JP4276643B2 - Exhaust valve - Google Patents

Description

  The present invention relates to an exhaust valve provided in a vent pipe that communicates a gas phase portion of a tank that stores a volatile liquid such as petroleum with outside air.

  In gas stations that handle petroleum, such as gasoline and light oil, underground tanks are used for storage. And since the internal pressure of this underground tank changes due to the taking in and out of petroleum, vaporization, etc., a vent pipe is provided to communicate the gas phase part of the underground tank with the outside air so that the inside pressure of the tank matches the outside pressure. I have to.

  Conventionally, a vent pipe is generally provided as a simple pipe, and a fire net of about 40 mesh is attached to the vent on the outside air side so that a flame does not enter the tank even if a fire occurs outside. However, the inside of the tank and the outside air were always in communication with each other, and in normal times, harmful vapors such as gasoline were continuously released from the tank to the outside air.

  However, in recent years, due to increasing awareness of environmental problems, the release of harmful steam to the outside air has been regarded as a problem, and for example, as shown in FIG. 3, a vent valve equipped with an exhaust valve and an intake valve is being installed. . In addition, as for petroleum stored in tanks, E3 gasoline containing 3% ethanol has begun to be used for testing due to environmental issues. In particular, since ethanol is a liquid that dislikes moisture, Has been approved by the fire department to install a ventilation valve to shut off the inside and outside air of the tank, and the installation of the ventilation valve is also in progress from this point.

  The conventional vent valve shown in FIG. 3 includes an exhaust valve and an intake valve inside a cap-shaped vent valve main body 100. For the exhaust valve, the exhaust valve main body 101 normally closes the exhaust port 102 from above, When the pressure in the tank rises, the pressure rises and the exhaust port 102 is opened. The exhaust valve body 101 is normally biased downward by a coil spring 103 so as to close the exhaust port 102, and the exhaust set pressure is adjusted by adjusting the strength of the coil spring 103. The gas discharged from the exhaust port 102 is released to the outside air from the vent port 104 provided on the side surface of the vent valve body 100. Further, a fire net 105 of about 40 mesh is attached to the vent 104 so that flames do not enter the tank even if an external fire occurs.

  On the other hand, with respect to the intake valve, when the intake valve body 106 is normally closed, the intake port 107 provided in the exhaust valve body 101 is closed from the lower side, and when the pressure in the tank is lowered, the intake valve body 106 is lowered due to the differential pressure from the external pressure The air inlet 107 is opened. The intake valve body 106 is normally urged upward by a coil spring 108 so as to close the intake port 107, and the intake set pressure is adjusted by adjusting the strength of the coil spring 108. When the intake valve body 106 moves downward and the intake 107 is opened, outside air flows into the tank through the vent 104 and the intake 107.

  However, in the conventional vent valve shown in FIG. 3, the exhaust valve has the following problems. That is, since the exhaust valve body is urged in the closing direction (downward) by the coil spring, when the pressure inside the tank rises and the exhaust valve body rises when unloading the tank, the amount of increase The larger the is, the stronger the force to close the exhaust valve body, and the coil spring tends to vary in the force on the periphery that tries to hold the exhaust valve body. There is a problem that a so-called chattering phenomenon that the exhaust valve body repeatedly opens and closes frequently occurs because the height difference of the opening of the body tends to occur. When this chattering phenomenon occurs, vibration sound and striking sound of the exhaust valve main body are generated, causing a problem of noise in the vicinity and a problem of shortening the valve life.

  On the other hand, Patent Document 1 discloses an exhaust valve in which the exhaust valve body is urged in the closing direction (downward) by the weight of the weight, and the exhaust set pressure is adjusted by the weight. Yes. The exhaust valve of Patent Document 1 is not intended to prevent chattering, but if the exhaust valve body is urged in the closing direction (downward) by the weight of the weight, the exhaust valve body rises. Since there is no change in the urging force due to the change in the amount, there is a possibility that the chattering phenomenon can be suppressed as compared with that shown in FIG.

  However, in the exhaust valve of Patent Document 1, since the weight for adjusting the exhaust set pressure is attached above the exhaust valve body, that is, above the exhaust port, the center of gravity of the exhaust valve body is higher than the position of the exhaust port. The balance becomes worse. Therefore, when the exhaust valve main body moves up and down, the balance is easily lost and tilted, and the chattering phenomenon may still occur, and the problem of the conventional exhaust valve shown in FIG. 3 cannot be solved.

Further, in the vent valve shown in FIG. 3, the gas from the tank passes through a fire net attached to the vent on the side of the vent valve body and is released to the outside air. There is also a problem that rust and dust are easily clogged in the fire net, and a sufficient ventilation area cannot be secured.
JP 2001-163400 A

  The problem to be solved by the present invention is to provide an exhaust valve capable of preventing the occurrence of chattering phenomenon in which the exhaust valve body repeatedly opens and closes due to fluctuations in pressure in the tank.

The present invention attaches a weight that urges the exhaust valve body in the closing direction (downward) so as to be positioned below the exhaust valve body and below the exhaust port, so that the center of gravity of the exhaust valve body is positioned. The above-described problem has been solved by providing a guide portion that is positioned below the exhaust port and inscribed in the inner peripheral edge of the exhaust port, and moving up and down while the exhaust valve body is guided by the guide portion .

That is, the exhaust valve of the present invention is an exhaust valve that is attached to a front end portion of an air pipe that communicates a gas phase portion of a tank that stores a volatile liquid and the outside air, and the gas in the tank is connected to the outside air side. a circular exhaust port for discharging to, and a disk-shaped exhaust valve body for opening and closing the exhaust port, the exhaust valve body is disposed so as to close the exhaust port from the upper, the exhaust valve body The weight is attached below the exhaust port so that the center of gravity of the exhaust valve body is located below the exhaust port. The exhaust set pressure is adjusted by the weight of the weight, and the exhaust the valve body, the pressure in the tank is above the exhaust set pressure rises by the pressure to open the exhaust port, descends by its own weight and the pressure in the tank is less than the exhaust set pressure to close the exhaust port, further The exhaust valve body has a circular exhaust The guide portion is inscribed in the inner peripheral edge of the mouth, and the guide portions are provided at three or more locations at equal intervals along the inner peripheral edge of the circular exhaust port, and the exhaust valve body is guided by the guide portion. It is characterized by moving up and down .

In the exhaust valve of the present invention, since the weight for urging the exhaust valve body in the closing direction (downward) is attached to the lower side of the exhaust valve body and below the exhaust port, the exhaust valve not only the change in the urging force is eliminated due to a change in the amount of increase in body, since the centroid position of the exhaust valve body and at a position lower than the outlet, the balance of the exhaust valve body is improved, it can move up and down smoothly become. As a result, the occurrence of chattering can be substantially eliminated.

Further, in the present invention, the exhaust valve body, the guide portion inscribed in the inner periphery of the circular outlet, provided in three or more at equal intervals along the inner periphery of the circular outlet, the exhaust valve body guide The vertical movement of the exhaust valve main body becomes smoother because it is configured to move up and down while being guided by the portion.

  Moreover, in this invention, it is preferable to cover the whole upper part of an exhaust port and an exhaust valve main body with a fire net. As a result, the portion of the fire net that serves as the vent can be widened, and a sufficient vent area can be secured.

  The present invention has the following effects.

  1. The occurrence of chattering phenomenon in which the exhaust valve body repeatedly opens and closes due to fluctuations in the pressure in the tank can be substantially eliminated, no noise problem occurs in the vicinity, and the life of the valve is extended.

  2. Since the fire net portion can be secured widely, a sufficient ventilation area can be secured even if rust, dust, etc. in the ventilation pipe are clogged.

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

  FIG. 1 is a cross-sectional view showing a vent valve provided with an exhaust valve according to an embodiment of the present invention. This vent valve is attached to the front end portion of the outside air side of a vent pipe (not shown) that communicates the gas phase portion of the tank that stores the volatile liquid and the outside air.

  In FIG. 1, the exhaust valve includes a circular exhaust port 2 and a disc-shaped exhaust valve body 3 provided in the upper part of the vent valve body 1, and the exhaust valve body 3 normally closes the exhaust port 2 from above. When the pressure in the tank increases, the pressure increases to open the exhaust port 2. An O-ring 4 is provided between the exhaust valve body 3 and the exhaust port 2 in order to ensure that the exhaust port 2 is closed by the exhaust valve body 3.

  Further, a weight 5 is integrally provided below the exhaust valve body 3. The weight 5 is extended so as to be positioned below the exhaust port 2. As a result, the center of gravity of the exhaust valve main body 3 is lower than the exhaust port 2, and the balance of the exhaust valve main body 3 is improved so that the exhaust valve main body 3 can move up and down smoothly. Further, by adjusting the weight of the weight 5, the exhaust set pressure (pressure when the exhaust valve main body 3 just rises) can be adjusted.

  The weight 5 also functions as the guide portion 6 in the present invention. The guide portions 6 are provided at four locations at equal intervals along the outer periphery of the exhaust valve body 3, and each guide portion 6 is provided so as to be inscribed in the inner peripheral edge of the exhaust port 2. As a result, when the exhaust valve main body 3 moves up and down, it is guided by the guide portion 5, so that the vertical movement of the exhaust valve main body 3 becomes smoother. In addition, in the Example, although the guide part 6 was provided in four places, what is necessary is just to provide in at least three places or more. However, it is preferable to provide each guide part at equal intervals in which the weight is balanced.

  The ventilation valve shown in FIG. 1 includes an intake valve in addition to the above-described exhaust valve. When the intake valve body 7 is normally closed, the intake valve 8 closes the intake port 8 provided in the exhaust valve body 3 from the lower side, and when the pressure in the tank is lowered, the intake valve is lowered by the differential pressure from the external pressure. 8 is configured to open. The intake valve body 7 is normally urged upward by a coil spring 9 so as to close the intake port 8. Adjustment of the intake set pressure (pressure when the intake valve body 7 is just lowered) is adjusted by a coil spring. This is done by adjusting the strength of 9.

  Further, the vent valve shown in FIG. 1 includes a fire net 10 so that a flame does not enter the tank from the vent valve even if a fire occurs outside. The fire net 10 is made of a metal mesh of about 40 mesh, is provided so as to cover the entire upper part of the exhaust port 2 and the exhaust valve body 3, and is fixed to the vent valve body 1 by caulking pins 11 and clasps 12. Yes. A cap 13 is provided above the fire net 10 to remove rain and dust, and is fixed to the vent valve main body 1 with a tapping screw 14. As described above, in the ventilation valve shown in FIG. 1, no housing is provided above the exhaust port 2 and the exhaust valve main body 3 (outside air side) except for the fire net 10 and the cap 13. 2 and the exhaust valve main body 3 are provided so as to cover the entire upper part of the exhaust valve body 3, the fire net portion serving as a vent can be widened, and a sufficient ventilation area can be secured.

  In the above configuration, at normal times when the pressure in the tank is substantially equal to the outside air pressure, the exhaust valve body 3 and the intake valve body 7 close the exhaust port 2 and the intake port 8, respectively, and the tank is shut off from the outside air, The gas in the tank is not released to the outside air. When the pressure in the tank rises above the set exhaust pressure, the exhaust valve body 3 rises due to the pressure and opens the exhaust port 2. The gas in the tank is exhausted from the exhaust port 2 and passes through the fire net 10 to the outside air side. To be released. When the pressure in the tank becomes lower than the exhaust set pressure due to this gas release, the exhaust valve body 3 descends due to its own weight and closes the exhaust port 2 again. As described above, the vertical movement of the exhaust valve main body 3 is very stable and smooth by providing the weight 5 and the guide portion 6 on the lower side of the exhaust valve main body 3, so that a chattering phenomenon occurs. There is no.

  On the other hand, when the pressure in the tank falls below the intake set pressure, the intake valve body 7 is lowered by the pressure difference from the external pressure to open the intake port 8, and the outside air passes through the fire net 10 and the intake port 8, and the tank Flows in. When the pressure in the tank exceeds the intake set pressure due to the outside air inflow, the intake valve body 7 is raised by the urging force of the coil spring 9 and closes the intake port 2 again.

  Thus, even if the pressure in the tank fluctuates, the pressure in the tank returns to a state almost equal to the external air pressure by the operation of the exhaust valve body 3 and the intake valve body 7.

  FIG. 2 is a cross-sectional view showing a vent valve provided with an exhaust valve according to another embodiment of the present invention. In the vent valve shown in FIG. 2, the same components as those of the vent valve in FIG.

  In the embodiment of FIG. 1, the weight 5 on the lower side of the exhaust valve body 3 and the guide portion 6 are made of the same member. However, in the embodiment of FIG. 2, the weight 5 is removably suspended from the guide portion 6. I have to. Specifically, a locking claw 6a is provided at the lower end of the guide portion 6, and the weight 5 is removably suspended by engaging an engaging portion 5a provided on the weight 5 with the locking claw 6a. .

  According to this embodiment, the weight 5 can be easily exchanged with one having a different weight, so that the exhaust set pressure can be adjusted arbitrarily and easily.

It is sectional drawing which shows the vent valve provided with the exhaust valve based on one Example of this invention. It is sectional drawing which shows the vent valve provided with the exhaust valve based on the other Example of this invention. It is sectional drawing which shows the vent valve provided with the conventional exhaust valve.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ventilation valve main body 2 Exhaust port 3 Exhaust valve main body 4 O-ring 5 Weight 5a Engagement part 6 Guide part 6a Locking claw 7 Intake valve main body 8 Inlet port 9 Coil spring 10 Fire net 11 Caulking pin 12 Clasp 13 Cap 14 Tapping Screw

Claims (2)

An exhaust valve attached to an outer air side tip of a vent pipe that communicates a gas phase portion of a tank that stores a volatile liquid and the outside air,
A circular exhaust port for discharging the gas in the tank to the outside air side, and a disc-shaped exhaust valve body for opening and closing the exhaust port,
The exhaust valve body is arranged to close the exhaust port from above,
By attaching a weight on the lower side of the exhaust valve body so as to be positioned below the exhaust port, the center of gravity of the exhaust valve body is positioned below the exhaust port,
The exhaust set pressure is adjusted by the weight of this weight, and when the pressure in the tank becomes equal to or higher than the exhaust set pressure, the exhaust valve body rises due to the pressure and opens the exhaust port, and the pressure in the tank becomes less than the exhaust set pressure. Then it descends by its own weight and closes the exhaust port ,
Further, the exhaust valve main body has a guide portion inscribed in the inner peripheral edge of the circular exhaust port, and the guide portions are provided at three or more locations at equal intervals along the inner peripheral edge of the circular exhaust port. An exhaust valve that moves up and down while being guided by the guide portion . The exhaust valve according to claim 1 , wherein the entire upper part of the exhaust port and the exhaust valve body is covered with a fire net.

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