JP4879032B2 - Underground tank vent pipe equipment - Google Patents

Description

  The present invention relates to underground tank vent pipe equipment, and in particular, incorporates a valve mechanism that opens and closes appropriately according to a pressure change inside and outside the underground tank in the middle of the vent pipe connected to the underground tank. The present invention relates to a vent pipe facility for an underground tank that can prevent discharge and maintain the pressure in the underground tank at almost atmospheric pressure.

  For example, in an underground tank buried underground such as a gas station, the air in the upper space is exhausted or supplied as the liquid level rises or falls due to the oil filling operation and the oil sending. The vent pipe is in communication. One end of the vent pipe communicates with the upper space of the underground tank, and the other end is formed to extend upward so as to be opened at a high place (for example, 4 meters above the ground).

  By the way, in recent years, a valve mechanism (atmosphere) that combines an exhaust valve and an intake valve configured to open or close depending on a pressure difference between atmospheric pressure and pressure in the pipe (underground tank pressure) at the upper end opening of the ventilation pipe. There is a vent pipe facility provided with a valve (see Non-Patent Document 1).

When the underground tank becomes pressurized due to the rise in the liquid level of the underground tank caused by unloading or the occurrence of vapor accompanying the rise in temperature, the exhaust valve opens to reduce the tank pressure to atmospheric pressure. Alternatively, when a negative pressure is generated in the underground tank due to the suction of the oil liquid by the pump of the measuring machine, the intake valve is opened to increase the pressure in the underground tank to atmospheric pressure. Therefore, in a state where the liquid level in the underground tank does not fluctuate or in a state where the tank pressure does not fluctuate, the air valve is closed and the vent pipe is closed.
Showa Kikai Kogyo Co., Ltd., trade name, ECO ventilation CO, industry paper, oil industry cooperative organization paper, Zenseki, dated August 25, 2006 (4) New revenue creation ability VOL. 496

  By the way, in the configuration in which the air valve is provided at the upper end (high place) of the ventilation pipe, the work for attaching it and the maintenance work are the high place work. Since it will rise, there is a problem that the burden on the worker is large and a lot of labor is required for the work.

  In addition, when conducting a leak inspection of underground tanks, in order to perform the inspection with the atmospheric valve closed, it is necessary to work at a high place in the same way as described above. There was a problem of requiring labor.

  In view of the above circumstances, an object of the present invention is to provide an underground pipe vent pipe facility that solves the above-described problems.

  In order to solve the above problems, the present invention has the following means.

  The present invention relates to an underground tank, an underground pipe comprising an underground pipe, an air pipe connected to the underground tank and the other end opened to the atmosphere at a high place, and an air pipe joint provided in the middle of the air pipe. A vent pipe joint having a lower end communicating with an upper space of an underground tank and an upper end communicating with the vent pipe extending to a predetermined height above the ground; and a flow of the joint pipe A valve mechanism that is provided in the middle of the road and opens or closes according to a pressure difference between the inside and outside of the underground tank; and a first opening that opens to the side of the joint pipe so that the valve mechanism can be attached and detached. A first lid member that closes the first opening, a second opening that is provided below the first opening and that opens to the side of the joint pipe, and closes the second opening. A second lid member, and providing the vent pipe joint at a position suitable for mounting work. The above-mentioned problems are solved.

  Further, according to the present invention, when performing the leak inspection of the underground tank, after the valve mechanism is taken out from the first opening, the communication in the vertical direction of the flow path is blocked from the first opening into the joint pipe. The above-mentioned problem is solved by mounting a leakage inspection block valve.

  Further, it is desirable that the second opening has a connection part for connecting a pipe for pressurizing or depressurizing the vent pipe when performing a leak inspection of the underground tank.

  In addition, the present invention provides a valve seat in the joint pipe, the leak check closing valve, a valve body that contacts the valve seat, a head that contacts the edge of the upper opening of the joint pipe, One end is fitted into the recess of the valve body, the other end is fitted into the recess of the head, the shaft is moved in the axial direction to press the valve body against the valve seat, and the head And a pressing mechanism that presses the portion against the edge of the upper opening.

  The present invention also relates to an underground tank comprising an underground tank, a vent pipe having one end connected to the underground tank and the other end open to the atmosphere at a high place, and a vent pipe joint provided in the middle of the vent pipe. A tank vent pipe facility, wherein the vent pipe joint has a lower end in communication with the upper space of the underground tank, and an upper end in communication with the vent pipe extending to a predetermined height above the ground, and A valve mechanism that is provided in the middle of the joint pipe and opens or closes according to a pressure difference between the inside and outside of the underground tank, and a first that opens to the side of the joint pipe so as to allow the valve mechanism to be attached and detached. A first lid member that closes the first opening, a second opening that is provided below the first opening and that opens to the side of the joint pipe, and the second opening A second lid member that closes the air pipe, and the vent pipe joint is installed at a position suitable for mounting work. Therefore, when performing the leak inspection of the underground tank, the leak inspection blockage that blocks the communication in the vertical direction of the flow path from the first opening into the joint pipe after the valve mechanism is taken out from the first opening. A valve is attached, and the second opening is provided with a connection portion for connecting a pipe for depressurizing the inside of the vent pipe when performing leak inspection of the underground tank, and the first lid member has The above-described problems are solved by providing a discharge connection portion of the pipe for discharging the sucked gas.

  The present invention also relates to an underground tank comprising an underground tank, a vent pipe having one end connected to the underground tank and the other end open to the atmosphere at a high place, and a vent pipe joint provided in the middle of the vent pipe. A tank vent pipe facility, wherein the vent pipe joint has a lower end in communication with the upper space of the underground tank, and an upper end in communication with the vent pipe extending to a predetermined height above the ground, and A valve mechanism that is provided in the middle of the joint pipe and opens or closes according to a pressure difference between the inside and outside of the underground tank, and a first that opens to the side of the joint pipe so as to allow the valve mechanism to be attached and detached. A first lid member that closes the first opening, a second opening that is provided below the first opening and that opens to the side of the joint pipe, and the second opening A second lid member that closes the air pipe, and the vent pipe joint is installed at a position suitable for mounting work. Therefore, when performing the leak inspection of the underground tank, the leak inspection blockage that blocks the communication in the vertical direction of the flow path from the first opening into the joint pipe after the valve mechanism is taken out from the first opening. A valve is mounted, and the second opening is provided with a connection portion for connecting a pipe for depressurizing the inside of the vent pipe when the underground tank is inspected for leakage, and the joint pipe is inspected for leakage inspection The above problem is solved by providing a pipe discharge connecting portion for discharging the sucked gas at a position above the position closed by the valve and suitable for the mounting operation. It is.

According to the present invention, since the vent pipe joint is provided at a position suitable for the mounting work, when the underground tank is inspected for leakage, the leak inspection block valve is removed after the valve mechanism is taken out from the first opening of the joint pipe. By attaching the valve 1 to the valve seat from the opening of 1, the inspection hose can be easily connected and the pipe communicating between the joint pipe and the underground tank can be easily sealed. By pressurizing the inside of the flow path and the underground tank in a sealed state, it is possible to efficiently perform a leak inspection, and it is possible to reduce the burden on the worker by eliminating the work at a high place as in the past.
Further, according to the present invention, the second opening is provided with a connection portion for connecting a pipe for decompressing the inside of the vent pipe when the underground tank is inspected for leakage, and the first lid member has By providing a pipe connection for discharging the sucked gas, it is possible to easily connect the inspection hose when performing a leak inspection by the decompression method, and to work at a high place as in the past. Eliminating the burden on workers can be reduced.
Further, according to the present invention, the discharge connecting portion is located above the position closed by the leakage check closing valve of the joint pipe, and is provided at a position suitable for mounting work. It is possible to reduce the burden on workers by eliminating the work at such high places.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  FIG. 1 is a configuration diagram showing an embodiment of an underground pipe vent pipe facility according to the present invention. As shown in FIG. 1, the vent pipe facility 10 is attached at a height suitable for an attachment operation in the middle of the vent pipe 30 communicated with the upper space of the underground tank 12. Since the vent pipe joint 40 is provided in the middle of the path of the vent pipe 30 for venting (supplying and exhausting) the underground tank 12, for example, an underground installed in a gas station using the pressure monitoring unit 11 After the nitrogen gas is supplied to the tank 12 and pressurized to a predetermined pressure, the presence or absence of leakage can be determined based on the presence or absence of pressure change or the rate of pressure change.

  The pressure monitoring unit 11 includes a compressor for generating nitrogen gas (not shown), a pressure sensor for detecting pressure in a pressurized state, a storage unit for storing pressure detected by the pressure sensor, and a pressure A leakage determination unit (both not shown) for determining the presence or absence of leakage from the rate of change of change;

  On the ground of the gas station, a meter 14 for refueling, a manhole (arranged in three places in this embodiment) 16 opened above the underground tank 12, an oil inlet 18 for the underground tank 12, and an upper space of the underground tank 12 A vent pipe 30 is provided in communication with each other. In the underground tank 12 buried underground in the fueling station, an oil supply pipe 22 communicated with the oil supply system of the measuring machine 14 and an oil supply pipe 24 communicated with the oil supply port 18 are inserted.

In the internal space of the manhole 16, the oil supply pipe 22, the oil supply pipe 24, and the vent pipe joint 40 are accommodated.
Here, the vent pipe 30 includes a lower vent pipe 30a and an upper vent pipe 30b, and a vent pipe joint 40 is provided therebetween.

  One end of the lower vent pipe 30a is connected to the underground tank 12 through the vent pipe joint 40, and the other end projects to the ground surface and extends from the ground surface to a height of 1 meter to 1.2 meters. This height is suitable for the installation of the vent pipe joint 40 itself performed by an operator, and the installation work such as assembly of parts to the vent pipe joint 40 and various piping work without using a ladder or legs. It is in the height position.

  The upper end of the upper vent pipe 30b is provided at the upper end of the vent pipe joint 40, and the upper end opening 30c extends upward so as to be located at a high place (the height from the ground surface is about 4 meters). ing.

  Further, as will be described later, the pressure hose 70 from the pressure monitoring unit 11 is connected to the vent pipe joint 40 at the time of leakage inspection.

  The laterally extending portions extending in the lateral direction of the oil supply pipe 22, the oil supply pipe 24, and the lower ventilation pipe 30a have a low connection portion with the underground tank 12 so that the oil liquid in the pipe falls into the underground tank 12. It is provided so as to be inclined at a predetermined angle from the horizontal. In addition, the underground tank 12 is provided with an inspection port, a liquid level gauge (both not shown) and the like in addition to the above-described pipes, but the description thereof is omitted.

  Here, the configuration of the vent pipe joint 40 of the present invention will be described. FIG. 2 is a longitudinal sectional view showing the mounting structure of the vent pipe joint 40.

  As shown in FIG. 2, the vent pipe joint 40 includes a joint pipe 80, an atmospheric valve 90, a first opening 100, and a second opening 110. The joint pipe 80 is provided at a height of about 1 to 1.2 meters from the ground surface at the lower end, and the lower end opening 82 communicates with the upper space of the underground tank 12 through the lower vent pipe 30a. The upper end opening 84 communicates with the lower end of the upper vent pipe 30b extending to a predetermined height on the ground.

  The atmospheric valve 90 has a valve mechanism that opens or closes a flow path 86 penetrating the inside of the joint pipe 80 in the vertical direction, and a valve seat 88 provided in an intermediate portion of the flow path 86, and unloading When the inside of the underground tank 12 becomes pressurized due to the rise in the liquid level of the underground tank 12 accompanying the occurrence of the vapor and the occurrence of vapor accompanying the rise in temperature, The tank 12 has an intake valve 94 that opens when a negative pressure is reached.

  The exhaust valve 92 is pressed against the valve seat 88 by a large-diameter coil spring 98 that abuts on a spring receiver 96 screwed into the upper end of the flow path 86 to close the flow path 86, and the pressure in the underground tank 12 is high. When it rises above the pressing force of the radial coil spring 98, it is separated from the valve seat 88 and changes to a valve open state. As a result, the pressure in the underground tank 12 is released to the atmosphere via the vent pipe 30, and the pressure in the upper space of the underground tank 12 is reduced to almost atmospheric pressure. When the pressure in the underground tank 12 is reduced to a pressure equal to or less than the pressing force of the large-diameter coil spring 98, the exhaust valve 92 returns to the closed state again.

  The intake valve 94 is provided on the lower surface side of the exhaust valve 92, and a shaft 94a extending upward is slidably supported by a bearing portion 92a provided on the upper surface side of the exhaust valve 92. The upper end of the shaft 94a is urged upward by a small-diameter coil spring 99 disposed between the upper end of the bearing portion 92a, and the intake valve 94 is formed on the lower surface of the exhaust valve 92 by this urging force. The valve seat 92b is pressed to keep the valve closed. When the liquid level in the underground tank 12 is lowered due to refueling and the tank pressure is reduced, the intake valve 94 moves downward due to the difference between the pressing force of the small-diameter coil spring 99 and the tank pressure, and from the valve seat 92b. Separate. As a result, the intake valve 94 opens to introduce outside air into the underground tank 12 and raise the pressure of the underground tank 12 to almost atmospheric pressure. Eventually, when the tank pressure is increased to a pressure higher than the combined pressure of the atmospheric pressure and the spring force of the small diameter coil spring 99, the intake valve 94 returns to the closed state again.

  The first opening 100 is provided at a height position on the side of the valve seat 88 and is formed in a horizontal direction perpendicular to the extending direction (vertical direction) of the flow path 86. The first opening 100 is normally closed by a first lid member 112 so that the atmospheric valve 90 cannot be seen from the outside. Therefore, when the maintenance of the atmospheric valve 90 is performed, the bolt 112a for fastening the first lid member 112 is removed, and the first lid member 112 is separated from the first opening 100, so that the first lid 100 is separated from the first opening 100. Work such as inspection or repair can be performed.

  Therefore, the work of climbing to a high place by using a ladder can be eliminated as in the conventional case where an air valve is provided at the upper end of the vent pipe 30, and the burden of maintenance work can be reduced accordingly. become.

  The second opening 110 is provided at a height position below the first opening 100 and the valve seat 88, and extends in the same direction as the first opening 100 in the extending direction (vertical direction) of the flow path 86. ) In the horizontal direction orthogonal to the horizontal axis. The second opening 110 is normally closed by the second lid member 114 so that the channel 86 cannot be seen from the outside. The second opening 110 is provided in the same direction as the first opening 100, and the second lid member 114 is removed during maintenance as described above to check the state of the intake valve 94 on the lower surface side. In addition to being used as a window for the inspection, it is also used as a connection port for connecting the pressure hose 70 during a leak inspection as will be described later.

In the state where the liquid level in the underground tank 12 does not fluctuate, or the pressure in the underground tank 12 does not fluctuate, the air valve 90 is closed, so the vent pipe 40 is closed and air or vapor ( Oil vapor) is stopped.
Here, in the above-described embodiment, the atmospheric valve 90 is configured such that the exhaust valve 92 is seated on the valve seat 88 provided in the intermediate portion of the flow path 86, but the valve provided in the flow path is not necessarily required. The seat 88 may not be seated. That is, the atmospheric valve 90 has a configuration in which the exhaust valve 92 is opened when the pressure in the underground tank 12 is increased, and the intake valve 94 is opened when the pressure in the underground tank 12 is decreased. Just do.

  Now, the manager of the gas station is obliged by the Fire Service Act to periodically inspect the underground tank 12 and each pipe for leakage. Here, the procedure of the preparation work when performing the leakage inspection will be described. First, as shown in FIG. 3, the first lid member 112 and the second lid member 114 are removed from the joint pipe 80. Next, the first opening 100 and the second opening 110 are used to disassemble the parts such as the exhaust valve 92, the intake valve 94, and the large-diameter coil spring 98 that constitute the atmospheric valve 90 to disassemble the first opening 100. Take out from the outside. As a result, the valve seat 88 and the spring receiver 96 remain in the joint pipe 80.

  Next, as shown in FIG. 4, a leak check closing valve 120 is attached between the valve seat 88 and the spring receiver 96. The leakage inspection blocking valve 120 is configured to remove the exhaust valve 92 and the intake valve 94 constituting the valve mechanism of the atmospheric valve 90 from the first opening 100 when the underground tank 12 is inspected for leakage. It is mounted in the flow path 86.

  The leakage inspection blocking valve 120 includes a valve body 122 that contacts the valve seat 88, a head portion 124 that contacts the upper opening of the joint pipe 80, one end fitted into the recess 122a of the valve body 122, and the other end connected to the head. The shaft 126 fitted in the recess 124a of the portion 124, the shaft 126 is moved in the axial direction, the valve body 122 is pressed against the valve seat 88, and the head 124 is pressed against the spring receiver 96 screwed into the upper opening. And a pressing mechanism 130.

  The pressing mechanism 130 includes a male screw 132 formed on the outer periphery of the upper end of the shaft 126, a female screw 134 formed on the inner periphery of the concave portion 124 a of the head portion 124, and the outer periphery of the shaft 126 projecting in the radial direction. And an operation unit 136. When the operating portion 136 is rotated while the valve body 122 is in contact with the valve seat 88, the pressing mechanism 130 rotates the head screw 124 relatively upward because the male screw 132 of the shaft 126 rotates. A pressing force acts on the.

  Then, when the head 124 abuts on the spring receiver 96 and the operation portion 136 is further rotated, the valve body 122 is pressed against the valve seat 88 and the head 124 is pressed against the spring receiver 96. Retained. As a result, the flow path 86 of the joint pipe 80 is closed by the leakage inspection blocking valve 120. Further, a packing 140 is fixed to the lower surface of the valve body 122 in order to improve the sealing performance. Therefore, the packing 140 of the valve body 122 can be in close contact with the valve seat 88 by the pressing force of the pressing mechanism 130 to seal the flow path 86 in a liquid-tight manner.

  Here, the portion of the head portion 124 of the leakage inspection blocking valve 120 does not need to be kept airtight. That is, the head portion 124 receives a reaction force for closing the valve body 122 by abutting against the spring receiver 96, and thus the upper end flange portion 124b of the head portion 124 is provided with a plurality of notches 124c. ing. The plurality of cutouts 124 c communicate with the vent pipe 30, and gas (including vapor) sucked in the underground tank 12 sucked when performing a pressure-reduction-type leak test described later is passed through the upper vent pipe 30 b of the vent pipe 30. It becomes a passage when discharging through.

  Next, the hose connection joint 150 that holds the pressure hose 70 from the pressure monitoring unit 11 is screwed into the second opening 110. Since the hose connection joint 150 holds the end of the pressure hose 70, the second opening 110 is closed and the inside of the flow path 86 is pressurized to be inspected.

  When a pressurized gas such as nitrogen is supplied from the pressurized hose 70 into the joint pipe 80 by the pressure monitoring unit 11, the valve seat 88 is liquid-tightly closed by the leakage inspection closing valve 120. The pressurized gas is supplied into the underground tank 12 through the lower vent pipe 30 a and the vent pipe joint 40. At this time, the underground tank 12 is brought to a predetermined pressure by closing the ventilation pipe joint 40 communicated with the other oil supply pipe 22 and the oil supply pipe 24 communicated with the underground tank 12 by a closing member (not shown). It becomes possible to pressurize. The pressure monitoring unit 11 monitors the pressure change until a predetermined time set in advance, and if the pressure change is within the allowable range, it is determined that there is no leakage (passed inspection), and the pressure change is within the allowable range. If it is outside, it is determined that there is a leak (failed inspection).

  When the leakage inspection of the lower vent pipe 30a is performed, the vent pipe joint 40 is closed by the closing member (not shown), and the vent pipe joint 40 in which the other end of the lower vent pipe 30a is communicated is closed. By doing so, it becomes possible to maintain the lower vent pipe 30a in a pressurized state, and the leak monitoring can be performed by the pressure monitoring unit 11 as described above.

  In addition, a display tag 152 that indicates that the inspection is being performed is suspended by a chain 154 at the center of the lower surface of the valve body 122. The display tag 152 is located at a position where it can be seen from the second opening 110. For example, even if it is forgotten to remove the leakage inspection blocking valve 120 after the leakage inspection is completed, the second lid member 114 is placed in the second opening 110. By visually recognizing the display tag 152 at the time of attachment, it can be recognized that the leakage inspection blocking valve 120 remains in the joint pipe 80. Thereby, the leakage inspection block valve 120 can be reliably removed from the flow path 86 after the leakage inspection is completed.

  In addition, after completion | finish of a leak test, first, the pressurization by the pressure monitoring unit 11 is stopped, and then the hose connection joint 150 is separated from the second opening 110. Then, the head 124 can be lowered and separated from the spring receiver 96 by rotating the operation portion 136 of the leakage inspection blocking valve 120 in the reverse direction. Thereby, the pressing force of the valve body 122 against the valve seat 88 can be reduced, and the members of the leakage inspection blocking valve 120 can be disassembled and taken out from the first opening 100.

  In this embodiment, since the vent pipe joint 40 is attached at a position suitable for the work of attaching the vent pipe 30, the removal and attachment of the atmospheric valve 90, the attachment and removal of the leakage check blocking valve 120, and the pressurization hose 70 Installation and removal can be done easily and safely without using a ladder, stepladder, or step ladder.

  In the embodiment shown in FIG. 4, the underground tank 12 is inspected for leakage by a nitrogen gas pressurization test, but there is a method in which the underground tank 12 is depressurized by a predetermined pressure to perform the leakage inspection.

  An inspection method for performing leakage inspection by reducing the predetermined pressure will be described with reference to FIG.

  In this case, similarly to the inspection in the pressurized state, the upper and lower communication of the vent pipe 30 is blocked using the leakage inspection blocking valve 120. Then, instead of the pressurizing hose 70, a decompression hose (not shown) connected to the decompression pump is attached to the second lid member 150 to suck the vapor in the underground tank 12. The paper sucked by the vacuum pump is discharged to the outside through a discharge pipe connected to the vacuum pump. In this example, as indicated by a broken line in FIG. 4, the distal end of the discharge pipe 160 is inserted into and held by a discharge pipe holding lid member 162 mounted instead of the first lid member 120.

  In this way, the discharge pipe 160 is held in a state where the discharge side end portion is inserted into the space in which the leakage inspection blocking valve 120 of the vent pipe joint 40 is incorporated, and therefore the underground tank 12 sucked by the decompression pump 12 This vapor can be discharged from the upper ventilation pipe 30b of the ventilation pipe 30 into the atmosphere. Further, the head portion 124 of the leakage check blocking valve 120 is simply pressed against the spring receiver 96, and the space in which the blocking valve 120 is incorporated and the inside of the vent pipe 30 are in communication with each other. Since the discharged vapor can be discharged at a height of about 4 meters through the vent pipe 30, safety can be improved. In this case, by attaching the discharge pipe holding lid member 162 instead of the first lid member 112, the mounting operation of the discharge pipe 160 can be simplified.

  FIG. 5 shows another embodiment of the inspection method in which the leakage inspection is performed by reducing the pressure by a predetermined pressure. Note that the same components as those in the embodiment shown in FIG. 4 are denoted by the same reference numerals as those in FIG. 4, the description thereof is omitted, and only different portions will be described. In this embodiment, the head 124 does not have a plurality of notches. As a result, the head portion 124 of the leakage inspection blocking valve 120 abuts against the spring receiver 96 and blocks communication between the upper and lower sides.

  A discharge pipe connection port (for discharge) for connecting the discharge pipe 160 to the side of the upper ventilation pipe 30b or the ventilation pipe member 40 above the portion blocked by the head portion 124 of the leakage check blocking valve 120 Connecting portions) 170 and 180 are formed. Then, the communication between the upper and lower sides of the vent pipe 30 is blocked using the leakage inspection blocking valve 120. Then, instead of the pressurizing hose 70, a discharge pipe 160 connected to a decompression pump (not shown) is attached to the second lid member 150, and the vapor in the underground tank 12 is sucked. For the paper sucked by the vacuum pump, the end of the discharge pipe 160 connected to the vacuum pump is connected to either the discharge pipe connection port 170 or 180, and the vapor is at a height of about 4 meters through the vent pipe 30. Can be discharged. Thereby, the safety | security at the time of performing the leakage test of a pressure reduction system can be improved.

  In this embodiment, for convenience of explanation, the exhaust pipe connection ports 170 and 180 are provided in both the vent pipe 30 and the vent pipe joint 40, but only one of the connection ports may be provided.

  Further, in the case of this embodiment, since the inspection can be performed with the first lid member 112 removed, the number of times of attaching and removing the first lid member 112 can be reduced, and the working efficiency is greatly improved.

  Further, the “position suitable for the mounting operation” described in claim 6 is a position above the position where the joint pipe 80 is closed by the leakage check closing valve 120, and is an upper part of the joint pipe 80. And a region including the flange portion of the vent pipe 30 coupled to the upper portion of the joint pipe 80 and the lower portion of the vent pipe 30. In FIG. 5, the portions provided with the discharge pipe connection ports 170 and 180 are shown. Show.

  Here, the case where vapor recovery is performed at the time of unloading in the above underground tank facility will be described. FIG. 6 is a longitudinal sectional view showing a configuration in the case of performing vapor recovery during unloading. As shown in FIG. 6, the vapor recovery joint 300 is screwed into the second opening 110. The vapor recovery joint 300 includes a tubular joint body 310, a check valve (backflow prevention valve) 320 that closes the end of the joint body 310, and a coil spring 330 that biases the check valve 320 in the valve closing direction. 332, a bearing 340 that guides the valve shaft 322 of the check valve 320 to the side, and a cap 350 that fits to the outer end of the joint body 310. The check valve 320 is pressed against the end of the joint body 310 by the large-diameter coil spring 330 provided in the flow path 86 and is closed by the spring force of the small-diameter coil spring 332 that urges the valve shaft 322 in the valve closing direction. Held in valve position.

  As shown in FIG. 7, the discharge port of the bottom valve (not shown) of the tank truck 400 and the oil supply port 18 of the underground tank 12 are communicated by an unloading hose 410. Further, the vapor recovery hose 420 communicates between the loading port 402 provided in the upper portion of the hatch of the tank truck 400 and the vapor recovery joint 300.

  At that time, in the vapor recovery joint 300, the cap 350 is removed, and instead, a coupler (not shown) provided at the end of the vapor recovery hose 420 is fitted to the outer end of the joint body 310. This coupler has a built-in rod (not shown) that presses the valve shaft 322 of the check valve 320 so that the check valve 320 can be kept open when coupled to the joint body 310. It is configured.

  As a result, the oil liquid loaded in the hatch of the tank truck 400 is unloaded to the underground tank 12 via the unloading hose 410 and the oil supply pipe 24, and the liquid level of the underground tank 12 rises so that the pressure in the tank is also reduced. To rise. The vapor (oil vapor) generated in the gas phase region of the underground tank 12 passes through the lower vent pipe 30a, the vent pipe joint 40, and the vapor recovery hose 420 to the hatch in the tank truck 400 unloaded. Collected. In addition, in the hatch during unloading, the liquid level descends with unloading, so that a negative pressure is generated in the hatch, and the vapor is sucked by the difference from the pressure in the underground tank 12.

  In addition, when the vapor recovery amount at the time of unloading cannot catch up with the unloading amount and the pressure of the underground tank 12 rises too much, the exhaust valve 92 of the atmospheric valve 90 opens and the pressure of the underground tank 12 is reduced to the ventilation pipe. The underground tank 12 is depressurized by letting it escape from 30 to the atmosphere.

  As described above, the vent pipe joint 40 can be connected to the vapor recovery hose 420 so as to perform the vapor recovery at the time of unloading. Therefore, the vent pipe joint 40 can be used for multipurpose purposes other than the leakage inspection. Moreover, since the said 1st opening 100 and the 2nd opening 110 are provided in the same side, the ventilation pipe joint 40 uses the 2nd opening 110 for uses other than the said leak test | inspection and vapor recovery. For example, an inspection fiberscope for inspecting the ventilation pipe 30 and the lower ventilation pipe 30 a can be inserted from the second opening 110.

  In the above embodiment, the case where the fuel tank is installed at the gas station has been described as an example. However, the present invention is not limited to this, and the present invention is also applied to the case where leakage inspection is performed in an underground tank provided in a facility other than the gas station. Of course, it can be applied.

  Moreover, in the said Example, although illustrated about the case where oil liquid is unloaded from a tank truck to an underground tank, this invention is also applied when unloading liquids other than oil liquid (for example, liquids, such as chemicals and foodstuffs). Of course, can be applied.

It is a block diagram which shows one Example of the vent pipe installation of the underground tank by this invention. 3 is a longitudinal sectional view showing a mounting structure of a vent pipe joint 40. FIG. 4 is a longitudinal sectional view showing a state in which a valve mechanism of the atmospheric valve 90 is taken out from the vent pipe joint 40. FIG. It is a longitudinal cross-sectional view which shows the closed state at the time of performing a leak test | inspection. It is a longitudinal cross-sectional view which shows the closed state at the time of performing a leak test | inspection by a pressure reduction system. It is a longitudinal cross-sectional view which shows the structure of the vent pipe joint 40 in the case of performing vapor recovery at the time of unloading. It is a figure which shows the hose connection in the case of performing unloading from a tank truck and vapor recovery.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Vent pipe equipment 11 Pressure monitoring unit 12 Underground tank 14 Metering machine 16 Manhole 22 Oil supply pipe 24 Oil supply pipe 30 Ventilation pipe 40 Ventilation pipe joint 70 Pressurizing hose 80 Joint pipe 86 Flow path 88 Valve seat 90 Air valve 92 Exhaust valve 94 Intake Valve 100 First opening 110 Second opening 112 First lid member 114 Second lid member 120 Leakage inspection blocking valve 122 Valve body 124 Head 130 Press mechanism 136 Operation unit 150 Hose connection joint 152 Display tag 160 Discharge Pipe 162 Drain pipe holding lid member 170, 180 Drain pipe connection port 300 Vapor recovery joint 310 Joint body 320 Check valve 350 Cap 400 Tank truck 402 Loading port 410 Unloading hose 420 Vapor recovery hose

Claims (6)

An underground tank vent pipe facility comprising an underground tank, a vent pipe having one end connected to the underground tank and the other end opened to the atmosphere at a high place, and a vent pipe joint provided in the middle of the vent pipe. And
The vent pipe joint,
A joint pipe having a lower end communicated with the upper space of the underground tank and an upper end communicated with the vent pipe extending to a predetermined height above the ground;
A valve mechanism provided in the middle of the flow path of the joint pipe and opened or closed according to a pressure difference between the inside and outside of the underground tank;
A first opening that opens to the side of the joint pipe so as to allow the valve mechanism to be attached and detached;
A first lid member that closes the first opening;
A second opening provided below the first opening and opening to a side of the joint pipe;
A second lid member for closing the second opening;
Consisting of
A vent pipe facility for an underground tank, wherein the vent pipe joint is provided at a position suitable for mounting work.   When the leak inspection of the underground tank is performed, a leak check blocking valve for blocking the communication in the vertical direction of the flow path from the first opening into the joint pipe after taking out the valve mechanism from the first opening. The underground pipe vent pipe installation according to claim 1, which is mounted.   The said 2nd opening has a connection part for connecting the piping for pressurizing or depressurizing the inside of the said air pipe when performing the leak test of the said underground tank, The said 1st opening is characterized by the above-mentioned. Underground tank vent pipe equipment. While providing a valve seat in the joint pipe,
The leak check closing valve,
A valve body in contact with the valve seat;
A head abutting against an edge of the upper opening of the joint pipe;
A shaft having one end fitted into the recess of the valve body and the other end fitted into the recess of the head;
A pressing mechanism that moves the shaft in the axial direction to press the valve body against the valve seat and presses the head against the edge of the upper opening;
The underground pipe vent pipe facility according to any one of claims 2 to 3, characterized by comprising: An underground tank vent pipe facility comprising an underground tank, a vent pipe having one end connected to the underground tank and the other end opened to the atmosphere at a high place, and a vent pipe joint provided in the middle of the vent pipe There,
The vent pipe joint,
A joint pipe having a lower end communicated with the upper space of the underground tank and an upper end communicated with the vent pipe extending to a predetermined height above the ground;
A valve mechanism provided in the middle of the joint pipe and opened or closed according to a pressure difference between the inside and outside of the underground tank;
A first opening that opens to the side of the joint pipe so as to allow the valve mechanism to be attached and detached;
A first lid member that closes the first opening;
A second opening provided below the first opening and opening to a side of the joint pipe;
A second lid member for closing the second opening;
Consisting of
The vent pipe joint is provided at a position suitable for mounting work,
When the leak inspection of the underground tank is performed, a leak check blocking valve for blocking the communication in the vertical direction of the flow path from the first opening into the joint pipe after taking out the valve mechanism from the first opening. Wearing,
The second opening is provided with a connecting portion for connecting a pipe for decompressing the inside of the vent pipe when performing leak inspection of the underground tank,
A vent pipe facility for an underground tank, wherein the first lid member is provided with a pipe discharge connecting portion for discharging the sucked gas. An underground tank vent pipe facility comprising an underground tank, a vent pipe having one end connected to the underground tank and the other end opened to the atmosphere at a high place, and a vent pipe joint provided in the middle of the vent pipe There,
The vent pipe joint,
A joint pipe having a lower end communicated with the upper space of the underground tank and an upper end communicated with the vent pipe extending to a predetermined height above the ground;
A valve mechanism provided in the middle of the joint pipe and opened or closed according to a pressure difference between the inside and outside of the underground tank;
A first opening that opens to the side of the joint pipe so as to allow the valve mechanism to be attached and detached;
A first lid member that closes the first opening;
A second opening provided below the first opening and opening to a side of the joint pipe;
A second lid member for closing the second opening;
Consisting of
The vent pipe joint is provided at a position suitable for mounting work,
When the leak inspection of the underground tank is performed, a leak check blocking valve for blocking the communication in the vertical direction of the flow path from the first opening into the joint pipe after taking out the valve mechanism from the first opening. Wearing,
The second opening is provided with a depressurizing connection portion for connecting a pipe for depressurizing the inside of the vent pipe when performing leak inspection of the underground tank,
A pipe discharge connecting portion for discharging the sucked gas is provided at a position above the position where the joint pipe is closed by the leakage check closing valve and at a position suitable for mounting work. Ventilation pipe equipment for underground tanks.

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