DE7834410U1 - TUBULAR HEATER FOR HEATING THIS FLOWING GAS FLOW, IN PARTICULAR AIR - Google Patents

Description

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* Tubular heater for Heating of a gas flow flowing through this, in particular air "

The invention relates to a tubular heater, the genre identified in the preamble of claim 1.

In a heating element known from DE-OS 2 608 510 of this type, the ladder is made of a support that is to be inserted into the channel and has a polygonal profile electrically non-conductive and highly heat-resistant material wound essentially following a helical line and in sections according to the profile of the girder angled.

Here, however, the carrier forms a considerable flow resistance for the gas flow. In addition, with such an arrangement of the electrical heater, the efficiency that can be achieved with it relatively low, because in this case the heating of the air flowing through is essentially only near the duct wall takes place, so that a relatively long duct and a relatively long heating is required to

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to warm the air flow at least approximately evenly.

With the invention is now for the purpose of improving the efficiency while shortening the Channel and the electrical heater arranged in it a more even distribution of the heat transfer surfaces in the canal than strived for so far.

However, the manufacturing costs should also be reduced.

The solution to this problem is characterized by the features disclosed in claim 1.

As a result of these measures, a previously additionally required Support body for the Heisleiter dispensable, which on the one hand significantly reduces the manufacturing costs will. On the other hand, the flow resistances previously caused by the carrier body are also omitted, from which at same cross-sectional design as before, lower Air flow velocities and a result resulting in longer exposure to the heater Air flow than before.

In addition, there is a much more even distribution of the heatsealing band achieved via the channel than before, which results in a further increase in efficiency.

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Especially with one angled twice per turn It is advantageous if the winding sections have the same lengths and preferably also heating conductors the lengths of the winding sections correspond approximately to the greatest clear width of the channel. In particular, when the heat conductor is bent more than twice, preferably three times per turn, it is to achieve even heating over the total air flow cross-section advantageous, the Turn sections per turn to each other to develop different lengths.

For this purpose, an advantageous development is characterized in that exclusively BEZW. in connection with the above-described feature per turn, the angles formed by the turn portions with respect to one another have different sizes.

With all of this, the corner corners can be more or less be rounded.

An embodiment of the above-described subject that additionally improves the efficiency, which is also another more compact design of which can be achieved than before is characterized by claim 7

Another feature which increases the heat transfer surface in a small space is characterized in that the

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Heat conductor formed into a long line or similar before winding has been.

Embodiments of the invention are shown in the drawing and are described in more detail below.
Show it

1 shows a part of an electrical heater for heating an air stream in a front view j

2 likewise in cross section;

Fig. 3 shows a further embodiment also in Cross-section;

4 shows a further design of a detail.

Here, the electric heater 1 is in a channel 2 of circular cross section through which the air flow can flow used.

The heater consists of a ribbon-shaped electrical conductor 5 with high electrical resistance, which is in the essentially following a helical line, angled in sections and arranged in channel 2, that the conductor 3 is supported only with its corner corners 4 on the inner wall of the channel 2.

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Channel 2 consists of electrical, highly heat-resistant insulation material.

The channel 2 can only be lined with the aforementioned material.

It is also possible at the angle corners 4 of the conductor to hold warrproof insulating pieces in order to reliably prevent winding and ground faults in any case. The square corners 4- are from conductor turn to conductor turn arranged offset to one another and an angled thigh every turn of the conductor is directed almost diametrically. To produce one shown in FIGS. 1 and 2 Heater 1 shown is a ribbon-shaped conductor 3 initially around a substantially rectangular profile Rod with small and rounded short cross-sectional sides, helical and close to the rod been developed.

If the wound conductor 3 is then stripped from the rod, the heating conductor relaxes while enlarging the angles 6 formed by the winding sections 5 and at the same time increasing the winding pitch, so that now the angle corners ^ _1, as can be seen in FIG Winding offset from one another and the essentially straight winding sections are arranged approximately in a star-shaped manner in relation to one another.

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£ To produce the heating system shown in Fig. 3

ι, - element is a head 3 preferably around a

ι], in cross-section triangular rod with mutually unequal

long cross-sectional sides, which represents an even greater degree of scarcity than with the one in the heating conductor shown in FIGS. 1 and 2 can be achieved. It is also possible to use a conductor 3, e.g. around an im

; Cross-section of a rhombic or trapezoidal rod

wrap.

In Fig. 4 is a ribbon-shaped conductor 3 for enlargement the heat transfer surface meander-shaped before winding been reshaped.

In terms of production engineering, the manufacture of the heater is easiest when a conductor 3 is rectangular around a rod Cross-section of small thickness is wound, after which the heater shown in Figures 1 and 2 nan receives.

It is also advantageous to use a ribbon-shaped conductor instead of a conductor with a round cross-section use, as this can be brought into the prescribed spatial shape much more easily than round wire know without twisting.

Claims (8)

Protection claims: 1. Tubular heater for heating one of these gas flow flowing through, in particular air, consisting of an electrical wire-shaped or strip-shaped, insulated Mounted conductor with high electrical resistance, which essentially follows a helical line in sections is angled, characterized by the following features: a.) The conductor (3) is supported in the channel (2) exclusively with the angular corners (4) on the inner wall of the channel arranged, b.) the corner corners (4) follow the helical line from Turn to turn arranged offset to one another, and c.) per turn at least one of the angle legs is the Center axis of the channel (2) arranged at least approximately crossing. Hot set 7087/78 2. Heater according to claim 1, characterized by winding sections of equal length (5). 3. Heater according to claim 1 or 2, characterized in that that the lengths of the winding sections (5) correspond approximately to the largest clear width of the channel (2). 4. Heater according to one or more of the preceding Claims, characterized in that the winding sections (5) have different lengths per winding are. 5. Heater according to one or more of the preceding Claims, characterized in that for each turn the angles (6) formed by the turn sections (5) have different sizes to each other. 6. Heater according to one or more of the preceding claims, characterized in that the angle corners (4) are more or less rounded. 7. Heater according to one or more of the preceding claims, characterized in that more than one Head (3) is provided and that the head (3) in the channel (2) are mutually multi-threaded. Hot set 7087/78 8. Heater according to one or more of the preceding claims, characterized by mäanderfb'rtnig or similarly shaped conductors (3). DIPL.-ING. CONRAD KOCHLlWG PATE NTAN WA LI