JP4119912B2 - Intake and exhaust valves - Google Patents

Description

  The present invention relates to an intake / exhaust valve provided in a vent pipe that communicates with outside air from a tank that stores volatile liquids such as petroleum.

As a tank for storing a volatile liquid, for example, in an underground storage tank of a gas station, as shown in FIG. 2 , in addition to a liquid level sensor pipe B for checking the level of stored fuel in the underground tank A In addition, the piping related to the increase or decrease of the stored fuel in the underground tank A includes a piping C for unloading the fuel from the lorry vehicle to the underground tank A, and a fuel supply pipe D for supplying fuel to consumers. Furthermore, in order to adjust the gas pressure in the underground tank, a vent pipe E opened to the outside air from the space in the underground tank A is provided. That is, in the underground tank A, since the internal pressure changes due to the taking in and out of fuel, vaporization, etc., the vent pipe E is provided to connect the gas phase portion of the underground tank A and the outside air, and the internal pressure and the outside air pressure of the underground tank A are Try to match.

  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 steam such as gasoline was continuously released from the tank to the outside air.

  However, in recent years, due to the growing awareness of environmental problems, the release of harmful steam to the outside air has been regarded as a problem. For example, as described in Patent Document 1, a structure having an intake valve and an exhaust valve is provided. It is being adopted. The applicant of the present application also proposed an intake / exhaust valve applied to a vent pipe in Japanese Patent Application No. 2005-224484.

FIG. 3 shows the structure of an intake / exhaust valve proposed by the present applicant. The intake / exhaust valve shown in FIG. 3 includes a circular exhaust port 2 and a disc-shaped exhaust valve body 3 provided at the top of the valve body 1 as an exhaust valve, and the exhaust valve body 3 normally has the exhaust port 2. Is closed from above, and when the pressure in the tank rises, the pressure rises due to the pressure and the exhaust port 2 is opened. Further, the intake valve closes the intake port 8 provided in the exhaust valve body 3 from the lower side when the intake valve body 7 is normal, and when the pressure in the tank decreases, the intake valve lowers due to a differential pressure from the external pressure. The mouth 8 is configured to be opened.
JP 2001-163400 A

However, in the intake / exhaust valve as shown in FIG. 3 , the intake valve and the exhaust valve are deteriorated due to secular change, or rust in the ventilation pipe due to blowing up from the tank or the like adheres to the operation parts of the intake valve and the exhaust valve. Otherwise, it may not work properly. When the intake valve and the exhaust valve do not operate normally, the tank is pressurized or depressurized. In particular, if the intake valve malfunctions and outside air cannot be sucked, the tank may be excessively depressurized and serious damage may occur, such as damage to the tank.

  The problem to be solved by the present invention is that, in an intake / exhaust valve provided in a vent pipe communicating with the outside air from the inside of the tank, the outside air can be sucked even if the intake valve malfunctions, and the tank is excessively depressurized. It is to be able to prevent.

The present invention provides an intake / exhaust valve provided in a vent pipe that communicates with the outside air from the inside of the tank, and includes an exhaust valve and an intake valve that maintain the pressure in the tank within a certain range. As an auxiliary intake mechanism that intakes outside air when the pressure reaches a predetermined pressure, an auxiliary intake valve that opens and closes an auxiliary intake port provided in the intake valve body of the intake valve is provided.

In order to reliably perform intake by the auxiliary intake valve, the auxiliary intake valve is preferably configured to operate (open) at a pressure lower than or equal to the operating pressure of the intake valve. On the other hand, depending on the type of volatile liquid in the tank, the usage environment, and the like, when the auxiliary intake valve is always operated, there is a risk that the aging, wear, etc. of the parts constituting the auxiliary intake valve will be remarkably manifested. If there is such a risk, the auxiliary intake valve is operated at a pressure stronger than the operating pressure of the intake valve, and the auxiliary intake valve is not operated at all times without being operated at all times, that is, It can be operated only when the pressure in the tank is out of a certain range.

  Further, the auxiliary intake mechanism can also be configured by an auxiliary intake port provided in the vicinity of the intake valve body of the intake valve and a valve membrane that closes the auxiliary intake port. In this case, when the pressure in the tank becomes lower than the operating pressure of the intake valve, the valve membrane is ruptured to take in the outside air. Of course, the valve membrane is set so as to be ruptured before the pressure is reduced so that the tank is damaged.

  According to the present invention, even if the intake valve malfunctions, outside air can be sucked in by the auxiliary intake mechanism, so that the tank is prevented from being excessively depressurized, and the tank is damaged. Serious damage can be prevented.

  Embodiments of the present invention will be described below based on the embodiments shown in the drawings. In the following examples, the intake / exhaust valve of the present invention was provided at the tip of the vent pipe.

Figure 1 shows an embodiment of the intake and exhaust valves of the present invention. The intake / exhaust valve shown in FIG. 1 includes, as an exhaust valve, a circular exhaust port 2 and a disc-shaped exhaust valve body 3 provided in the upper part of the valve body 1, and the exhaust valve body 3 is normally used as an exhaust port. 2 is closed from the upper side, and when the pressure in the tank rises, the pressure rises due to the pressure, and the exhaust port 2 is opened. The specified opening pressure (pressure when the exhaust valve body 3 just rises) 5 kPa was used. 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.

  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 specified opening pressure is adjusted to 5 kPa.

  The weight 5 also functions as the guide portion 6. 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 body 3 moves up and down, it is guided by the guide portion 6 so that the vertical movement of the exhaust valve 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 intake / exhaust valve shown in FIG. 1 includes an intake valve in addition to the 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 due to a differential pressure from the outside air 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, and the regulation pressure for opening (the pressure when the intake valve body 7 is just lowered) is adjusted by a coil. This is done by adjusting the strength of the spring 9. In the examples, the regulation pressure for opening was adjusted to be -5 kPa.

  In the intake / exhaust valve of FIG. 1 having the intake valve and the exhaust valve in this way, when a high pressure of 5 kPa or more is generated in the tank due to an increase in the inventory amount due to unloading to the tank or the like, the viewpoint of safety The exhaust valve automatically opens to release the pressure to the outside air and maintain a high pressure range within 5 kPa. At other times, the exhaust valve with improved airtightness by the O-ring mechanism is always closed, forming a substantially sealed space in the tank and actively reducing volatilization loss.

  If a low pressure of -5 kPa or less occurs in the tank due to a decrease in inventory due to refueling from the weighing machine to the car, etc., the intake valve automatically opens and the outside air is taken in. Avoid negative pressure of 5 kPa or less. At other times, the intake valve is always closed, forming an almost sealed space and actively reducing volatilization loss. In addition, the tank is temporarily in a negative pressure state due to a decrease in inventory due to refueling from the weighing machine to the car, but after refueling etc., the pressure higher than atmospheric pressure is maintained within 5 kPa due to the volatilization of liquid fuel. .

  Thus, in the intake / exhaust valve of FIG. 1, if the intake valve and the exhaust valve are operating normally, the pressure in the tank is maintained within a certain pressure range (± 5 kPa). However, when the intake valve and the exhaust valve do not operate normally, the tank is pressurized or depressurized. In particular, if the intake valve malfunctions and outside air cannot be sucked, the tank may be excessively depressurized and serious damage may occur, such as damage to the tank.

  Therefore, in the embodiment of FIG. 1, an auxiliary intake valve is provided as an auxiliary intake mechanism. This auxiliary intake valve closes the auxiliary intake port 16 provided in the intake valve main body 7 from the lower side when the auxiliary intake valve main body 15 is normal. When the pressure in the tank decreases, the auxiliary intake valve lowers due to the differential pressure from the external pressure. As shown in FIG. 1B, the auxiliary intake port 16 is configured to be opened. Therefore, even if the intake valve malfunctions, outside air can be taken in by the auxiliary intake valve, so that the tank is prevented from being excessively decompressed.

  The auxiliary intake valve body 15 is normally urged upward by a coil spring 17 so as to close the auxiliary intake port 16, and has a specified opening pressure (pressure when the auxiliary intake valve body 15 is just lowered). The adjustment is performed by adjusting the strength of the coil spring 17. In the embodiment, the opening pressure is adjusted to be −3 kPa so that the pressure is lower than that of the intake valve body 7. In addition, when setting so that the auxiliary | assistant intake valve main body 15 may operate | move with a pressure stronger than the intake valve main body 7, the regulation pressure of the opening shall be about -6kPa.

  The contact area between the auxiliary intake valve main body 15 and the auxiliary intake valve valve seat 21 is smaller than the contact area between the intake valve main body 7 and the intake valve valve seat 22. As a result, even if the intake valve malfunctions due to adhesion of rust or the like in the vent pipe due to blowing up from the tank or the like, the similar malfunction of the auxiliary intake valve is less likely to occur.

  The auxiliary intake valve is not necessarily provided integrally with the intake / exhaust valve, and can be provided at a location where outside air can be sucked, for example, at the vent pipe E.

  Further, the intake / exhaust valve shown in FIG. 1 includes a strainer 20 for dust removal on the side of the vent pipe E. By providing the strainer 20, dust such as rust in the ventilation pipe E due to blowing up from the tank or the like is captured, so that dust does not easily adhere to the intake valve and the exhaust valve, and malfunction does not easily occur.

  Furthermore, the intake / exhaust valve shown in FIG. 1 includes a fire net 10 so that flames do not enter the tank from the intake / exhaust 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. Further, a cap 13 is provided above the fire net 10 to remove rain and dust, and is fixed to the vent valve body 1 by a tapping screw 14. As described above, in the intake / exhaust valve shown in FIG. 1, no housing other than the fire net 10 and the cap 13 is provided above the exhaust port 2 and the exhaust valve body 3 (outside air side), and the fire net 10 is exhausted. Since it is provided so as to cover the upper part of the port 2 and the exhaust valve main body 3, the portion of the fire net that becomes the vent can be widened, and a sufficient vent area can be secured.

1 shows an embodiment of an intake / exhaust valve of the present invention. A typical gas station piping is shown. The structure of the conventional intake / exhaust valve is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Valve body 2 Exhaust port 3 Exhaust valve body 4 O-ring 5 Weight 6 Guide part 7 Intake valve body 8 Inlet 9 Coil spring 10 Fire net 11 Caulking pin 12 Clasp 13 Cap 14 Tapping screw 15 Auxiliary intake valve body 16 Auxiliary intake Port 17 Coil spring 20 Strainer 21 Auxiliary intake valve seat 22 Intake valve seat

Claims (4)

In an intake / exhaust valve provided with an exhaust valve and an intake valve that is provided in a vent pipe that leads to the outside air from the inside of the tank and maintains the pressure in the tank within a certain range,
In addition to the intake valve, an auxiliary intake valve that opens and closes the auxiliary intake port provided in the intake valve body of the intake valve is provided as an auxiliary intake mechanism that takes in outside air when the pressure in the tank reaches a predetermined pressure. An intake and exhaust valve characterized by The intake / exhaust valve according to claim 1, wherein the auxiliary intake valve is operated at a pressure lower than or equal to an operation pressure of the intake valve. The intake / exhaust valve according to claim 1 , wherein the auxiliary intake valve is operated at a pressure stronger than an operation pressure of the intake valve. The contact area between the auxiliary intake valve body of the auxiliary intake valve and the valve seat portion for the auxiliary intake valve is smaller than the contact area between the intake valve body of the intake valve and the valve seat portion for the intake valve. The intake and exhaust valves described in 1.

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