JPH10332075A - Piping warm-keeping structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce cost by reducing weight by installing an air layer forming metalware on a piping surface and arranging a warm-keeping material on the outside of the same metalware. SOLUTION: Air layer forming metalwares consisting of band plates 6, 7 and two pieces of flat plates 8 are made into one set with two pieces of them each and arranged on a surface of a piping 1 by making their respective flat plates 8 approach each other, and they are fixed on the piping 1 by winding an annealing wire on an outer periphery. Constant intervals are provided on the axial direction of the piping 1, a plural number of sets of the air layer forming metalwares 3 are installed on the surface, the outer periphery of the air layer forming metalware 3 for each of the sets is fastened by the number line 4, and they are fixed on the piping 1. A warm-keeping material 2 is installed on the outer periphery of the air layer forming metalware 3, a surface of the piping 1 is covered and formation of a piping warm-keeping structure is completed. An air layer 5 having a high warm-keeping effect is provided between the piping 1 and the warm-keeping material 2, a sufficient heat insulating effect is provided even in the case of using the thin warm-keeping material 2, and weight reduction of the warm-keeping structure is realized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal insulation structure for piping applied to high-temperature piping of nuclear power plants, thermal power plants, chemical plants and the like.

[0002]

2. Description of the Related Art In a conventional pipe, when the temperature is to be maintained, the surface of the pipe 1 is covered with a heat insulating material 2 to prevent heat dissipation as shown in FIG. I was letting it.

[0003] In keeping the above-mentioned pipe warm, the thickness of the heat insulating material 2 varies depending on the temperature conditions.
mm to about 250 mm, the weight is considerable, and the cost is increased. Accordingly, a pipe support and a pipe gantry having strength corresponding to the weight have been used.

[0004]

As described above, in the conventional heat insulation of pipes, the thickness of the heat insulation material varies depending on the temperature conditions. Had become something.

[0005] For example, when the temperature inside the pipe is 540 ° C and a pipe having a nominal diameter of 550A is made of a heat insulating material of calcium silicate, the heat insulating material is about 75 kg per meter.
The support of the pipes and the pedestal of the pipes have to be designed and manufactured so as to be able to support the weight obtained by adding the weight of the heat insulating material to the total weight of the pipes, which increases the weight and the cost. The present invention is intended to solve the above problems.

[0006]

According to a first aspect of the present invention, there is provided a heat insulation structure for a pipe, wherein an air layer forming metal having a cylindrical surface having an outer diameter larger than the outer diameter of the pipe is mounted on the pipe surface, and the outer surface of the metal is provided. It is characterized in that a heat insulating material is provided on the rim.

In the present invention, since the heat insulating material is provided via the air layer forming metal and covers the pipe, the air layer having a larger heat insulating effect than the heat insulating material is provided between the surface of the pipe and the inner surface of the heat insulating material. Is formed.

Therefore, the thickness of the heat insulating material is reduced as compared with the conventional heat insulating material in which the heat insulating material is disposed in close contact with the surface of the pipe,
The weight can be reduced, the size of the piping support and the size of the gantry can be reduced, and the cost can be reduced.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A pipe heat insulating structure according to an embodiment of the present invention will be described with reference to FIG. In the present embodiment shown in FIG. 1, a plurality of air layer forming hardware 3 arranged on the surface of a pipe 1 at a constant interval in the axial direction, and the pipe 1 provided outside the metal 3 Is formed of a cylindrical heat insulating material 2 that covers the surface of the radiator.

As shown in FIG. 1 (b), the air layer forming metal member 3 is formed in a semicircular shape and has a band-shaped plate 6 which is in close contact with the surface of the pipe 1, and a semicircular shape larger than the band-shaped plate 6. And a band-shaped plate 7 disposed outside the band-shaped plate 6 at a fixed interval and in close contact with the inner surface of the heat insulating material 2, and a band-shaped plate 6 having a semicircular shape.
7 comprises two flat plates 8 which are respectively connected between the ends and form the same plane.

The air layer forming hardware 3 composed of the band-shaped plates 6, 7 and the two flat plates 8 is arranged on the surface of the pipe 1 so that the two flat plates 8 are arranged as a set, and the flat plates 8 are brought close to each other. Line 4
Is wound and fixed to the pipe 1.

Next, the formation of the pipe insulation structure according to this embodiment will be described. First, a plurality of sets of air layer forming hardware 3 are mounted on the surface of the pipe 1 at predetermined intervals in the axial direction of the pipe 1, and the outer peripheries of the air layer forming hardware 3 for each set are fixed to the pipe 1 by tightening with a number line 4. I do. Next, the heat insulating material 2 is attached to the outer periphery of the air layer forming metal 3 to cover the surface of the pipe 1, and the formation of the pipe heat insulating structure is completed.

In the pipe heat insulating structure formed as described above, since the air layer 5 having a large heat insulating effect is provided between the pipe 1 and the heat insulating material 2, even when a thin heat insulating material 2 is used, a sufficient heat insulating effect is obtained. And the weight of the heat retaining structure can be reduced.

The heat retaining effect when the air layer 5 is provided will be described below based on a specific example. In this specific example, the nominal diameter of the pipe is 500 A, and the temperature in the pipe is 54 A.
0 ° C., the outside air temperature is 35 ° C., and the amount of heat dissipated is constant.

When the temperature in the pipe is 500 ° C., the thermal conductivity of air λa = 0.0562 [W / m · K] and the thermal conductivity of calcium silicate λc = 0.0817 [W / m · K]. And each of them is represented by the heat transfer resistances R _a and R _c , and each is represented by the following equation. Note that L is the heat transfer length and S is the heat transfer cross-sectional area.

R _a = L / 0.0562S ≒ 17.8 L / S R _c = L / 0.0817S ≒ 12.2 L / S According to the above, when the heat insulating material is an air layer, the calcium silicate heat insulating cylinder It can be seen that the heat transfer resistance is increased by about 46% and the thickness can be reduced to about 69%.

When a calcium silicate heat insulating cylinder is used as a heat insulating material under the above conditions, the thickness thereof is usually 200 mm. When the same heat insulating effect is to be obtained by using the pipe heat insulating structure according to the present embodiment, when the thickness of the air layer is half that of the calcium silicate heat insulating cylinder and is expressed by t [m], the following equation is obtained. Holds.

0.2 × 12.2 L / S = t × 17.8 L
/S+2t×12.2L/S ∴t = 0.058 [m] 2t = 0.116 [m] When a 200mm-thick calcium silicate insulation tube is directly installed on the piping like the conventional piping insulation structure Since the bulk specific gravity of calcium silicate is 150 kg / m ³ , the weight of the heat retaining cylinder is as follows.

3.14 × ｛(0.25 + 0.200) ²
−0.25 ² ｝ × 150 ≒ 66 [kg] On the other hand, the weight of the calcium silicate insulation tube in the case of the present embodiment is as follows.

3.14 × ｛(0.25 + 0.058 +
0.116) ² − (0.25 + 0.058) ² ｝ × 15
0 ≒ 40 [kg] Therefore, the weight of 66-40 = 26 [kg] is reduced, and about 4
The weight was reduced by 0%.

[0021]

The pipe insulation structure according to the present invention comprises an air layer forming metal member having a cylindrical surface having an outer diameter larger than the outer diameter of the pipe, the metal member being provided on the surface of the pipe at regular intervals in the axial direction of the pipe; Because the air layer formed between the pipe surface and the inner surface of the heat insulating material exerts a heat insulating effect by being formed by the heat insulating material disposed outside the The thickness of the heat insulating material can be reduced and the weight can be reduced as compared with the conventional one in which the materials are provided, and the size of the pipe support and the gantry can be reduced, so that the cost can be reduced.

[Brief description of the drawings]

FIGS. 1A and 1B are explanatory views of a pipe heat insulating structure according to an embodiment of the present invention, wherein FIG. 1A is a perspective sectional view, FIG. 1B is a front view, and FIG.
FIG. 3 is a view taken along the line AA in FIG.

FIG. 2 is an explanatory view of a conventional pipe heat insulating structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Piping 2 Heat insulation material 3 Air layer forming hardware 4 Track 5 Air layer 6, 7 Strip plate 8 Flat plate

Claims (1)

[Claims] 1. A heat insulation structure for a pipe, wherein an air layer forming metal having a cylindrical surface having an outer diameter larger than the outer diameter of the pipe is mounted on the surface of the pipe, and a heat insulating material is provided outside the metal.