JPH0418199B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is used for repairing, maintaining, inspecting, replacing, etc. a pump or equipment for delivering liquefied gas installed in a combustible liquefied gas storage tank. This relates to a method of transporting from the storage tank.

[Technical background]

Regardless of the physical properties of the stored fluid, pumps or equipment installed in the storage tank must be removed from the storage tank for maintenance and inspection purposes, and may need to be repaired or replaced as the case may be. working on it.

In particular, when the stored fluid is a flammable liquefied gas, such as liquefied propane or liquefied butane gas, vaporized gas is generated from the fluid, so the pressure inside the storage tank is higher than atmospheric pressure. (7 atm for liquefied propane, 1.2 atm for liquefied butane).

Therefore, when transporting the delivery pump or equipment installed in the flammable liquefied gas storage tank, due to the risk of explosion of the vaporized gas, it is necessary to completely prevent leakage into the atmosphere outside the storage tank. Prevention has become an essential requirement.

[Conventional technology]

Fluid storage tank and stored fluid delivery equipment,
A patent owned by the patent applicant ( Patent No.
There is a technology published as No. 1171492 (Special Publication No. 57-41639).

[Problem to be solved by the invention]

The target substance in the prior art mentioned above belongs to petroleum or petroleum-based oils, and some of these oils generate some volatile gas, so the gas pressure in the storage tank is higher than atmospheric pressure. It did not become abnormally high.

Therefore, when replacing the equipment in the storage tank, it is sufficient to have a pressurizing means that generates a pressure slightly higher than atmospheric pressure. In addition, since it does not have shocking explosive properties in the absence of fire, the safety during replacement work of equipment materials in the prior art is much higher than in the case of flammable liquefied gas, which is the subject of the present invention. It is.

In view of the above, there is a problem that cannot be solved by the above-mentioned conventional technology when transporting a delivery pump or equipment installed in a flammable liquefied gas storage tank to the outside of the storage tank, which is the subject of the present invention. It was hot.

The present invention has been made to solve the above problems, and its purpose is to replace equipment such as a delivery pump, a thermometer, a level meter, etc. installed in a storage tank of flammable liquefied gas with flammable liquefied gas. Then, the vaporized gas generated is safely and reliably transported outside the storage tank without leaking, and maintenance/inspection is carried out.
To repair or replace.

The equipment to be transported is maintained and inspected through a protection pipe installed in the storage tank, but a water shield is used to separate the outside world from which the equipment is transported and the high-pressure combustible liquefied gas in the tank. After isolating and placing the equipment to be carried out in a shielding area by pouring water, it is carried out to the outside world outside the tank. In particular, this invention is a method for processing the equipment to be carried out before carrying out the work. The present invention is a means for expelling flammable liquefied gas or combustible gas remaining in the above-mentioned protection pipe and the discharge pipe connected to the equipment to be transported.

This residual flammable liquefied gas or combustible gas is returned to the stored combustible liquefied gas by passing through a shield made of pumped water to separate the flammable liquefied gas stored in the tank from the outside air. .

As this reduction means, high-pressure water is used for combustible liquefied gas, and high-pressure inert gas is used for gasified combustible gas to forcibly reduce the stored combustible liquefied gas, and then the inert gas and When high-pressure water is depressurized, the high-pressure action of the combustible liquefied gas in the tank increases the water level in the protection pipe and discharge pipe in the low-pressure area, increasing the shielding area range. The purpose is to make it possible to transport equipment currently in storage to the outside world.

[Means to solve the problem]

As a means for achieving the above-mentioned object, the present invention has a protective tube that opens near the bottom of a sealed combustible liquefied gas storage tank and is installed with the upper end outside the tank. A discharge pipe or connecting member equipped with a protruding pump or equipment is installed inside the tank and guided out of the tank, and the flammable liquefied liquid stored in the closed tank is used as a means for transporting these pumps and equipment out of the tank. Water is injected against the gas pressure until the bottom opening of the protective tube, pump, or equipment is submerged in water to isolate it from the flammable liquefied gas, and pressurized water is pumped back from the outside of the discharge tube to remove any combustible material that may be present. After discharging the liquefied gas into the storage tank and injecting inert gas into the protection tube to forcefully discharge the remaining combustible gas into the tank, the supply of the inert gas is stopped. The pressure decreases, and the pressure decrease and the high pressure inside the tank combine to raise the water level at the lower end of the protection tube, causing the water to act as a shield between the high-pressure combustible liquefied gas and the atmosphere. It is constructed so that the pump or equipment can be carried out of the tank together with the discharge pipe through the protection pipe.

[Effect]

This invention carries out the discharge pipe to the outside atmosphere outside the tank from the lower end of the protection tube through which the discharge pipe and the pump or related equipment inserted in the discharge pipe are inserted. The equipment to be transported is placed in water that has been pressure-injected to form a shield for the purpose of blocking flammable liquefied gas from the atmosphere. Since the liquefied gas and its upper part contain steam at the same level as that of the liquefied gas, it is necessary to pass this through the water level using the shield and reduce it to the liquefied gas in the tank.

Liquefied gas in a relatively small volume discharge pipe is expelled using pressurized water against the pressure held by the liquefied gas, and combustible liquefied gas in a protection pipe is expelled. The liquefied gas in the protective tube is removed by pressurizing water that resists the pressure of It is pumped back into the tank.

In this way, the combustible liquefied gas in the discharge pipe and the protection tube is reduced to the combustible liquefied gas liquid by passing through the shield formed by the water layer by the pressurizing action. When the active gas is depressurized and brought to normal pressure, the water level in the protection pipe and discharge pipe rises due to the pressure of the flammable liquefied gas in the tank, increasing the shielding layer that blocks the atmospheric pressure region and the combustible liquefied gas. to prevent the flammable liquefied gas from flowing out of the tank.

In this way, water is interposed as a shield at the interface between the atmosphere and the combustible liquefied gas, and the object to be transported is placed within the shield, and then the object to be transported is transported to the outside world. .

〔Example〕

Next, an embodiment of the present invention will be described with reference to the drawings. Reference numeral 1 indicates a storage tank, which communicates with the outside world through a vertical hole 2, and a plurality of partition walls 3 and 4 are provided in the vertical hole 2. The inside of the tank is tightly isolated from the outside world. These partition walls 3 and 4 are covered with protective tubes 5 that are densely penetrated through them.
is fixedly installed, and a discharge pipe 7 equipped with a pump for delivery at its tip is installed inside the protective tube 5. The water bed 16 is installed at the deepest position. The discharge pipe 7 airtightly closes and supports the upper end of the protective tube 5 that protrudes to the outside world through the inside of the protective tube 5, and is connected to the upper end of the protective tube 5 through a valve 8 that is detachably attached to the upper end that protrudes to the outside. Usually, a pipe 9 for transportation is connected thereto. A valve 11 with a hose 13 interposed in the vicinity of the upper end of the discharge pipe 7 and the upper end sealed portion of the protection pipe 5,
12 are connected.

Similarly to the protection tube 5 described above, the other protection tube is installed so as to penetrate closely through the plurality of partition walls 3 and 4, and its lower end is lowered to a position where the waterbed 16 described above is formed. The tube is further equipped with an instrumentation protection tube 14, which houses measurement equipment such as a thermometer and a level meter. It is closed in a sealed state.

In addition to these plurality of protection tubes 5, there is also a communication tube 10
closely penetrates the plurality of isolations 3 and 4, the lower end thereof is open in the storage tank 1, and the upper end protruding to the outside world is usually in a position for mounting a pressure gauge.
During the operation for the purpose of the present application, for example, a water hose 15 is attached via a valve so that pressure water can be injected, and the water hose 15 and the tip of the instrument protection tube 14 can be communicated via the valve. Further, the communication pipe 10 is provided with a valve 22 at the upper end thereof so as to be able to communicate with each of the protection pipes 5.

Further, as shown in Figure 4, in order to use an inert gas such as nitrogen gas for the purpose of the present invention, an inert gas hose 19 is inserted into the protective tube 5, and a valve is attached to the upper end of the inert gas hose 19. It is connected to a hose 21 which is connected to an inert gas container 20 through the inert gas container 20.

A water hose 15 is connected to the communication pipe 10 and water is injected under pressure until the lower end of the protection pipe 5 is completely immersed in the water in the water bed 16, and then the valve 8 is
, then open valves 11 and 12 and hose 1.
The liquefied gas in the transport pipe 9 is returned to the tank via the pipe 3. Then attach the water hose 18 to the top of the valve 8.
Attach the valve 8 and pressurize and inject water into the discharge pipe 7 (1 in Figure 3), or remove the valve 8 at the top of the discharge pipe 7 and connect the water hose to the hole (not shown) in the closing plate 17. 18, pressurized water is injected into the discharge pipe 7, and the liquefied gas in the discharge pipe 7 is returned to the storage tank (2 in Figure 3) The liquefied gas is returned to the storage tank by pressurized water injection. After that, if the pressurization is stopped and the pressure is reduced, the water at the bottom of the storage tank rises into the discharge pipe 7, and the liquefied gas can be replaced. After that, remove the valve 12 at the top of the protection tube 5, connect the hose 21 from the inert gas cylinder 20, and open the valve 22.
Inert gas is pressurized into the protection tube 5 and flammable vaporized gas in the protection tube 5 is returned to the storage tank via the valve 22 and the communication tube 10. After the liquefied gas is reduced, if the pressure is reduced, water at the bottom of the storage tank will naturally rise into the protective tube 5 due to the pressure inside the storage tank, and the liquefied gas can be replaced.

Once the reduction is complete, pull out the discharge pipe 7, take out the pump or equipment, repair or replace it, reinsert the discharge pipe 7 into the protective tube 5, and return it to its original state. This is where the pipe 9 is attached.

[Effect of the invention] In a combustible liquefied gas storage tank, the location of the material to be carried out that is present in the combustible liquefied gas is replaced with a shielding layer formed by the injection of water, and the shielding layer is The remaining combustible liquefied gas and combustible gas contained in the protection pipe and discharge pipe located above the layer are injected with pressurized water and pressurized inert gas, and the remaining substances are passed through the shield layer formed of the water layer and turned into combustible liquefied gas. The combustible liquefied gas is reduced to the gas liquid and can be pulled up to the outside world from within the shield layer formed at the interface between the atmosphere and the combustible liquefied gas. This has the effect of allowing desired work to be carried out safely without leakage.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of the entire combustible liquefied gas storage tank.
FIGS. 2 to 4 are sectional views for explaining the working conditions. 1...Storage tank, 5...Protection tube, 7...Discharge pipe.

Claims (1)

[Claims] 1. A discharge pipe or a discharge pipe equipped with a pump or equipment protruding from the lower end of the protective tube, which opens near the bottom of a sealed combustible liquefied gas storage tank and is installed with the upper end outside the tank. A connecting member is installed inside and guided out of the tank, and as a means of transporting these pumps and equipment out of the tank, the lower end opening of the protective tube and the pump resist the pressure of the flammable liquefied gas stored in the sealed tank. Alternatively, water is poured into the equipment until it is submerged in water to isolate it from the flammable liquefied gas, and pressurized water is sent back from the outside of the tank in the discharge pipe to discharge the flammable liquefied gas contained within the tank, and then After injecting inert gas and forcibly discharging the remaining combustible gas into the tank, the supply of the inert gas is stopped to lower the pressure, and the pressure lowering effect and the high pressure inside the tank are combined. The water level at the lower end of the protection tube is raised to cause the water to act as a shield between the high-pressure combustible liquefied gas and the atmosphere, and the pump or equipment along with the discharge pipe is removed from the tank through the protection tube from the water that acts as a shield. 1. A method for transporting a pump or equipment in a combustible liquefied gas storage tank, characterized in that the pump or equipment can be transported.