JP2008127080A - Tank facility - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent excess pour on unloading from a tank truck. <P>SOLUTION: In tank facilities, an excess unloading preventing valve 80A intercepts a ventilating path 183 so that air in an underground tank 12 is not discharged into a ventilating tube 26 by shutting down two or more ventilating holes 194 on a sheet 193 at the same time with a packing 220 provided at the upper face of a float valve 210 when the level of a liquid surface in the underground tank 12 reaches the upper limit of the liquid surface Hmax. By this the pressure in the upper space of the underground tank 12 is increased to balance the level difference (height difference) between the tank truck 20 and the liquid surface of the underground tank 12 and the air pressure in the upper space of the underground tank 12 to stop unloading. By this excess pour in unloading operation from the tank truck 20 to the underground tank 12 can be prevented. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a tank facility, and more particularly, to a tank facility configured to prevent excessive liquid injection so that the liquid level does not exceed the upper limit position of the tank when liquid is injected into the tank.

  For example, in a gas station or the like, when the remaining amount of a tank buried underground (hereinafter referred to as “underground tank”) decreases below a predetermined level, the oil liquid is transported by a tank truck. The tanker truck driver who arrived at the filling station connected one end of the unloading hose to the discharge port of the bottom valve of the hatch and connected the other end of the unloading hose to the oiling port of the underground tank. By opening the valve, the oil liquid loaded in the hatch of the tank truck is unloaded to the underground tank via the unloading hose.

  The underground tank is equipped with a liquid level gauge, and the operator of the tank truck checks the remaining amount of the underground tank before starting the unloading operation. In order to predict the reduction amount and order the delivery amount of the oil liquid, when the tank truck arrives at the gas station, the remaining amount of the oil liquid in the underground tank may be larger than expected. In such a case, unloading all of the oil liquid (quantity that has been ordered) loaded into the hatch of the tank truck will cause over-injection of the oil liquid beyond the capacity of the underground tank. The bottom valve must be closed before over-injection occurs while looking at the surface gauge reading.

If such a bottom valve closing operation is delayed, there is a possibility of over-injection.Therefore, the float rises due to the rise in liquid level in the injection pipe inserted in the underground tank, and the inside of the injection pipe is There is a valve provided with a closing valve for closing (see, for example, Patent Document 1).
Utility Model Registration No. 2506264

  However, when the structure having the closing valve in the injection pipe line as in Patent Document 1 described above, the valve body is closed against the flow of the injected oil liquid, so that an excessive load is applied to the valve body. Therefore, there is a possibility that a failure such as deformation may occur in the mechanism for closing the valve body.

  Furthermore, in the thing of the said patent document 1, when the closing valve in an injection pipe line became inoperable, there existed a problem that unloading itself from a tank truck to an underground tank could not be performed.

  In view of the above circumstances, an object of the present invention is to provide a tank facility that solves the above problems.

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

  The present invention includes a tank for storing liquid therein, a liquid injection line for injecting liquid into the tank, a supply line for supplying liquid from the tank to an external device, and a communication with the tank. A piping joint that relays the rising pipe line and a horizontal pipe line that extends in a horizontal direction from the rising pipe line, and is connected to the horizontal pipe line, and absorbs and discharges air according to a change in the liquid level of the tank. A vent passage that communicates with the vent conduit when the liquid level of the liquid poured from the liquid fill conduit reaches an upper limit liquid level inside the tank. The above-mentioned problem is solved by providing an over-injection prevention valve that shuts off the above.

  In the present invention, the over-injection prevention valve is provided so as to be movable in the vertical direction with respect to the pipe joint, and can be adjusted to an arbitrary height position according to the upper limit liquid level inside the tank. It solves the problem.

  According to the present invention, the piping joint is provided with an opening at the top and a lid member that closes the opening, and the over-injection prevention valve is configured so that the position in the vertical direction can be adjusted from the top opening of the piping joint. Thus, the above-mentioned problem is solved.

  The present invention solves the above problem by configuring the over-injection prevention valve so that the valve opening is gradually reduced as the liquid level in the tank rises.

  The present invention solves the above problem by configuring the over-injection prevention valve so that the valve opening is continuously throttled as the liquid level inside the tank rises.

  According to the present invention, since the liquid level of the liquid injected from the liquid injection line reaches the upper limit liquid level inside the tank, the over-injection prevention valve for blocking the air flow path connected to the air flow line is provided. The liquid injection from the liquid injection line can be stopped when the liquid level reaches the upper limit liquid level when unloading to the tank, and the over-injection prevention valve is not subjected to resistance due to the flow of liquid. Therefore, the load during the valve closing operation is extremely small, and the failure of the over-injection prevention valve does not occur even during long-term use, and the reliability of the over-injection prevention in the tank can be improved.

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

  FIG. 1 is a block diagram showing an embodiment of a tank facility according to the present invention. As shown in FIG. 1, an underground tank facility 10 including a tank buried underground is installed in, for example, a fueling station, and includes an underground tank 12, a weighing machine 14 for refueling, and a ground above the underground tank 12. There are manholes (disposed in three places in this embodiment) 16 opened on the surface, an oil supply line 24 having an oil supply port 18 for unloading, and a ventilation line 26 communicated with the upper space of the underground tank 12.

  The underground tank 12 is inserted with an oil supply line 22 and an oil supply line 24 communicated with the oil supply system of the weighing machine 14. The vent line 26 has a vent hole 26a at the upper end standing on the ground, and the lower end communicates with a horizontal pull line 70 extending substantially horizontally between the ground surface (reinforced concrete 30) and the top of the underground tank 12. Has been. The laterally extending portions extending in the lateral direction of the oil supply conduit 22, the oil supply conduit 24, and the ventilation conduit 26 are connected to the underground tank 12 so that the oil liquid in the tubes falls into the underground tank 12. Is inclined at a predetermined angle with respect to the horizontal so as to be lower. In addition, the underground tank 12 is provided with an inspection port, a liquid level gauge (both not shown), etc. in addition to the above-mentioned pipelines, but the description thereof is omitted.

  The driver of the tank truck 20 arriving at the gas station confirms the oil type and the remaining amount in the underground tank 12 and loads the corresponding oil type in the discharge port and the oil supply port 18 of the hatch bottom valve (not shown). And an unloading hose 28. Then, after the driver confirms the oil type, the bottom valve is opened, so that the oil liquid loaded in the hatch is taken from the unloading hose 28 through the oil supply line 24 using the height difference and the underground tank 12. Unloaded. For example, the unloading hose 28 is provided with a transparent monitoring window (not shown) so that the flow of oil during unloading can be visually observed from the outside. The unloading state of the oil can be confirmed from the window.

In the gas station, the ground surface is formed of reinforced concrete 30 having a thickness of 30 cm, and a soil layer 32 having a thickness of 30 cm is formed below the reinforced concrete 30. Furthermore, the underground tank 12 is embedded in a soil layer 34 formed below the earth and sand layer 32, and is placed on a concrete foundation layer 36 laid in the ground.
In addition, when resin piping is used for the oil supply line 22, the oil supply line 24, and the ventilation line 26, the resin line is laid under the earth and sand layer 32 due to an earthquake or a load from a large vehicle such as the tank truck 20 or the like. I try not to break it.

  The manhole 16 is provided at a location where the oil supply line 22, the oil supply line 24, and the vent line 26 are connected to the upper part of the underground tank 12, and a pipe joint 60 is accommodated in the internal space of the manhole 16. ing. Further, the pipe joint 60 communicated with the vent pipe 26 absorbs and discharges air in the vent pipe 26 when the liquid level in the underground tank 12 reaches a preset upper limit level when unloading from the tank truck 20. An overload prevention valve 80A that shuts off and stops the unloading of the oil is provided.

  FIG. 2 is an enlarged longitudinal sectional view showing the mounting state of the pipe joint 60 and the overload prevention valve 80A of the first embodiment. As shown in FIG. 2, the pipe joint 60 is fastened to the flange 52 of the rising pipe 50 provided at the upper part of the underground tank 12 by bolts 54 and nuts 56.

  The pipe joint 60 includes a lower connection port 62 connected to the rising pipeline 50, a side connection port 64 connected to the horizontal pulling pipeline 70, a maintenance port 66 opened in the manhole 16, and a lower connection. A relay chamber 68 that connects a lower flow path that communicates with the port 62 and a side flow path that communicates with the side connection port 64 and changes the direction of the flow path, and a lid member 69 that closes the maintenance port 66 are provided.

  Around the lower connection port 62, a lower flange 63 is provided that is fastened to the flange 52 of the rising pipe line 50 via a nut 56. The lower connection port 62 is provided with an overload prevention valve 80A for closing the lower connection port 62 when the liquid level L in the underground tank 12 reaches the upper limit liquid level (excess injection limit liquid level). ing.

  In this example, it is assumed that the liquid level L exists below the excessive unloading prevention valve 80A. On the inner periphery of the maintenance port 66, a lid member attaching screw portion 94 into which the lid member 69 is screwed is provided. The lid member 69 compresses the sealing member 67 between the maintenance port 66 and seals the maintenance port 66. The lid member 69 includes a lid portion 69a that closes the maintenance port 66, a flange portion 69b that presses the seal member 67 against the maintenance port 66, and projects downward from the flange portion 69b and is screwed into the lid member attaching screw portion 94. And a male screw portion 69c.

  The space communicates with the side connection port 64, and a side flange 98 is provided on the outer periphery of the side connection port 64. In the horizontal pulling conduit 70, a flange 72 abutting on the side flange 98 is formed on the outer periphery, and the annular flange 100 abutting on the flange 72 is 102 with respect to the side flange 98 via a nut 104. It is concluded.

  Here, the side flange 98 and the lower flange 63 are provided so as to face in directions orthogonal to each other, and the outer circumferences thereof are disposed at positions close to each other. Since the height position of the side flange 98 is set low, it is possible to attach the horizontal pulling pipeline 70 at a height position closer to the underground tank 12. As a result, it is possible to make the burying position of the tank shallow relative to the ground surface.

  In recent years, the tank embedding position tends to be deepened by increasing the size of the underground tank 12 or adopting resin piping (in the case of resin piping, the embedding position is 30 cm deeper than that of a steel pipe). When the underground tank 12 is buried in such a deep position, the pump head of the measuring machine 14 at the filling station becomes high, and the liquid becomes difficult to suck up.

  That is, as described above, the pipe joint 60 has a structure in which the height position of the side flange 98 with respect to the lower flange 63 is lowered, so that the buried position of the underground tank 12 can be shallowed and the head for the pump is lowered. This contributes to the maintenance of liquid suction performance.

The excessive unloading prevention valve 80 </ b> A is integrally coupled to the pipe joint 60 by being screwed into a female screw 62 a formed inside the lower connection port 62 of the pipe joint 60. Therefore, when the lower flange 63 of the pipe joint 60 is fastened to the flange 52 of the rising pipe 50, the overload prevention valve 80A is inserted into the rising pipe 50 from above and suspended in the underground tank. It is attached to 12 upper spaces (gas phase region).
Further, the excessive unloading prevention valve 80A is used for unloading work from the tank truck 20 when the liquid level of the underground tank 12 is not more than the upper limit liquid level (for example, the liquid level that is 90% of the tank capacity). The valve is opened so that air is exhausted through the vent pipe 26 as the liquid level rises.

  The overload prevention valve 80A includes an upper pipe 180 that is screwed into the female screw 62a of the lower connection port 62 and extends in the hanging direction, and a lower pipe that is screwed to the male screw 182 on the outer periphery of the lower end of the upper pipe 180. 190, a float guide shaft 200 that passes through the center of the lower end of the lower pipe 190, and a float valve body 210 that is fitted to the float guide shaft 200 so as to be movable up and down.

  Since the outer diameters of the upper pipe 180, the lower pipe 190, and the float valve body 210 are smaller than the inner diameter of the rising pipe line 50, the overload prevention valve 80A is attached to the lower connection port 62 of the pipe joint 60. It can be inserted into the underground tank 12 as it is. Further, since the excessive unloading prevention valve 80 </ b> A is directly screwed into the female thread portion 62 a of the lower connection port 62, it can be taken out by separating the pipe joint 60 from the rising pipe line 50.

  The upper pipe 180 is formed with a male screw 181 to be screwed into a female screw 62a of the lower connection port 62 on the outer periphery of the upper end, and has a male screw 182 formed on the outer periphery of the lower end, and passes through the inside in the axial direction (vertical direction). It is a hollow pipe having a path 183. In addition, a small hole 184 that communicates the ventilation channel 183 with the outer periphery penetrates the upper pipe 180 in the radial direction. The small hole 184 gradually exhausts the air in the underground tank 12 little by little after the float valve body 210 of the overload prevention valve 80A is closed to stop the unloading.

  Thereby, the oil liquid remaining in the unloading hose 28 can gradually fall into the underground tank 12 as the air in the underground tank 12 is gradually exhausted from the small hole 184. Since the small hole 184 is formed to have a small diameter that allows a small amount of air to be exhausted, it takes time to drain the oil remaining in the unloading hose 28, but the float valve element 210. It is provided so as not to hinder the exhaust stop due to the valve closing operation.

  The lower pipe 190 includes a cylindrical portion 192 having a female screw 191 that is screwed into the male screw 182 of the upper pipe 180, a seat portion 193 formed at the bottom of the lower end, and a plurality of vent holes 194 provided in the seat portion 193. Have As shown in FIG. 3, the plurality of vent holes 194 are arranged at predetermined intervals in the circumferential direction that is concentric with the shaft hole 195 through which the float guide shaft 200 is inserted.

  The lower pipe 190 is configured such that the height position is adjusted by screwing with the male thread 182 of the upper pipe 180. For example, the position of the seat portion 193 according to the capacity of the underground tank 12, that is, The valve closing height position can be adjusted to an arbitrary position.

  The float valve body 210 is made of a material having a lighter specific gravity than the oil liquid or a floating bag structure in which air is enclosed. When the bottom surface is immersed in the liquid level L, the float valve body 210 receives buoyancy and floats along with the liquid level L. Ascend along axis 200. Further, an elastic packing 220 that adheres to the seat portion 193 and closes the vent hole 194 from below is fixed to the upper surface of the float valve body 210. Since the packing 220 is formed in a ring shape, the plurality of air holes 194 provided in the seat portion 193 can be closed simultaneously.

The float guide shaft 200 is fastened by a nut 230 with the upper end inserted through the shaft hole 195 of the seat portion 193. A disc-shaped drop-off prevention member 240 for preventing the float valve body 210 from dropping off is engaged with the lower end of the float guide shaft 200.
Here, the closing operation of the overload prevention valve 80A configured as described above will be described.

  As shown in FIGS. 2 to 4, when the oil liquid loaded in the hatch of the tank truck 20 is unloaded to the underground tank 12 via the unloading hose 28 and the oiling conduit 24, The liquid level gradually rises. Normally, unloading is completed before the liquid level in the underground tank 12 reaches the upper limit liquid level. For example, when there is more oil liquid in the underground tank 12 than expected at the filling station, loading of the hatch is performed. The amount may exceed the capacity of the gas phase region of the underground tank 12.

  As described above, when the remaining amount in the underground tank 12 is more than expected, the liquid level of the underground tank 12 reaches the upper limit liquid level Hmax (for example, the liquid level that is 90% of the tank capacity). The float valve body 210 comes into contact with the raised liquid level L immediately before the liquid level height of the underground tank 12 reaches the upper limit liquid level Hmax, and thereafter rises as the liquid level rises. Further, when the liquid level height of the underground tank 12 reaches the upper limit liquid level Hmax, the packing 220 provided on the upper surface of the float valve body 210 simultaneously closes the plurality of vent holes 194 of the seat portion 193, and the underground tank The ventilation flow path 183 is blocked so that 12 air is not exhausted to the ventilation duct 26. Therefore, since the float valve body 210 only closes the plurality of vent holes 194, it is not necessary to receive the resistance of the oil and can be closed with a relatively small force (buoyancy).

  As described above, when the liquid level rise due to the unloading operation from the tank truck 20 reaches the upper limit liquid level Hmax, the float valve body 210 of the excessive unloading prevention valve 80A is closed to flow to the air through the ventilation pipe line 26. Shut off. As a result, the pressure in the upper space of the underground tank 12 rises, and the lift (height difference) between the tank truck 20 and the liquid level L of the underground tank 12 and the upper air pressure in the underground tank 12 are balanced, and unloading stops. Is done. Therefore, excessive injection in the unloading work from the tank truck 20 to the underground tank 12 is prevented.

  In this way, the overload prevention valve 80A shuts off the ventilation channel 183 communicated with the ventilation pipe 26 when the liquid level L reaches the upper limit liquid level Hmax inside the underground tank 12, so The liquid injection from the liquid injection line 18 can be stopped when the liquid level L reaches the upper limit liquid level Hmax at the time of unloading, and the float valve body 210 does not receive resistance due to the flow of liquid. Therefore, the load during the valve closing operation can be extremely small, no failure occurs, and it is possible to reliably prevent excessive injection in the underground tank 12.

  On the other hand, the driver of the tank truck 20 confirms that the liquid level L of the underground tank 12 has reached the upper limit liquid level Hmax by using a liquid level gauge (not shown) of the underground tank 12, and is provided in the unloading hose 28. A monitoring window (not shown) is used to check whether oil remains in the hose. Then, the driver closes the hatch bottom valve to which the unloading hose 28 is connected. When the unloading is stopped with the oil remaining in the unloading hose 28, the air in the upper space of the underground tank 12 passes through the small hole 184 provided in the upper portion of the upper pipe 180 as described above. The oil remaining in the unloading hose 28 is dropped into the underground tank 12 by flowing out into the ventilation channel 183 and gradually exhausting the air in the underground tank 12.

  Thereafter, the driver of the tank truck 20 confirms that the oil in the unloading hose 28 has been removed by a monitoring window (not shown) of the unloading hose 28 and the vibration sound of the hose, and then turns the unloading hose 28 to the bottom valve. Are separated from the discharge port and the oil supply line 24.

  In the first embodiment, an over-injection prevention valve 80A for blocking the ventilation channel 183 communicating with the ventilation pipe 26 is provided, and the lower pipe 190 is screwed into the male screw 182 of the upper pipe 180. For example, the position of the seat portion 193, that is, the valve closing height position can be adjusted to an arbitrary position according to the capacity of the underground tank 12. .

  FIG. 5 is an enlarged vertical cross-sectional view illustrating an attached state of the excessive unloading prevention valve 80B according to the second embodiment. In FIG. 5, the same parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  As shown in FIG. 5, the excessive unloading prevention valve 80 </ b> B includes an upper pipe 280 that is screwed into the female screw 62 a of the lower connection port 62 and extends in the hanging direction, and a female screw at the center of the lower end of the upper pipe 280. A height adjustment screw 300 screwed into 281, a lower pipe 290 slidably fitted to the outer periphery of the lower end of the upper pipe 280, and a disk-like member 310 coupled to the lower end of the height adjustment screw 300, The float valve body 210 is fitted to the float guide shaft 200 of the lower pipe 290 so as to be movable up and down.

Further, the height adjustment screw 300 and the female screw 281 of the upper pipe 280 into which the height adjustment screw 300 is screwed are multi-threads such as two or three threads, and are rotated with a relatively light operating force to increase the height. The height adjustment screw 300 is irreversible so that the height adjustment screw 300 is not turned even if a force in the rotational direction is applied to the lower pipe 290. Therefore, even when a force in the rotational direction is applied when the float valve body 210 rises to the valve closing position and abuts the lower surface of the lower pipe 290 to close the ventilation flow path, the height is increased by the irreversible action of the multi-thread screw. Since the adjustment screw 300 is not rotated, the valve closing position is prevented from shifting.
The upper pipe 280 has a guide portion 282 whose lower portion is smaller in diameter than the upper portion. In addition, the female screw 284 is provided at the center of the bottom portion 283 of the guide portion 282, and a plurality of vent holes 286 communicating with the vent flow channel 285 penetrate in the axial direction outside the female screw 284.

  The lower pipe 290 has a pair of sliding guide portions 292 fitted on the outer periphery of the guide portion 282 of the upper pipe 280 at the upper portion. Further, the sliding guide portion 292 disposed above is provided with a seal member 320 that seals the space between the guide portion 282 and the outer periphery. In addition, the lower pipe 290 is formed such that an annular wall portion 293 that contacts the upper surface of the disk-like member 310 protrudes inward at the lower inner side. The annular wall portion 293 is provided with a vent hole 294 that communicates with the vent hole 286. Further, an escape portion 295 is provided above the annular wall portion 293 to allow the guide portion 282 of the upper pipe 280 to enter when the height is adjusted.

  Further, a float sheet member 330 facing the lower surface of the disk-like member 310 is screwed into the lower end opening of the lower pipe 290. The float sheet member 330 is formed in a disc shape, and a sliding plate 340 for reducing sliding resistance with the disc-like member 310 is fixed to the upper surface of the float sheet member 330. Therefore, when the height adjustment screw 300 is rotated, the disk-shaped member 310 rotates while slidingly contacting the sliding plate 340, so that the height can be adjusted with a relatively small operating force.

  The lower surface of the float sheet member 330 is provided with a plurality of ventilation holes 332 that form ventilation channels, and the float guide shaft 200 extends downward in the center of the lower surface. The float valve element 210 inserted through the float guide shaft 200 stops the discharge of air in the underground tank 12 by closing the vent hole 332 of the float sheet member 330 when the liquid level L rises to the upper limit position. Can do. Thereby, the unloading to the underground tank 12 is stopped and excessive injection into the underground tank 12 is prevented.

  The height adjustment screw 300 has a tool engagement recess 302 at the upper end. Moreover, since the height adjustment screw 300 is attached below the relay chamber 68 of the pipe joint 60, it can be operated from above.

  Here, an adjustment method when adjusting the liquid level height for closing the valve by rotating the height adjustment screw 300 will be described with reference to FIGS. 5 and 6. The lid member 69 of the pipe joint 60 is removed from the maintenance port 66. Then, the tool 350 shown in FIG. 6 is inserted from the maintenance port 66 of the pipe joint 60. The tool 350 is provided with an operation handle 354 at the upper end of a rod 352 that is sufficiently longer than the height of the pipe joint 60, and is formed in a semicircular shape at the lower end of the rod 352 that can be easily fitted into the tool engagement recess 302. The engaged portion 356 is integrally provided.

  When rotating the height adjustment screw 300, the tool 350 is inserted from the maintenance port 66, and the engagement portion 356 provided at the lower end of the rod 352 is inserted into the tool engagement recess 302 of the height adjustment screw 300. Engage. Then, by rotating the operation handle 354 protruding upward from the maintenance port 66, the height adjusting screw 300 can be rotated to move the disk-shaped member 310 up and down.

  Since the disk-shaped member 310 is interposed between the annular wall portion 293 and the float sheet member 330 inside the lower pipe 290, the lower pipe 290 is moved up and down by the turning operation of the height adjusting screw 300. Is raised and lowered with respect to the upper pipe 280. Thereby, it is possible to adjust the height position of the float seat member 330 closed by the float valve body 210, and the position of the upper limit liquid level Hmax in the underground tank 12 can be easily adjusted.

  FIG. 7 is an enlarged vertical cross-sectional view showing an attachment state of the overload prevention valve 80C of the third embodiment. In FIG. 7, the same parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  As shown in FIG. 7, the excessive unloading prevention valve 80 </ b> C includes an upper pipe 180 that is screwed into the female screw 62 a of the lower connection port 62 and extends in the hanging direction, and a male screw 182 on the outer periphery of the lower end of the upper pipe 180. A lower pipe 190 screwed into the lower pipe 190, a float guide shaft 200 penetrating the center of the lower end of the lower pipe 190, and a float valve mechanism 410 fitted to the float guide shaft 200 so as to be movable up and down.

  The float valve mechanism 410 includes a first float valve 420 which is guided by the float guide shaft 200 and moves up and down, and an annular second float valve 430 which is guided by the outer periphery of the first float valve 420 and lifts and lowers. A disc-shaped float support plate 440 that is integrally fixed to the lower surface of the first float valve 420 and prevents the second float valve 430 from dropping off, and a dropout prevention member 240 that locks the float support plate 440; Have

  The first float valve 420 has a hollow shape having a central hole 422 through which the float guide shaft 200 is inserted, and the upper end of the first float valve 420 is in contact with the seat portion 193 of the lower pipe 190 and the flow paths of the plurality of vent holes 194. A disc-shaped diaphragm plate 450 for reducing the area is fixed. As shown in FIG. 8, the aperture plate 450 is formed in a disc shape, and a hole 452 through which the float guide shaft 200 is inserted is provided in the center, and the hole 452 is formed in an arc shape on the outside. A pair of apertures 454 penetrates. The aperture 454 is formed concentrically so as to face the vent hole 194 of the seat portion 193.

  The second float valve 430 has an annular packing 432 fixed to the upper end, and has a smaller height than the first float valve 420. Further, the second float valve 430 is made of a material having a higher specific gravity than the first float valve 420.

Further, the second float valve 430 has a central hole 434 into which the first float valve 420 is inserted, and the inner diameter of the central hole 434 is larger than the outer diameter of the first float valve 420. The first float valve 420 is inserted between the float support plate 440 and the throttle plate 450 so as to be movable up and down independently. Therefore, since the second float valve 430 is loosely fitted to the first float valve 420, the sliding resistance when sliding in the vertical direction is reduced, and the first float valve 420 has It is attached so that it can move up and down without interference.
Here, the stepwise valve closing operation of the float valve mechanism 410 will be described with reference to FIGS.

  As shown in FIG. 9A, the liquid level L of the underground tank 12 rises due to unloading from the tank truck 20, and the liquid level L is formed on the lower surfaces of the first float valve 420 and the second float valve 430. By contact, the first float valve 420 and the second float valve 430 begin to rise. Since the throttle plate 450 fixed to the upper end of the first float valve 420 is at a higher position than the second float valve 430, the throttle plate 450 comes into contact with the seat portion 193 first.

  When the throttle plate 450 comes into contact with the sheet portion 193, the vent hole 194 of the sheet portion 193 is greatly throttled by the flow path area of the throttle 454. Therefore, the air in the underground tank 12 is exhausted to the vent pipe 26 at a flow rate corresponding to the flow path width of the throttle 454.

  As a result, when the liquid level L in the underground tank 12 reaches a position immediately before the upper limit liquid level Hmax, the unloading flow rate from the liquid injection pipe 18 becomes the amount of air exhausted by the flow path width of the throttle 454. Decrease to a small flow rate. When the throttle plate 450 provided integrally with the first float valve 420 comes into contact with the seat portion 193, the ascending operation of the first float valve 420 is stopped.

  9B, the second float valve 430 is separated from the float support plate 440 after the throttle plate 450 abuts against the seat portion 193 and the ascending operation of the first float valve 420 is stopped. Then it gradually rises as the liquid level rises. Further, the second float valve 430 has a higher specific gravity than the first float valve 420, and therefore rises with a slight delay.

  Accordingly, when the liquid level L in the underground tank 12 reaches the upper limit liquid level Hmax when a predetermined time has elapsed after the throttle plate 450 provided in the first float valve 420 contacts the seat portion 193, the first level is reached. An annular packing 432 fixed to the upper end of the second float valve 430 closes the throttle 454 of the throttle plate 450. Thereby, the unloading to the underground tank 12 is stopped and excessive injection into the underground tank 12 is prevented.

  Thus, since the first float valve 420 and the second float valve 430 are closed in a stepwise manner, the float valve mechanism 410 in the unloading operation to the underground tank 12 by the tank truck 20 is performed in the underground tank 12. The unloading is not stopped abruptly when the liquid level L reaches the upper limit liquid level, but after the valve closing operation by the first float valve 420, the flow area of the throttle 454 of the throttle plate 450 depends on the flow area. The oil liquid unloading due to the air flow rate is reduced to a small amount.

  Further, due to the stepwise closing operation by the first float valve 420 and the second float valve 430, unloading from the liquid injection line 18 is stopped with a predetermined time difference, and the unloading hose 28 Can reduce the impact of stopping unloading. Note that the valve closing time difference between the first float valve 420 and the second float valve 430 can be set in advance by the difference in height of the respective upper end positions and the specific gravity of the respective materials. The material may be selected so that the time difference is as follows.

  FIG. 10 is an enlarged vertical cross-sectional view illustrating an overloading prevention valve 80D according to the fourth embodiment. In FIG. 10, the same parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  As shown in FIG. 10, the excessive unloading prevention valve 80 </ b> D is provided with a plurality of constricted portions 500 formed in a conical shape inserted into the vent hole 194 of the seat portion 193 on the upper surface of the float valve body 210. Yes. The plurality of throttle portions 500 are erected at predetermined intervals in the circumferential direction on the same radius facing the vent hole 194 of the sheet portion 193 and have a tapered surface. The narrowed portion 500 protrudes upward such that a sharp tip is located at the center of the vent hole 194 of the sheet portion 193.

  Here, the valve closing operation of the excessive unloading prevention valve 80D will be described. When the liquid level L in the underground tank 12 rises and comes into contact with the bottom surface of the float valve body 210, the float valve body 210 rises together with the liquid level L while receiving buoyancy from the liquid level L. The sheet portion 193 is inserted into the vent hole 194.

  Since the restricting portion 500 has a conical shape, the flow passage area of the vent hole 194 is more restricted as the float valve body 210 is raised. Therefore, the unloading flow rate to the underground tank 12 by the tank truck 20 is gradually reduced in the flow passage area of the vent hole 194 by the ascending operation of the restricting portion 500 as the liquid level rises. The unloading flow rate from the tank truck 20 is gradually reduced by the amount of air corresponding to the decrease in the flow passage area of the vent hole 194.

  When the vent hole 194 is closed by the throttle unit 500, the exhaust from the underground tank 12 is stopped. Thereby, the unloading to the underground tank 12 is stopped and excessive injection into the underground tank 12 is prevented.

  Therefore, the excessive unloading prevention valve 80D does not stop the unloading suddenly when the liquid level L in the underground tank 12 reaches the upper limit liquid level, but according to the throttle amount of the passage area of the vent hole 194. The unloading of the oil liquid is continuously (steplessly) reduced by the air flow rate. Therefore, the valve closing operation of the float valve body 210 can alleviate the impact caused by the unloading stop on the unloading hose 28.

  In the above embodiment, the underground tank facility installed in the gas station has been described as an example. However, the present invention is not limited to this, and when overloading in a tank on the ground provided in a facility other than the gas station is performed. Of course, the present invention can also be applied.

  Further, in the above embodiment, the case of unloading the oil liquid from the tank truck to the underground tank is illustrated, but the present invention is also applied to the case of unloading a liquid other than the oil liquid (for example, a liquid such as a chemical or food). Of course, can be applied.

It is a block diagram which shows one Example of the tank installation by this invention. It is a longitudinal cross-sectional view which expands and shows the attachment state of the piping joint 60 of Example 1, and the excessive unloading prevention valve 80A. 6 is a bottom view showing the configuration of a sheet portion 193. FIG. It is a longitudinal cross-sectional view for demonstrating the valve closing operation | movement of the excessive unloading prevention valve 80A of Example 1. FIG. It is a longitudinal cross-sectional view which expands and shows the attachment state of the excessive unloading prevention valve 80B of Example 2. FIG. 3 is a perspective view showing a configuration of a tool 320. FIG. It is a longitudinal cross-sectional view which expands and shows the attachment state of 80 C of excessive unloading prevention valves of Example 3. FIG. 5 is a plan view showing a configuration of a diaphragm plate 450. FIG. FIG. 6 is a longitudinal sectional view for explaining a stepwise valve closing operation of the float valve mechanism 410. It is a longitudinal cross-sectional view which expands and shows the attachment state of overload prevention valve 80D of Example 4. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Underground tank equipment 12 Underground tank 14 Measuring machine 16 Manhole 20 Tank truck 22 Oil supply line 24 Oil supply line 26 Ventilation line 28 Unloading hose 50 Standing line 60 Pipe joint 62 Lower connection port 66 Maintenance port 80A, 80B, 80C, 80D Overload prevention valve 180, 280 Upper pipe 183 Ventilation flow path 184 Small hole 190, 290 Lower pipe 193 Seat part 194 Vent hole 200 Float guide shaft 210 Float valve element 220 Packing 282 Guide part 286 Vent hole 292 Sliding Movement guide portion 300 Height adjusting screw 310 Disk-shaped member 320 Seal member 330 Float seat member 340 Sliding plate 350 Tool 410 Float valve mechanism 420 First float valve 430 Second float valve 440 Float support plate 450 Aperture plate 454 Aperture 50 Throttle portion

Claims (5)

A tank for storing liquid inside,
An infusion line for injecting liquid into the tank;
A supply line for supplying liquid in the tank to an external device;
A pipe joint that relays a rising pipe communicated with the tank and a horizontal pulling pipe extending in a horizontal direction from the rising pipe;
In a tank facility comprising: a vent line that communicates with the horizontal pulling line and that sucks and discharges air according to a change in the liquid level of the tank.
An over-injection prevention valve is provided that shuts off a vent flow path communicating with the vent pipe when the liquid level of the liquid poured from the liquid fill pipe reaches an upper limit liquid level inside the tank. Tank equipment to do.   2. The over-injection prevention valve is provided so as to be movable in a vertical direction with respect to the pipe joint, and can be adjusted to an arbitrary height position corresponding to an upper limit liquid level inside the tank. Tank equipment as described in. The pipe joint is provided with an opening at the top and a lid member that closes the opening,
The tank facility according to claim 1, wherein the over-injection prevention valve is configured such that a position in a vertical direction can be adjusted from an upper opening of the pipe joint.   The tank equipment according to claim 1, wherein the over-injection prevention valve is configured to throttle the valve opening stepwise as the liquid level in the tank rises.   The tank facility according to claim 1, wherein the over-injection prevention valve is configured to continuously throttle the valve opening as the liquid level rises in the tank.

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