JPH0219359B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a liquefied gas evaporator that evaporates and consumes liquefied gas in a storage tank using atmospheric heat, and particularly relates to a liquefied gas evaporator that consumes liquefied gas from an evaporator while being liquefied. This makes it possible to reliably prevent the liquid from leaking out of the device or the device.

[Conventional technology and its problems]

Conventionally, the liquefied gas is drawn out as a liquid from the bottom of the storage tank, and the pressure is reduced using a spring-based self-pressure liquid pressure reducing valve, then vaporized in an evaporator, and the pressure is regulated via a pressure regulator before being sent to the consumer. It was common to supply

In this case, the means to prevent the liquefied gas from the evaporator from flowing out to the consumer in a liquefied state are as follows:
At the time of overload, a method has been adopted in which the gas phase gas pressure in the upper layer of the storage tank is applied to the liquid pressure reducing valve via a liquid level transmitter (for example, Japanese Patent Publication No. 50-16009).
However, the self-pressure type liquid pressure reducing valve having a structure in which a spring acts in the valve opening direction under normal conditions still has the following drawbacks.

When the pressure inside the storage tank drops below the spring pressure of the liquid pressure reducing valve, the valve is always open and it is impossible to prevent the liquefied gas to be consumed from flowing out from the evaporator.

In the above liquid pressure reducing valve, if the bellows or diaphragm is damaged, the valve will remain open at all times.
It is not possible to prevent the leakage of liquefied gas from the outside.

Therefore, the above-mentioned conventional evaporator can be replaced with, for example, LPG.
When used to evaporate flammable gas such as liquid, (a) If LPG liquid flows directly to the burner side,
Because the gas expands to 250 times its volume, it can cause major disasters such as explosions.

(b) If the diaphragm breaks, LPG liquid will leak into the atmosphere, resulting in 250 times the amount of gas as described above.

Therefore, there is a strong desire for an evaporation device that does not allow the liquefied gas to leak directly to the consumer or outside the device under any circumstances.

[Means for solving problems]

In view of these circumstances, the present invention provides that in this type of evaporator, even if the diaphragm that controls the pressure reduction or pressure regulation function is damaged, the liquefied gas remains liquefied and is delivered to the consumer or outside the device. It is designed to completely prevent leakage.

That is, in an evaporation device that extracts liquefied gas from a storage tank and heats and vaporizes it using atmospheric heat, a pressure regulating on-off valve (hereinafter simply referred to as a "pressure opening valve") that has a closing spring built into the conduit between the storage tank and the evaporator is used. ) is installed, and the gas phase gas in the upper layer of the storage tank is applied to the upper diaphragm chamber of the pressure-opening valve via the pilot regulator, throttle valve, level sensor, etc., and the pressure of the liquefied gas taken out from the storage tank is reduced and adjusted. The pressure inside the evaporator is configured to be constant, and
When the level of liquefied gas in the evaporator rises and liquefied gas flows into the level sensor chamber, the pilot gas pressure in the upper diaphragm chamber of the pressure-opening valve is released to the evaporator side by operating the inner valve of the level sensor. , the pressure-opening valve's upper diaphragm chamber and lower diaphragm chamber are at the same pressure, and the closing spring inside the pressure-opening valve
While the valve body is closed, when the liquid level in the level sensor chamber decreases due to evaporation of the liquefied gas in the evaporator, the inner valve of the level sensor operates in reverse, causing the pilot gas pressure to be higher than the pressure in the evaporator. is added to the upper diaphragm chamber of the pressure-open valve, and the differential pressure created between it and the lower diaphragm chamber opens the valve body against the valve closing spring, thereby solving all of the problems described above. It is.

[Effect]

The liquefied gas evaporator of the present invention has a pressure-opening valve equipped with a valve-closing spring in the conduit between the storage tank and the evaporator, so that the pressure inside the evaporator can be kept constant, and the pressure-opening valve is By communicating with the outlet side of the evaporator via a level sensor, and opening and closing the above-mentioned pressure opening valve depending on the liquid level in the level sensor chamber, the liquefied gas itself is not consumed by the consumer or equipment in any case. This has a special effect of reliably preventing the leakage of the outer shell.

〔Example〕

Hereinafter, its specific configuration will be described in more detail according to the embodiment shown in the drawings. In the normal state in FIG. The pressure is regulated, and accordingly, the liquefied gas L inside the evaporator is kept at a low temperature.

Now, the pressure opening valve 8 allows the gas phase gas pressure in the storage tank, which has been regulated from pressure P ₁ to P ₂ by the pilot regulator 2, to the throttle valve 3 and the level sensor 5.
The valve is opened by being applied to the upper diaphragm chamber A of the pressure-opening valve via the pressure-opening valve.

That is, as shown in FIG. 2, the valve body 14 is normally in the closed position due to the valve closing spring 15, but there is a pressure P ₂ in the upper diaphragm chamber A sufficient to overcome the upward force Fs of the valve closing spring 15. The valve opens only when

At the same time as the pressure opening valve 8 is opened, the evaporator 1
Since the pressure Pv within 0 is applied to the lower diaphragm chamber B via the level sensor chamber 5', the pressures _P2 and Pv move up and down through one diaphragm 16 so that they are equalized, and in conjunction with this, the valve By changing the opening degree of the body 14, the internal pressure Pv of the evaporator can be kept constant at all times.

In other words, under normal conditions, P ₁ > P ₂ > Pv > Ps.

However, Ps indicates the gas pressure at the consumption side outlet of the pressure regulator 12.

Next, the check valve 7 prevents the _P2 of the upper diaphragm chamber A from changing due to the vertical movement of the diaphragm 16 of the pressure-opening valve 8, and thereby preventing the Pv from gradually increasing. The throttle valve 6 also serves to prevent the pilot gas pressure P ₂ from increasing due to the reverse flow when the generated gas pressure in the evaporator 10 increases due to the stoppage of the flow. It is provided to change the characteristics.

In this way, the pressure of the liquefied gas L in the evaporator 10 is controlled to be constant, and the gas generated therein is further pressure-regulated by the pressure regulator 12 and sent to the consumer through the consumer outlet.

However, due to increases in gas consumption, decreases in outside temperature, etc.
If the amount of evaporation becomes insufficient due to a change in the situation, the liquefied gas will flow into the level sensor chamber 5' in its liquefied state. The internal valve is equipped with an inner valve (not shown), which operates when the liquid level is detected, and the pilot gas pressure P ₂ that was being sent from the upper part of the storage tank 1 to the pressure opening valve 8 is reduced. At the same time, by communicating the upper diaphragm chamber A of the pressure opening valve 8 with the outlet side of the evaporator 10, the pressure inside the upper diaphragm chamber A is reduced to Pv.
Therefore, the relationship of Pv×S (downward force acting on the diaphragm 16) < Fs+Pv×S (also upward force) is established in the pressure-opening valve 8, and the pressure-opening valve 8 is immediately closed. From then on, This can reliably prevent a situation in which the liquid level in the evaporator does not rise and the liquefied gas flows out to the consumer in a liquefied state.

Note that S represents the effective area of the diaphragm 16 of the pressure-opening valve 8.

On the other hand, even if the pressure-opening valve 8 is closed, the liquefied gas in the evaporator 10 continues to evaporate, but if there is a shortage in its consumption, a separate gas phase gas in the upper layer of the storage tank 1 is provided. It is constantly and stably supplied to the consumer through the pressure regulator 13. However, in this case, the set pressure P ₁₃ of the pressure regulator 13 and the set pressure P ₁₂ of the pressure regulator 12 are set to have a difference such that P ₁₂ = P ₁₃ + α, and the amount of gas generated from the normal evaporator 10 is reduced. This is done so that a sufficient gas supply pressure Ps can be maintained.

As mentioned above, while the pressure opening valve 8 is closed, the amount of evaporated gas is insufficient, so the consumption side outlet pressure Ps of the pressure regulator 12 also gradually decreases, which becomes the set pressure _P12 .
When the pressure falls below, the pressure regulator 13 automatically operates to maintain the gas pressure Ps at the outlet on the consumption side at a predetermined pressure.

In summary, the device of the present invention allows the valve opening condition to be arbitrarily selected by appropriately setting the strength Fs of the spring 15 of the pressure opening valve 8.
Furthermore, even if the bellows or diaphragm of the pressure opening valve 8 is damaged, the valve element 14 will be reliably closed by the action of the valve closing spring 15.
Under no circumstances will the liquefied gas be allowed to flow out of the consumer or the equipment in its liquefied state.

Furthermore, as mentioned above, the level sensor chamber 5'
Since the liquefied gas in the evaporator 10 continues to evaporate even after the pressure opening valve 8 is closed by the operation of the level sensor 5, the liquid level gradually decreases and the level sensor 5 no longer detects the liquid level, the pilot gas pressure higher than the evaporator internal pressure is again applied to the upper diaphragm chamber A of the pressure opening valve 8 by the inner valve operation of the level sensor, and the valve body 14 is opened. As described above, the pressure regulation within the evaporator is resumed.

In this case, when the amount of gas sent from the evaporator 10 is sufficient, the gas pressure Ps at the consumption side outlet recovers to the set pressure _P12 of the pressure regulator 12, and the pressure regulator 13
This automatically shuts off the replenishment of gas phase gas from the storage tank.

In FIG. 1, the line segments connecting each member indicate conduits.

〔Effect of the invention〕

As is clear from the above description, the present invention provides (a) control of evaporated gas pressure, (b) Complete prevention of liquefied gas leakage before consumption.
(c) It plays an important role in preventing the leakage of liquefied gas in the atmosphere when the diaphragm is damaged, and can also automatically replenish the gas phase gas in the upper layer of the storage tank when the amount of gas sent is insufficient due to a drop in evaporation. In addition to having features not available with conventional evaporators of this type, it is extremely safe and economical as it does not require any heat source or other power source to control each part.
Moreover, it has many advantages, such as the ability to safely supply gas.

[Brief explanation of drawings]

FIG. 1 is a system diagram of the liquefied gas evaporator of the present invention,
FIG. 2 is a longitudinal sectional view of the pressure regulating on-off valve. In the figure, 1... Storage tank, 2... Pilot regulator, 3, 6... Throttle valve, 5... Level sensor, 7... Check valve, 8... Pressure adjustment on-off valve (pressure opening valve). , 10... Evaporator, 12, 13... Pressure regulator, 14... Valve body, 15... Valve closing spring.

Claims (1)

[Claims] 1 In a liquefied gas evaporator that extracts liquefied gas in a storage tank to an evaporator, heats and vaporizes the gas using atmospheric heat, and sends the evaporated gas to a consumer outlet via a pressure regulator, the storage tank 1 and the evaporator are connected to each other. A pressure regulating on-off valve 8 with a built-in valve closing spring 15 is installed in the conduit between the containers 10, and one of the conduits from the upper layer of the storage tank is equipped with a pilot regulator 2, a throttle valve 3, and an inner valve. It communicates with the upper diaphragm chamber A of the pressure regulating on-off valve through a level sensor 5 consisting of a The level sensor chamber 5' communicates with the level sensor 5, and the level sensor chamber communicates with the lower diaphragm chamber B of the pressure regulating on-off valve, and a check valve is connected to the conduit connecting the upper diaphragm chamber and the outlet side of the evaporator. 7 and a throttle valve 6.