JPH0972439A - Three-way valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent every back flow from the downstream even in case of emergency so that the back flow does not adversely affect the upstream side by forming a sub- valve seat on the back side of an upper valve seat, and providing a sub-valve body opening and closing by receiving different driving from the operations of upper and lower valve bodies. SOLUTION: When a main cylinder 9 is lowered with the start of normal operation, upper and lower valve bodies 5, 6 are lowered, the lower valve body 6 closes an outlet port C, and the upper valve body 5 opens an outlet port B. Simultaneously with these actions, a sub-cylinder 11 is raised to separate a sub-valve body 8 from a sub-valve seat 7. Since the sub-valve body is reised a full stroke and stopped, clean air is passed through the outlet port B from an inlet port A to flow into a passage (B). When an emergency occurs and is sensed by sensor, etc., and reaches a three-way valve from a control panel, etc., by a direct command, raising of the main cylinder 9 is started immediately to quickly complete the shut-off of an upper valve seat 2 leading to the outlet port B, and the sub-cylinder 11 is lowered to shut-off the sub-valve seat 7 to close the sub-valve body 8 just before reversely advancing, high temperature gas reaches the upper valve body, and thus the abnormally high pressure, impure high temperature gas con be prevented from entering.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-way valve which is interposed in a flow path and switches a fluid to move in a desired direction.

[0002]

2. Description of the Related Art A three-way valve is a case in which a single valve is provided with a flow passage in three directions and an inlet in one direction and an outlet in two directions are provided, and an inlet from two directions. In some cases, it may be composed of an outlet in one direction, and is properly used depending on the application. For example, a fluid outlet is provided in two directions with respect to an inlet from one direction, and fluid is normally supplied from one direction via a specific outlet, but an abnormality occurs on the downstream side of the flow path. Or when it becomes necessary to urgently block the ingress of fluid,
Alternatively, the function of switching the movement of the fluid to another remaining outlet may be indispensable for the maintenance of the pipeline when the fluid is temporarily stopped for inspection or repair work.

FIG. 3 is a system diagram showing an example thereof, in which the three-way valve opens in three directions of an inlet A, an outlet B and an outlet C,
At the end of the flow path (A) connected to the inlet A, the air compressor 1
01 is attached, and its operation supplies clean air to the inlet A. The flow path (B) is a line that is connected to the outlet B and is used steadily, and clean air is changed to high-temperature gas by combustion of oil or coal in the boiler 102 disposed on the way, and is connected to the end of the line. The gas is supplied to the arranged gas turbine 103 and then discharged. An emergency shutoff valve 104 is provided between the boiler 102 and the gas turbine 103 so that the supply of high-temperature gas is immediately stopped when an abnormality occurs in the operation of the gas turbine.

The flow path (C) is an emergency evacuation discharge line, and it is difficult to stop the air compressor 101 rapidly because of the mechanism. Therefore, in an emergency, the three-way valve is operated to close the outlet B and close the outlet C. To switch the outflow of clean air from the flow path (B) to the flow path (C) to temporarily block the flow path for supplying the clean air to the boiler. Needless to say, the outlet B may be closed and the outlet C may be opened for maintenance such as regular inspection and repair.

As the prior art of the three-way valve, the structure illustrated in FIG. 4 is generally adopted. The valve box 1a has an inlet A that opens to the flow path (A), an outlet B that opens to the flow path (B) used in steady operation, and a flow path used for discharge and maintenance at the time of emergency shutoff. It opens in three directions of the outlet C that opens to (C), and the upper valve seat 2 is provided at two upper and lower positions in the valve box 1a.
a, a lower valve seat 3a. One valve rod 4a, which is vertically supported in the valve housing 1a, has a coupling 12 at the upper end.
It is connected to the main cylinder 9a through a, and is driven by the main cylinder 9a to move up and down in the valve box. The valve rod 4a has an upper valve body 5a and a lower valve body 6a which are spaced apart from each other in the valve box 1a. When one valve body comes into contact with the valve seat and is closed by the vertical movement of the valve rod, the other The valve body has a reverse operation relationship in which the valve body separates from the other valve seat to open the valve.

If the opening direction of the three-way valve is connected to such a mode, the flow passage (A) has a high pressure and the flow passages (B) and (C) have a low pressure, so that the upper and lower valve bodies of the three-way valve. Is advantageous in that the airtightness is maintained because the pressure of the clean air is applied to each outlet side, and the clean air leaks to the side of the flow path (C) that is closed in the steady operation and the capacity of the air compressor is insufficient. Or the mixture ratio of oil and coal in the boiler combustion is lowered, and the operating performance of the system is deteriorated.

In a steady operation, the main cylinder 9a descends in response to a command from the operation panel or the like, and the upper valve body 5a of the three-way valve is lowered.
Is fully opened, the lower valve body 6a is fully closed, and the clean air enters the valve box 1a from the flow path (A) through the inflow port A and is guided to the flow path (B) through the outflow port B. It is supplied to the boiler 102. In this case, the pressure acting on the upper valve body 5a is almost equal to the pressure of the clean air, and this pressure is the main cylinder 9a.
Will be the standard for selecting the capacity. When inspecting, repairing, or otherwise suspending downstream equipment such as a boiler or a gas turbine, the flow path (B) is fully closed and the flow path (C) is opened. This case is called a "normally closed" state, in which the valve rod 4a moves up and the opening and closing of the upper and lower valve bodies are reversed, and the clean air from the flow path (A) is switched to the flow path (C) and discharged. To be done.

When the gas turbine suddenly breaks down during operation and becomes inoperable, the high-temperature gas supplied to the gas turbine must be immediately shut off. Therefore, an automatic command from the operation panel or sensor is used. Directly works to stop the supply of clean air from the three-way valve. The valve closing operation is performed in the same manner as the above-mentioned normal closing, and the passage (B) is closed at the same time as the passage (B) is closed by the rise of the valve rod, and the passage (A) is opened.
Clean air supplied from is switched to the flow path (C) and is discharged as an emergency evacuation.

[0009]

The supply of clean air is immediately stopped by the operation of the three-way valve, but in the case of the flow path as shown in FIG. 3, another emergency operation is automatically issued on the downstream side. As a result, new problems will arise in the three-way valve itself. That is, when an abnormality occurs in the gas turbine and the operation is stopped, the emergency shutoff valve 104 provided in front of the flow path to prevent the failure of the gas turbine automatically operates to close the valve, and the high temperature gas is The normal maintenance system is to protect the gas turbine by shutting it off so that it does not flow into the gas turbine. However, due to such a shutoff action, the pressure in the flow path between the outlet B of the three-way valve and the emergency shutoff valve rises sharply, and the outlet B is temporarily closed to an abnormally high pressure.
There is a reaction of pressing the upper valve body 5a.

The fluid that has entered the boiler on the downstream side of the outlet B is supplied to burn oil or coal, and the high temperature gas in the pipe from the boiler to the emergency cutoff valve is burned by fuel. Is a solid-gas mixture containing impurities and is a high temperature fluid. When this impure and high temperature fluid flows back into the valve box and enters the flow channel (A) and the flow channel (C), Various instruments such as valve devices and sensors installed in the flow path, air compressor, and other accessories attached to the upstream side are contaminated and have a heat effect, and significantly impair the function,
It often causes malfunctions and malfunctions.

In order to guarantee that the fluid does not flow backward from the downstream side in an emergency, it is necessary to absolutely maintain the airtightness of the upper valve body, and for that reason, the driving force required to open and close the valve in a steady state is required. It is assumed that a cylinder has a much larger capacity. It is not always easy to predict and estimate the level of abnormal high pressure in advance because technically unknown elements are complicatedly related to each other, so it is difficult to estimate it on the safety side and win. I can't blame you. However, as long as this assumption is followed, even in steady operation, there is no choice but to operate a cylinder with an unnecessarily large capacity, so the energy required for driving becomes unnecessarily large.
Also, the diameter of the valve rod must be designed to be large to accommodate this capacity, and the size and strength of the valve itself must be set too large.

In order to solve the above-mentioned problems, the present invention has the capacity and size necessary for steady operation,
Even in an emergency, backflow from the downstream side is completely blocked into the valve box,
The purpose is to provide a three-way valve that does not adversely affect the upstream side.

[0013]

The three-way valve according to the present invention comprises:
An inflow port A, an outflow port B that also needs an emergency shutoff, and an upper valve seat 2 that communicates with the outflow port B in a valve box 1 that opens in three directions of an outflow port C that opens when the outflow port B is closed. The upper valve body 5 and the lower valve body 6 are reversely opened and closed by the movement of one valve rod 4 so that the lower valve seat 3 communicating with the outlet C faces each other. A sub-valve seat 7 is formed on the back surface of the seat 2, and a sub-valve body 8 that opens and closes the sub-valve seat 7 by receiving a drive different from the operation of the valve bodies 5 and 6 is slidable on the valve rod 4. Characterized by loose fitting. During steady operation, the upper valve body 5 is opened to guide the fluid to the outlet B, but in an emergency, the valve rod 4 is lifted in response to a command and the upper valve body 5 is brought into close contact with the upper valve seat 2 and closed. At the same time, another driving force is actuated, the sub valve body 8 slides down the valve rod 4 and descends, the sub valve seat 7 on the back side of the upper valve seat 2 is quickly closed, and the reverse flow from the outflow port B enters. The function of preventing the above-mentioned action works to solve the above problems.

In this structure, two auxiliary valve rods 10 are fixed near both side edges of the auxiliary valve body 8 which is loosely fitted to the valve rod 4 whose tip is connected to the main cylinder 9, and the upper end of the auxiliary valve rod 10 is fixed. It is desirable to adopt a configuration in which two sub-cylinders 11 standing on the outer surface of the valve box 1 are connected.

In each of the above constructions, the movement stroke of the auxiliary valve rod 10 is at least 30 times the opening diameter of the upper valve seat 2.
% Is a mode in which a design having is desirable. This numerical limitation is unavoidable during normal operation because the sub-valve body 8 is always present on the downstream side of the upper valve body 5, that is, in the outlet B, so that flow resistance is unavoidable, but its adverse effects are adversely affected. It is a condition that is excluded as much as possible so as not to obstruct the flow. The opening area S of the valve seat is S = πD if the diameter of the opening is denoted by D.
A ^2/4, while the range s influence the resistor interposed in the flow path, if the distance from the opening and H, since theoretically equal to the opening area S, s = πDH = S It is generally accepted that From the above formula, it means that if the resistor is separated from the opening by H = D / 4 or more, the influence on the fluid almost disappears. Therefore, strictly speaking, the auxiliary valve 8 is separated by 25% or more of the upper valve seat diameter. It will be good if it is in the right position. Here, the effect of solving the problem is eliminated by separating the auxiliary valve body by a distance of 30% with a margin and defining the auxiliary valve body as the stroke of the auxiliary valve rod 10 that moves up and down.

[0016]

1 and 2 are vertical front views showing an embodiment of the present invention, in which a flow path (A) and a flow path (B) communicate with each other and a boiler (not shown) is shown in FIG. 2 is a state in which clean air is being supplied from an air compressor to FIG. 2 and is normally closed, or in an unsteady state in which the channel (B) is closed and air is discharged to the channel (C) in an emergency. Shows. The valve box 1 is opened in three directions of an inflow port A, an outflow port B, and an outflow port C, and has a flange 13 at each end that connects to a mating pipe. The outflow port B and the outflow port C are located at right angles to the direction of the inflow port A, and the upper valve seat 2 and the lower valve seat 3 are provided facing each other at positions vertically separated from each other. . One valve rod 4 is vertically inserted in the upper and lower parts of the valve box 1 and
And a lower bearing 15, which is vertically movably supported, and the upper end of which is connected to the lower end of the piston of the main cylinder 9 by the coupling 12, so that the main cylinder 9 is actuated to move up and down. The main cylinder 9 is a stand 18 connected to the upper part of the valve box.
It is desirable that it is placed and fixed on top of. In the example of this figure, a hydraulic cylinder is applied as the main cylinder used for lifting and lowering the valve rod, but it is also possible to apply the operation of another type of hydraulic cylinder by water pressure or atmospheric pressure. There are various forms.

The upper valve body 5 is attached to the valve rods 4 in the upper and lower valve seats in the direction in which it is pressed against the upper valve seat 2, and the lower valve body 6 is installed in the direction in which it is pressed against the lower valve seat 3 at a distance. To be The position of the valve body on the valve stem is fixed,
Here, a male screw is threaded on a predetermined outer peripheral surface of the valve rod 4, and nuts 16 and 17 are screwed and fastened to the male screw to fasten both valve bodies 5 and 6.
When the upper valve body 5 is separated from the upper valve seat 2 and the outlet B is opened, the lower valve body 6 is in close contact with the lower valve seat 3 and the outlet C is closed. (FIG. 1), when the upper valve body is in close contact with the upper valve seat, the lower valve body always opens the lower valve seat (FIG. 2). In this figure, two valve elements are attached to the top and bottom of the valve rod, but a single cylindrical valve element is fitted onto the valve rod so that the top surface forms the upper valve element and the bottom surface forms the lower valve element. The form can be selected.

A sub-valve seat 7 is formed on the back side of the upper valve seat 2 in the valve box 1, and a sub-valve body 8 for opening and closing the sub-valve seat 7 is inserted through the valve rod 4 and slidably loosely fitted therein. ing. It is the driving force of the sub-cylinder 11 mounted on the outer surface of the valve box 1 via the sub-valve 10 that raises and lowers the sub-valve 8, and the two sub-cylinders 11 that are erected on both upper sides of the valve box 1 The piston shaft of the sub valve rod 10 serves as the sub valve rod 10 as it is, and the rear end of the sub valve body 10 is attached to the mounting bracket 19
It is fastened and fixed to.

Main cylinder 9 required for the structure of the present invention
Unlike the prior art, since the auxiliary valve body is closed even when the emergency valve is closed, the reverse pressure of the abnormally high pressure from the outlet B does not act, so that the required output of is small enough to simply allow normal valve opening and closing. It has the characteristic that the capacity is sufficient. At the same time, the shaft diameter of the valve rod may be a thin one commensurate with its capacity, which reduces the weight of the entire valve and avoids the need to increase the size. On the other hand, with respect to the sub-cylinder, since the upper valve body is quickly closed in an emergency, no pressure acts on the sub-valve seat. In addition, since it may be closed before the abnormal high pressure is applied, a large output is not required for driving. Moreover, since it is sufficient to raise the sub valve body to open the sub valve seat after the abnormal high pressure back pressure has ended, operation at this point is also possible with a small output and the shaft diameter of the sub valve rod is sufficient. Since it is thin and sufficient, it does not have to be a burden to increase the total weight of the three-way valve.

To summarize the behavior of each valve element, the main cylinder 9 is operated based on a command from the operation panel or the like at the time of normal operation start.
And the upper and lower valve bodies 5, 6 also descend, the lower valve body 6 closes the outlet C, and the upper valve body 5 opens the outlet B. Simultaneously with this operation, the sub-cylinder 11 which has received the command rises and the sub-valve body 8 separates from the sub-valve seat 7, and ascends to the full stroke and stops. It flows to the flow path (B).

When a sensor or the like detects the occurrence of an emergency and a command reaches the three-way valve via the operation panel or directly from another control circuit, the raising of the main cylinder 9 is instantly activated. While the closing of the upper valve seat 2 leading to the outflow port B is completed promptly by the ascending, the descending of the sub-cylinder 11 also progresses and the auxiliary valve seat 7 is closed, and the hot gas that is moving backward reaches the upper valve body. Since the sub-valve is closed and the airtightness is maintained, the impure hot gas of abnormally high pressure is prevented from entering the upper valve body.

When it is normally closed due to maintenance or the like, the main cylinder 9 is lifted to release the lower valve body 6 and close the upper valve body 5 in the same manner as in an emergency to close the outlet B. In this case, if the sub-cylinder 11 does not have to move together with the main cylinder, the sub-cylinder 11 may not be operated as it is and may remain stationary in the raised position.

[0023]

In the three-way valve according to the present invention, the backflow of the high temperature gas from the outflow port B cannot enter the inflow port A or the upstream side of the flow path (A) from the valve body when the valve is closed in an emergency. Therefore, there is no fear that the equipment will be dirty or the function will be deteriorated. Moreover, since the main cylinder for driving the upper valve body to prevent backflow does not require a large capacity for emergency, unlike the prior art, the minimum necessary for normal valve opening / closing, pump, motor Since the capacity of all equipment is also reduced, the weight of the entire device is reduced and the size is reduced, which reduces the burden of equipment costs and the operating costs, contributing to the reduction of production costs. Is obtained.

According to the second aspect of the present invention, the sub-valve element is slidably fitted in the valve rod and is connected to the sub-valve rod hanging from the sub-cylinder erected on the outer surface of the valve box to receive its drive. Even when compared with the conventional technology, the total length and width of the valve box itself have not changed,
The only difference is that another member is placed slightly above the valve box. Therefore, the space required for installation is equivalent to that of the conventional technique, and there is an advantage that it is not necessary to change the connection with other devices and flow paths.

According to the third aspect, as described above, the addition of the sub-valve causes a new resistor to appear in the flow path in terms of shape. However, as long as this numerical limitation is obeyed, the effect disappears. The effect of maintaining a normal flow is obtained as well.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view showing an embodiment of the present invention.

FIG. 2 is a vertical sectional front view showing another state of the previous figure.

FIG. 3 is an example of a system diagram of a flow channel to which the present invention is applied.

FIG. 4 is a vertical sectional front view of a conventional technique.

[Explanation of symbols]

 1 Valve box 2 Upper valve seat 3 Lower valve seat 4 Valve rod 5 Upper valve body 6 Lower valve body 7 Sub valve seat 8 Sub valve body 9 Main cylinder 10 Sub valve rod 11 Sub cylinder A Inlet B Outlet (steady) C Outlet (unsteady)

Claims (3)

[Claims] 1. A valve box 1 that opens in three directions: an inflow port A, an outflow port B that also requires an emergency shutoff, and an outflow port C that opens when the outflow port B is closed, leading to the outflow port B. Upper valve seat 2
And the lower valve seat 3 leading to the outflow port C face each other, and the upper valve body 5 and the lower valve body 6 are reversely opened and closed by the movement of one valve rod 4, the upper valve seat Sub valve seat 7 on the back of 2
And a sub-valve body 8 for opening and closing the sub-valve seat 7 by receiving a drive different from the operation of the upper valve body 5 and the lower valve body 6 is slidably loosely fitted to the valve rod 4. A three-way valve characterized by that. 2. A sub-valve body 8 loosely fitted to a valve rod 4 whose tip is connected to a main cylinder 9 according to claim 1, wherein 2 is provided near both side edges.
The auxiliary valve rod 10 of the book is fixed, and the upper end of the auxiliary valve rod 10 is the valve box 1
A three-way valve characterized in that it is connected to two sub-cylinders 11 which are erected on the outer surface of the. 3. The auxiliary valve rod 10 according to claim 1 or 2.
The three-way valve is characterized in that its moving stroke is at least 30% of the opening diameter of the upper valve seat 2.