FR2676464A1 - HEATING DEVICE EQUIPPED WITH AN ANTI-DEPOSIT MEANS, ESPECIALLY SCALE. - Google Patents

Abstract

Device for heating a liquid comprising an elongate heating element (8) which extends in this liquid, in particular with a view to producing steam. On this elongated heating element (8) is freely arranged an anti-deposit means (12), in particular scale, comprising a succession of parts which are wound around the heating element and spaced in the longitudinal direction of the latter and which, under the effect of the movement of the liquid possibly charged with vapor and / or of the formation of vapor bubbles on the peripheral surface of the heating element (8), moves relative to this surface, thus making it possible to avoid at least partly the deposition of solids, in particular scale, on the heating element. Said anti-deposit means may be constituted by a spring.

Description

1 HEATING DEVICE EQUIPPED WITH A MEANS

ANTI-DEPOSIT, ESPECIALLY TARTAR

  The present invention relates to a heating device

  fage of a liquid comprising an elongated heating element which extends in this liquid, in particular with a view to producing steam. In many steam generators, the vaporization of water is achieved by heating elements which extend

  in water and which contain electrical heating resistances.

  In some installations, all the steam produced is used.

  The steam generators are therefore supplied with the required amount of water continuously. In other installations, the steam produced is recycled in the form of condensate. However, taking into account the necessary leaks and purges and possibly partial use of the vapor produced with lost fluid, it is necessary anyway

  to constantly replenish the generators with new water.

  Unfortunately, the water available is often of poor quality, in particular due to its high lime content. In the absence of water treatment, deposits of solid matter, mainly tartar, occur on the elements. above-mentioned heaters These deposits slow down the transmission of heat and rapidly destroy these heating elements due to overheating. These drawbacks also occur in

  electric water heaters, without steam production.

  To overcome these drawbacks, the main remedy used consists in adding water heaters or steam generators to the supply water using heating elements with high thermal flux very sensitive to the smallest deposits, chemical dispersants This remedy has the disadvantage, however

  generate a high operating cost due mainly to the installation

  lation of accessories necessary for the continuous supply of these

  chemical dispersants in water and in the quantities of dispersants used

  related to high water consumption.

  The present invention aims to remedy at least partially-

  1 Lement to the problem associated with the aforementioned deposits in a simple and inexpensive manner.

  According to an object of the invention, the heating device

  f age of a liquid, which comprises an elongated heating element which extends in this liquid, with a view in particular to producing steam, is such that on this elongated heating element is freely disposed an anti-deposit means, in particular of scale , comprising a succession of parts which are wound around the heating element and spaced apart

  in the longitudinal direction of the latter and which, under the effect of the movement-

  ment of the liquid possibly charged with vapor and / or the formation of vapor bubbles on the peripheral surface of the heating element, moves relative to this surface, thus making it possible at least in part to avoid the deposition of solid materials, including tartar, on

the heating element.

  According to a preferred embodiment of the invention, the aforementioned anti-deposition means comprises at least one wire element wound in

  helix around the above-mentioned elongated heating element.

  According to the invention, the aforementioned anti-deposition means can

be of circular section.

  According to the invention, the aforementioned anti-deposition means may have at least one edge located on the side of the surface of the element.

elongated heater.

  According to the invention, the aforementioned anti-deposition means may comprise at least one face inclined relative to the surface of

the elongated element.

  According to a variant of the invention, the aforementioned anti-deposition means is freely disposed between two stops fixed on the element

elongated heater.

  In another variant, one end of the aforementioned anti-deposit means is connected to the elongated heating element, its other

end being free.

  According to the invention, the anti-deposition means can be in one

spring material.

  According to the invention, the above-mentioned elongated heating element can advantageously extend through a passage formed in the wall of a liquid tank, this passage being dimensioned so as to be able to be traversed by said heating element equipped with

  its periphery of the aforementioned anti-deposition means.

  The invention also relates to a heating element

  f elongated with internal electrical resistance, equipped with anti

  deposit according to any of the above specifics.

  The present invention will be better understood from the study of various anti-deposition means according to the invention, described by way of nonlimiting examples and illustrated by the drawing in which: FIG. 1 shows in longitudinal section a heating device having a elongated heating element equipped with a first anti-deposit means according to the invention; 2 shows in longitudinal section an anti-deposit means corresponding to the anti-deposit means of Figure 1, mounted differently; and Figures 3 to 6 show, in section,

  parts of four different anti-deposit means.

  Referring to Figure 1, we see that we have represented

  smelled a steam generator generally identified by the reference 1 which comprises a tank 2 having a cylindrical envelope 3, two radial walls of ends 4 and 5, a duct 6

  of water supply provided at its lower part and a drainage conduit

  tion of steam 7 provided at its upper part.

  In the tank 2 is arranged horizontally an elongated heating element 8 which passes through and which is carried in a sealed manner by the radial partition 4 This elongated heating element 8 is

  of circular section and contains an electrical resistance not shown

  felt capable of being connected to a source of electrical energy supply by means of connection 9 provided for its

  end outside the tank 2.

  In the tank 2, the heating element 8 carries, near its free end, a ring 10 and, near the radial wall 4, a ring 11, these rings 10 and It being for example

fixed by welding.

  On the elongated heating element 8, between the abovementioned stops 10 and II, there is freely arranged an anti-deposition means constituted in this example by a wire element 12 of circular section which is wound in a helix with regular or variable pitch around the heating element 8 and which is made of a spring material The turns of this spring 12 constitute a succession of parts which are wound around the heating element 8 and which are spaced in the direction

longitudinal of the latter.

  The internal diameter of this spring 12 can correspond to

  lay substantially on the outside diameter of the heating element 8 but it is preferably slightly greater. Its total length may correspond substantially to the distance between the abovements 10 and 11 above, but it is preferably slightly less.

  spring 12 is freely mounted on the heating element 8.

  In order to be able to install by threading the heating element

  fant 8 fitted with stops 10 and 11 and spring 12, the end wall

  mity 4 of the reservoir 2 has a circular passage 13 whose diameter is at least equal to the largest diameter of the spring 12 and the stops 10 and 11, a conventional means 14 for example with rings

  allowing the fixing of the heating element 8 in this passage 13.

  Of course, the tank 2 can be equipped in its lower part with several parallel heating elements mounted in the same way as the heating element 8 and equipped in the same way with an anti-deposit means 12 disposed freely between two stops.

and 11.

  In the absence of heating, the anti-deposit means cons-

  held by the spring 12 rests by its turns at different points on

the heating element 8.

  To activate the generator 1, the heating element 8 is supplied with electrical energy and water is brought into the tank 2 through its supply duct 6 so that the water level in this tank is at above the heating element 8. 1 In the tank 2 there is a heating of

  water and a continuous formation of vapor bubbles on the peri-surface

  of the heating element 8, which escape passing between the turns of the spring 12, the vapor formed rising and being evacuated by the evacuation duct 7. Under the effect of the movement of the water in the tank 2 possibly charged with water vapor and, mainly, under the effect of the brutal formation of vapor bubbles on the peripheral surface of the heating element 8, the turns of the anti-deposit means constituted by the spring 12 move relative at the peripheral surface of

  the heating element 8 The turns effect, almost independently

  pending, reciprocating or radial and / or longitudinal and / or rotational movements which may be brutal and / or

  jerky The spring 12 thus stressed strikes the peripheral surface

  risk of the heating element 8 by producing shocks and / or rubs on the latter These effects on the peripheral surface of the heating element 8 prevent or at least delay the formation of a deposit of solid matter, in particular of tartar on the heating element 8, between stops 10 and 11, acting continuously, in particular as soon as a deposit of solid matter is likely to

happen.

  In a possible execution example, the heating element

  fant 8 can have a diameter of 19 mm The diameter of the wire

  killing the spring 12 can be 1.5 mm The internal diameter of this spring can be 21 mm, thus leaving a radial clearance of 2 mm The

  pitch of its turns can be 11 mm, thus leaving a long space

  tudinal of 9.5 mm between successive turns, and its length can be

  1500 mm for a distance between stops 10 and 11 of 1600 mm.

  Referring now to Figure 2, we see that

  shows an elongated heating element 15 surrounded by an anti-

  deposit 16, which correspond to the heating element 8 and to the spring 12 of the previous example This example of FIG. 2 differs from the previous one by the fact that the end turn 17 of this spring 16 is fixed to a ring 18 fixed on the heating element 15, the spring 16

being otherwise free.

  Referring now to Figures 3 to 6, we see that there are shown different sections of anti-deposit means wound helically on elongated heating elements, which also correspond to the anti-deposit means described above and whose shape can

  allow their mechanical effects on the peripheral surface to be increased

  of the elements that carry them.

  In FIG. 3, the anti-deposition means is constituted by a wire 19 of square section, one of the angles of which is on the side of the peripheral surface of the heating element 20 so as to constitute an edge 21 going around this heating element, on either side of which extend faces 22 and 23 inclined in opposite directions relative to its peripheral surface This structure of the anti-deposit means 19 makes it possible to amplify the aforementioned movements of its turns and to cause improved scraping or scraping of the surface

  heater element 20.

  In Figure 4, there is shown an anti-deposit means 24 of very flat rectangular section which also has a scraping edge 25 and a main face 26 inclined relative to the peripheral surface of a heating element 27, thus promoting the

  rotation of this anti-deposit means 24 or of its turns in one direction.

  The anti-deposit means 28 shown in Figure 5 differs from the anti-deposit element 19 shown in Figure 3 only

  by the fact that it is of V-shaped section with two sensitive branches

  slightly equal and whose outer faces face the peripheral surface of a heating element 29 and inclined relative to

to the latter.

  Referring now to FIG. 6, it can be seen that the anti-deposit element 30 is constructed from a wire of rectangular section wound around a heating element 31 like that of FIG. 4 This wire 30 has on the side of this element 31 of zones 32 and 33 folded alternately on one side and the other so as to present successive faces 34 and 35 inclined alternately by

  relative to the peripheral surface of the heating element 31.

  1 It can be noted that none of the different forms of the anti-deposition means described presents any obstacle to the escape of the vapor bubbles forming on the peripheral surface of the elements.

  heated, thus avoiding any local overheating of the latter.

  The present invention is not limited to the examples described above. Many other variants are possible without departing.

  of the scope of the appended claims.

at

Claims (9)

  1 device for heating a liquid comprising an elongated heating element (8) which extends in this liquid, with a view in particular to producing steam, characterized in that on this elongated heating element (8) is freely arranged a anti-depositing means (12), in particular of tartar, comprising a succession of parts which are wound around the heating element and spaced apart in the longitudinal direction of the latter and which, under the effect of the movement of the liquid possibly charged with vapor and / or the formation of vapor bubbles on the peripheral surface of the heating element (8), moves relative to this surface, thus making it possible at least in part to avoid the deposition of solid materials, in particular scale, sure the heating element.   2 Device according to claim 1, characterized in that the aforementioned anti-deposition means comprises at least one wire element (12) wound helically around the aforementioned elongated heating element.   3 Device according to one of claims 1 to 2 ,,   characterized in that the aforementioned anti-deposition means present at   at least one edge (21) located on the side of the surface of the heating element elongated fant (20).   4 Device according to any one of claims   above, characterized in that the aforementioned anti-deposition means comprises at least one face inclined relative to the surface of the elongated element.   Device according to either of Claims 1 and 2,   characterized in that the aforementioned anti-deposition means (12) is circular section.   6 Device according to any one of claims   above, characterized in that the aforementioned anti-deposition means is disposed freely between two stops (10, 11) fixed on the element elongated heater (8).   7 Device according to any one of claims   1 to 5, characterized in that one of the ends (17) of the above-mentioned anti-dep 8 t means 1 is connected to the elongated heating element, its other end being free.   8 Device according to any one of the preceding claims, characterized in that the anti-dep means 8 t is made of a spring material.   9 Device according to any one of claims   above, characterized in that the above-mentioned elongated heating element (8) extends through a passage (13) formed in the wall of a liquid tank, this passage (13) being dimensioned so as to be able to be crossed by said heating element equipped with   its periphery of the aforementioned anti-dep 8 t means.   Elongated heating element with internal electrical resistance, equipped with an anti-deposit means according to any one of the previous claims.