FR2528263A1 - ELECTRIC HEATING ELEMENT - Google Patents

Abstract

A. ELECTRIC HEATING ELEMENT. B. IT IS CONSISTING OF A HEATED WIRE PROPELLER 1 SUPPORTED THROUGHOUT ITS LENGTH BY SUPPORTING MEMBERS OF ELONGATED AND SPACED SHAPE 7-9 WHICH SUPPORT EACH SPIRE AND KEEP THEM SPARE. THESE SUPPORT ORGANS MAY BE CONSTITUTED BY FLAT STRIPS WITH HOLES 10 IN WHICH THE PROPELLER IS THREADED. ALTERNATIVELY, THE SUPPORT ORGANS MAY BE CONSTITUTED OF TWISTED STRIPS OF A HEAT-RESISTANT MATERIAL. C. APPLICATION: FOR CONVECTION HEATING APPLIANCES.

Description

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  The invention relates to an electric heating element, in particular

  convection heaters For effective convection heating of air, it is important to ensure that the heating surface is well distributed and has as little resistance as possible to the passage of air.

  In addition, the heating wire or resistance wire must be,

  stretched, electrically isolated from the elements that surround it.

  A known heating element consists of a heating wire concentrically supported inside a metal sleeve via an electrically

  insulating materials, such as magnesium oxide powder for

  To obtain a good heat transfer, fins are generally associated with this element. Such a device is expensive and it is difficult to ensure a good flow of heat.

the air.

  Another known heating element consists of a heating wire wound helically supported so that the air can pass directly on him Or, it is difficult to support a thin wire wound helically so that it is isolated on all its length because it may bend and vibrate.

  It is therefore advantageous to use a heating wire of

  Consequently, there is the problem that the neighboring turns may touch each other and cause a short circuit. The nature of the support device imposes limitations with regard to the speed of rotation. rigidity

  of the helix, the diameter of the heating wire and the pitch of the helix.

  An object of the present invention is to provide a device

  an improved support rod for a heating element consisting of a

heating wire wound helically.

  To do this, the subject of the invention is an electric heating element comprising a helically wound heating wire and at least two elongated support members extending over

  the entire length of the propeller substantially at the general level.

  respective tracts thereof, the support members being

  electrically insulating and heat-resistant and being

  positioned to engage each turn of the propeller

  to keep the heating wire in place.

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  There are two preferred embodiments of the support members According to the first preferred embodiment according to the invention, the support members consist of strips

  insulating plates pierced with spaced holes, the wire helix

  ghost being threaded into the holes we can use only

  two support members but there are preferably three.

  The threading of the heating wire can be done in the same way

  only in the helical binding technique.

  According to the second preferred embodiment, each support member consists of a pair of ropes, the ropes being twisted so as to maintain the turns of the heating wire in the torsions. Preferably, the ropes cross only once. between the turns around the helix, but the turns

  adjacent to the propeller may be separated by more than one

if we.

  Two, but preferably three, support members of this type provide a rigid support structure and the turns of the propeller are spaced to allow air to pass while avoiding the risk that neighboring turns In particular, it has been found that twisting pairs of ropes in the same direction and then twisting the whole (propeller and support ropes) in the same direction

  meaning, the strings tighten and the whole becomes rigid

  As a result, the support ropes extend obliquely around the helical assembly,

  such a provision falling within the scope of this invention.

  tion. An embodiment of the present invention is hereinafter described by way of example with reference to the accompanying drawings in which

  FIG. 1 is a perspective view of a heating element

  according to one embodiment of the invention; Figure 2 shows, on a larger scale, a detail of the element of Figure 1;

  FIG. 3 is a perspective view of a heating element

  according to another embodiment of the invention.

tion; and

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  FIG. 4 represents, on a larger scale, a detail of

the element of Figure 3.

  Figures 1 and 2 show a first mode of

  The invention includes a helix 1 of heating wire with three spaced support members 7 to 9 in this embodiment.

  each support organ consists of a strip of material

  insulating material, for example mica, pierced with holes 10 (Figure 2).

  The propeller 1 is threaded into the holes, so that the support members carry and maintain spaced the turns of

the propeller.

  To perform the threading, the three strips are stacked one on the other, the holes being aligned, and the heating wire is passed through the holes using a machine of the type used to connect the sheets of paper. in the manufacture of notebooks with helical binding Once the heating wire on this

  way, we separate the 600 strips for editing.

  Figures 3 and 4 also show a heating element

  gh consisting of a helix 1 of an electric heating wire.

  Three support members 2, 3 and 4 are spaced according to the circumference.

  As can be seen in Figure 4, each

  support element consists of a pair of electrical strings

  insulating and heat-resistant 5, 6 The strings are

  twisted around the turns of the propeller, a twisting being effected

  killed between each pair of neighboring turns.

  It should be noted that all the support members are twisted in the same direction and in the same direction as the propeller, in the direction

  clockwise from the left to the right.

  Finally, the entire set consisting of the helix 1 and the support elements 2 to 4 is twisted in the same direction as the helix and the strings, which has the effect of tightening the turns of the strings and to make the rigid assembly It follows that the support members extend obliquely around the helix Thus,

  a large length of the propeller can be supported without

  It is obvious that when it is a propeller

  very long, one or more intermediate supports

diaries.

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Claims (5)

  1 Electric heating element, characterized in that it comprises a helix (1) of heating wire and at least two organs   1-elongated airport (7-9) sits on all the length   of the propeller substantially following generators res-   of the latter, the support members (7-9) being electrically   insulation and resistance to the   On the way to rv: by April each spi of the hlice for hand tie the thread in place.   Electric heating element according to claim 1,   characterized in that the support members (7-9) are constituted   killed olate insulating strips pierced with holes (10), the propeller   (1) heating wire being threaded into the holes (10).   Electric heating element according to claim 2,   characterized in that it comprises three support members (7-9).   4 A method of producing an electric heating element according to claim 2 or claim 3, characterized in that it consists in stacking the strips (7-9) so that their holes (10) are aligned, threading the thread helicoidal heating (1) in the holes (10) using a machine of the type used to connect the sheets of paper with helical binders, and to seize the strips to arrange them with spacing around the propeller.   Electric heating element according to Claim 1, characterized in that each support member (2, 3, 4) consists of a pair of ropes (5, 6), the ropes being twisted so as to hold the turns of the heating wire. (1) in the twists. Electrical heating element according to Claim 5, characterized in that the pairs of cords (5, 6) are twisted   in the same direction and then, by a subsequent twist of the   seems whole (propeller and support ropes in the same direction, the ropes are tight.