JP5539282B2 - Relief valve - Google Patents

Description

  The present invention is used for a closed container such as a tank, and when the pressure in the closed container reaches a set value, the gas in the closed container is released to the outside so as to ensure the soundness of the closed container. Relates to the relief valve.

  In the above-described sealed container, the internal pressure may increase due to a change in temperature, a change in internal vapor pressure, or the like, and may reach a set pressure or higher.

  For example, in a tank as an airtight container installed in a chemical tanker, an oil tanker, or the like, the gas in the tank may be compressed due to the loading of the load, and the internal pressure may increase. For safety reasons, the surplus space where the load is loaded is filled with an inert gas or the like. In this case, the inert gas may expand due to the temperature, and the internal pressure may increase.

  In order to suppress such pressure rise, a relief valve is provided in the sealed container, and when the internal pressure reaches the set pressure, the gas in the sealed container is released to the outside and the internal pressure is kept within the set pressure. To be done.

For example, in a relief valve installed in a chemical tanker or the like, the intrusion of a fire into the tank is prevented by always exhausting upward at a high speed of 30 m / sec or more from the opening to the closing of the valve. Safety measures are taken.
In order to increase the exhaust speed to 30 m / sec or higher, it is necessary to increase the valve opening speed of the valve element. As a method of increasing the valve opening speed of the valve body by using this tank internal pressure, a first pressure receiving surface for opening the valve body at a set pressure and a second pressure receiving surface having a larger area are provided. There is a method of increasing the valve opening speed by applying an internal pressure from the first pressure receiving surface to the second pressure receiving surface. In this method, the force to lift the valve body increases by the area ratio between the first pressure receiving surface and the second pressure receiving surface, so that the valve opening speed can be increased by increasing this area ratio.

  However, in this method, conversely, since the valve is not closed unless the pressure is sufficiently lower than the set pressure required for opening the valve, so much inert gas is released. This is because the function of the second pressure receiving surface for increasing the valve opening speed acts reversely in the valve closing operation.

  In this regard, the technique described in Patent Document 1 is intended to prevent the repetitive phenomenon of the opening and closing operation of the relief valve due to the pressure change of the released gas when the internal gas is released. By providing a magnet that pulls the valve body downward, the valve closing speed is increased so that an early sealing operation can be performed when the pressure drops below the set pressure.

Japanese Patent No. 4282326

However, such a method of providing a magnet that draws the valve body downward has problems to be solved in the following points.
(1) The manufacturing cost is increased by the amount of magnets that are expensive parts.
(2) The number of parts such as not only magnets but also magnet mounting means increases.
(3) Since the relief valve is often installed in a tanker or the like, the magnet is corroded by corrosive gas.
(4) Since the magnet attracts iron, iron easily adheres to the valve box where the magnet exists.
In the pressure valve described in Patent Document 1, there is still room for improvement in the responsiveness of the valve opening operation.
Thus, conventionally, it has been difficult to achieve both the responsiveness of the valve opening operation and the responsiveness of the valve closing operation.
For these reasons, there has been a demand for a novel solution that can enhance the responsiveness in both the gas release operation during valve opening and the sealing operation during valve closing.

  The present invention has been made in view of the above-described conventional problems, and includes a gas releasing operation when the pressure in the sealed container exceeds a set value, and a sealing operation when the pressure falls below the set value. It is an object of the present invention to provide a novel technique that can improve responsiveness.

- relief valve of the present invention, in order to solve the aforementioned problems, a valve body, the valve body is energized and a valve body a valve seat which is brought into contact is formed hermetically, the valve box When the pressure of the introduced gas reaches a set value, the relief valve is configured to release the gas in the valve box to the outside by separating the valve body from the valve seat by the pressure, The valve body is provided with a movable body that is provided integrally with the valve body and that forms the gas flow path between the valve body and the inner wall of the valve box. Is formed, and a second pressure receiving surface on which the pressure in the valve box acts when the valve body is separated from the valve seat is formed on the movable body. A third pressure receiving surface for receiving the pressure in the valve box is formed, and the valve body is separated from the valve seat on the inner wall of the valve box. When the, is characterized in that the small diameter portion narrowing the flow path in cooperation with said movable member is formed.

  With such a configuration, when the pressure in the valve box reaches a predetermined pressure, the valve body and the movable body move in the valve opening direction by the force acting on the first pressure receiving surface formed on the valve body. Be made.

  In the initial stage of the valve opening operation, when the valve body is separated from the valve seat, the second pressure receiving surface formed on the valve body is communicated with the valve box, and the second pressure receiving surface is connected to the inside of the valve box. And the force acting on the second pressure receiving surface is applied to the valve body, so that the valve opening operation of the valve body is accelerated.

  In the state in which the valve body is in the valve closing position, the gas pressure surrounding the movable body inside the valve box is constant, and therefore no force in the opening / closing direction of the valve acts on the movable body.

When the valve opening operation by the force acting on the first pressure receiving surface and the second pressure receiving surface proceeds, the pressure on the valve body side of the movable body (that is, the downstream side of the flow path) decreases, and the flow path of the movable body A force for moving the movable body in the valve opening direction is newly added to the upstream side of the valve.
Thereby, the valve opening operation of the valve body is accelerated.

  When the valve opening operation further proceeds, the movable body moves to the small diameter portion of the valve box and the flow path in the valve box is narrowed, thereby increasing the gas pressure on the upstream side of the movable body. The acting force in the valve opening direction is further increased, and the valve opening operation of the valve body is further accelerated.

  Thus, after the force acting on the second pressure receiving surface is added to the force acting on the first pressure receiving surface, and further the force acting on the movable body is added, this force is amplified as the pressure increases. Thus, the valve opening operation of the valve body is performed quickly.

  On the other hand, the valve closing operation is performed in reverse to the valve opening operation described above, but before the pressure acts effectively on the second pressure receiving surface, the movable body moves away from the small diameter portion of the valve box and moves to the large diameter portion. Be positioned.

At this time, the gas pressure on the upstream side of the movable body decreases, and thereby the force in the valve opening direction applied to the movable body decreases.
At this time, since the valve body is moving in the valve closing direction, the valve body is brought into contact with the valve seat by the inertia force and the decrease in the force in the valve opening direction acting on the movable body described above. And the relief valve is closed.
Therefore, the valve body is quickly closed.

  The amount of decrease in the force in the valve opening direction acting on the movable body can be adjusted by changing the design of the inner diameter difference between the small diameter portion and the large diameter portion of the valve box. If the force is set larger than the force in the valve opening direction generated on the second pressure receiving surface during the valve closing operation, the valve closing operation is further accelerated.

  In addition, the adjustment of the amount of decrease in the force in the valve opening direction acting on the movable body described above is also the adjustment of the pressure at the time of valve closing. It is possible to set the pressure.

Therefore, it is possible to bring the pressure at the time of closing the valve as close as possible to the set pressure at the time of opening the valve, and it is possible to suppress excessive gas discharge and suppress excessive pressure drop in the sealed container in which the relief valve is installed. it can.
Incidentally, it is considered that the pressure when the valve is closed is preferably about 70% to 80% of the set pressure when the valve is opened.

  Thus, if excessive gas release is suppressed, it can be expected that, for example, the release amount of an inert gas or the like to be filled for safety is reduced to reduce the management cost.

A preferred form of the relief valve of the present invention, the pressure receiving surface is further characterized in that said first an area larger than the pressure receiving surface.
By setting it as such a structure, the valve opening operation | movement of a valve body can be made quicker.

A preferred form of the relief valve of the present invention, the movable body, and a large diameter portion and a small diameter portion, when the valve body has been moved away from the valve seat, wherein a large diameter portion of said movable member The flow path is narrowed between the small diameter portion of the valve box.
In such a configuration, a function like a valve body can be given to the large diameter portion of the movable body and a function like a valve seat can be given to the small diameter portion of the valve box with a simple structure.

Preferred embodiments of the relief valve of the present invention, the valve box, that the guide portion into which the valve body is brought slidably fitted in an airtight state is formed to surround the second pressure receiving surface It is a feature.

  By setting it as such a structure, the force which acts on a 2nd pressure receiving surface can be obtained reliably by suppressing the quantity of the gas exhausted from a 2nd pressure receiving surface by the said guide part.

Preferred embodiments of the relief valve of the present invention, the valve body and the movable body is movable in the vertical direction, and wherein the valve body is biased toward the valve seat by their mass To do.

  By adopting such a configuration, only for the total mass of the mass of the valve body and the mass of the movable body, various conditions for the valve opening operation and the valve closing operation are set, the areas of the various pressure receiving surfaces, the movable body Therefore, the setting is simple and easy.

  According to the present invention, it is possible to improve the responsiveness of the gas release operation when the pressure in the sealed container exceeds the set value and the seal operation when the pressure falls below the set value.

It is a longitudinal section showing one embodiment of the present invention. It is a longitudinal section for explaining operation of one embodiment of the present invention. It is an expanded longitudinal cross-sectional view of the principal part which shows one Embodiment of this invention. It is a front view which shows other embodiment of the movable body of this invention.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 3.
In FIG. 1, the code | symbol 1 has shown the relief valve concerning this embodiment. The relief valve is a valve box 3 having a valve body 2, a gas inlet 3 a that is attached to a sealed container (not shown) and communicates with the inside thereof, and a gas outlet 3 b that discharges the gas in the sealed container to the outside. And.

  A movable body 4 that forms a gas flow path L between the valve body 2 and the inner wall of the valve box 3 is coaxially provided. The valve body 2 has a substantially frustoconical shape in which the first pressure receiving surface 2a on which the pressure in the valve box 3 always acts and the valve body 2 are formed on the inner surface of the gas outlet 3b of the valve box 3 are formed. A second pressure receiving surface 2b is formed on which the pressure in the valve box 3 acts when separated from the valve seat 3c. The movable body 4 is formed with a third pressure receiving surface 4a larger than the first pressure receiving surface 2a. When the valve body 2 is separated from the valve seat 3c, a small-diameter portion 3d that narrows the flow path L in cooperation with the movable body 4 is formed on the inner wall of the valve box 3. The upstream side of the portion 3d is a large diameter portion 3e. Reference numeral 3f denotes an intake valve mounting portion.

The valve body 2 and the movable body 4 are integrally attached to an upper end portion and a substantially intermediate portion of a rod 5 which is mounted on a central portion of the valve box 3 so as to be able to reciprocate in one direction (vertical direction in the present embodiment). It has been.
That is, the movable body 4 is fitted on the rod 5 and is attached to the rod 5 with the pin 6 being restricted from moving in the axial direction. It is fixed to the rod 5 by nuts 8 screwed at intervals.

The valve body 2 is fitted on the rod 5, a step portion (not shown) formed in the vicinity of the upper end portion of the rod 5, and a nut 9 screwed onto the end portion of the rod 5, It is clamped and fixed by.
Further, the second pressure receiving surface 2b formed on the valve body 2 is formed in an outer surface shape substantially the same as the inner surface shape of the valve seat 3c, and is brought into airtight contact with the valve seat 3c. It has become.

  The valve box 3 is constituted by a main body 10 having a cylindrical shape and a stay 10a formed at a substantially intermediate portion, and a lid 11 detachably attached to an upper end portion of the main body 10.

  A guide bush 12 to which the rod 5 is slidably fitted is integrally attached to the center of the stay 10a. Further, the valve seat 3c is formed on the inner surface of the upper end portion of the lid body 11, and a guide 13 into which the rod 5 is slidably fitted is provided at a plurality of stays 14 at a substantially intermediate portion in the vertical direction. It is provided integrally through.

As shown in FIG. 1, the relief valve 1 according to the present embodiment configured as described above causes the second pressure receiving surface 2 b of the valve body 2 to abut against the valve seat 3 c of the lid body 11 in an airtight manner over the entire circumference. As a result, the valve is closed.
In the present embodiment, the valve body 2 and the movable body 4 and the contact between the valve body 2 and the valve seat 3c are determined by the mass of the rod 5, the stopper 7, the pin 6, the nut 8, the nut 9, and the like that connect them. Contact is made.

The relief valve 1 used by being connected to a closed container (not shown) such as a tanker tank has an internal pressure balanced with the pressure in the closed container, and the pressure is the first pressure receiving pressure of the valve body 2. Acting on the surface 2a, a force in the valve opening direction is acting.
And since the said valve body 2 is located in the valve closing position in the said movable body 4, since the uniform pressure is acting over the perimeter, the force by gas does not act.

  When the pressure in the sealed container rises, the pressure in the valve box 3 also rises, the force in the valve opening direction acting on the first pressure receiving surface 2a increases, and when the pressure becomes 2 or higher, the valve body 2 It is moved in the opening direction.

  As the valve body 2 moves in the opening direction, the second pressure receiving surface 2b moves away from the valve seat 3c, and pressure is applied to the second pressure receiving surface 2b to generate a force in the valve opening direction. The valve body 2 is moved in the valve opening direction together with the force applied to the pressure receiving surface 2a.

Further, when the valve opening operation of the valve body 2 continues, as shown in FIG. 2, the valve box 3 is largely opened, and the pressure on the valve seat 3c side of the movable body 4 is reduced.
As a result, a pressure difference is generated between the upstream side and the downstream side of the flow path L of the movable body 4, and the movable body 4 is moved in the direction of the valve seat 3 by this pressure difference.

  Further, due to the movement of the movable body 4, the movable body 4 moves to the small diameter portion 3 d of the valve box 3 to narrow the flow path L, the pressure on the upstream side of the movable body 4 increases, and the valve opening of the movable body 4 is performed. The pressing force in the direction is increased.

  Thus, a plurality of pressing forces are combined to act in the valve opening direction, and the valve opening speed is significantly improved.

When the pressure in the closed container becomes lower than the set pressure, the valve closing operation is started. During this valve closing operation, the force for moving the valve body 2 in the opening direction is the large diameter portion of the movable body 4. It decreases rapidly by moving to 3e.
Therefore, the valve body 2 moves rapidly toward the valve closing position, and quick valve closing is performed in combination with the inertia force.

  Note that the shapes, dimensions, and the like of the constituent members shown in the above embodiment are merely examples, and various changes can be made based on design requirements and the like.

  For example, as shown in FIG. 3, a guide portion 15 is formed in the valve box 3 so that the valve body 2 is slidably fitted in an airtight state so as to surround the second pressure receiving surface 2b. The action of pressure on the second pressure receiving surface 2b can be enhanced.

Moreover, although the movable body 4 of the said embodiment has shown the example which cut the thick cylindrical member and formed the small diameter part and the large diameter part, as this movable body 4 is shown in FIG. Alternatively, it may be constituted by a cylindrical main body portion 41 and a perforated disk 42 fixed to the upper end portion thereof.
When configured in this manner, the productivity of the movable body 4 itself is easy, and the cost can be further reduced.

DESCRIPTION OF SYMBOLS 1 Relief valve 2 Valve body 2a 1st pressure receiving surface 2b 2nd pressure receiving surface 3 Valve box 3a Gas inlet 3b Gas outlet 3c Valve seat 3d Small diameter part 3e Large diameter part 4 Movable body 5 Rod 6 Pin 7 Stopper 8 Nut 9 Nut 10 Body 10a Stay 11 Lid 12 Guide bush 13 Guide 14 Stay 15 Guide part

Claims (5)

A valve body and a valve box formed with a valve seat that is urged and brought into airtight contact with the valve body, and when the pressure of the gas guided to the valve box reaches a set value, A relief valve in which the valve body is separated from the valve seat to release the gas in the valve box to the outside;
The valve body is provided with a movable body that is provided integrally with the valve body and forms the gas flow path between the valve body and the inner wall of the valve box,
A first pressure receiving surface on which the pressure in the valve box always acts on the valve body, and a second pressure receiving surface on which the pressure in the valve box acts when the valve body is separated from the valve seat. And formed,
The movable body is formed with a third pressure receiving surface that receives the pressure in the valve box,
The inner wall of the valve box is formed with a small diameter portion that narrows the flow path in cooperation with the movable body when the valve body is separated from the valve seat,
The valve box is formed so that a guide portion that is slidably fitted in the valve body in an airtight state surrounds the second pressure receiving surface,
The relief valve according to claim 1, wherein the guide portion rises from the outer peripheral portion of the valve seat toward the valve body .   The relief valve according to claim 1, wherein the third pressure receiving surface is larger than the first pressure receiving surface.   The movable body has a large-diameter portion and a small-diameter portion, and when the valve body is separated from the valve seat, the movable body is between the large-diameter portion of the movable body and the small-diameter portion of the valve box. The relief valve according to claim 1, wherein the flow path is narrowed. Said valve body and movable body, movable in the vertical direction, the mass by according to claim 1, wherein the valve body is characterized in that it is biased toward the valve seat Relief valve. The relief valve according to claim 1 , wherein the means for biasing the valve body is a spring.

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