Heatable part of a pump housing

Abstract

The description relates to a heatable pump housing part comprising a heat distribution sheet fixed on the housing part and a tubular heating element fixed on the heat distribution sheet. According to the invention the tubular heating element is positioned in a groove or a step on the housing part that is covered by the heat distribution sheet.

Description

[0001]This invention refers to a heatable part of a pump housing on which a heat distribution sheet is fixed on which a tubular heating element is arranged. Such a pump housing part is known from DE 199 03 951 A1. Heatable pump housing parts are, for example, required for washing machines or dishwashers.[0002]The pump housing known from DE 199 03 951 A1 has an aluminium heat distribution sheet fixed on a flat or conical cover surface. The heat distribution sheet distributes the heat generated from a tubular heating element, which is soldered onto the plate, quickly over a large area and transmits it to the stainless steel housing part situated below it.[0003]Furthermore, EP 1 507 914 B1 discloses another pump housing part. A tubular heating element is arranged in a suitably shaped groove of the housing part. To facilitate a good heat coupling between the tubular heating element and the housing part, joints and any free spaces between the tubular heating element and the walls and bot...

AI Technical Summary

Benefits of technology

[0005]A constant goal in the development of heatable pump housing parts for washing machines or dishwashers has always been to achieve with as little costs as possible a heat coupling as ideal and reliable as possible between the tubular heating element and the pump housing. The better the heat coupling, the faster is the rate, with which the heat generated by the tubular heating element is transmitted to the pump housing and from there to the fluid flowing through the pump housing. Moreover, with a better heat coupling one can reduce the operating temperature of the tubular heating element further. Lower operating temperatures of the tubular heating element help reduce the free spaces between this element and other components in the washing machine or dishwasher and particularly allow the use of more economical plastics in the vicinity of the tubular heating element, since these have to withstand less high temperatures.

[0007]An object of the present invention is to show a way, in which the heat coupling between the tubular heating element and the pump housing can be improved in a reliable manner at minimum costs.SUMMARY OF THE INVENTION

[0008]A pump housing part according to this invention has a groove or step, which is covered by the heat distribution sheet. When the tubular heating element is fixed in this groove or step, its area of contact with the heat distribution sheet increases, which subsequently improves the dissipation of heat.

[0010]To establish a large-surface contact between the tubular heating element and the heat distribution sheet in a reliable manner, the tubular heating element of a housing part according to this invention preferably has a more or less angular cross-section. For example, the tubular heating element can have an approximately rectangular, trapezoidal or triangular cross-section. In that case, it is preferred if the lower side of the tubular heating element, i.e. the side facing the pump housing, encases an angle less than 90°, particularly 60° to 80°, with an adjacent side. Thus, an enlarged contact area can be created easily and reliably between the tubular heating element and the heat distribution sheet. As another option, a rounded tubular heating element can be fixed in an groove having a round bottom, e.g. in a groove with a semi-circular cross-section.

[0011]Preferably, the heat distribution sheet extends on both the sides of the groove or step, so that the heat generated by the tubular heating element is spread quickly over a maximum possible area of the housing part.

[0012]Preferably, the tubular heating element is arranged in a groove of the housing part that is covered by the heat distribution sheet. This offers the advantage that an even larger area of contact can be created between the tubular heating element and the heat distribution sheet, as compared to the arrangement of the tubular heating element in a step, because a groove with a trapezoidal or rectangular cross-section is formed by two steps; and this enables the heat distribution sheet to touch the tubular heating element on three side faces.

Problems solved by technology

It is generally known that the process of soldering a tubular heating element to a heat distribution sheet and the heat distribution sheet to a steel body causes relative movements between the tubular heating element and the heat distribution sheet as well as between the heat distribution sheet and the steel body due to the heating in a soldering furnace; these movements are unproblematic only in case of soldered joints on plane surfaces.

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