JP3796243B2 - Vent valve structure for liquid storage tank vent pipe - Google Patents

Description

  The present invention relates to a structure of a vent valve incorporated in a vent pipe connected to a liquid storage tank.

  A liquid storage tank installed in the basement of a gas station is connected to a vent pipe for releasing internal gas to prevent an increase in internal pressure. The vent pipe is raised from the ground to a certain height and gas is To be released. The vent pipe is also provided with a branch portion for collecting the gas inside the liquid storage tank, which is released when unloading from the tank lorry vehicle to the liquid storage tank, to the tank lorry vehicle side.

  FIG. 8 is a schematic view showing the connection between such a vent pipe and a tank lorry vehicle. A gas recovery hose 52 is connected to a branch 51 provided in the vent pipe 50 raised from an underground liquid storage tank, The hose 52 is connected to a gas recovery device at the upper end of the tank of the tank truck 53.

  As described above, when unloading from the tank truck 53, the gas is collected to the tank truck 53 side by the hose 52. At this time, since it is necessary to prevent the gas from being released from the upper end of the vent pipe 50, it has been usual that the vent pipe 50 has a built-in vent valve 54 for automatically closing the flow path when unloading. It is.

  As the vent valve 54, the applicant of the present application previously described in Patent Document 1 is provided with an umbrella-shaped valve body that closes the flow path in response to an increase in internal pressure during unloading, and gas in the liquid storage tank is supplied to the tank lorry vehicle 53. Disclosed is a valve structure that discharges only to the side and stops the discharge from the upper end of the vent pipe 50. In addition, this valve structure incorporates a valve mechanism that works in conjunction with the umbrella-shaped valve body, and in the event of an abnormal pressure increase in the liquid storage tank, the flow path is instantly opened and gas is released. It becomes the composition to discharge.

  Further, the applicant of the present application stores the valve structure of Patent Document 1 in a valve casing so that the maintenance and inspection of the ventilation valve can be easily performed. Patent Document 2 discloses a vent valve having a configuration in which it can be freely inserted into and removed from a housing incorporated in a passage.

  However, the above vent valve is based on the assumption that a gas recovery device is mounted on a tank truck, and if an attempt is made to unload liquid in a tank truck that is not equipped with a gas recovery device, At this time, the vent valve is closed and the gas in the liquid storage tank is not discharged to the outside, so that unloading cannot be performed at all.

  In this case, the tanker truck must return to the oil tank station, etc. with the liquid loaded, and then return to the tanker truck equipped with a gas recovery facility at a later date, resulting in a significant loss in both time and labor costs. .

In addition, he dislikes this loss, so that the lorry driver forcibly unloads the gas recovery hose 52 is connected only to the branch pipe 51 side of the vent pipe 50 and the other end of the hose 52 is left on the driveway. In some cases, it may be mishandled, for example, by discharging gas from there, and in this case, a fire accident may occur, which is extremely dangerous.
Japanese Patent Publication No.55-29878 Japanese Patent No. 3045466

  The problem to be solved by the present invention is to provide a vent valve structure for a liquid storage tank vent pipe that enables safe unloading even in a tank truck equipped with no gas recovery device. is there.

  In order to solve the above-described problems, the present invention provides a valve body of a vent valve that opens and closes a flow path according to the state of unloading to a liquid storage tank when unloading with a tank truck equipped with a gas recovery device. When unloading with a tanker truck that is in a normal operating state and does not have a gas recovery device installed, the valve body is gas-recovered so that the valve body of the vent valve is in a fixed state that always opens the flow path. Switching is possible depending on whether or not the device is installed.

That is, the present invention is incorporated in the middle of the vent pipe connected to the liquid storage tank and downstream of the branch portion connecting the gas recovery hose to the tank lorry vehicle, and unloading the liquid storage tank. In a vent valve structure for a liquid storage tank vent pipe having a vent valve having a valve body that opens and closes a flow path according to a state, the valve body operates to open and close the flow path according to an unloading state of the liquid storage tank Switching means for switching between a state and a fixed state in which the valve body is always opened without closing the flow path, and when unloading with a tank truck equipped with a gas recovery device, operates by the switching means In the case of unloading with a tank lorry vehicle that is not equipped with a gas recovery device, it is characterized in that it is fixed by the switching means .

  In this configuration, the switching unit may include an operation unit for switching between the operating state and the fixed state, and a drive unit coupled to the operation unit. When the operation unit is positioned on the operating state side, the drive unit is positioned at a position where it does not interfere with the valve body, and when the operation unit is positioned on the fixed state side, the drive unit is positioned on the valve body. The valve body can always be opened by interfering with. Here, it is preferable that the operation portion is provided at a position where it can be operated from the outside of the vent valve.

  Further, as another means for solving the above-mentioned problems, the present invention provides a bypass pipe that bypasses the vent valve in the vent pipe, and is used for unloading with a tank truck equipped with a gas recovery device. When unloading using a tank lorry vehicle that is not equipped with a gas recovery device, the gas from the liquid storage tank can be bypassed by opening the bypass pipe when the pipe is closed and unloading is performed using the ventilation valve as usual. It can be discharged from the vent pipe at any time via the pipe.

  That is, the present invention is incorporated in the middle of the vent pipe connected to the liquid storage tank and downstream from the branch portion connecting the gas recovery hose to the tank lorry vehicle, and unloading to the liquid storage tank. In a vent valve structure for a liquid storage tank vent pipe having a vent valve having a valve body that opens and closes a flow path according to a state, the vent pipe structure includes a bypass pipe that bypasses the vent valve, and an upstream end portion of the bypass pipe is It is connected to a vent pipe between the branch portion and the vent valve, and an end on the downstream side is connected to a vent pipe downstream from the vent valve, and the pipe line is provided in the middle of the bypass pipe. An on-off valve that opens and closes is provided.

  According to the present invention, it is possible to unload even a tank truck equipped with no gas recovery device. Therefore, there is no need to re-delivery with a tank truck equipped with a gas recovery device as in the prior art, and there is no loss related to time and labor costs.

  Also, when unloading with a tank truck equipped with no gas recovery device, the gas from the liquid storage tank can be released from the vent pipe, so that the gas is released to the driveway by incorrect handling as before. Safety is greatly improved.

  Embodiments of the present invention will be described below based on examples shown in the drawings.

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

  In the figure, the vent valve 10 is in the middle of the vent pipe rising from the liquid storage tank and is connected to the gas recovery hose (downstream side) in the same manner as described above with reference to FIG. Built in. That is, a flange 11a is integrally provided at the lower end of the housing 11 of the vent valve 10, and an internal thread 11b is formed at the inner periphery of the upper end, and upper and lower vent pipes 50a, 50b are connected to the pipes, respectively. ing.

  The housing 11 has an opening on the front side, and the opening is closed by a removable lid 12. The lid 12 is connected in a watertight manner by a packing 12b covering an end surface around the opening.

  As shown in FIG. 3, a cartridge type valve casing 13 is incorporated in the housing 11 so as to be freely inserted and removed from the opening. The valve casing 13 is a hollow cylindrical body having an outer diameter substantially equal to the inner diameter of the inner peripheral wall of the housing 11, and in which the valve element is integrally stored, and annular packings 13a, 13b is attached and it is incorporated in the housing 11 in a watertight manner.

  The valve element in the valve casing 13 is the same as that described in Patent Document 1 mentioned in the background section, and an umbrella-like valve body 14 is provided on a rod 14a fixed in the axial direction so as to be movable up and down. In addition, a valve body receiver 15 on which the lower end of the valve body 14 is seated is incorporated in the inner periphery of the lower end side of the valve casing 13. An annular valve seat 16 for a safety valve is coaxially arranged above the valve body 14 and is urged downward by a compression spring 17, and a valve hole 16a opened in the valve seat 16 is used for degassing. This is a flow path.

  All of these valve elements are incorporated in the valve casing 13 as a unit in advance, and the valve casing 13 can be inserted into and removed from the housing 11 in a cartridge manner.

  Further, the vent valve 10 has a switching means for switching between an operating state in which the valve body 14 opens and closes the flow path in response to fluctuations in the internal pressure of the liquid storage tank and a fixed state in which the valve body 14 always opens the flow path. 20 is provided.

  The switching means 20 includes a switching knob 21 as an operation unit and a set arm 22 as a driving unit connected to the switching knob 21. The switching knob 21 is attached to the outside of the lid 12 of the housing 11, and the lid 12 is provided with stopper pins 23 a and 23 b that define the switching position of the switching knob 21. As shown later in FIG. 4, the set arm 22 is formed in an L shape in which a distal end portion 22 a is bent, and is disposed so that the distal end portion 22 a is positioned above the valve body 14. The switching means 20 including the switching knob 21 and the set arm 22 is rotatably attached to the housing 11 via a set spring 24 and an oil seal 25.

  FIG. 4 is a longitudinal sectional view and a plan view of the main part taken along line B-B in FIG. 3, and shows the operation of the switching means 20. 4A and 4B, the upper side is a plan view and the lower side is a cross-sectional view.

  As shown in FIG. 4A, when the switching knob 21 is positioned on the lorry collection side (see FIG. 1), the tip portion 22a of the set arm 22 becomes horizontal and does not hinder the vertical movement of the valve body 14. That is, it is located at a position where it does not interfere with the valve body 14. Therefore, this state is an operating state in which the valve body 14 moves up and down in accordance with the internal pressure fluctuation of the liquid storage tank to open and close the valve hole 16a of the valve seat 16, that is, the flow path.

  On the other hand, as shown in FIG. 4B, when the switching knob 21 is rotated to the atmospheric discharge side (see FIG. 1), the set arm 22 is also rotated and the tip end portion 22 a contacts the valve body 14. . In this state, even if the internal pressure of the liquid storage tank rises, the valve body 14 cannot rise any further, and the valve hole 16a of the valve seat 16 is always in a fixed state in which it is open.

  In the above configuration, when unloading with a tank truck equipped with a gas recovery device, the valve element 14 is brought into the above-described operating state by the operation of the switching knob 21. As a result, when unloading, the pressure in the liquid storage tank also rises due to the gas pressure from the tank truck, so that the valve body 14 rises to a position where it closes the valve hole 16a and the release of gas from the vent pipe 50b is blocked. The gas is recovered by the gas recovery device of the tank truck. When the internal pressure in the liquid storage tank rises abnormally during unloading, the valve seat 16 also rises due to the internal pressure, and the pressure in the liquid storage tank can be released to the atmosphere.

  On the other hand, when unloading with a tank truck equipped with no gas recovery device, the valve element 14 is brought into the above-described fixed state by operating the switching knob 21. As a result, the valve hole 16a is always open, so that the gas from the liquid storage tank is released to the atmosphere through the vent pipe 50b. Therefore, even a tank truck equipped with no gas recovery device can be normally unloaded. As means for operating the switching knob, automatic operation using air, electricity, or the like can be performed.

  FIG. 5 is a longitudinal sectional view showing a vent valve structure according to a second embodiment of the present invention. The vent valve structure of the present embodiment is different from the first embodiment only in the switching means, and the other configurations are the same. Therefore, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. Omitted.

  The switching means 30 of the present embodiment includes a shaft gripping portion 31 as an operation portion and a switching shaft 32 as a drive portion connected integrally with the shaft gripping portion 31. The shaft gripping portion 31 is exposed and attached to the outside of the lid 12 of the housing 11. The switching means 30 including the shaft gripping portion 31 and the switching shaft 32 is attached to the housing 11 via an oil seal 33 so as to be able to advance and retract.

  FIG. 6 is a schematic longitudinal sectional view of the main part showing the operation of the switching means 30.

  As shown in FIG. 6A, when the shaft gripping portion 31 is operated to retract the switching shaft 32, the switching shaft 32 also retracts and does not interfere with the vertical movement of the valve body 14, that is, does not interfere with the valve body 14. Located in position. Therefore, this state is an operating state in which the valve body 14 moves up and down in accordance with the internal pressure fluctuation of the liquid storage tank to open and close the valve hole 16a of the valve seat 16, that is, the flow path.

  On the other hand, as shown in FIG. 6B, when the shaft gripping portion 31 is operated to advance the switching shaft 32, the tip of the switching shaft 32 comes into contact with the valve body 14. In this state, even if the internal pressure of the liquid storage tank rises, the valve body 14 cannot rise any further, and the valve hole 16a of the valve seat 16 is always in a fixed state in which it is open.

  As described above, it is possible to switch between the operating state and the fixed state of the valve body 14 also by the switching means 30 of the present embodiment, and the gas recovery device is mounted as in the case of the first embodiment. When unloading with a tank lorry vehicle, the valve body 14 is activated by the switching means 30, and when unloading with a tank lorry vehicle not equipped with a gas recovery device, the valve body 14 is fixed with the switching means 30. Use as As a result, even a tank truck equipped with no gas recovery device can be unloaded normally. Automatic operation using air, electricity, or the like can also be performed as means for operating the switching shaft.

  FIG. 7 is a front view showing a vent valve structure according to a third embodiment of the present invention.

  In FIG. 7, the vent valve 10 has the same configuration as that of the first and second embodiments except that no switching means is provided, and is in the middle of the vent pipe 50 set up from the liquid storage tank and collects gas. It is incorporated above (downstream side) a branch part (not shown) for connecting the hose for use.

  In this embodiment, a bypass pipe 40 that bypasses the vent valve 10 is provided in the vent pipe 50. The upstream end of the bypass pipe 40 is connected to the vent pipe 50a between the above-described branch (not shown) and the vent valve 10, and the downstream end is downstream of the vent valve 10. It is connected to the vent pipe 50b. In the middle of the bypass pipe 40, an on-off valve 41 for opening and closing the pipe line is provided.

  In the above configuration, when unloading with a tank truck equipped with a gas recovery device, the on-off valve 41 is closed and the bypass pipe 40 is closed. As a result, the vent valve 10 operates normally, and as described above, the pressure in the liquid storage tank also rises due to the gas pressure from the tank lorry vehicle during unloading, so the valve body 14 as shown in FIG. Rises to a position where it closes the valve hole 16a, and the release of the gas from the vent pipe 50b is blocked, and the gas is recovered by the gas recovery device of the tank truck.

  On the other hand, when unloading with a tank truck equipped with no gas recovery device, the on-off valve 41 is opened to open the bypass pipe 40. Thus, the gas from the liquid storage tank is released from the vent pipe 50b to the atmosphere via the bypass pipe 40 without passing through the vent valve 10. Therefore, even a tank truck equipped with no gas recovery device can be normally unloaded. As the on-off valve, a valve operated by air, electricity, or the like can be used.

  The present invention can be applied to a vent valve incorporated in a vent pipe for exhausting gas from an underground tank installed in a gas station.

It is a front view which shows the vent valve structure of 1st Example of this invention. It is a top view which shows the vent valve structure of 1st Example of this invention. It is a longitudinal cross-sectional view by the AA arrow of FIG. It is the longitudinal cross-sectional view of the principal part by the BB line arrow of FIG. 3, and its top view. It is a longitudinal cross-sectional view which shows the vent valve structure of 2nd Example of this invention. It is a schematic longitudinal cross-sectional view of the principal part which shows operation | movement of the switching means of 2nd Example. It is a front view which shows the vent valve structure of 3rd Example of this invention. It is the schematic which shows the condition which connected between the ventilation pipe and the tank truck with the collection | recovery hose for gas collection | recovery.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Ventilation valve 11 Housing 12 Lid 13a, 13b Packing 14 Valve body 15 Valve body receptacle 16 Valve seat 16a Valve hole 17 Spring 20 Switching means 21 Switching knob (operation part)
22 Set arm (drive unit)
23a, 23b Stopper pin 24 Set spring 25 Oil seal 30 Switching means 31 Shaft gripping part (operation part)
32 Switching shaft (drive unit)
33 Oil seal 40 Bypass pipe 41 Open / close valve 50 Vent pipe 50a Upstream vent pipe 50b Downstream vent pipe 51 Branching portion 52 Gas recovery hose 53 Tank truck 54 Ventilation valve

Claims (3)

In the middle of the vent pipe connected to the liquid storage tank, it is incorporated downstream from the branch section connecting the gas recovery hose between the tank and the tank truck, and the flow path according to the unloading state to the liquid storage tank In a vent valve structure for a liquid storage tank vent pipe provided with a vent valve having a valve body for opening and closing
A switching means for switching between an operating state in which the valve body opens and closes the flow path according to an unloading state to the liquid storage tank and a fixed state in which the valve body always opens without closing the flow path ; When unloading with a tanker truck equipped with a gas recovery device, it should be activated by the switching means, and when unloading with a tanker truck without a gas recovery device, it should be fixed with the switching means. vent valve structure for a liquid storage tank vent pipe, characterized in that the. When the switching means includes an operation unit for switching between the operation state and the fixed state, and a drive unit coupled to the operation unit, and the operation unit is positioned on the operation state side, When the drive unit is located at a position where it does not interfere with the valve body, and the operation unit is located on the fixed state side, the drive unit interferes with the valve body and always opens the valve body without closing. The vent valve structure for a liquid storage tank vent pipe according to claim 1.   The vent valve structure for a liquid storage tank vent pipe according to claim 2, wherein the operation section is provided at a position operable from the outside of the vent valve.

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