DE4418108A1 - Hot water storage tank with foam insulation jacket - Google Patents

Abstract

A hot water storage tank (1) is enclosed in a foamed plastic insulation jacket (5,6) comprising inner (12) and outer (13) foamed layers. Inner layer (12) temp. resistance is greater than the outer layer (13) and inner layer (12) thickness is sufficient to maintain outer layer (13) temp. below the max. usable temp. for the material of that layer (13).

Description

The invention relates to a hot water tank with a Water container in a foam plastic manufactured insulation jacket, which sits in an outer jacket.

Such a hot water tank is in the DE-GM 71 07 082 described. The insulation is there made entirely of expanded polystyrene (EPS). He is out put together two mold shell halves that and are feathery or stepped.

It has been shown that the permanent temperature resistance of EPS is not sufficient. Especially when Going dry and boiling tests, which the Hot water tank subject to security reasons become, the insulation layer softens and disintegrates.

It is also known to use foamed polyurethane as a material to use for the insulation jacket. This will increase however, the cost. In addition, one is constructed in this way Hot water tank hardly recyclable.

The object of the invention is a hot water tank of the type mentioned above with regard to the insulation improve.  

According to the invention, the above task is for one Hot water tank of the type mentioned above solved that the insulation jacket from a foamed Inner layer and a foamed outer layer, that the temperature resistance of the inner layer is larger than that of the outer layer and that the Wall thickness of the inner layer is such that the maximum temperature on the outer layer at or below the value of the temperature resistance of the The outer layer remains.

Due to this two-layer structure of the insulation jacket whose temperature resistance improves because the Inner layer of those occurring on the water tank Withstands temperatures, for example up to 120 ° C. In the inner layer emerges towards the outer layer Temperature gradients, so that only on the outer layer lower temperatures, for example up to 75 ° C, occur. The outer layer can therefore consist of one cheaper material than the inner layer.

The inner layer preferably consists of Polyphenyl oxide (PPO) modified expanded Polystyrene (EPS) and the outer layer consists of expanded polystyrene. Have comparative calculations shown that such an insulation jacket is cheaper than one Insulation jacket made of polyurethane.

Another advantage is that the insulation is recyclable. The insulation is not on the Outer jacket and the water tank foamed or with this glued. As a result, it is used for recycling Disassembly possible without any problems.

In an embodiment of the invention, the outer layer is on foamed the inner layer. However, it is also possible the outer layer and the inner layer separated to manufacture.

Further advantageous embodiments of the invention result from the subclaims and the following Description. The drawing shows:

Fig. 1 is an exploded view of a hot water reservoir,

Fig. 2 shows the mounting manner of the connection of the outer jacket,

Fig. 3 shows the connection according to Fig. 2 and

FIG. 4 shows a cross section enlarged compared to FIG. 1.

A hot water tank has a water tank ( 1 ) made of steel or plastic. The water tank ( 1 ) is provided with a flange ( 2 ) to which a flange plate (not shown) carrying an electric heater and other components can be fastened. In addition, an inlet pipe ( 3 ) and an outlet pipe ( 4 ) are provided on the water tank ( 1 ).

An insulating jacket consisting of two half-shells ( 5 , 6 ) is used for the thermal insulation of the water tank ( 1 ).

The hot water tank ( 1 ) has an outer jacket ( 7 ), which is made of sheet metal, for example, and is divided into a front shell ( 8 ), a rear shell ( 9 ), an upper cap ( 10 ) and a lower cap ( 11 ).

Each of the half-shells ( 5 , 6 ) has an inner layer ( 12 ) adjoining the water tank ( 1 ) and an outer layer ( 13 ) adjoining the outer casing ( 7 ). The inner layer ( 12 ) has a uniform wall thickness (d) on the circumference of the water container ( 1 ). The wall thickness (d) is smaller in most places than the thickness of the outer layer ( 13 ). The outer layer ( 13 ) lies directly against the inner layer ( 12 ) or is foamed onto the latter and is adapted to the contour of the outer jacket ( 7 ).

The inner layer ( 12 ) consists of expanded polystyrene, which is modified with polyphenyl oxide. With this choice of material, it can withstand continuous temperatures of up to around 115 ° C. The outer layer ( 12 ) consists of expanded polystyrene. The material of the inner layer ( 12 ) is considerably more expensive than the material of the outer layer ( 13 ). The aim is therefore to keep the wall thickness (d) of the inner layer ( 12 ) as small as possible. The wall thickness (d) of the inner layer ( 12 ) is dimensioned such that a temperature gradient occurs in the inner layer ( 12 ) when the water container ( 1 ) dries out or during boil-out tests, which leads to a maximum temperature on the inside ( 14 ) of the outer layer ( 13 ) leads, which does not damage the outer layer ( 13 ), that is at or below the value of the permanent temperature resistance of the material of the outer layer ( 13 ). This makes it possible to use a material for the outer layer ( 13 ) that has a lower permanent temperature resistance than the material of the inner layer ( 12 ).

Fig. 4 shows that the volume of the outer layer (13) is substantially greater than the volume of the inner layer (12), so that the volume of - expensive - inner layer (12) is correspondingly small to the overall calculation of the half-shells (5, 6) affects.

In Fig. 4 it is shown that additional heat insulation plates ( 15 ) can be provided at those locations where the outer layer ( 13 ) is comparatively thin due to the contour of the outer jacket ( 7 ). The thermal conductivity of these heat insulation plates ( 15 ) is less than that of the material of the outer layer ( 13 ), so that they improve the heat insulation in critical areas. Such heat insulation panels are, for example, vacuum insulation panels (VIP). The heat insulation plates ( 15 ) are inserted into corresponding outer recesses in the outer layer ( 13 ).

The half-shells ( 5 , 6 ) can be produced, for example, as follows:
To form the inner layer ( 12 ), pre-expanded, PPO-modified EPS is blown into a warm mold, steam applied and foamed. Then this mold opens and the pre-expanded inner layer ( 12 ) is inserted into a next warm mold. After closing this mold, normal EPS is blown into this mold from a storage container and steam is applied to it. The foaming and welding process takes place between the inner layer ( 12 ) and the outer layer ( 13 ). Then the prefabricated half-shell ( 5 , 6 ) is inserted into a third, cold mold for stabilization and then ejected.

After placing the half-shells ( 5 , 6 ) on the water tank ( 1 ), the upper cap ( 10 ) and the lower cap ( 11 ) are axially printed on the insulating jacket formed by the two half-shells ( 5 , 6 ). This is shown in Fig. 1 and 2 by the arrow (A). The upper cap ( 10 ) or the lower cap ( 11 ) press a nose ( 16 ) formed on the outer layer ( 13 ) flat (cf. FIG. 3). This leads to an axially fixed seat of the insulation jacket in the outer jacket ( 7 ). The front shell ( 8 ) and the rear shell ( 9 ) are then pressed onto the half-shells ( 5 , 6 ) in the direction of the arrows (B) (cf. FIG. 1, FIG. 2). The front shell ( 8 ) and the rear shell ( 9 ) overlap the upper cap ( 10 ) and the lower cap ( 11 ) by means of an angled edge ( 17 ) (cf. FIG. 3).

Simultaneously, the front shell (8) and the rear shell (9) snap together and thereby snag an edge fold (18) of the front shell (8) and an edge fold (19) of the rear shell (9).

Bends can be provided in the area of the edge folds ( 18 , 19 ), which absorb the expansion of the insulating jacket ( 5 , 6 ).

A conductor structure ( 20 ) is formed on the rear shell ( 9 ) used for wall mounting. This improves the transmission of the weight of the water container ( 1 ) to the rear shell ( 9 ) by means of the half-shell ( 6 ).

Due to the structure described, recycling can be carried out on site by an installer in a simple manner after the service life of the hot water tank. For this purpose, the edge folds ( 18 , 19 ) are opened like a zipper, then the front shell ( 8 ) and the rear shell ( 9 ) are removed, whereby the upper cap ( 10 ) and the lower cap ( 11 ) are released. Then the half-shells ( 5 , 6 ) can be removed from the water tank ( 1 ).

Claims (12)

1. Hot water tank with a water tank in an insulating jacket made of foamed plastic, which sits in an outer jacket, characterized in that the insulating jacket ( 5 , 6 ) consists of a foamed inner layer ( 12 ) and a foamed outer layer ( 13 ) that the temperature resistance the inner layer ( 12 ) is larger than that of the outer layer ( 13 ), and that the wall thickness (d) of the inner layer ( 12 ) is dimensioned such that the maximum temperature at the outer layer ( 13 ) at or below the value of the temperature resistance of the outer layer ( 13 ) remains. 2. Hot water tank according to claim 1, characterized in that the inner layer ( 12 ) made of polyphenyl oxide (PPO) modified expanded polystyrene (EPS) and the outer layer ( 13 ) consists of expanded polystyrene (EPS). 3. Hot water tank according to claim 1 or 2, characterized in that the outer layer ( 13 ) on the inner layer ( 12 ) is foamed. 4. Hot water tank according to one of the preceding claims, characterized in that the wall thickness (d) of the inner layer ( 12 ) is uniform, and the wall thickness of the outer layer ( 13 ) is adapted to the contour of the outer jacket ( 7 ). 5. Hot water tank according to one of the preceding claims, characterized in that at least one heat insulation plate ( 15 ) is arranged on the outside of the outer casing ( 7 ) at comparatively thin locations. 6. Hot water tank according to claim 5, characterized in that the heat insulation plates ( 15 ) are vacuum insulated panels. 7. Hot water tank according to one of the preceding claims, characterized in that the insulating jacket is divided into two half-shells ( 5 , 6 ). 8. Hot water tank according to one of the preceding claims, characterized in that the outer jacket ( 7 ) presses the insulating jacket ( 5 , 6 ) on the water tank ( 1 ). 9. Hot water tank according to one of the preceding claims, characterized in that the outer jacket ( 7 ) in a front shell ( 8 ), a rear shell ( 9 ), an upper cap ( 10 ) and a lower cap ( 11 ) is divided. 10. Hot water tank according to claim 9, characterized in that the front shell (8) and the rear shell (9) with edges (17) engage over the upper cap (10) and the lower cap (11), wherein the top cap (10) and the lower cap ( 11 ) press axially on the insulation jacket ( 5 , 6 ). 11. Hot water tank according to claim 9 or 10, characterized in that the front shell ( 8 ) and the rear shell ( 9 ) with edge folds ( 18 , 19 ) are hooked together. 12. Hot water tank according to one of the preceding claims, characterized in that the outer jacket ( 7 ) in the insulating jacket ( 5 , 6 ) engaging conductor structure ( 20 ) for transferring the weight of the water tank ( 1 ) on the insulating jacket ( 5 , 6 ) has the outer jacket ( 7 ).