JPH0363331A - Piping execution - Google Patents

Abstract

PURPOSE:To reduce the number of welding spots and to shorten a term of works by a method wherein, in execution of a piping work in which a piping route is complicated and narrow and which is attended with stereo bending, piping is made such that a steel pipe in a coil is uncoiled as the tip of the steel pipe is coarsely bent, and both ends are finally interconnected. CONSTITUTION:A steel pipe 2 in a coil 1 has bending of 30-100DR at a part where coarse bending is made at an acutemost angle and bending of approximate 3-5DR by a bending work. Piping is effected such that a tip 21 of the steel pipe is uncoiled as coarse bending along a piping route, and a bending work is finally applied in a given position to interconnect both ends by welding.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a piping construction method, and particularly to a method for facilitating piping construction in a narrow space. [Conventional technology]

Generally, piping is performed by connecting straight pipes of a fixed length or curved pipes of a predetermined shape. When using conventional piping methods, many pipes with limited lengths are connected, so it takes a lot of effort to connect pipes and inspect the joints, whether by welding or screwing. It takes time and effort. This becomes a serious problem, especially when attempting to install piping in a narrow space. Recently, coiled long steel pipes have become available on the market. This is used to straighten the long steel pipes wound into coils at the construction site by unwinding them from the coils and straightening them to the required curvature. Construction methods that minimized the number of joints, such as welding, were attempted and were successful. However, the construction method described above requires a large space for the work, and is not suitable for pipes arranged in three dimensions. Therefore, there has been a need for a piping construction method that allows the use of coiled steel pipes even when the piping route is complex and involves three-dimensional bends, or when passing through narrow passages, cells, chimneys, etc. [Problems to be Solved by the Invention] The purpose of the present invention is to meet the above-mentioned needs, and by using a coiled steel pipe, the number of connection parts can be significantly reduced, and it can be used in narrow spaces or three-dimensional spaces. It is an object of the present invention to provide a construction method that allows easy piping even if it is arranged. [Means for Solving the Problems] As shown in FIG. 1, the piping construction method of the present invention involves unwinding a long steel pipe (2) for piping that has been wound into a coil (1) shape to create a piping route. Unroll it while roughly bending it along the
Place the steel pipe by routing the tip (21) of the steel pipe toward the position to be connected, or by moving the coil (not shown), and then connect one end as shown in Figure 2. (In the example shown, the pump (4) to be connected by piping
) and tank (from the latter of 5)), the steel pipes are sequentially bent to a predetermined bending radius at a predetermined position, and finally both ends of the steel pipe are connected to a predetermined location by welding or other methods. . The coiled steel pipe used in the present invention is typically an ERW steel pipe produced by high-frequency induction welding, or a seamless steel pipe produced by hot extrusion or hot rolling, heated in a continuous heating furnace. This is a steel pipe that has been reduced in diameter by reduction rolling and finished to a predetermined size, and then wound into a coil. The commercially available product is “Pipe In C”.
o11) j (manufactured by Nippon Steel Corporation), and currently,
There are several grades ranging from outer diameter 42.7# to length 110TrL. (Small-diameter items can be made into longer lengths.) Of course, steel pipes can be bent using a regular pipe bender. Steel pipes can be connected in the same way as before, such as by welding or screwing. This is done by an appropriate means. [Function] When a long steel pipe in the form of a coil is uncoiled and unfolded while being roughly bent, the bending applied to the steel pipe is usually 50 to 100 DR,
The maximum is only 30DR. Even if such bending is repeated several times, it will not cause work hardening in the steel pipe. When stainless steel pipes are used for piping that requires corrosion resistance, there was concern that repeated bending would reduce the corrosion resistance, but as shown in the examples below, it was confirmed that there was almost no effect. Ta.

【Example】

First, 5US304 steel pipe (outer diameter 13.8M, wall thickness 2mm)
The effect of cold bending on corrosion resistance was investigated. This steel pipe was cut into a length of 30 crn, subjected to the following bending process, and then cut along the axis, and the resulting half pieces were subjected to a corrosion test (uueytest: 48 hours x 5 cycles). (A) One bending process at a radius of 652m (50DR) (B)
West bending 10 times at a radius of 652 m (C) 90' bending at a radius of 50 mm (3,6D R>) (D) Bending 10 times at a radius of 652 a, then 90" bending at a radius of 50 m (E) Bending The corrosion rate of each test material is as shown below, and the decrease in corrosion resistance due to bending was within a practically acceptable range. Therefore, using this stainless steel pipe, The piping connecting the pump and the tank was constructed according to the present invention as shown in Figure 1. Both ends of the steel pipe were welded to the pump (4) and the tank (5) at points X and Y, respectively. In this case, for example, the symbol (
At the various points shown in a-g>, it was necessary to weld straight pipes, bent pipes, zero-shaped pipes, etc. Test material Corrosion rate (A O. B O. CO9 D (L E O. g/bottom/h) 7 2 0 3 9 [Effect 1 of the invention According to the piping construction method of the present invention, the pipes in the middle of the piping Connections with pipes and inspections required accordingly can be significantly reduced, shortening construction time and costs, and improving plant safety.Therefore, the present invention is applicable to nuclear fuel reprocessing plants. It is especially significant when applied to piping in facilities such as industrial and food manufacturing plants, where piping construction is often required in confined spaces and where leakage and contamination must be prevented as much as possible.
Needless to say, this method is advantageous when applied to general chemical plants.

[Brief explanation of drawings]

Figures 1 and 2 are for explaining an example of piping construction by the method of the present invention. FIG. 1... Coil 2... Steel pipe 4... Pump X, Y... Welded part 5... Tank

Claims (2)

[Claims] (1) A long steel pipe for piping that has been wound into a coil is unwound and unfolded while being roughly bent along the piping route.
Route the tip of the steel pipe toward the location you want to connect, or
Alternatively, piping consists of arranging the steel pipe by moving the coil, then bending the steel pipe sequentially from one end to a predetermined bending radius at a predetermined position, and finally connecting both ends of the steel pipe to a predetermined location. Construction method. (2) Rough bending of the steel pipe is 30 to 1 at the most strongly bent part.
00DR, and the pipe construction method according to claim 1, wherein the bending process is performed to about 3 to 5DR.