19... Relay valve, 20... Biasing spring, 21... Hydraulic directional control valve , 23... Main cylinder, 24... Piston, 25... Rod, 26... Valve body, 29... Input relay cylinder, 34... Orifice means.

Claims (1)

[Scope of utility model registration request] A valve body located in a valve chamber having an opening provided in the middle of the steam turbine system, and which moves forward and backward with respect to the opening to open and close the opening to regulate the inflow of steam into the steam turbine. The other end of the main control valve is located within a main cylinder having a hydraulic output chamber and a hydraulic input chamber, and defines a hydraulic input/output chamber. A biasing spring that always biases the main control valve in the closing direction with respect to the opening is provided on the output chamber side of the main cylinder in a passage connected to the input chamber of the main cylinder. In the steam valve mechanism, a hydraulic directional control valve is provided between an oil passage connected to the relay valve and an oil passage connected to the output chamber of the main cylinder, and this hydraulic directional control valve is connected to the input There are three cases: when hydraulic pressure is applied only in one direction between the chamber and the output chamber, and when the hydraulic pressure in both chambers is balanced by communicating the circuit connecting the input/output chamber with this hydraulic directional control valve. A steam valve mechanism comprising a direction switching means.