JPS6326491A - Method of closing piping - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for closing piping, and in particular, to a method for effectively closing the vicinity of a location where a piping component is attached.

[Prior Art] Generally, when replacing, repairing, or cleaning piping parts attached to piping in nuclear power plants, chemical plants, etc., two stop valves are installed at a distance in the middle of the piping. The stop valves are installed in advance, and the piping path is shut off by the stop valves, and the piping parts located between the two stop valves are removed.

In addition, in this case, if the distance between the two stop valves is long, the effort required to remove the fluid between them will be large, so it is necessary to freeze the piping on both sides of the piping parts and use a fluid-based faucet (ice plug). A method has been considered in which the piping path is blocked by forming a pipe, thereby reducing the range of fluid removal and reducing the work.

``Problems to be Solved by the Invention'' However, the edge of a water faucet freezes on the inner surface of the piping and is fixed by the bonding force of the contact portion, but when slipping occurs, the frictional resistance of the water is small and the water is not engaged. Because the stopping power becomes weaker,
It is difficult to apply this method when the piping route has a large force or to large-diameter piping.

The present invention is intended to solve these problems, and aims to increase the fixing force of the faucet and expand its range of application.

"Means for Solving the Problem" In the method for closing a pipe according to the present invention, a locking protrusion is protruded from the inner surface of a pipe to be frozen, and the locking protrusion is The pipe hole is blocked by freezing the area around it, and the locking protrusion bites into the faucet formed by freezing, and in addition to the bonding force with the inner surface of the pipe due to freezing, the faucet's shearing resistance This is to suppress movement by using

``Example'' Hereinafter, a first example in which the piping closing method of the present invention is applied to a valve installation location will be described based on FIGS. 1 and 2.

As shown in FIG.
The structure is such that the valve 3 is interposed in the recess of the valve 2, and when removing the valve 3, the pipes on both sides
The area near the flange portion 2 is the area to be frozen.

At an appropriate position on the inner surface of the tube to be frozen (pipe) l, that is, at a location slightly apart from the flantz portion 2 (the location to be frozen), the pipe protrudes inward at least when the faucet is formed by freezing the fluid. An appropriate number of locking protrusions 4 are provided in advance. Further, a cooling jacket 5 for supplying a freezing refrigerant such as liquid nitrogen is attached so as to surround the outer surface of the pipe 1 in the vicinity of the locking projection 4. moreover,
The inside of the tube 1 is kept filled with fluid.

Then, a cooling medium such as liquid nitrogen is fed into the cooling jacket 5 to cool the pipe wall in the vicinity of the locking protrusion 4 from the surrounding area, and freezes the fluid to form a water faucet C, thereby forming a pipe line. (tube hole). The locking protrusion 4 is wedged into the faucet C, and in addition to the freezing bonding force at the contact area between the faucet C and the inner surface of the pipe 1, the water at the locking protrusion 4 is A synergistic effect with the addition of the shear resistance force of the faucet C occurs, causing the faucet C to be displaced.

The adhesion strength of the faucet C formed as shown by the chain line in FIG. An example of the calculation is shown in Table 1.

Table 1 (Pipe diameter and cross-sectional area of locking protrusion) However, F=ApXP P is 40mmA q (0.04kg/mm”)A
p=F/σ0 σo is the compressive stress of ice (2 kg/mm') In addition, in the embodiment shown in FIGS. Therefore, the flange portion 2 is disassembled and the valve 3 is removed for replacement, cleaning, inspection, etc.

Further, after the work is performed, the faucet C becomes liquid by heating or returning to a normal state, thereby releasing the blocked state of the pipe I.

Next, examples of the locking protrusion 4 will be explained based on FIGS. 3 to 5.

The locking protrusion 4 in the example shown in FIG. 8, and a sealed case 9 surrounding the boss portion 8.
It is a groove structure that is integrally attached to the outer surface of the pipe 1, and a lid IO is attached to the sealing case 9 with a fastener 11 such as a bolt to seal the penetrating portion of the locking protrusion 4.

Further, the hole 6 is provided with a hole 6 that restricts the outward movement of the locking projection 4, and in this movement restricted state, the inner surface of the locking projection 4 and the inner surface of the pipe 1 are arranged as shown in FIG. 3(A). A stepped portion 12 is formed on the surface to make it flush.

When protruding the locking protrusion 4 like this, it is done by rotating the threaded part 7 with the lid lO removed, and in FIG. 3(B), the threaded part 7 and the boss part 8 are flush. The amount of protrusion is set by protruding inward until one state is reached. At the end of the freezing operation, the locking protrusion t is moved back to return to the flush state as shown in FIG. 3(A) to reduce the fluid resistance of the piping.

The locking protrusion 4 in the example shown in FIG. 4 is movable along the radial direction of the tube l between the hole 6 and the inside of the sealed case 9, and is closed by an expandable member 13 made of a shape memory alloy. It is attached to the pipe lO and has a structure that causes it to protrude inward due to shape deformation due to the low temperature during freezing. Under normal conditions, the locking protrusion 4 is flush with the inner surface of the pipe l, and the piping line is This reduces fluid resistance.

Furthermore, the locking protrusion 4 in the example shown in FIG. 5 is rod-shaped made of a shape memory alloy, is integrally attached to the inner surface of the pipe l, and is in a state lying in the downstream direction of the flow path in a normal state. It has a structure that expands and protrudes inward due to shape deformation due to the low temperature during freezing.

In addition, if the usage conditions are such that the influence of turbulence does not become a problem in the piping route, fix a simple locking protrusion on the inner surface of the pipe in advance so that it protrudes inward. be established by this. Moreover, the shape of the locking protrusion can be made arbitrary.

"Effects of the Invention" As explained above, according to the method for closing a pipe of the present invention, the locking protrusion is protruded from the inner surface of the pipe to be frozen, and the pipe is locked while the pipe to be frozen is filled with fluid. Since the vicinity of the stop protrusion is frozen to close the pipe hole, the stop protrusion bites into the faucet formed by freezing, and the locking process is caused by the bonding force between the inner surface of the pipe and the faucet due to freezing. The stopping force is obtained in combination with the shearing resistance force of the faucet where the locking protrusion bites, and the strong locking force enables reliable freezing and closing.

Moreover, it has excellent effects such as easy implementation and high practicality.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway front view showing a first embodiment of the method for closing piping according to the present invention, FIG. 2 is a view taken along the line ■-■ in FIG. 1, and FIGS. 3 to 5 are FIG. 3 is a front sectional view showing each row of locking protrusions. 1... Pipe (pipe to be frozen), 2... Flange portion, 3... Valve, 4... Locking protrusion,
5... Cooling jacket, 6... Hole, 7...
...Screw part, 8...Boss part, 9°°・Sealed case, IO...Lid, 11...Fastener, 12...
...Stepped portion, 13...Extendable member, C...
Water faucet. Applicant Ishikawajima Harima Heavy Industries Co., Ltd. Figure 1 L Figure 2 Figure 4 (A Figure 51 (AI Figure (ED)

Claims (1)

[Claims] A method for closing piping, which comprises: protruding a locking protrusion from the inner surface of a pipe to be frozen, and freezing the vicinity of the locking protrusion to close the pipe hole while the pipe to be frozen is filled with fluid. .