JPS60201198A - Heat-insulating piping material - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD The present invention relates to a heat insulating piping material used in piping construction for conveying a thermal fluid such as hot water.

PRIOR ART Conventional heat-insulating piping materials employ a method in which a thermal fluid transfer pipe 2 such as a copper pipe is coated with a foamed synthetic resin 7, as shown in FIGS. 6 and 7. A resin with low foaming does not have sufficient heat insulation performance, and a resin with high foaming has good heat insulation performance, but its performance depends on the layer thickness, which has the disadvantage of increasing external dimensions.

Therefore, the inventors previously filed a Japanese Patent Application No. 58-182570 by inserting a small-diameter conveyor tube (copper@) in a bellows-like shape into the inner resin tube. developed an insulating piping material that is coated with a low thermal emissivity film and placed inside a bellows-shaped resin outer tube. According to this piping material, the heat radiation coefficient of the foamed resin coating method is K =
0.33 to 0.34, whereas this one has K =
Good results of 0.16 to 0.18 have been obtained. However, since this type has a more complex structure than the extrusion coating type, it is unavoidable that the manufacturing process is complicated.In particular, when the conveyor pipe is connected to a hot water heater, It is preferable to use it as a pair with a return pipe, whereas
When two inner tubes with conveyor tubes inserted are tied side by side and inserted into an outer tube, there is a gap of 2 mm each on the top and bottom and 1 mm each on the left and right between the inner tube and the outer tube, so the insertion work is difficult. The fact that it is not necessarily easy makes manufacturing complicated.

Purpose An object of the present invention is to provide a heat insulating piping material that has a simple structure, is easy to manufacture, and has excellent heat insulation performance.

Description This invention provides a method for providing a film having a low thermal emissivity in close contact with a thermal fluid transport pipe having a heat insulating coating on its outer surface and a bellows-shaped synthetic resin outer pipe in which the pipe is housed. May it become! This is an insulated piping l with IO characteristics.

The thermal fluid transfer pipe was inserted into the outer pipe as it was (115
In the built-in pipe 4A, between the outer pipe and the conveying pipe,
Although there is a certain amount of space and the contact between the outer tube and the conveying tube is point or linear, the heat radiation from the conveying tube to the outer tube is not insignificant.

By the way, the possible ways of dissipating heat from the conveyor tube to the outer tube are: 1) conduction through the air, 2) convection through the air, 3) radiation between the outer surface of the conveyor tube and the inner surface of the outer tube. Considering the means for prevention and their advantages and disadvantages, first, in order to prevent conduction in 1), if a bellows-shaped resin tube is used as the outer tube, contact between the conveying tube and the outer tube can be sufficiently reduced. For convection (2), it is desirable to reduce the space ratio between the outer tube and the conveyor tube, but since the insertion of the conveyor tubes becomes difficult, especially in the case of two tubes in a pair, there is a limit to this as well. be.

The present invention is a heat-insulating piping material for a thermal fluid transfer pipe that reduces radiation as described in 3) and facilitates insertion of the transfer pipe into the outer pipe.The specific structure thereof will be explained with reference to the drawings.

As shown in FIG. 1, two thermal fluid transfer tubes 2 made of, for example, steel tubes are inserted in a pair into an outer tube 1 made of a resin tube shaped like a coal goo. These conveyor pipes, for example, circulate and supply hot water to a radiator; one pipe is the outgoing pipe,
The other one has been reinstated.

A feature of the present invention is that a polyethylene coating 3, for example, is provided as a heat insulating coating on the outer surface of the conveying tube 2, and the outer tube 1 and the conveying tube 2 are connected in close contact with the surface of the insulating coating 3 of the conveying tube 1. A film 4 made of a material having a low thermal emissivity (for example, an aluminum foil laminated film) is interposed between the two. That is, as shown in the figure, the aluminum foil laminated film 4 is wrapped around the outer surface of the heat insulating cover 3 of the transport pipe with the aluminum foil surface facing outward so as to bind the pair of transport pipes 2 together. There is.

The aluminum foil laminated film 4 is, for example, a ribbon made by laminating aluminum foil with a thickness of 7 to 50 μ on a PE or PVC film with a thickness of 25 μ, as shown in FIG.
It is wrapped around two conveyor tubes 2 so that the edges overlap by 1/3, and a similar ribbon-like tape 5 with glue is pasted on top of it to prevent it from unwinding. Make it.

FIG. 5 shows another specific example of a film 4 with a low thermal emissivity.
In this example, a film having an aluminum vapor-deposited layer is used instead of the aluminum foil laminated film described above. In this case, the film 4 is placed parallel to the transport tube 2 and wound around the transport tube 2 so that the edges meet at the joint 6. Attached [Buru.

Note that the aluminum foil laminated film 4 used in the specific example of FIG. If an aluminum foil laminated film is used, the stopper tape 5 can be omitted.

The aluminum foil laminated film and aluminum vapor deposited film are
Due to this effect, it has the effect of insulating the radiant heat, thereby reducing the amount of heat dissipated during transport.

By the way, the amount of heat for the width of the heating body is proportional to the fourth power of the surface temperature of the heating body. In the piping material of the present invention, a heat insulating coating 3 is applied to the outer surface of the conveying tube 2, and this heat insulating coating 3 reduces the amount of heat transferred from the outer surface of the conveyor tube 2 to the outer surface of the coating layer. As a result, the outer surface temperature of the coating layer is lowered, which contributes to a reduction in heat dissipation due to radiation from the conveying pipe 2. Furthermore, this heat-insulating coating also has the effect of preventing heat transfer between the outgoing pipe and the returning pipe.

The thickness of the heat insulating coating 4 may be about 0.25 to 5 mm, but
It is determined by the degree of foaming and peelability of the resin. However, in principle, the thickness should be such that the outer surface temperature of the coating is preferably 10° C. lower than the outer surface temperature of the conveying tube 2.

In addition, as shown in the figure, in the piping material of the present invention, an inner pipe is not provided between the transport pipe 2 and the outer pipe 1, so that the space between the transport pipe 2 and the outer pipe 1 is It can be relatively wide, and therefore the conveying tube 2 can be easily inserted into the outer tube 1.In particular, the two conveying tubes 2 can be integrated with a low thermal emissivity film 4 such as an aluminum foil laminated film. Even if the tube is bundled with the inner tube, the distance between the outer tube 1 and the outer tube 1 is increased by a little less than 2 mm compared to the case where an inner tube is provided, so it can be easily inserted.

In addition, in the case where the hot water transfer pipe is composed of an outgoing pipe and a returning pipe, heat transfer occurs between the two pipes. In order to reduce this heat transfer, a bridge may be installed between the heat insulating coatings 3 of the outgoing pipe and the returning pipe, if necessary. This bridge can be integrally formed at the same time that both tubes are coated with resin. In addition, it is possible to heat up the heat by using a highly foamed resin (2 to 3 times) as the coating resin, or by interposing a spacer such as a hard foamed resin plate or a resin plate woven with glass fiber between the outgoing pipe and the returning pipe. Movement can be reduced. Furthermore, this spacer can also improve compressive load resistance.

Next, the insulation performance of the piping material of the present invention will be described. A material having the structure shown in FIG. 1 was used as a test material, and its heat insulation performance was measured by the BL method.

This piping material consists of two conveyor tubes made of steel tubes with an outer diameter of 8 mm and a polyethylene coating of 0.5 mm in thickness.Both tubes are tied together, and aluminum foil is laminated on the coated surface of the conveyor tubes. The film was wound with the aluminum foil facing outward, and this was inserted into an outer corrugated resin tube with external dimensions of 20 x 30 nv, with a tube length of 11 m.

The test equipment places the sample piping material between a constant-temperature water tank and a heat exchanger, and sends the hot water from the constant-temperature convex through the outgoing pipe inside the piping material to the heat exchanger, where the hot water is heat-exchanged. is sent to the return pipe of the piping material, and then returned to the constant temperature water tank through the return pipe.
Hot water is circulated through a conveying pipe. Using this device, the heat dissipation coefficient K was calculated using the following formula, with the inlet temperature of the outgoing pipe being 80°C and the inlet temperature of the returning pipe being 60°C. However, W: Water m (kg/min > Cp: Specific heat of water (1tcal/k (1℃) = IT
r: Room temperature < °C) (average of 3 points) -1: Outgoing pipe inlet temperature 11 (°C) T2: Same outlet temperature (°C) T3: Return pipe inlet temperature (°C) T4: Same outlet temperature (°C) 〒: (TI +T2 +T3 +T4) /4(°
C) 〒r: Room temperature (°C) (Tr + +-rr 2 +T
3)/3 ('C) As a result, the K of the sample material was in the range of 0.15 to 0.16. An example of the measured data is shown below.

T , = 80.07°C T 2 = 77.86°C T 3 = 60.42°C T + = 61.22°C 〒r = 19.90°C K = 0.155kCal / mh'C Also, coating of the conveyor pipe The average humidity on the surface was 58°C. Next, for comparison, we investigated the insulation performance of conventional insulation piping materials in the same way as the above equipment.

This comparative sample material has the structure shown in Figs. 6 and 7, and a steel pipe 2 is coated with an extruded low-foam polyethylene coating 7 having a thickness of 4IIll11, and this material is stabilized as a pair. It is integrally covered with a polyethylene outer skin 8. This comparative sample material had a K of 0.33 to 0.34. From the above results, it can be seen that the piping material of the present invention has significantly improved heat insulation performance.

In addition, in the case of the present invention, the heat insulating coating is in close contact with the conveying pipe, so ii! When curing the throat of the conveyor pipe during pipe construction, the required length of the conveyor pipe with the resin-coated surface is exposed.
Cut the outer tube into rings and remove it, unwrap and cut out a film with low thermal emissivity such as aluminum foil laminated film, and seal the opening between the heat insulating coating surface and the outer tube. By inserting the pipe into the outer pipe, it is possible to prevent rainwater from entering into the piping material, and also to reliably keep the end of the transport pipe warm.

This invention is not limited to piping materials connected to a pair of two conveyor pipes as described in the specific examples,
It is also applied to piping materials for a single conveyance pipe such as a hot water supply pipe.

Effects As explained above, the heat insulating piping material according to the present invention has improved heat insulating performance and can be easily inserted into the outer pipes even when there are two conveyor pipes, so it is easy to manufacture. Therefore, productivity is improved. In addition, the insulation effect is
The same effect can be obtained not only when the main body of the conveying pipe is a steel pipe but also when it is a resin pipe.

[Brief explanation of drawings]

Fig. 1 is an axial sectional view showing a specific example of the heat insulating piping material of the present invention, Fig. 2 is a side sectional view of Fig. 1, Fig. 3 is a perspective view of the above specific example, and Fig. 4 is a sectional view of this specific example. FIG. 5 is a side view, not showing an example of one piece of the conveying pipe; FIG. 6 is a side view, not showing another specific example of the same conveying pipe; FIG. The figure is a perspective view of the same. 1... Outer pipe, 2... Conveying pipe, 3... Heat insulating coating,
4...Low thermal emissivity film, 5...Securing tape, Patent applicant Tokyo Gas Co., Ltd. Sumitomo Light Metal Industries Co., Ltd. Agent Patent attorney Hide Komatsu Agent Patent attorney Hiroo Asahi 1. -31"!1 Sea-4t* Tsudo 5 1"41 O6 Figure 24/7th

Claims (1)

[Claims] A film having a low thermal emissivity is provided in close contact with the thermal fluid transport pipe between the thermal fluid transport pipe having a heat insulating coating on the outer surface and a bellows-shaped outer resin pipe housing the heat fluid transport pipe. Insulated piping material.