JP3045466B2 - Vent valve for underground tank vent pipe - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vent valve incorporated in a vent pipe connected to an underground tank in a gas station to automatically close a passage when internal pressure rises and to collect gas into a tank of a tank truck. About.

[0002]

2. Description of the Related Art A gas pipe is connected to an underground tank of a gas station to discharge internal gas and prevent an increase in internal pressure. The gas pipe is raised from the ground to a certain height to discharge gas. I am trying to do it. The vent pipe is also provided with a coupling for collecting the gas in the underground tank, which is released when unloading from the tank truck into the underground tank, to the tank truck.

FIG. 5 is a schematic view showing the connection between such a ventilation pipe and a tank truck. A gas recovery hose 52 is connected to a coupling 51 provided on a ventilation pipe 50 which is set up from an underground tank. The collection hose 52 is connected to the tank upper end of the tank truck 53.

As described above, the tank truck 53
When unloading from the tank, gas is collected by the collection hose 52 to the tank truck 53 side. At this time,
Since it is necessary to prevent the gas from being released from the upper end of the ventilation pipe 50, a ventilation valve 54 for automatically closing the flow path is usually incorporated in the ventilation pipe 50 at the time of unloading. .

The vent valve 54 is disclosed in, for example, Japanese Patent Publication No. 55-29878.
This is provided with an umbrella-shaped valve body that closes a flow path in response to an increase in internal pressure at the time of unloading. The gas in the underground tank is discharged only to the tank truck 53 and the upper end of the ventilation pipe 50 is opened. It has the function of stopping the release from In addition, by incorporating a valve mechanism that works in conjunction with the umbrella-shaped valve element, when the pressure inside the underground tank rises abnormally, the gas passage is instantaneously opened greatly to release the gas.

[0006]

The vent valve provided in the vent pipe for the gas station, including the one described in the above-mentioned publication, also serves as a joint for connecting the upper and lower vent pipes. Other elements, including the umbrella-shaped valve element, are also incorporated in the two housings that are screwed to the upper and lower ventilation pipes. By screwing these housings together, the ventilation pipe is formed. Will be launched.

However, in such a built-in structure of the ventilation valve, it is necessary to disassemble not only the ventilation valve itself but also the piping of the ventilation pipe when maintaining the internal valve mechanism or replacing parts. This not only increases the time required for maintenance and replacement of parts, but also causes gas to be released from the disassembled vent pipes, creating a dangerous environment around them. It also has a significant effect on gas station operations.

As described above, the conventional vent valve has a problem in that maintenance and replacement of parts such as the valve element are complicated and time-consuming.

The problem to be solved in the present invention is to make it possible to easily perform maintenance and inspection work only by disassembling only a ventilation valve incorporated in a ventilation pipe.

[0010]

SUMMARY OF THE INVENTION The present invention is directed to a branch pipe for connecting a gas recovery hose between a tank of a tank truck and a midway of a vent pipe which is set up from an underground tank for storing gasoline and the like. A vent valve that is incorporated above and has a valve body that opens and closes a flow path according to the internal pressure fluctuation of the underground tank, and the inside of the vent pipe communicates with the internal flow path of the vent pipe. An opening is provided in a peripheral wall of the housing, and a valve casing including a valve element including the valve body is freely inserted into and removed from the housing through the opening, and can be connected to the ventilation pipe. A lid for closing the opening is detachable from the housing.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION A housing having an interior communicating with a flow path of a ventilation pipe is previously incorporated in the piping of the ventilation pipe, so that the valve casing can be detachably operated in a cartridge manner from an opening of the housing. Therefore, when replacing the valve casing, it is not necessary to separate the upper and lower ventilation pipes of the housing, and the operation can be simplified.

[0012]

1 is a front view showing a vent valve according to the present invention, FIG. 2 is a plan view thereof, FIG. 3 is a vertical sectional view taken along line AA of FIG. 1, and FIG. FIG.

In the figure, the housing 1 of the vent valve is shown in FIG.
As shown in (1), it is installed in the middle of the ventilation pipe rising from the underground tank and above the coupling connecting the collection hose. That is, a flange 1a is integrally provided at the lower end of the housing 1, and a female screw 1b is formed at the inner periphery of the upper end.
a and 50b are respectively connected by piping.

As shown in FIG. 4, a part of the peripheral wall of the housing 1 is opened by a substantially rectangular opening 1c, and the chamber 1d inside the opening 1c faces the outside from the opening 1c. A female screw hole 1e is provided along the edge of the opening 1c, and the cover 2 closing the opening 1c can be fixed to the housing 1 with a screw 2a screwed into the female screw hole 1e. The lid 2 is connected in a watertight manner by a packing 2b covering an end surface around the opening 1c.

In the chamber 1d of the housing 1, FIG.
As shown in (1), the cartridge type valve casing 3 is inserted into and removed from the opening 1c. The valve casing 3 is a hollow cylindrical body having an outer diameter substantially equal to the inner diameter of the inner peripheral wall of the chamber 1d, in which a valve element is integrally housed.
a and 3b are attached and installed in the chamber 1d in a watertight manner.

The valve elements in the valve casing 3 are the same as those described in Japanese Utility Model Publication No. 55-29878 described in the section of the prior art, and the umbrella-shaped valve element 4 is attached to a rod 4a fixed in the axial direction. A valve seat 5 on which the lower end of the valve body 4 is seated is incorporated in the lower end side inner periphery of the valve casing 3 while being provided so as to be movable up and down. An annular sub-valve seat 6 for a safety valve is coaxially disposed above the valve body 4 and is urged downward by a compression spring 7 so that a valve hole 6a opened in the sub-valve seat 6 is filled with gas. It is a channel for removal.

These valve elements are all provided in the valve casing 3
And the valve casing 3 can be put in and taken out of the housing 1 in the form of a cartridge. When unloading from the tank truck 53 as shown in FIG. The pressure in the underground tank also increases. Thereby, at the time of unloading, the valve body 4 rises to a position where the valve body 4 closes the valve hole 6a, and discharge of gas from the ventilation pipe 50b is blocked.
When the internal pressure in the underground tank rises abnormally during unloading, the sub-valve seat 6 also receives the internal pressure and rises, so that the pressure in the underground tank can be released to the atmosphere.

The screw 2a has a special specification,
It is preferable that the lid 2 cannot be removed by making it inoperable only by a special tool.

In the above configuration, the valve casing 3
Is housed in a chamber 1d of the housing 1 with all of the valve elements housed therein, and the chamber 1d is shut off from the outside by a lid 2. And the function by the valve element in the valve casing 3 is as described above,
Gas discharge during unloading from the tank truck is cut off.

In the replacement and maintenance and inspection work of the valve element in the valve casing 3, the valve casing 3 can be taken out simply by removing the screw 2 a and removing the lid 2 from the housing 1. Can be replaced with a new one and stored in the chamber 1d. Therefore, conventionally, the ventilation pipes 50a, 50
In contrast to the necessity of separating the piping including b, such an operation is not required at all, and maintenance and inspection can be performed in a short operation time.

[0021]

According to the present invention, since the valve casing can be freely inserted into and removed from the housing incorporated in the middle of the ventilation pipe, the ventilation pipe is disassembled for maintenance and inspection of the valve element and replacement of parts. All you have to do is get the valve casing in and out without any hassle.The shortening of the working time will not hinder the operation of the gas station, and the emission of gas during the work will be kept small, thus maintaining a safe environment. .

[Brief description of the drawings]

FIG. 1 is a front view showing one embodiment of a ventilation valve of the present invention.

FIG. 2 is a plan view of the vent valve of FIG. 1;

FIG. 3 is a longitudinal sectional view taken along line AA of FIG. 1;

FIG. 4 is an exploded perspective view of a housing, a valve casing, and a lid.

FIG. 5 is a schematic diagram showing a state in which a ventilation pipe and a tank truck are connected by a collection hose for gas recovery.

[Explanation of symbols]

 1: Housing 1c: Opening 1d: Chamber 2: Lid 2a: Screw 2b: Packing 3: Valve casing 3a: Packing 3b: Packing 4: Valve body 4a: Valve seat 5: Valve seat 6: Sub-valve seat 6a: Valve hole 50a ： Ventilation pipe 50b ： Ventilation pipe

Claims (1)

(57) [Claims] 1. An underground tank which is installed in a middle of a vent pipe which is set up from an underground tank for storing gasoline and the like and above a branch portion for connecting a gas recovery hose to a tank of a tank truck. A ventilation valve provided with a valve body that opens and closes a flow path in response to an internal pressure fluctuation of the ventilation pipe, wherein the housing includes a housing in which the inside of the ventilation pipe is connected to an internal flow path of the ventilation pipe and is incorporated. An opening is provided in a peripheral wall of the housing, and a valve casing containing a valve element including the valve body can be freely inserted into and removed from the housing through the opening, and can be connected to the ventilation pipe, and a lid for closing the opening is further provided in the housing. Ventilation valve for underground tank ventilation pipe that can be attached to and detached from.