JPS6038595B2 - Buried pipe structure for high and low temperature fluids - Google Patents

Description

[Detailed description of the invention] The present invention relates to a buried pipe structure for high and low overflow fluid.

When a pipeline for transporting high-temperature fluids is installed underground, it is usually a double pipe system in which a steel pipe 1 insulated with a heat insulating material 3 is placed in a protective pipe (outer pipe) 2 as shown in Figure 1, or an underground tunnel system is used. A conventional method has been adopted in which a pipe is installed and piping is installed inside the pipe. However, in the case of the double pipe system, a spacer 4 between the main pipe and the outer pipe, a bellows 5 to absorb expansion and contraction, and a concrete bit 6 for installing the bellows are required, and the tunnel piping method In this case, it is necessary to construct an underground tunnel, so both methods have the disadvantage of requiring large-scale equipment and increasing construction costs. On the other hand, in order to reduce construction costs, a piping system can be considered in which the temperature expansion and contraction of the piping is fixed and no expansion joints are used.

Figures 2 and 3 show this method, in which the main pipe I is piped into a concrete U-shaped groove 7, etc., and the surrounding area is filled with heat insulating material 3, and the expansion joint is - Not used. In this case, in the straight piping section, pipe 1 and insulation material 3
Frictional force 10 acts between the tube and the tube, and the temperature expansion and contraction of the tube due to the fluid inside the tube is somewhat suppressed, but not completely.In particular, in the case of high-temperature fluid, the tube section expands, and this elongation is concentrated in the curved tube section. The police officer receives a force 19 in the direction of the arrow shown in FIG. 2, and begins to extend in the direction of the arrow 9'. If the tube stretches out, it may destroy the U-shaped groove, causing moisture intrusion, or the tube itself may collapse. The present invention was devised in order to eliminate the various drawbacks of the conventional buried pipe structure, and its purpose is to solve the problem of expansion and contraction of the pipe due to temperature changes at the bend in the pipe structure as illustrated in FIGS. 2 and 3. It is an object of the present invention to provide a buried pipe structure for high-temperature fluid that can reliably suppress damage to the pipe and prevent destruction of the U-shaped groove.

The present invention relates to a high-temperature fluid pipe that is disposed in a concrete U-shaped groove and has a curved pipe section in a part of which is filled with a heat insulating material, and in which a plurality of pipes are installed in a straight pipe section following the curved pipe section. Fix the protrusion.

As a result, the connecting protrusion is restrained by the heat insulating material filled in the U-shaped groove, and the straight pipe section is restrained from expanding and contracting due to the temperature of the fluid in the pipe, and the expansion and contraction of the straight pipe section is suppressed. Deformation of the tube portion is prevented. The present invention will be described in detail below with reference to FIGS. 4 to 6, in which the same reference numerals as in FIGS. 2 and 3 indicate the same parts. That is, Fig. 4 shows a case where there is a bend in the horizontal plane, and Fig. 5 shows a case where there is a bend in the vertical plane. A protrusion such as a plate 11 is provided. In this case, the number of disks 11 to be installed varies depending on conditions such as the amount of temperature change, pipe size, and heat insulating material properties, and is appropriately determined in consideration of these conditions. Next, the operation of the present invention will be explained.

In the vicinity of the Z-bend, the force 9 that causes the pipe to stretch due to temperature change is expressed by the following equation. F=
AEQ△T …{1' However, F: Extension force (kg) A: Cross-sectional area of pipe (ground)
Z E: Elastic modulus of the tube (k9/young) Q: Coefficient of linear expansion of the tube (/°C) △T: Amount of temperature change (00) When the elongation force 9 acts, the disk 11 placed in the direct inspection area
Since vertical surface pressure acts on from the surrounding insulation material 3, the reaction force 1
2 comes into play.

Load in the axial direction (axial force) when multiple discs 11 are installed
The distribution becomes step-like as shown in Figures 4b and 5b.
If the force handled by one disk is △F, then AEQ△T=
If n disks are attached so that n·ΔF...'21, the tube will be completely fixed, and the expansion and contraction at the curved tube portion can be reduced to almost zero.

The method of attaching the disk 11 is as shown in FIG. 6, by welding the collar 13 to the tube body 1 and then welding the disk 11 thereto.
Alternatively, it may be directly welded to the tube body 1.

Further, in the embodiment, an example in which the disk 11 is provided as the buried pipe restraining section has been described, but of course, the present invention is not limited to a disk, and any protruding object may be used. Table 1 shows specific examples of dimensions of the buried pipe structure according to the present invention, which makes it possible to reliably prevent expansion and contraction of the pipe at the bent pipe section.

Table 1 *1 Temperature difference △T was set to 10,000.

*2 The pipe standard is SGP.

Since this invention is configured as described above, even if the high-temperature fluid pipe having a curved pipe section is buried in a concrete U-shaped groove, the disk etc. disposed in the straight pipe section following the curved pipe section will be damaged. Since the protrusions can share the expansion and contraction force due to temperature changes in the tube, it has the advantage of reliably preventing expansion and contraction of the tube at the bend and damage to the tube and U-shaped groove caused by this. .

[Brief explanation of drawings]

Figures 1, 2, and 3 are explanatory diagrams showing the buried piping structure of the slave, and Figure 4 shows an example of the present invention, where a is an explanatory diagram showing the buried piping structure, and b is the shaft. Universal direction load distribution diagram, Figure 5 shows another example of the present invention, a is an explanatory diagram showing a buried pipe structure, b is an axial universal direction load distribution diagram, and Figure 6 shows a method of attaching a protrusion. Figure A is a partially sectional front view, Figure B is a plan view of Figure A, and Figure 7 is a view taken along the line X--X in Figure 3. 1: Main pipe, 2: Outer pipe, 3: Insulation material, 4: Baseer, 5
: Expansion joint, 6: Concrete bit, 7: U-shaped groove, 8
: Bent pipe part, 9: Extension force due to temperature change, 10: Frictional resistance, 11: Disc, 12: Surface pressure acting on the disc, 13:
Color, 14: Maximum extension force, 15: Disc installation pitch, 16: Reaction force handled by one disc, 17: Direct inspector. Figure 3 Figure 7 Figure 1 Figure 2 Figure 4 Figure 5 Figure 6

Claims (1)

[Claims] 1. Piping for high-temperature fluids having a curved pipe section in at least a part of the pipeline is installed in a concrete U-shaped groove, etc.
In a buried pipe structure that is filled with insulation material around it,
A buried pipe for high-temperature fluid, characterized in that a plurality of buried pipe restraining protrusions are attached to the straight pipe part following the bent pipe part of the buried piping part to suppress expansion and contraction in the bent pipe part due to temperature changes. tube structure.