DE19605996C2 - Process for the manufacture of electric instantaneous water heaters for liquid media - Google Patents

Description

The invention relates to a method for producing electrical Instantaneous water heater according to the preamble of patent claim 1.

Such instantaneous water heaters usually consist of one pass flow tube and a helically wound tube around this tube radiator, which can then be surrounded by a jacket.

It is essential for such instantaneous water heaters, that the thermal surface load is kept low, d. that is, the temperature gradient between which the heat is generated the heating conductor and the medium absorbing this heat if possible is low.

According to DE-AS 22 40 382, this is largely achieved by that the radiator is inserted between sleeves and with these un ter reduction in cross-section is pressed. Remain here however, gaps between the radiator and the that medium to be heated leading inner sleeve that the heat transfer affect.

In contrast, DE 26 52 656 C3 proposes a tubular heater ver with a flow tube on a common support plate some, the cross sections of these components being both rectangular can also be circular. The structure thus made is however, it can only be used to a limited extent, especially for coffee machines and similar devices equipped with a flat water heater.

The object of the present invention was to achieve high processing to develop a process to avoid temperatures position of instantaneous water heaters in which a tubular heater in Shape of a spiral is wound on the flow tube, such that in the operating state between these parts only a relatively ge there is a slight temperature gradient.  

This task is characterized by the characteristic features of Pa claim 1 solved. Due to the success of these procedures The aluminum comes in at a high pressure  of the tubular heater jacket in its flow area, so that the The resulting deformations on the tubular heating element are too large Serts contact surfaces between tubular heater and flow tube to lead.

The object of the invention is in one embodiment shown and explained below.

Show it

Fig. 1 is a, partially cut, side view of the heater and

Fig. 2 is a view from the front.

The water heater shown consists of a flow tube 1 , a coiled on the flow tube 1 tubular heating body coil 2 and a structure 1 + 2 enveloping steel jacket 3rd Furthermore, at one or both ends of the radiator coil 2, a molded part 4 made of aluminum sheet is also pressed between the coil 2 and the flow tube 1 , which serves to fasten a regulator 5 and / or temperature limiter.

This instantaneous water heater is manufactured as follows:

The prefabricated tubular heating coil 2, which, from a rectangular aluminum provided with casing 7 in cross-section, preferably as square, consists tubular heater, is pushed onto the existing at play, of chrome-nickel steel flow tube. 1 Before this pushing, the front end 6 of the tubular heating coil 2 to diameter level slipped down-bent and bent back upwards again after pushing the helix. 2

This structure is now pressed under high pressure, thus reducing the diameter of the flow tube 1 . As a result, the circumference of the flow tube 1 is simultaneously reduced by 2% and the wall thickness is increased accordingly by this compression. This compression process creates an extremely intimate connection between the aluminum jacket of the tubular heater and the flow tube. Between the immediately adjacent turns of the tubular radiator are two aluminum walls of the same gene and thus offer very good heat conduction from the outer area of the tubular heater to the flow tube. The temperature on the outside of the heater is kept much lower.

Before pressing, the molded part 4 made of aluminum sheet is inserted under the first two or three windings of the tubular heating element coil, which then intimately connects the heating element with the tube and the flow tube during the pressing process.

If the heater is equipped with a regulator and limiter, this molded part 4 made of aluminum can also be attached in the same way to the other end of the heating element coil 2 .

This very close thermal coupling enables a very ra response of the controller and / or limiter and ensures the heater reliably against thermal overload, too at high power concentrations.

In addition, it is added that when the structure consisting of radiator coil 2 and flow tube 1 is pressed, an impression 8 is formed in the tube interior, which has the advantage of preventing an inherently undesirable laminar flow of the medium. It is also added that the Stahlman tel 3 is provided with flanges 9 on both sides to prevent the lateral pressing out of the tubular heating element coil 2 when pressing.

Claims (2)

1. A process for the manufacture of electric instantaneous water heaters, consisting of a flow tube ( 1 ), a tubular heating element coil ( 2 ) wound on the latter, and a steel jacket ( 3 ) enveloping the above-mentioned parts, characterized in that the flow tube ( 1 ) and the, with Aluminumman tel ( 7 ), rectangular in cross-section tubular heating element formed by helix ( 2 ), the turns of which lie directly against each other and the parts ( 1 , 2 , 7 ) enveloping steel jacket ( 3 ) existing structure is pressed under high pressure reducing the cross-section . 2. The method according to claim 1, characterized in that before the pressing a for receiving control and / or temperature limiting elements ( 5 ) serving molded part ( 4 ) made of aluminum between the radiator coil ( 2 ) and the flow tube ( 1 ) and then inserted is pressed in such a way that an indentation ( 8 ) protruding into the cross section of the flow tube ( 1 ) is formed.