JPS58203337A - Heat insulating method for hot water storage tank - Google Patents

Abstract

PURPOSE:To improve the temperature retaining capacity of the titled tank by integrating all the constitutional elements of the tank by a method wherein a low pressure foaming hard urethane material is interposed between the ceiling plate of a cover surrounding the hot water storage tank having a semi-spherical bottom, and the side plate 8 of the cover, a spacer having a communication hole is interposed between the semi-spherical bottom of the tank and the bottom plate of the cover and a soft urethane material is filled into the space between the bottom of the tank and the bottom plate of the cover without leaving any gap. CONSTITUTION:The spacer having the communication hole 11 is interposed between the hot water storage tank 6 having the semi-spherical bottom 7, and the bottom plate 12 of the cover surrounding the tank and an injection port 13 is provided at a part, and gas escape ports 14 and 15 at other parts, of the bottom plate 12. Then the low pressure foaming hard urethane material 17 is injected from the injection port 13 into the space defind by the tank 6, the ceiling plate 9 and the side plate 8 of the cover. The urethane material 17 may be in the form of a shaped frame of small thickness and light weight since the foaming pressure thereof is low and it is released immediately after foaming. Thus, upon completion of the filling of the urethane material 17 into the space up to a part near the bottom, the soft urethane resin material 18 is injected into the space through the port 13. The urethane resin material 18 thus injected passes the communication hole 11 and enters the space where it foams to thereby form a heat insulating layer. As a result, all the constitutional elements of the tank are made integral with one another by the urethane materials 17 and 18.

Description

[Detailed description of the invention] The present invention relates to a method of insulating a hot water storage tank.

As shown in FIG. 1, the conventional method of insulating a hot water storage tank is to attach a heat insulating material 2 that has been processed and formed in advance to the outer periphery of a hot water storage tank 1, and then to attach a top plate 3a and a bottom plate 3b.

It was covered with an exterior body 3 consisting of side plates 3C. The problem with this conventional method is that the hot water storage tank 1
Also, a gap 4 is formed between the exterior body 3 and the heat insulating material 2, resulting in a decrease in heat retention performance, and the space 5 between the hot water storage tank, the hemispherical bottom 1a, and the bottom plate 3b cannot be completely insulated.

The present invention solves these conventional problems and provides a method of insulating a hot water storage tank with excellent heat retention.

That is, the insulation method of the present invention involves interposing a spacer having a communication hole between a hot water storage tank having a hemispherical bottom and the bottom plate of the exterior body, providing an inlet in one part of the bottom plate and a gas vent in the other part. An exterior body is arranged to surround the tank, and low-pressure foamed rigid urethane is applied from the injection port of the bottom plate of the exterior body to the space surrounded by the hot water storage tank, top plate, and solid body, and between the bottom of the hot water storage tank and the bottom plate of the exterior body. The space between them is filled with soft urethane. With this configuration, each component is integrated, and the space surrounded by the top plate and side body of the exterior body (high temperature part of the hot water storage tank) is filled with low-pressure foamed rigid urethane with low thermal conductivity, resulting in a low hot water temperature. The space surrounded by the bottom of the hot water storage tank and the bottom plate of the exterior body is filled with soft urethane without any gaps, improving heat retention performance.

An embodiment of the present invention will be described below with reference to FIGS. 2 to 4.

Figure 2 shows a hot water storage tank for an electric water heater that is widely used in ordinary households, and is shown upside down to accommodate insulation.

In the same figure, A is the outer diameter, B is the height, and C and D are the insulation gap dimensions, which are 0.67 m, 1.7 m, and 0.0, respectively.
The heat dissipation area is 4.3 doors at 5 m, o, and 10 m. 6 is a cylindrical hot water storage tank made of a steel plate with a thickness of 3 mm and has a hemispherical bottom 7; 8 and 9 are side plates and a top plate of the exterior body surrounding the hot water storage tank 6, which are vinyl chloride coated steel plates with a thickness of 0.5 mm. Made in Japan. 1o is an annular spacer made of iron having a thickness of 20mm and a width of 25m+n, and has a plurality of communication holes 11 with a diameter of 14cm along the circumference. An external view of this is shown in Figure 3.

The communication hole 11 is made of foamed insulation material that connects the bottom part 7 of the hot water storage tank and the bottom plate 1.
This is provided for the purpose of inflowing into the gap of No. 2. Bottom plate 1
2 is a concave iron plate with a thickness of 3 Mn and a diameter of 0.68 m, with an inlet 13 at one end and a gas vent 1 at the other end and in the center.
4.15 is installed. When the heater protection cover 16' is not attached, there is a thickness of 1 on the outside of the exterior material 8 and the top plate 9.
．． Place the formwork in column 5 (omitted in the drawing) from the injection port 13 with the injection gun 16 to achieve a bulk density of 30/9/silence and a thermal conductivity of 0.0.
2k, a/m, h.

The space surrounded by the hot water storage tank 6, the top plate 9, and the side body 8 was filled with low-pressure foamed rigid urethane 17 of 1.5 deg.

Low-pressure foaming rigid urethane has a foaming pressure of 0.05 kg/
ctlt and a thin, lightweight formwork with a low plate thickness;
Although there are advantages such as not needing to heat the hot water storage tank 6, mold, etc. during injection foaming and the ability to release the mold immediately after foaming, there is a drawback that the resin is foamy and has poor fluidity. Therefore, it is possible to fill the space surrounded by the hot water storage tank 6, the top plate 9, and the side bodies 5・′′8 with few obstacles, but the space surrounded by the hemispherical bottom of the hot water storage tank 6, the spacer 10, and the bottom plate 12 is is not filled evenly.

For this reason, after filling the hot water storage tank 1 with hard urethane to the vicinity of the bottom, soft urethane resin was injected through the injection port 13. The resin flowed into the space through the communication hole 11 provided in the spacer 10 and foamed to form a heat insulating layer. Soft urethane 18 has a bulk density of 18Kp/silence, thermal conductivity of 0.032, and ij/
It is a heat insulating material made of open cells of m, h, dog.

By the above method, each component as shown in FIG. 4 was integrated with the low pressure foamed hard urethane 18 and the soft urethane 19.

Next, the protective cover 16' was attached, the electric heater 2° was energized, 370 liters of 86°C hot water was stored in the hot water storage tank 6, and the amount of heat released was measured when it was left for 13 hours under an outside air condition of 20°C. Then on the 24th it was 7/h, 7)/.

On the other hand, as shown in Figure 1, the thickness is 50 mm and the density is 61'-
The heat dissipation amount of a conventional hot water storage tank filled with a glass wool insulation material of 16 Kf/m' is 39 k7/h, -, which is a 60% increase in heat dissipation and the heat retention performance is low.

As described above, the present invention provides low pressure foamed rigid urethane in the space between the top plate of the exterior body surrounding the hot water storage tank having a hemispherical bottom and the solid body, and the hemispherical bottom of the hot water storage tank and the bottom plate of the exterior body. A spacer with a communicating hole is interposed between them, and the space between the bottom of the hot water storage tank and the bottom plate is filled with soft urethane without any gaps, thereby integrating each component and improving heat retention performance.

Furthermore, unlike the conventional method using only hard urethane, the heat insulation method according to the present invention does not require a preheating step and does not require an hour of curing, making it highly suitable for mass production.

[Brief Description of the Drawings] Fig. 1 is a sectional view showing a conventional example, Fig. 2 is a sectional view showing an embodiment of the heat insulation method of the present invention, Fig. 3 is a perspective view of the spacer, and Fig. 4 is a sectional view showing an example of the heat insulation method of the present invention. It is a sectional view showing the same example. 7. - 6...Hot water tank, 8...Side body, 9.
...Top plate, 1o...Spacer, 17.
...Low pressure foaming hard urethane, 18...Soft urethane. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 6 Figure 3 Figure 4

Claims (1)

[Claims] (1) A hot water storage tank having a hemispherical bottom is placed in a space inside an exterior body consisting of a top plate, a side body, and a bottom plate, a spacer having a communication hole is interposed between the hot water storage tank and the bottom plate of the exterior body, and An inlet is provided in one part of the bottom plate, and a gas vent is provided in the other part, and low-pressure foamed rigid urethane is applied from the inlet in the bottom plate to the space between the hot water storage tank and the top plate and side body. 2) A method of insulating the hot water tank with the bottom plate on top and using hard urethane in the space between the hot water tank and the top plate and side body.