JPS5846317Y2 - Shutoff valve with relief valve - Google Patents

Description

[Detailed description of the invention] The present invention relates to a shutoff valve with a built-in relief valve, and when the outlet side of the shutoff valve becomes higher pressure than the inlet side during shutoff, the fluid on the outlet side can be returned to the inlet side. Since the relief valve is built into the stem of the shutoff valve, there is no need for a separate relief valve, and the fluid can be returned to the inlet side without being wasted into the atmosphere. It is an object of the present invention to provide a shutoff valve that can shut off and communicate fluid passages as a shutoff valve.

The shutoff valve of the present invention can be used for general fluids, but is particularly suitable as a liquid take-off valve installed at the outlet of an LPG tank for automobiles.

As shown in FIG. 5, the conventional shutoff valve installed at the outlet of an automobile LPG tank has an inlet 2 and an outlet 3 opened in a body 1, and a valve seat 4 provided at the back of the inlet 2 that is axially opened. The lower end surface of the stem 40 that advances and retreats comes into contact with the valve seat 4 to block the flow of fluid as shown by arrows A and B. connection, completely blocking fluid flow.

The stem 40 is always urged away from the valve seat 4 by the spring 5, so that the stem 40 is brought into contact with the lower end of the spindle 8 via the diaphragm 6 and the piece 7.

The diaphragm 6 is tightly attached to the body 1 by a gland nut 9 screwed onto the body 1, and the gland nut 9 is provided with a screw 10 for rotating the spindle 8 back and forth, into which the spindle 8 is screwed. ing.

Note that the valve seat 4. Stem 40° piece 7, spindle 8. The gland nuts 9 and the like are arranged on the same axis.

In the conventional shutoff valve described above, the spindle 8 is rotated downward, and the stem 40 is pushed down against the urging force of the spring 5 through the piece 7 and the diaphragm 6, and the seat seal 41 is attached to the valve seat 4. They are brought into contact and crimped to block the fluid passage and prevent the supply of fluid to the outlet 3 side, but in this blocked state, the internal pressure of the pipe on the outlet 3 side may rise due to some reason such as sunlight or heating. If it rises too much, body 1
Since the side is isolated from the atmosphere by the diaphragm 6, there is no means to prevent this pressure increase.

Conventionally, in order to prevent this pressure increase, it was necessary to separately install a relief valve on the outlet 3 side piping, release fluid to the atmosphere by the amount of pressure increase, and reduce the outlet 3 side pressure.

This pressure increase when shutting off the outlet 3 side is particularly important for automotive L
This is likely to occur in the PG supply piping, and when the LPG remaining in the outlet 3 side piping after shutoff expands and vaporizes due to heating,
There is a risk of piping bursting due to increased pressure. Even if a relief valve is installed separately, there is a risk of fire due to vaporized fuel released into the atmosphere.Furthermore, fuel consumption increases due to wasteful release of fuel into the atmosphere. It also contributed to air pollution.

In this invention, a relief valve is built into the stem and the pressurized fuel is discharged back to the inlet 2 side, thereby eliminating the pressure increase valve for the inlet 2 side pressure on the outlet 3 side and preventing the fuel from being released into the atmosphere. It has become possible to
The configuration will be explained below with reference to the drawings.

Although FIG. 1 shows the first embodiment, each structure described below is the same as that of a conventional shutoff valve.

That is, in FIG. 1, an inlet 2 and an outlet 3 are opened in a body 1, and the lower end surface of a stem 11 moving back and forth in the axial direction comes into contact with a valve seat 4 provided at the back of a fluid passage 12 on the side of the inlet 2. An inlet 2 in which fluid flows in the directions shown by arrows A and B.
A structure that blocks the fluid passage 12 and the fluid passage 13 on the outlet 3 side in the example, and a sheet packing 14 on the lower end surface of the stem 11.
is installed and the valve seat 4 and stem 11 are crimped together,
The stem 11 is always urged away from the valve seat 4 by the spring 5, so that the stem 11 is connected to the spindle 8 through the diamond 7 ram 6 and the piece 7. The diaphragm 6 is in close contact with the bow F41 by a gland nut 9 screwed onto the body 1, and the gland nut 9 is provided with a screw 10 for rotating the spindle 80 back and forth. , the configuration in which the spindle 8 is screwed, and the valve seat 4. Stem 11. Piece 7, spindle 8. Each structure in which the gland nuts 9 and the like are arranged on the same axis is tilted in the same way as a conventional shutoff valve.

In the first embodiment of the present invention, as shown in FIG.
It is characterized in that the stem 11 is provided with a relief valve 15.

The discharge side opening 16 of the relief valve 15 passes through the axis of the seat packing 14, is opened at the lower end surface of the stem 11 facing the fluid passage 12 on the inlet 2 side, and is opened in the fluid passage 13 on the outlet 3 side. A communicating opening 17 is formed on the side surface of the stem 11.

A valve body 18 is disposed within the stem 11 at its axial center position. A small spring 20 is provided inside, and the valve body 18 is urged by the small spring 20 in a direction in which the valve head 19 constantly closes the port 16 from the fluid passage 12 side.

The opening 17 is a gap 2 between the side surface of the stem 11 and the body 1.
1, it communicates with a fluid passage 13.

Therefore, even when shut off, the pressure in the fluid passage 13 is transmitted to the opening 16 in the stem 11 and is applied to the inside of the valve head 19, acting as a force that pushes the valve body 18 toward the fluid passage 12.

By appropriately selecting the size of the pressure application area of the valve head 19 on the opening 16 side, the strength of the small spring 200, etc., when the pressure on the fluid passage 13 side rises by a predetermined pressure difference from the pressure in the fluid passage 12, , relief valve 15
The fluid passage 1 can be operated without releasing the fluid under excessive pressure in the fluid passage 13 to the atmosphere.
It can be returned to the second side.

In the second embodiment shown in FIG. 2, only the structure of the relief valve 23 built into the stem 22 differs from the first embodiment, and all other structures of the cutoff valves are the same as in the first embodiment. It's the same.

The relief valve 23 has an opening 25 that passes through the approximate axis of the seat gasket 24 and communicates with the fluid passage 13.
An opening 26 is formed on the lower end surface of the stem 22 and on the side surface of the stem 22, and a cavity 27 is bored approximately at the axis of the stem 22 inside the seat packing 24.
A valve seat 28 is provided at the innermost part of the valve seat 28 and communicates with the opening 26 .

A valve body 29 is installed in the cavity 27 so as to be slidable in the axial direction, and a small spring 30 installed inside the valve body 29 always keeps the valve seat 28
The relief valve 23 of this example has the above-mentioned configuration, so that the pressure on the fluid passage 13 side,
Therefore, the pressure inside the passage 31 causes the valve body 29 to move against the valve seat 28.
A force is applied to the valve body 29 in a direction away from the valve body 29 , while the pressure within the fluid passage 12 and thus the cavity 27 causes the valve body 29 to move away from the valve body 29 .
A force is applied to the valve body 29 in the direction of making it contact the valve seat 28, and at the point when the pressure on the fluid passage 13 side rises by a predetermined pressure difference from the pressure in the fluid passage 12, IJI77
The valve 23 is operated 3, the valve body 29 is separated from the valve seat 28, the fluid passages 12 and 13 are communicated, and the fluid under excessive pressure in the fluid passage 13 can be returned to the fluid passage 12 side.

The pressure difference at which the relief valve 23 should operate can be determined by appropriately selecting the size of the pressure receiving area from the passage 31 on the valve seat 28 side of the valve head 29, the strength of the small spring 30, etc.
In the third embodiment shown in FIGS. 3 and 4, only the structure of the relief valve 33 attached to the stem 32 differs from the first embodiment, and all other structures of the cutoff valve are the same. This is the same as the first embodiment.

The configuration of the relief valve 33 is as follows.

That is, a capillary tube 35 whose lower end is closed protrudes into the fluid passage 12 and extends to the outside of the lower end surface of the stem 32 through the seat packing 34, and extends to the outside of the lower end surface of the stem 32. 32 and communicates with an opening 36 drilled in the side of the stem 32.

As shown in FIG. 4, a relief hole 37 is bored in the side wall of the protruding portion of the thin tube 35 into the fluid passage 12. It is covered with a tube 38 made of an elastic material such as rubber.

In the relief valve 33 of this embodiment, in a normal state where the pressure on the fluid passage 12 side is higher than the pressure on the fluid passage 13 side, or the circumferential pressure is approximately the same, the tube 38 due to its elasticity In this state, the stem 32 functions as a shutoff valve, just like the conventional stem 40 shown in FIG. 5.

Therefore, when the shutoff valve is shut off, that is, when the seat gasket 34 is pressed against the valve seat 4 and communication between the fluid passages 12 and 13 is cut off, the pressure in the fluid passage 13 increases abnormally. When the pressure exceeds the pressure in the fluid passage 12, the pressure in the thin tube 35 communicating with the fluid passage 13 also rises, and the pressure difference between the two fluid passages 12 and 130 causes the inner wall of the tube 38 to pass through the relief hole 37. Acts as a force to bulge outward against the elasticity of the tubule 35. The fluid passages 12 and 13 are communicated through the relief hole 37, and the fluid under excessive pressure in the fluid passage 13 can be returned to the fluid passage 12 side.

The pressure difference at which the relief valve 33 should operate is the pressure difference between the tube 3
It can be obtained by appropriately selecting the elasticity, thickness, length, etc. of No. 8.

The present invention has the structure described in the claims for utility model registration, and by attaching a small relief valve to the stem that operates within the shutoff valve, the body remains unchanged from that of conventional shutoff valves. Therefore, it can be installed in the same location as a conventional shutoff valve, and under normal conditions, where the pressure on the inlet side is lower than the pressure on the outlet side, the operation of the shutoff valve is not obstructed at all, and the outlet In the event of an abnormality where the pressure on the side is higher than the pressure on the inlet side, the relief valve operates to connect the fluid passages on the inlet and outlet sides, and the fluid under excessive pressure on the outlet side is returned to the inlet side. There is no release into the atmosphere and therefore there is no problem of fluid loss, fire risk or air pollution due to fluid release, and there is no leakage outside the isolation valve. This is an excellent invention that does not require a separate relief valve, no extra space for a separate relief valve, and no extra work costs, equipment costs, maintenance costs, etc.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view of the first embodiment, showing a stem partially in longitudinal section, FIG. 2 is an enlarged partial vertical sectional view of the stem of the second embodiment, and FIG. 3 is a longitudinal sectional view of the third embodiment. FIG. 4 is an enlarged vertical cross-sectional view of a portion of the relief valve, and FIG. 5 is a vertical cross-sectional view of a conventional example. 1...Body, 4...Valve seat, 6...
...Diaphragm, 8...Spindle, 9.
...Grand Nut, 11.22,32...
・Stem, 12, 13...Fluid passage, 15, 2
3,33...Relief valve.

Claims (1)

[Scope of utility model registration request] A spindle that rotates up and down in a gland nut screwed into the body presses the stem, which is always urged away from the valve seat, onto the valve seat via the diaphragm, creating a fluid passage from the inlet to the outlet. In a shutoff valve that shuts off, a relief valve that operates only when the pressure on the outlet side of the shutoff valve becomes higher than the pressure on the inlet side, and that communicates the inlet side and the outlet side of the shutoff valve, completely contacts the body. A relief valve material cutoff valve, characterized in that the relief valve material is installed at an axial center position of the stem.