JP2531880Y2 - Abnormal pressure absorption device for ball valve - Google Patents

Description

[Detailed description of the invention] Purpose of the invention (industrial application field) The present invention is mainly mounted on a floating ball type ball valve, and the cavity between the body and the ball in the open state and the closed state. The present invention relates to an abnormally pressurized absorption device for preventing a liquid contained in a container from expanding due to a subsequent rise in temperature and abnormally increasing the pressure of a cavity to damage or deform a sheet, a body, a ball, a stem packing and the like.

(Prior art and its problems) In a valve having a structure in which seats are mounted on both sides of a ball as a closing member, such as a floating ball type ball valve, and sealing is performed at these two places, an upstream side and a downstream side are used. A chamber, that is, a cavity, is isolated from the flow path. In a ball valve, this cavity is also formed in the valve-opened state shown in the longitudinal sectional view of FIG.

If the liquid is a liquid, the liquid enclosed in this cavity expands with a subsequent rise in temperature. However, there is no place to accommodate this increased volume of liquid, so the pressure in the cavity rises sharply. This phenomenon is called abnormal pressure increase.

When this abnormal pressure rise occurs, the seat is pushed into the flow path, the body or ball is deformed, the body assembly bolt is stretched, the stem packing or the body gasket is damaged, and the function of the valve is lost or lost. Decrease.

In order to prevent such undesirable phenomena, conventionally, the following measures have been taken.

One is to provide a lip portion 21a on a part of the seat 21 as shown in the enlarged partial longitudinal sectional view of FIG. 4, and the lip portion 21a separates from the ball 23 when the cavity 22 is abnormally pressurized. It was made into an easy shape.

This structure can be used in either the valve open state or the valve closed state, but there are some difficulties in reliably preventing abnormal pressure rise at the set pressure.

The next countermeasure is to form a passage hole 23b in the ball 23 connecting the ball flow path 23a and the cavity, as shown in the vertical sectional view of the ball in FIG.

In this method, when the valve is open, the cavity communicates with the flow path, and abnormal pressure rise does not occur. However, when the valve is closed, the ball flow path 23a also becomes a part of the cavity, so that there is a problem that abnormal pressure rise occurs. doing.

As shown in the vertical sectional view of the ball in FIG.
There is a method of providing b. With this method, communication between the cavity and the flow path is performed in both the open state and the closed state, and abnormal pressure increase can be prevented. However, in the valve closed state, the passage hole 23
If b is communicated to the downstream side, it must be sealed with the upstream seat.In general, it is difficult to seal the floating ball valve on the upstream side, so the passage hole 23b communicates with the upstream side in the closed state. However, there is a problem that it is difficult to surely do so without misuse, and it cannot be used for applications in which the high pressure side fluctuates.

The device for preventing abnormal pressure rise of a ball valve according to the present invention is intended to solve all of the problems of the prior art.

Configuration of the Invention (Means for Solving the Problems) The abnormal pressure increase absorption device for a ball valve of the present invention is an abnormal pressure increase absorption device that is attached to the body of the ball valve to absorb the abnormal pressure increase of the cavity. The pressurized pressure absorption device inserts a piston fitted with packing on the outer peripheral surface into a cylinder-shaped main body, one side of this piston communicates with the cavity, and the other side is resilient by a spring mounted inside the main body. Then, a rod-shaped indicator provided on the other side of the piston was movably provided through the main body.

Also, a spike is attached between the cap and the cap screwed to the body, and this sprung one side of the piston,
In addition, the indicator is provided movably by penetrating the cap.

(Operation) Since the abnormal pressure-absorbing device for a ball valve of the present invention is configured as described above, one side of the piston of the abnormal pressure-absorbing device is in communication with the cavity. The spring is compressed to move to a position where the cavity pressure and the spring force of the spring are balanced.

When the pressure inside the cavity rises abnormally due to the temperature rise, the piston compresses the sprung and moves further,
The volume of the fluid increased by the heat of expansion in the cavity is accommodated to prevent abnormal pressure rise in the cavity.

In this case, the packing attached to the outer peripheral surface of the piston is
When a ring is used, the sealing performance is good, and there is no leakage of the fluid to the sprung portion and no leakage of the fluid from the abnormally pressurized absorption device.

Also, since the bar-shaped indicator fixed to the other side of the piston protrudes outward through the cap,
The pressure state in the cavity can be known from the protruding state of the indicator. In this case, it is convenient to know the degree of the pressure by properly inserting the score line of the indicator.

In addition, since the cap of the present abnormal pressure rise absorption device is screwed to the main body, the resilience of the spring can be adjusted depending on the degree of screwing, and it is preferable to use the cap by adjusting according to the normal pressure of the fluid. .

Further, since the degree of freedom in the design and setting of the seat is not impaired at all, a suitable seat can be mounted, and the directivity of the valve is not affected at all, so that abnormal pressure increase can always be reliably absorbed.

It should be noted that this abnormal pressure absorption device can be used for other valves such as a gate valve.

(Embodiment) FIG. 1 is a longitudinal sectional view of a ball valve equipped with an embodiment of the abnormal pressure-absorbing device of the present invention.

In FIG. 1, 1 is a ball valve, 2 is an abnormally pressurized absorption device, 3 is a bolt of the ball valve 1, and the abnormally pressurized absorption device 2 is screwed into a female screw hole 3 b communicating with a cavity 3 a of the bottom 3. It is attached.

4 is a cylinder-shaped main body, 5 is a piston, 6 is an O-ring type packing, 7 is a cap, 8 is a splicer, 9 is a rod-shaped indicator, and is a packing groove 5b formed on the outer peripheral surface 5a of the piston 5. Packing 6 is mounted, piston 5 is inserted into body 4, one side 5c of piston 5 is in communication with cavity 3a.

Further, the cap 7 is screwed into the main body 4, and the other side 5 d of the piston 5 is repelled by the ridge 8 mounted between the piston 5 and the cap 7.

Furthermore, a score line 9a is formed in the shape of a bar, and the indicator 9
However, it is fixed to the piston 5 through the cap 7.

10 is a ball, 11 is a seat, 12 is a stem, 13 is a lever handle, and the ball valve 1 is a lever handle 13
Is operated to rotate the ball 10 via the stem 12 to open and close.

FIG. 2 is a longitudinal sectional view showing another embodiment of the abnormal pressurizing absorption device of the present invention. In this abnormal pressurizing device 2, the piston 5 is inserted into the threaded portion 4a of the main body 4, and the abnormal pressurizing absorption device is used. An extra pool is not created in the device 2.

Next, the operation will be described based on the embodiment shown in FIG.

Since one side 5c of the piston 5 of the abnormally pressurized absorption device 2 communicates with the cavity 3a, the piston 5 compresses the firing 8 according to the pressure of the cavity 3a,
It has moved to a position where the pressure of 3a and the resilience of spring 8 are balanced.

When the pressure in the cavity 3a rises abnormally due to the temperature rise, the piston 5 compresses the sprung 8 and moves further, so that the volume of the fluid increased by the thermal expansion in the cavity 3a is accommodated therein. Prevent abnormal pressure rise.

In this case, since the packing 6 mounted on the packing groove 5b formed on the outer peripheral surface 5a of the piston 5 is formed into an O-ring shape, the sealing performance is excellent, and the leakage of fluid to the sprung portion and the abnormal pressurization preventing device 2 No fluid leakage.

Further, since the rod-shaped indicator 9 fixed to the other side 5d of the piston 5 projects outward through the cap 7, it is possible to know the pressure state in the cavity 3a by the projected state of the indicator 9. Can be. Since the indicator 9 is provided with a score line 9a as appropriate, it is convenient to know the degree of pressure.

In addition, since the cap 7 of the abnormal pressure-boosting absorber 2 is screwed to the main body 4, the elasticity of the spring 8 can be adjusted according to the degree of screwing. Good.

Furthermore, since the degree of freedom in the design and selection of the seat 11 is not impaired at all, a suitable seat 11 can be mounted, and the directionality of the valve 1 is not affected at all, and abnormal pressure increase can always be reliably absorbed. .

Further, when the liquid pool is almost eliminated as in the abnormal pressure rise prevention device 2 shown in FIG. 2, a trouble due to the liquid pool can be prevented.

It should be noted that this abnormal pressure absorption device can be used for other valves such as a gate valve.

Effects of the Invention Since the present invention is configured and operates as described in detail, the following excellent effects can be obtained.

Abnormal pressurization can be completely absorbed and prevented.

Since a degree of freedom in seat design and selection is not impaired, a suitable seat can be mounted.

Has no effect on the direction of the valve.

The state of the pressure in the cavity can be known from the protruding state of the indicator.

By adjusting the degree of screwing of the cap, the elasticity of the spring can be adjusted, and the liquid can be used in an optimum state according to the normal pressure of the liquid.

There is no leakage from this abnormal pressurization absorption device.

It can be applied to other valves.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view of a ball valve equipped with an embodiment of the abnormal pressure-absorbing device of the present invention, and FIG. 2 is a vertical sectional view showing another embodiment of the abnormal pressure-absorbing device of the present invention. . FIG. 3 is a longitudinal sectional view showing an open state of the floating ball type ball valve, and FIGS. 4, 5, and 6 are views each showing a conventional measure for preventing abnormal pressure increase. FIG. 4 is an enlarged partial longitudinal sectional view when a seat having a lip is formed, and FIGS. 5 and 6 are longitudinal sectional views of a ball provided with a passage hole communicating with a cavity. DESCRIPTION OF SYMBOLS 1 ... Ball valve, 2 ... Abnormal pressure absorption device 3 ... Body, 3a ... Cavity 4 ... Body, 5 ... Piston 5a ... Outer peripheral surface, 5c ... One side 5d ... The other side , 6 ... Packing 7 ... Cap, 8 ... Spring 9 ... Indicator

Claims (2)

(57) [Scope of request for utility model registration] 1. An abnormally pressurized absorption device mounted on a body of a ball valve to absorb abnormally pressurized cavities. The abnormally pressurized absorption device includes a piston having a packing mounted on an outer peripheral surface in a cylindrical main body. Inserting, one side of this piston communicates with the cavity, the other side is repelled by a spike mounted inside the main body, and the rod-shaped indicator provided on the other side of the piston penetrates the main body. An abnormal pressure-absorbing device for a ball valve, which is movably provided. 2. A sprocket is mounted between the cap and a cap screwed to the main body, and the sprung one side of the piston, and the indicator is movably provided through the cap. Abnormal pressure increase absorption device of ball valve.