FR2853399A1 - Helical heat exchanger for boiler, has burner comprising spiral tube wound along tapered helix, where tubes largest part is turned towards burner and exchanger has tapered shape - Google Patents

Abstract

The exchanger has a burner comprising spiral tube wound along a tapered helix, where tubes largest part is turned towards the burner (2). The exchanger has a tapered shape, and the tube has fins along its length. The burner is disposed in an upper part of a body (1) while a container (3) for retrieving condensates and an evacuation unit (5) of combustion gas are arranged in a lower part of the body. An independent claim is also included for a boiler.

Description

The invention relates to a helical fluid heat exchanger

coolant,

  and a boiler equipped with such an exchanger.

  It is known practice to produce a heating boiler, in particular a condensation boiler, by means of a helical exchanger in which circulates a heat transfer fluid, generally water, and above or in the upper part of which a burner is arranged.

  This is for example the case of the boiler described in document EP0 825 392 A2 or also in document DE-4309598 AI.

  In these known devices, the heat exchanger for a heating boiler provided with at least one burner is in the form of a cylindrical helical tube in which the heat transfer fluid circulates and around which the heat exchanges take place thanks to combustion gases from the burner.

  In order to improve the efficiency of a boiler fitted with such an exchanger and in particular to take account of the variation in the volume of the combustion gases over the height of the exchanger, the invention recommends a helical exchanger which is particularly remarkable. in that it consists of a tube wound along a frustoconical propeller and the widest part of which is intended to be turned towards the burner, said exchanger further comprising, if necessary, fins over at least part of its length.

  The invention of course also relates to a boiler provided with such an exchanger and more precisely a boiler provided with at least one burner and a helical heat exchanger which is therefore particularly remarkable in that it comprises a shaped body at least partly frustoconical in which is disposed the exchanger which is constituted by a tube wound according to a frustoconical propeller and the widest part of which is intended to be turned towards said burner.

  For example, the tube constituting the exchanger further comprises fins over at least part of its length and the burner is arranged in the upper part of the body, on the most flared side thereof, while a pot condensate recovery and combustion gas discharge is arranged under the exchanger in the lower part of said body, so as to thus produce a condensing boiler.

  According to one embodiment, its frustoconical body is surrounded by a fluid jacket which communicates with the upper end of the exchanger while the return in said exchanger of the cooled heat-transfer fluid takes place by a pipe connected to the lower end of the exchanger, the flow of the heated fluid from the exchanger being carried out by means of a pipe which opens into the upper part of said fluid jacket.

  In this case, the conical shape of the body ensures better guidance of the flow 5 of the combustion gases towards the fluid jacket and therefore better heat exchange of said gases with said fluid jacket.

  Advantageously in this case, between the fluid return pipe and the lower part of the fluid jacket, a bypass is provided so that said fluid is shared on the return between the exchanger and the fluid jacket. In this way, the lower part of the fluid jacket is cooled.

  The bypass is, for example, made by means of a small duct connecting the fluid return pipe and the bottom of the fluid jacket, or even by means of the fluid return pipe which for this purpose passes through the lower part of the fluid jacket while the through portion of said pipe is provided with a passage orifice for the fluid.

  The invention will be clearly understood on reading the description which follows and which refers to the appended drawings in which: - Figures 1 and 2 schematically represent a boiler according to the invention provided with an exchanger respectively with smooth tube and with fins, - Figures 3 and 4 correspond to Figures 1 and 2 according to a variant, - Figure 5 shows a bypass of the fluid at the return line 25 of the boiler, which is a variant compared to that shown on Figures 1 to 4.

  In FIGS. 1 to 4, one can see, by way of example, a boiler with heat transfer fluid (generally water), of the type here with condensation.

  The boiler shown has a body 1 in the upper part of which is a burner 2, here with reverse flames, and at the base of which is arranged a pot 3 condensate recovery tank and which is provided here with a discharge 4 for said condensates and an outlet 5 for the combustion gases.

  In the body 1 is disposed a helical heat exchanger with a smooth tube 6 (FIGS. 1 and 3) or with a tube 6 ′ with fins (FIGS. 2 and 4), at least part of the first turn having in this example no fin.

  Around the body 1 is provided here a fluid jacket 7 while the helical exchanger 6, 6 ′ is supplied by a pipe 8 for returning the cooled fluid, which is connected to the lower end of the tube constituting said exchanger 6, 6 ', its upper end opening as shown in the figures in the fluid jacket 7, the latter being further provided here, on the opposite side o opens the exchanger 6, 6', a pipe 9 for the start of the fluid heated.

  In the center of the exchanger 6, 6 ', there is also provided a pot 10 provided with an insulator 11 (Figures 1 and 2) or 11' (Figures 3 and 4), the insulator 11 'being in this example more important than the insulator 11 to also ensure the function of sound absorber.

  In the embodiments shown, the return pipe 8 is further provided with a bypass in the form of a pipe 12 (FIGS. 1 to 4) connecting said pipe 8 and the lower part of the fluid jacket 7, or in the form of an orifice 13 formed in a part of the pipe 8 which then passes for this purpose the bottom of the fluid jacket 7 as shown in FIG. 5.

  This bypass 12, 13 has the effect of supplying the fluid jacket 7 with the return fluid and therefore of cooling said jacket 7 at its base in order in particular to promote condensation and the efficiency of the boiler.

  As the drawings clearly show, the body 1 is frustoconical with its widest part facing the burner 2. Likewise, the smooth exchanger 6 or the exchanger 6 'with fins consists of a tube wound around a helix frustoconical, its widest part being turned towards said burner 2.

  This frustoconical shape of the exchanger 6, 6 ′ is advantageous due in particular to the variation in the volume of the combustion gases as a function of the distance of the corresponding zone of the exchanger from the burner and also due to better forced orientation of the flow of combustion gases towards the fluid jacket 7.

  It will be understood that the invention essentially relates to the exchanger, whether it is a smooth tube 6, or a tube 6 'with fins, but also any kind of boiler equipped with such an exchanger.

  To this end, it seemed unnecessary to show other boilers than those shown in Figures 1 to 4, equipped according to the invention and which can of course be condensing or not, with a fluid jacket or not.

  For example also, the burner can be different and in particular have a cylindrical shape with side flames, which burner being introduced into the upper part of the exchanger, the starting pipe could be on the same side as that where the end of the exchanger in the fluid jacket, etc.

Claims (9)

  1) Helical heat exchanger (6,6 ') with heat transfer fluid for a heating boiler provided with at least one burner (2), characterized in that it consists of 5 a tube wound according to a frustoconical propeller and the the widest part is intended to face the burner (2).   2) Heat exchanger according to claim 1, characterized in that the tube constituting the exchanger (6 ') further comprises fins over at least part of its length.   3) Heating boiler with heat transfer fluid provided with at least one burner (2) and a helical heat exchanger (6,6 '), characterized in that it comprises a body (1) of form at least in frustoconical part in which is arranged the exchanger (6,6 ') which is constituted by a tube wound in a frustoconical propeller and the widest part of which is intended to be turned towards said burner (2).   4) Heating boiler according to claim 3, characterized in that the tube constituting the exchanger (6 ') further comprises fins over at least part of its length.   5) Boiler according to one of claims 3 and 4, characterized in that the burner (2) is arranged in the upper part of the body (1), on the most flared side thereof, while a pot (3) condensate recovery and combustion gas discharge is arranged under the exchanger in the lower part of said body (1).   6) Boiler according to one of claims 3 to 5, characterized in that its frustoconical body (1) is surrounded by a jacket (7) of fluid which communicates with the upper end of the exchanger (6,6 ') while the return in said exchanger 25 (6,6 ') of the cooled heat transfer fluid takes place via a pipe (8) connected to the lower end of the exchanger, the flow of the heated fluid from the exchanger being carried out at by means of a pipe (9) which opens into the upper part of said fluid jacket (7).   7) Boiler according to claim 6, characterized in that between the pipe 30 (8) for the return of the fluid and the lower part of the jacket (7) of fluid, there is provided a bypass (12,13) so that said fluid is shared between the exchanger (6,6 ') and the jacket (7) of fluid.   8) Boiler according to claim 7, characterized in that the bypass is produced by means of a small conduit (12) connecting the conduit (8) for return of the fluid and the bottom of the jacket (7) of fluid.   9) Boiler according to claim 7, characterized in that the bypass is produced by means of the pipe (8) for return of the fluid which for this purpose passes through the lower part of the jacket (7) of fluid while the through part of said pipe is provided with an orifice (13) for passage of the fluid.