JPH054942Y2 - - Google Patents

Description

[Detailed explanation of the invention] [Industrial application field] This invention is a partial shielding system that creates an inert gas atmosphere in order to allow work to be carried out safely in areas where flammable gases may be generated. Regarding the work box, it is suitable for repair work such as LNG low temperature storage tanks.

[Conventional technology]

After starting operation of an LNG cryogenic storage tank or an LPG cryogenic storage tank, it may be necessary to conduct an open inspection and repair any areas that are found to need repair by welding.

If such repairs are necessary, first drain the stored liquid completely, replace the flammable gas remaining inside by supplying inert gas, etc., and confirm that it is safe before welding. I try to do some work.

[The problem that the idea attempts to solve]

However, in order to perform welding work etc. in an inert gas atmosphere inside the storage tank, workers must use LSS (Life
It is necessary to use a support system to ensure that there is no obstruction to breathing, etc., which can lead to problems such as restrictions on work time and poor work efficiency.

In addition, in the case of double-shell tanks, it is relatively easy to replace flammable gas in the inner tank with inert gas, but in the unlikely event that flammable gas leaks between the inner and outer tanks. In some cases, it is difficult to replace this with non-caustic gas, and there is no guarantee that flammable gas will not be generated during welding work, making it necessary to develop equipment that can work safely in such cases. be.

This idea was made in view of the problems of the prior art, and it is possible to partially create an inert gas atmosphere only in the areas necessary for the work, so that the operator can
The aim is to provide a partially shielded work box that allows work to be carried out safely without the use of special equipment such as LSS.

[Means to solve the problem]

In order to solve the problems of the above-mentioned prior art, the partially shielded work box of this invention has an opening corresponding to the workpiece, an antistatic mat that covers the workpiece, and an antistatic mat that covers the workpiece. A work tube connected to the opening of the prevention mat and whose top surface is closed with a transparent plate, and a closed work arm tube attached to the side wall of the work tube so that work can be performed inside the work tube with a hand inserted from the outside. The present invention is characterized by comprising an inert gas supply device that maintains the inside of the working cylinder in an inert atmosphere, and an insertion port formed in the working cylinder and into which a working tool is inserted.

[Effect]

Place an anti-static mat and work cylinder on the work area, and create an inert gas atmosphere inside the sealed work cylinder with inert gas from the inert gas supply device.
In addition to inserting hands using the work arm tube attached to the work tube, the designated work is performed using tools such as welding equipment inserted through the insertion port of the work tube, and only the work area is kept in an inert gas atmosphere. We are making it possible to do so.

〔Example〕

Hereinafter, one embodiment of this invention will be described in detail based on the drawings.

FIG. 1 is a schematic diagram of an embodiment of the partially shielded work box of this invention.

This partially shielded work box 10 is equipped with an antistatic mat 11 having an opening corresponding to the workpiece in the center thereof, and the workpiece is positioned within the opening of the antistatic mat 11. By placing the cover over the cover, it is possible to cover the area around the part to be worked on.

This antistatic mat 11 is thin and flexible, and is placed tightly around the workpiece to prevent air from entering from the surrounding area, and if necessary, the surrounding area is covered with masking tape. It is sealed with etc.

A cylindrical or polygonal cylinder-shaped work tube 12 is attached around the opening of the antistatic mat 11, and its lower end is connected to the antistatic mat 11.
and are connected in a sealed state. This work tube 12
are made of aluminum or acrylic resin, for example, and are protected from damage even by internal welding operations. And this work tube 1
A transparent plate 13 made of tempered glass or an acrylic plate is attached to the top of the work cylinder 12, so that the inside of the working cylinder 12 can be sealed and the inside can be monitored.

When attaching the transparent plate 13, as shown enlarged in the figure, rubber gaskets 14 are inserted on both upper and lower sides of the transparent plate 13, and ring-shaped clasps 1
5 and bolts, and can be opened and closed by removing the bolts.

In order to create an inert gas atmosphere inside the working cylinder 12, an inert gas supply nozzle 16 is attached to the side wall of the working cylinder 12, and is connected to an inert gas supply device 17 that supplies an inert gas such as argon or nitrogen. has been done.

In order to pressurize the inside of the work cylinder 12 with inert gas and prevent air from mixing in, an inert gas leakage passage 18 is formed in a part of the antistatic mat 11, and the inside is completely filled with inert gas by leaking in a small amount of inert gas. As shown enlarged in the figure, this inert gas leakage passage 18 is connected to the outside by adhering a brush-like member 19 to the underside of the antistatic mat 11, and is also designed to prevent air from entering.

Further, the working cylinder 12 has a discharge nozzle 20 for discharging internal gas such as air or inert gas.
is attached, and an oxygen concentration measuring nozzle 21 is also attached.

At least one pair of through holes (in the illustrated example, there are two pairs) are formed in the side wall of the working cylinder 12 for carrying out work in the working cylinder 12 which can be made into an inert gas atmosphere. A glove made of heat-resistant rubber is attached to the hole to form the working arm cuff 22, and it is now possible to work inside the working cuff 12 with the hand inserted into the working cuff 22 from the outside of the working cuff 12. There is.

As shown in an enlarged view in the figure, the working arm cylinder 22 is sealed around the through hole of the working cylinder 12 with an adhesive to prevent outside air from entering.

In addition, in order to insert the tools necessary for the work into the work cylinder 12, a tool insertion opening 23 is formed in the side wall of the work cylinder 12, and is enlarged in the figure to prevent outside air from entering as much as possible. As shown,
A brush-like member 24 is attached around the periphery.

Partially shielded work box 1 configured in this way
Repair work on the membrane of a double shell tank using 0 is carried out as follows.

First, remove the stored liquid and flammable gas from inside the tank, replace it with nitrogen gas, etc., and then fill it with air.

First, the part that requires work is the work cylinder 12.
The antistatic mat 11 is set in a predetermined position so that the antistatic mat 11 is located inside, and the periphery of the antistatic mat 11 is sealed with masking tape.

After this, an inert gas such as argon or nitrogen is sent into the working cylinder 12 from the inert gas supply device 17,
The discharge nozzle 20 is opened to discharge internal air and the like to create an inert gas atmosphere inside the work tube 12, and at the same time, a work tool such as a TIG welding torch is inserted through the tool insertion port 23.

The preparation is completed in this way, and the oxygen concentration measurement nozzle 2
1 to measure the internal oxygen concentration and confirm safety, insert your hand through the work arm tube 22 and remove the work tube 1.
Working cylinder 1 covered with gas cylinder 2 to create an inert gas atmosphere
Perform TIG welding etc. within 2. During this welding work, the inert gas is supplied from the inert gas supply device 17 and the work is carried out while causing a slight leak from the inert gas leak passage 18, and the internal oxygen concentration is measured using the oxygen concentration measuring nozzle 21. Work while checking safety.

In addition, to prevent the worker from becoming oxygen-deficient due to inert gas leaking from the work tube 12, fresh air is supplied from outside around the worker using a baby fan, etc., so that the worker can work safely. .

By performing the welding work in this manner, even if there is flammable gas on the back side of the part to be worked on, the gas will not leak into the working tube 12, and the work can be performed safely.

During the work, workers must use life-sustaining equipment.
There is no need to use the LSS and the work can be done as is, and the work arm cylinder 22 and transparent plate 13
You can easily perform the work by monitoring from

In addition, since the anti-static mat 11 is flexible, it can be sealed regardless of the shape of the part to be worked on, and can be used in any position or location, including not only downwards but also sideways and upwards. Can be used.

Furthermore, it can be inserted into the interior using manholes, etc., and can also be transported, making it highly versatile.

In addition, in the above embodiment, the case where the present invention is used for repairing the membrane of a low-temperature tank has been described, but the present invention is not limited to this, and can be widely applied to places where there is a possibility that flammable gas may be generated.

In addition, the size of the anti-static mat and work cylinder should be selected depending on the size of the work object, and making the anti-static mat sufficiently large compared to the size of the work cylinder will prevent air from entering. It is valid.

Further, the number of work arms may be selected depending on the content of the work, and at least one pair is sufficient.

[Effect of idea]

As explained above in detail along with one embodiment, according to this invention, the partially shielded work box can be
An antistatic mat having an opening corresponding to the part to be worked and covering the periphery of the part to be worked, and a work cylinder connected to the opening of the antistatic mat and having an upper surface closed with a transparent plate. a sealed working arm cylinder that is attached to a side wall of the working cylinder and allows work to be performed inside the working cylinder with a hand inserted from the outside; an inert gas supply device that maintains the inside of the working cylinder in an inert gas atmosphere; Since the work tube has an insertion hole formed in the work tube for inserting a work tool into the inside, the anti-static mat and the work tube are placed on the area to be worked, and the inside of the sealed work tube is connected to the inert gas supply device. Create an inert gas atmosphere and use the work arm attached to the work tube to insert your hands, and use tools such as welding equipment inserted through the insertion port of the work tube to perform the specified work. Work can be done with only the work area in an inert gas atmosphere.

Therefore, even if there is flammable gas on the back side of the workpiece, the gas will not leak into the work tube, allowing safe work.

In addition, workers must use life-sustaining equipment during work.
It is not necessary to use the LSS and the work can be carried out as is, and the work can be easily carried out by monitoring from the work arm and transparent plate.

Furthermore, the anti-static mat allows the workpiece to be shielded from the outside regardless of its shape, allowing it to be used in any posture or location.

In addition, it can be inserted into the interior using a manhole, etc., and can also be transported, making it highly versatile.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of an embodiment of the partially shielded work box of this invention. 10... Partial shielding work box, 11... Anti-static mat, 12... Working tube, 13... Transparent plate, 14... Rubber gasket, 15... Clasp, 1
6... Inert gas supply nozzle, 17... Inert gas supply device, 18... Inert gas leakage passage, 1
9, 24...Brush-like member, 20...Discharge nozzle, 21...Oxygen concentration measuring nozzle, 22...Working arm cylinder, 23...Tool insertion port.

Claims (1)

[Scope of utility model registration request] An antistatic mat is formed with an opening corresponding to the part to be worked and covers the periphery of the part to be worked, and a work cylinder is connected to the opening of the antistatic mat and has an upper surface closed with a transparent plate. a sealed working arm cylinder which is attached to the side wall of the working cylinder and allows work to be carried out inside the working cylinder with a hand inserted from the outside; an inert gas supply device which maintains the inside of the working cylinder in an inert gas atmosphere; A partially shielded work box characterized by having an insertion port formed in a work tube and into which a work tool is inserted.