JPH0423160B2 - - 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. It has become an essential requirement to prevent this from occurring.

[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).

In addition, for methods aimed at transporting pumps or equipment installed in combustible liquefied gas storage tanks, there is a method for replacing equipment, etc. that uses two types of media, pressurized water and high-pressure inert gas, as a means of transport. There is a patent application No. 170274 filed in 1985 (Japanese Unexamined Patent Publication No. 1983-31799) filed by the same applicant as the present applicant.

[Problem to be solved by the invention]

The target substance in the former prior art described above is
It belongs to petroleum or petroleum-based oils, and although some of these oils produce some volatile gas, the gas pressure in the storage tank did not become abnormally high compared to atmospheric pressure.

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.

In addition, in the latter method of transporting pumps and related equipment from flammable liquefied gas or combustible gas storage tanks, it is required to use pressurized water and high-pressure inert gas as the medium.
Aside from high-pressure water, since high-pressure inert gas is used, preparation of the high-pressure inert gas is a prerequisite.
There was a drawback that the preparation and carrying out operations themselves were expensive operations.

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 combustible liquefied gas or combustible gas is returned to the stored combustible liquefied gas liquid located through a shield using water pumped to isolate the flammable liquefied gas stored in the tank from the outside air. be.

As a means of reducing flammable liquefied gas, high-pressure water is used to forcibly extract the flammable liquefied gas or combustible gas according to the set work order, and then return it to the storage tank, resulting in a low pressure. Partly, the water level in the protection pipe and discharge pipe is increased by the high pressure action of the combustible liquefied gas in the tank, increasing the range of the shielded area, and the equipment to be transported in the shielded area can be transported to the outside world. The purpose is to do so.

[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 lower end opening of the protective tube and the pump or equipment are submerged in water to isolate them from the flammable liquefied gas, and the flammable liquefied gas in the discharge pipe is forced by the pump through the communication hose. Via the protection tube, return it to the storage tank along with the flammable liquefied gas in the protection tube,
The inside of the discharge pipe, which has become a negative pressure due to this action, is filled with water that is sucked in from its lower end, and then one end of the communication hose that was connected to the discharge pipe side is sealed airtight into the storage tank from the outside world. The combustible liquefied gas remaining in the protection tube is returned to the storage tank via the communication pipe, and the suction action of these pipes lowers the pressure and reduces the high pressure inside the tank. This together raises 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, allowing the pump or equipment to be passed through the protection tube along with the discharge pipe from the water that served as the shield. It is constructed so that it can be carried out of the tank.

[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 flows at the same level as the liquefied gas and the vapor is present above it, it is necessary to pass it through the water level using the shield and reduce it to the liquefied gas in the tank.

For liquefied gas in a relatively small volume discharge pipe, a pump capable of resisting the pressure held by the liquefied gas is used to return it to the storage tank via a protection pipe, and further remove the combustible gas in the protection pipe. For liquefied gas, a circuit through the pump is connected to a communication pipe, and the pump is reversed to force the flammable liquefied gas or combustible gas back into the tank via the communication pipe.

In this way, the flammable liquefied gas or combustible gas in the discharge pipe is transferred to the protection pipe, and the gas transferred to the protection pipe is transferred to the communication pipe. The water level in the pipe rises due to the pressure of the combustible liquefied gas in the tank, increasing the shielding layer that blocks the atmospheric pressure region from the combustible liquefied gas, thereby preventing the combustible 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 having a discharge pump 17 attached to its tip is installed inside the protective tube 5, and this pump 17 is made to protrude downward from the lower end opening of the protective tube 5, The water bed 16 is located at the deepest part of the water bed 1. 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. Valves 11 and 12 are connected to the vicinity of the upper end of the discharge pipe 7 and the upper end sealed portion of the protective tube 5, respectively, with a communication hose 13 interposed therebetween having a pump 18 therebetween. Similarly to the protection tube 5 described above, the other protection tube closely penetrates the plurality of partition walls 3 and 4, and its lower end is connected to the water bed 16 described above.
The tube is further equipped with an instrument protection tube 14, which houses measurement equipment such as a thermometer and level meter, with the upper end of the protection tube protruding into the outside world , the outer periphery of the inserted instrument protection tube 14 is closed in a hermetically sealed state.

In addition to these plurality of protection tubes 5, there is also a communication tube 10
penetrates the plurality of partition walls 3 and 4 closely, its lower end is open in the storage tank 1, and its upper end protrudes to the outside world, usually at a position where a pressure gauge is attached.
During the operation for the purpose of the present application, for example, a water hose 15 is attached via a valve 19 so that pressurized water can be injected.

A water hose 15 is connected to the communication pipe 10 and water is injected under pressure.Using the difference in specific gravity between the combustible liquefied gas and water, the injected water flows around the lower surface of the combustible liquefied gas, so that the lower end of the protection tube 5 Pour water into the water bed 16 until it is completely filled with water, then open the valve 8, and then open the valves 11 and 12 to connect the communication hose 1.
When the pump 18 interposed in the tank 3 is operated under pressure, the liquefied gas in the pipe 9 for transportation, etc. is returned to the tank via the communication hose 13 and the protection pipe 5. Once the combustible liquefied gas in the pipe 9 has been recovered in this way, the valve 8 is closed. As the pressure of the pump 18 continues, the liquefied gas in the discharge pipe 7 is returned to the storage tank 1 via the protection pipe 5 (Fig. 3).When the discharge pipe 7 becomes negative pressure in this way, the bottom of the storage tank is Water rises into the discharge pipe 7 and the entire volume of the discharge pipe 7 is filled with water. If this condition occurs, the end of the communication hose 13 removed from the valve 11 at the upper part of the discharge pipe 7 will be removed from the communication pipe 1.
If the pump 18 installed in the communication hose 13 is reversed, the flammable liquefied gas or combustible gas that is thought to remain in the protection tube 5 will be liquefied. Gas is returned to the storage tank 1 via a communication hose 13 and a communication pipe 10. When the inside of the protection tube 5 becomes negative pressure in this way, the water level in the protection tube 5 rises due to the pressure held in the storage tank 1, and the protection tube 5 is filled with water. In this way, the combustible liquefied gas or combustible gas in the protection tube 5 is transferred to the communication tube 1.
The method of returning the gas to the storage tank 1 through the gas is a means to confirm safety, and the combustible liquefied gas or combustible gas 18 in the discharge pipe 7, which is the previous step, is
The operation of pressurizing the water and returning it to the storage tank 1 via the protection pipe 5 continues for a long time, and as a result, the discharge pipe 7 is completely filled with water, and even the water is finally It is theoretically possible for the protective tube 5 to be filled, but since these cannot be visually observed, a final step via the communication tube 10 is performed as part of the safety measure to completely fill the protective tube 5. It is filled with water.

In this way, the inside of the protection tube 5 is filled with water,
When the water reaches the communication pipe 10, the negative pressure and pressurization modes of these operations are eliminated and the system automatically switches to a simple circulation action, and the load on the pump 18 is eliminated, so the inside of the protection pipe 5 is filled with water. It can be confirmed that this has happened.

When complete reduction is completed in the manner described above, the discharge pipe 7 is
The pump or equipment is removed, repaired or replaced, and the discharge tube 7 is reinserted into the protective tube 5, returned to its original state, and the valve 8 and tube 9 are attached.

〔Effect of the invention〕

In a combustible liquefied gas storage tank, the location of the transported object located in the combustible liquefied gas is replaced with a shielding layer formed by injecting water, and the location is placed above the shielding layer. The remaining combustible liquefied gas and combustible gas contained in the protection pipe and discharge pipe are returned to the storage tank, passed through a shield layer formed of a water layer, and returned to the flammable liquefied gas liquid, which is then separated from the atmosphere and combustible liquefied gas. Since the material to be transported can be pulled up to the outside world from within the shield layer formed at the interface of the The combustible liquefied gas is shielded by the shielding layer and does not leak to the outside world, so that the desired work can be carried out safely.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of the entire combustible liquefied gas storage tank, Fig. 2 is a schematic cross-sectional view for explaining the configuration of the main parts of Fig. 1, and Figs. 3 and 4 are cross-sectional views for explaining the operating state. FIG. 1...Storage tank, 5...Protection tube, 7...Discharge pipe, 1
0...Communication pipe, 13...Communication hose, 17...Pump, 18...Pump.

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, the equipment is injected with water until it is submerged in water to isolate it from the flammable liquefied gas, and the flammable liquefied gas in the discharge pipe is forcibly passed through the protection pipe by a pump through the communication hose, and the flammable liquefied gas in the protection pipe is At the same time, the water is returned to the storage tank, and the discharge pipe, which has become under negative pressure due to this action, is filled with water that enters in a state where it is sucked from its lower end, and then one end of the communication hose that was connected to the discharge pipe side is A communication pipe is installed that penetrates the storage tank from the outside in an airtight state, and the combustible liquefied gas remaining in the protection pipe is returned to the storage tank via the communication pipe, and the suction action of these The pressure lowering effect and the high pressure inside the tank combine to raise the water level at the lower end of the protection tube.
The water is characterized by creating a shielding effect between the high-pressure combustible liquefied gas and the atmosphere, so that the pump or equipment along with the discharge pipe can be carried out of the tank from the water acting as the shield through a protective pipe. A method for transporting pumps or equipment in combustible liquefied gas storage tanks.