JP2510263Y2 - Fluid isolation valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a fluid isolation valve, and more particularly to a fluid isolation valve suitable for controlling a vapor flow by a piston type valve body.

[Conventional technology]

Generally, a valve element of MSIV type is known as a fluid isolation valve.

As shown in FIG. 5, this valve body has a first piston 50
And the second piston 51 are connected to each other with an annular groove 52 in between, and a guide rib made of wear-resistant metal is provided at the end of the second piston 51.
53 is bulged.

Therefore, when the valve body slides along the valve body sliding portion of the fluid flow path, the valve body slides back and forth while being guided by the guide ribs 53, so that the valve opening / closing operation can be smoothly performed.

[Problems to be solved by the device]

However, in the case of the conventional isolation valve as described above, since the guide rib 53 is formed of a wear resistant metal,
When the valve body is in the valve open position and the valve body vibrates due to the steam flow or the vibration of the pipe due to the operation of the plant, as shown in FIG. Since it comes into pressure contact with, the rectangular recess 55 may be formed on the wall surface of the valve body sliding portion 54.

Therefore, when the valve body closes when the rectangular recess 55 is formed on the wall surface of the valve slide portion 54 as described above, the guide rib 53 falls into the recess 55, and the valve closing operation cannot be performed smoothly. There are cases.

An object of the present invention is to provide a fluid isolation valve capable of smoothly performing a valve closing operation even if a recess is formed in a valve body sliding portion due to contact of the valve body.

[Means for solving the problem]

In order to achieve the above-mentioned object, the present invention forms a valve seat on the inner wall surface of a fluid flow path, and forms a valve body sliding portion adjacent to the valve seat, and a fluid flow is achieved by contact with the valve seat. A valve body having a first piston that closes the passage and a second piston connected to the first piston with an annular groove in between is slidably inserted into the valve body sliding portion, and the second piston is a cylinder. An annular guide rib, which is connected to the cylinder via a rod and is in contact with the wall surface of the valve body sliding portion, is formed at both axial end portions of the second piston so as to bulge out, and the guide rib on the first piston side of the guide rib is formed. A taper portion having a gradually smaller diameter on the annular groove side is formed, and the minimum diameter of the taper portion is smaller than the diameter of the first piston.

[Action]

Since the present invention has the above-described structure, the guide rib formed on the second piston forming the valve body has a taper portion on the annular groove side of the guide rib on the first piston side. Even if a concave portion is formed in the valve body sliding portion due to contact with the body sliding portion, the same tapered portion as the guide rib is also formed in this concave portion. Moreover, the minimum diameter of the taper portion formed on the annular groove side of the guide rib on the first piston side is the first
Since the diameter is smaller than the diameter of the piston, the tapered portion does not entirely fall into the recess formed in the valve body sliding portion.

Therefore, when the valve body closes, the guide rib moves along the tapered portion of the recess, and the guide rib can be smoothly closed without being caught in the recess.

〔Example〕

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

In FIG. 1, a valve seat 11 is formed in the center of the inner wall surface of a valve box 10 that constitutes a fluid flow path, and an inlet side guide rib 12 as a valve body sliding portion is formed adjacent to the valve seat 11. Has been done.

The main steam is the inlet port 13 and the inlet side guide rib 1
2, and is discharged from the outlet port 14 via the valve seat 11.

A valve body 15 is slidably inserted into the inner peripheral side of the inlet side guide rib 12.

The valve body 15 has a first piston 16 that closes a fluid flow path by contact with a valve seat 11, and a first piston 16 with an annular groove 17 interposed therebetween.
A second piston 18 connected to 16 is provided, and the second piston 18 is connected to an oil cylinder 20 via a valve rod 19 as a cylinder rod.

The oil cylinder 20 is connected to the air cylinder 21, and when the air cylinder 21 is activated by an operation command from the control panel 22, the oil cylinder 20 moves to the valve rod 19.
It is designed to reciprocate.

The air cylinder 21 and the oil cylinder 20 include a spring 23, a spring guide 24, an air cylinder support shaft 25,
The valve cover 27 is fixed to the valve lid 27 while being supported by the spring seat 26, and the valve lid 27 is fixed to the valve box 10 by bolts 28.

In addition, the stanchion plate 2 is provided in the second piston 18.
9 and pilot spring 30 are stored,
A pilot hole 31 is formed in the center of the first piston 16.

As shown in FIGS. 2 and 3, the second piston 18 is formed with swelling guide ribs 32 and 33 at both axial end portions of the second piston 18, which are capable of contacting the inlet guide ribs 12. .

The guide ribs 32 and 33 are made of wear-resistant metal, and one of the guide ribs 32 and 33 has a tapered portion 34.

That is, on the annular groove 17 side of the guide rib 32, the annular groove
A taper portion 34 is formed whose diameter gradually decreases on the 17 side.

The diameter φA of the tapered portion 34 on the tip side is set to be smaller than the diameter φB of the first piston.

In the above structure, when the valve body 15 vibrates due to the steam flow or the vibration of the valve box 10 when the valve body 15 is in the valve opening position, the inlet side guide rib 12 has a recessed portion as shown in FIG. 35 are formed.

However, the recess 35 has the same shape as the outer shape of the guide rib 32, and the tapered portion 36 is formed on the valve seat 11 side of the recess 35. Therefore, when the valve body 15 closes from the open position,
The guide rib 32 can smoothly shift to the valve closing operation without being caught in the recess 35.

[Effect of device]

Since the present invention is configured as described above, according to the present invention, the guide rib on the first piston side of the guide ribs provided on the second piston forming the valve body is formed with a taper portion so that the valve body slides. By making contact with the portion, a recess having the same shape as the guide rib is formed in the valve body sliding portion. In this case, since the diameter of the first piston is larger than the minimum diameter of the taper part, the concave part formed by the taper part has a larger minimum diameter part than the taper part minimum diameter part. As a result, even if the guide rib falls into the recess, it does not get caught and the valve closing operation can be performed smoothly.
This has the effect that the valve closing operation can be smoothly performed even if the valve body sliding portion is worn.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of a main steam isolation valve showing an embodiment of the present invention, FIG. 2 is a plan view of a valve body, FIG. 3 is an enlarged view of a main part of the valve body, and FIG. 4 is an inlet side guide rib. FIG. 5 is an enlarged view of an essential part of a conventional valve body, and FIG. 6 is a sectional view of an essential part of a conventional guide rib on the inlet side. 10 …… Valve box 11 …… Valve seat 12 …… Inlet guide rib 13 …… Inlet port 14 …… Outlet port 15 …… Valve body 16,50 …… First piston 17,52 …… Annular groove 18,51 …… 2nd piston 19 …… Valve 20 …… Oil cylinder 21 …… Air cylinder 22 …… Control panel 23 …… Spring 24 …… Spring guide 25 …… Air cylinder support shaft 26 …… Spring seat 27 …… Valve lid 28 ...... Bolt 29 ...... Stantion plate 30 ...... Pilot spring 31 ...... Pilot hole 32, 33, 53 …… Guide rib 34 …… Tapered part 35, 55 …… Concave 36 …… Tapered part 54 …… Valve sliding part

Claims (1)

(57) [Scope of utility model registration request] 1. A valve seat formed on an inner wall surface of a fluid passage, a valve body sliding portion being formed adjacent to the valve seat, and the fluid passage being closed by contact with the valve seat. A valve body (15) having a piston (16) and a second piston (18) connected to the first piston (16) with an annular groove (17) in between is slidably inserted into the valve body sliding portion. Wear the second piston (18)
Is connected to the cylinder through a cylinder rod, and the second
Annular guide ribs (32, 33) that can come into contact with the wall surface of the valve body sliding portion are bulged at both axial ends of the piston (18), and the first piston (16) of the guide ribs (32, 33) is formed. )
A tapered portion (34) having a gradually smaller diameter on the annular groove (17) side is formed in the side guide rib (32), and the minimum diameter (φA) of the tapered portion (34) is set to the diameter (φB) of the first piston (16). A fluid isolation valve characterized by having a smaller diameter than