JPS6325232B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a gate valve used in wellhead equipment for oil production installed on land or under the sea.

Conventionally, in this type of gate valve, as shown in Figs. 1 and 2, a gate b, which has a gate passage c perpendicular to the axis of the flow line a and communicates with the flow line a, is raised and lowered by a cylinder d. There is a device that opens and closes the flow line a by doing this, and the sealing of the gate b is performed by pressing a ring seat e with a spring f. Also, if the spring f in Fig. 1 is only on the upstream side and not on the downstream side, the seat e can be used without using springs on both sides.
There is a fixed fitting type that provides the necessary clearance for sliding on the gate b. In both cases, the gate b is floating, and the gate is pressed against the sheet surface on the downstream side by the fluid pressure on the upstream side, thereby creating a seal. If the fluid pressure is high enough, the seat pressure on the downstream side will also be high enough, but if the pressure on the upstream side is low, the type without a spring will not generate enough surface pressure on the downstream side, causing leaks. tends to occur. Furthermore, even if a spring is provided, it is difficult to generate sufficient surface pressure due to the narrow space, and if there are pressure fluctuations on the upstream side, it is difficult to determine an appropriate spring strength. Further, there is a drawback that the reduction in the elastic effect due to fatigue of the spring f reduces the sealing effect and causes fluid leakage.

The present invention corrects the above-mentioned drawbacks, and is capable of freely sliding in the direction of blocking the flow line provided on the valve mounting seat, and the thickness dimension of the flow line in the axial direction varies from one end to the other along the sliding direction. A valve body having a tapered shape that gradually increases toward the end is provided, a flow path that can communicate with the flow line is formed at a predetermined position on the thin side of the valve body, and the end of the thin side of the valve body is connected to the sliding surface. The flow line is a ring seat that is attached to the piston rod of a hydraulic cylinder for movement so as to be freely movable in the direction of the flow line, and that forms a part of the flow line on both sides of the valve body and closely fits along the tapered surface of the valve body. A key is fixed to one of the ring seat and the valve mounting seat, and a key groove that engages with the key and extends in the axial direction of the flow line is provided on the other. The rotation of the seat is restricted, and the limit position of movement of the ring seat toward the side opposite to the valve body is restricted by contact between the stopper portion formed at the end of the groove of the key and the key, and the distance between the ring seat and the valve mounting seat is controlled. The ring seat is configured to be able to be press-fitted to the valve body by forming a hydraulic pressure chamber in the valve body and communicating the hydraulic pressure chamber with a hydraulic pressure source. This invention relates to a gate valve characterized in that it includes a return spring for slidingly biasing the valve body in a direction to move to a movement limit position and close a flow line.

Embodiments of the present invention will be described below with reference to the drawings.

A chamber 3 is formed in the middle of the flow line 2 that penetrates the valve mounting seat 1, and a flow path 4 that can match the flow line 2 is bored in the upper part, and the wall thickness in the direction of the flow line is smaller at the upper part and larger at the lower part. A valve body 5 formed into a tapered shape is housed in the chamber 3 so as to block the flow line 2. A ring seat 6, which is slidable in the direction of the central axis of the flow line 2 and forms a part of the flow line 2, is disposed in close contact with both tapered side surfaces of the valve body 5 facing the fluid. The outer shape of the ring seat 6 has a two-stage structure with a small diameter part and a large diameter part, and a key 7 is provided on the valve mounting seat 1 corresponding to the small diameter part, and the key 7 is provided on the outer peripheral surface of the small diameter part. A key groove 7a is formed which fits into the flow line 2 and extends in the axial direction of the flow line 2. When the stopper part 7b at the end of the key groove 7a hits the key 7, the side of the ring seat 6 opposite to the valve body The limit position of movement to is now regulated. Further, the large diameter portion and the large diameter portion storage portion of the valve mounting seat 1 form a first hydraulic pressure chamber 8, and the hydraulic pressure chamber 8 and a hydraulic pressure source (not shown) are connected to a first hydraulic pressure line 9.
We will communicate at A bearing 10 covering the chamber 3 and the valve body 5 is attached to the upper surface of the valve mounting seat 1, and an outer cylinder 11 surrounds the bearing 10. A hollow piston 12 having a flange formed at its lower end is slidably fitted into the outer cylinder 11, and a closing member 13 that guides the piston 12 in a liquid-tight manner is fixed to the upper end of the outer cylinder 11.
The second hydraulic pressure chamber 14 formed by the outer cylinder 11, the piston 12, and the closing member 13 is communicated with a hydraulic pressure source (not shown) through a second hydraulic pressure line 15, which is perpendicular to the center line of the flow line 2. The piston 12 and the valve body 5 are connected by a rod 21. At this time, the valve body 5 is attached to the lower end of the rod 21 so as to be freely movable in the axial direction of the flow line 2. Furthermore, piston 1
A spring seat 17 is attached to the upper surface of the piston 12, an external return spring 18 is disposed between the spring seat 17 and the valve mounting seat 1, and an internal return spring 19 is disposed in the hollow portion of the piston 12.

Next, the operation of the gate valve configured as described above will be explained.

When the flow line 2 is closed, pressure liquid is not supplied to either the first hydraulic chamber 8 or the second hydraulic chamber 14, and the pressure is reduced. The piston 12 automatically rises due to the action of the return springs 18 and 19, and the piston 12
As the piston 12 rises, the valve body 5 connected to the piston 12 also rises while pushing out the ring seat 6. At this time, the ring seat 6 moves toward the opposite side of the valve body without rotating due to the key groove 7a that engages with the key 7, but when the stopper part 7b at the end of the key groove hits the key 7, the ring seat 6 and the ring seat 6 are connected to each other. The seats 6 are wedged together (closed), and the valve body 5 and piston 12 stop rising. Therefore, when the flow line 2 is closed, a large surface pressure acts between the valve body 5 and the ring seat 6 due to the combined wedge force of the return springs 18 and 19, resulting in an extremely good fluid seal (Fig. 3, Figure 4 shows the occlusion state).

Next, when opening the flow line 2, pressure liquid is supplied to the second hydraulic pressure chamber 14 and the return springs 18, 19
The piston 12 and the valve body 5 are lowered against the pressure, and the flow path 4 of the valve body 5 and the flow line 2 are
and match them. The positioning of the valve body 5 when the flow line 2 is opened is carried out by abutting the lower end of the piston 12 against the bottom surface of the outer cylinder 11, or by providing a stopper 20 at a predetermined position below the valve body 5.
The operation of lowering the valve body 5 is performed by the ring seat 6.
This can be done easily since the direction is to unwedge the valve body 5 and the valve body 5. When the valve body 5 is lowered, there is a gap between the ring seat 6 and the valve body 5 because the valve body 5 has a tapered shape, but as shown in FIG. By supplying pressure liquid to the ring seat 6 and sliding the ring seat 6 to bring it into close contact with the valve body 5 and maintaining the supply of pressure liquid, surface pressure between the valve body 5 and the ring seat 6 can be generated and sealed. .

Since the present invention has the above configuration, (i) the slope of the valve body is such that the thickness dimension decreases when the valve body opens, and the hydraulic pressure in the first hydraulic pressure chamber that operates the ring seat is can be lowered, so
Low contact pressure between the valve body and ring seat prevents damage to the contact surface; (ii) During closing operation, the pressure in the first hydraulic chamber is released, so the contact pressure is low and damage to the contact surface is prevented, just as during opening operation. (iii) When the flow line of the valve body is in the open position, the contact surface pressure is maintained by supplying pressure fluid to the first hydraulic pressure chamber, and in the closed position, the wedge due to the tapered shape of the valve body is maintained. (iv) A return spring is provided to slide and bias the valve body to close the flow line, so when the valve is closed, No special pressure is required to slide the valve body. (v) The ring seat is always in close contact with the valve body when the valve is open or closed, so there is no risk of failure or malfunction due to foreign matter entering. , etc. can exhibit excellent effects.

In the above embodiment, the flow line was closed when the valve body and the ring seat were wedged together, but the above effect can also be achieved by providing a flow path in the valve body that opens the flow line when the valve body and ring seat are wedged together. Needless to say.

[Brief explanation of the drawing]

Figures 1 and 2 show conventional gate valves.
The figure is a front view, FIG. 2 is a side view, FIGS. 3 and 4 are gate valves according to the present invention, and FIG. 3 is a front view.
FIG. 4 is a side view, and FIG. 5 is an enlarged explanatory view showing the opening operation state of the flow line. 1 is the valve mounting seat, 2 is the flow line, 4 is the flow path,
5 is a valve body, 6 is a ring seat, 7 is a key, 7a is a keyway, 7b is a stopper part, 8 is a hydraulic chamber, 12
indicates a piston, and 18 and 19 indicate return springs.

Claims (1)

[Claims] 1. It is slidable in the direction of blocking the flow line provided on the valve mounting seat, and has a tapered shape in which the axial thickness of the flow line gradually increases from one end to the other end along the sliding direction. Provide a valve body,
A flow path that can communicate with the flow line is formed at a predetermined position on the thin wall side of the valve body, and the end of the thin wall side of the valve body is freely movable in the direction of the flow line to a piston rod of a hydraulic cylinder for performing the sliding movement. A ring seat is attached to the flow line and forms a part of the flow line on both sides of the valve body, and a ring seat is disposed in close contact with the taper surface of the valve body so as to be slidable in the direction of the center axis of the flow line, and the ring seat and the valve A key is fixed to one side of the mounting seat, and a key groove that engages with the key and extends in the axial direction of the flow line is provided on the other side to restrict rotation of the ring seat, and is formed at the terminal end of the groove of the key. The contact between the stopper part and the key regulates the limit position of movement of the ring seat toward the opposite side of the valve body, and a hydraulic pressure chamber is formed between the ring seat and the valve mounting seat, and the hydraulic pressure chamber and the hydraulic pressure source are connected. The ring seat is configured to be press-fittable to the valve body by communicating with the valve body, and the wall thickness of the flow line portion increases, and the ring seat moves to the movement limit position to close the flow line. A gate valve characterized by being equipped with a return spring for slidingly biasing the gate valve.