JPS62290519A - Rust prevention of internal surface of tube - Google Patents

Abstract

PURPOSE:To reduce installation cost as well as the consumption of nitrogen, by a method wherein a filmy material with several flexibilities is formed into a bellows type bag with an air feeding port and is inserted into a tube to inflate the bag by feeding air or inert gas and adhere the bag to the whole of the internal surface of the tube, then, a hole is plugged tightly and both ends of the tube are covered up by caps. CONSTITUTION:The film of plastics, rubber or rubber product, paper, cloth or soluble paper is formed into the shape of a bellows independently or in combined form and a bag 5, provided with a plurality of holes B on the part of the ebllows and with an air feeding port C at one end thereof, is connected to an air feeding pipe 6 through the air feeding port C, thereafter, is inserted into a tube 1 and caps 2 are connected to the tube 1 at places A. When an atmosphere releasing valve 3 and an air feeding valve 4 are opened fully, nitrogen flows into the bag 5 to inflate it while nitrogen is ejected through the holes B and air in the tube is discharged into atmosphere through the atmosphere releasing valve 3. When the bag 5 is adhered to the inside of the tube 1, the air in the tube is replaced perfectly with the nitrogen, thereafter, the atmosphere releasing valve 3 and the air feeding valve 5 are closed.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a method of replacing air with an inert gas to prevent rust during storage of pipes.

[Conventional technology]

As a method of replacing air with an inert gas, which is mainly used during storage of long and large pipes to prevent rust from forming on the inner surface of the pipes, there is a conventional method using nitrogen as described below.

(1) Vacuum displacement method The air inside the tube is exhausted using a vacuum pump, and then nitrogen is filled in.

(2) Pressure displacement method After filling the tube with pressurized nitrogen.

Emit a mixture of nitrogen and air into the atmosphere. By repeating this process, the concentration of nitrogen in the tube is gradually increased.

(3) Discharge displacement method Nitrogen is discharged into the tube from one end of the tube, and while a mixed gas of nitrogen and air is discharged from the other end, the concentration of nitrogen in the tube is gradually reduced.

Other rust prevention methods include:

(4) Encapsulation of volatile rust preventive agent, (5) Enclosure of silica gel.

(6) Application of film-type rust preventive agent, (7) Oil immersion.

[Problem that the invention seeks to solve]

Each of these methods has the following problems.

C1) Vacuum displacement method Equipment costs including the vacuum pump are high, and the process needs to be repeated two or three times. In addition, force from external pressure is applied to the tube, and it cannot be applied to thin-walled tubes due to stress.

(2) Pressure displacement method Usually requires 5 to 12 repetitions.

Both nitrogen material cost and labor cost are high. In addition, internal pressure acts on the pipe, so it cannot be applied to thin-walled pipes due to its strength.

(3) Discharge displacement method The amount of nitrogen discharged needs to be at least 10 times the internal capacity of the pipe, and the discharge requires a long time. Therefore, both the nitrogen material cost and labor cost are high.

These other replacement methods also have the following problems.

In either case of (4) inclusion of a volatile rust preventive agent or (5) silica gel, if the sealing is poor, moisture in the air inside the tube will condense, causing condensation on the inside of the tube. Furthermore, even if the pipe is completely sealed, when the temperature drops, the water vapor inside the pipe cannot be completely absorbed by the encapsulant, and dew condensation may occur locally, causing rust.

(6) Application of film-type rust preventive agent In the case of long pipes with one bend, it is difficult to completely coat the entire surface.

(7) The weight of oil cherry increases and the cost including sealing treatment is high.

[Means for solving problems]

The present invention solves all of these problems of the prior art at once.

That is, in the present invention, several types of flexible membrane materials are formed singly or in combination into a bellows-like bag with an air supply port, the formed bag is inserted into a pipe, and air is passed through the hole. Alternatively, to provide a method for preventing rust on the inside of a tube, which is characterized in that the bag is brought into close contact with the entire inside of the tube by supplying inert gas, the hole is tightly plugged, and both ends of the tube are covered with a cap having a means for venting to the outside. It is something.

[Effect]

A flexible bag is inserted into the tube, air or inert gas is blown through the hole, and the two bags are brought into close contact with the entire inside of the tube to seal the hole.

To protect the bag, caps with holes are fitted to both ends of the tube, and the caps are provided with means for venting to the outside in order to cope with the increase in pressure due to thermal expansion of the gas inside the tube due to temperature rise. By storing in this way, a long-term rust prevention effect can be obtained. [Example] Identical parts and parts are given the same reference numerals.

In FIG. 1, caps 2 are connected to both ends of the pipe 1 at portions A, and a pair of atmosphere release valves 3 and one air supply valve 4 are connected to each end of the pipe 1.
is joined to the cap 2. Plastic, rubber, or rubber product film 1 Paper, cloth, and water-soluble paper are each formed singly or in combination into a bellows shape, and a bag 5 having a plurality of holes B in the bellows part and an air supply port C at one end is supplied. After connecting it to the air supply pipe 6 at the air port C, insert it into the pipe 1.

The cap 2 and the tube 1 are joined at part A.

In FIG. 2, when the atmosphere release valve 3 and the air supply valve 4 are fully opened, nitrogen flows into one bag 5. As it expands, nitrogen is ejected from the hole B to release the air inside the pipe through the atmosphere release valve 3.
Emitted into the atmosphere.

In FIG. 3, when one bag 5 reaches a state in which it is in close contact with the inside of the pipe 1, the air inside the pipe is completely replaced with nitrogen, and the air release valve 8. The work is completed by closing the air supply valve 4.

Note that the vent portion of the atmosphere release valve 3 prevents the bag from being damaged due to contact with the bag 5. Bag thickness is 0.01~9.2
mm + The material is preferably polyethylene or polyvinyl chloride for plastics, or silicone rubber for rubber products. When water-soluble paper is used as a water pipe, the process of removing the bag during use can be omitted. Also, hole B provided in bag 5
The diameter of the pipe is preferably 0.01 to 5M depending on the size and shape of the pipe, and the total area is preferably smaller than the area of the air supply pipe.

In this example, a straight pipe is taken as an example, but the present invention can also be applied to a bicurved pipe, and a pipe standardized according to the pipe diameter and pipe length is used.

Note that the diameter of the small hole is appropriately selected and used depending on the situation.

Example 2 The following two examples of the method for preventing rust on the inside of a pipe according to the present invention will be described with reference to FIG. 4, FIG. 5.6.7, and FIG. 8. Each figure is shown in the order of steps of the present invention.

Therefore, the explanation will also be made according to the steps.

Fig. 4 2 Inside the pipe 1 with 8 welding grooves at both ends,
A film 5 made of plastic, rubber, or a rubber product having an air supply port C at the end, and a bellows-shaped material 5 made of paper, cloth, or water-soluble paper, either singly or in combination, are inserted. The thickness of the bag is 0.01-02M, and the material is preferably polyethylene, polyvinyl chloride, rubber for plastics, or silicone rubber for fc rubber products. When water-soluble paper is used as a water pipe, the process of removing the bag during use can be omitted.

Figure 5: Air or inert gas is fed into the bag 2 from the air supply port C to inflate the two bags. Note that nitrogen is desirable as the inert gas.

FIG. 6: The bag 2 is brought into close contact with the inner surface of the tube 1, eliminating the air layer at the contact area and completely discharging the air inside the tube.

Figure 7: Seal the air supply port C.

Figure 8: Attach fittings 2 to protect the bags at both ends of the tube.
Join at the part. Note that the metal fitting 3 is provided with a hole in order to prevent the metal fitting from coming off due to an increase in pressure due to thermal expansion of the gas inside the pipe due to a rise in temperature.

In this example, a straight pipe is shown as an example, but it can also be applied to a complicated curved pipe. Note that standardized bags are used depending on the diameter and length of the tube.

Note that the effects of the present invention can be further enhanced by spraying a volatile rust preventive agent or a volatile rust preventive oil onto the inner surface of the tube before applying the present invention.

can be given.

(1) No expensive equipment is required.

(2) Low nitrogen consumption.

(3) Work can be done in a single hour.

(4) Does not require skill.

(5) Can also be applied to thin-walled pipes.

[Brief explanation of drawings]

Figures 1.2.3 are process diagrams of one embodiment of the present invention. Figures 4.5, 6, and 7.8 are process diagrams of two other embodiments of the present invention. 1...Pipe, 2...Kicep, 3...Piping with shutoff valve. 4... Piping with a shutoff valve communicating with the bag, 5... Bag, B.
...Bag hole, C...Air supply port. Acting as a fiance during Akatsuki

Claims (1)

[Claims] Several types of flexible membrane materials are formed singly or in combination into a bellows-like bag with an air supply port, the formed bag is inserted into a pipe, and air or inert gas is supplied through the hole. A method for preventing rust on the inside of a pipe, which method comprises: tightly fitting a bag to the entire inside of the pipe, sealing the hole, and covering both ends of the pipe with a cap having a ventilation means for communicating with the outside.