FR2487051A1 - Mixed boiler for producing hot water - has hearth surrounded by water jacket exposed to hot combustion gases from solid, liq. or gaseous fuel - Google Patents

Abstract

The hot water is fed through heating radiators, and also to taps in kitchens, bathrooms etc. The boiler has a central hearth, which is surrounded on all sides by a jacket with a double wall; and water is heated while it flows through the jacket. The outer wall of the jacket is pref. covered by thermal insulation and an outer, protective metal casing. The inner wall of the jacket is pref. corrugated to form several deep, hollow fins projecting downwards in the boiler and exposed to the heating gases, to improve heat transfer to the water. Electric immersion heaters are pref. located in the water jacket for use in summer when no fire is lit in the boiler.

Description

 The present invention relates to a boiler for the production of hot water which, while having a particularly high calorific efficiency, is capable of using either liquid (fuel), solid (coal, wood) or gaseous fuel as a heat source. (city gas, propane, butane), or even electricity.

 The boiler according to the invention is mainly remarkable in that it comprises a double-walled envelope which surrounds on all sides the central part forming a hearth and whose external surface is suitably insulated to limit the loss of heat in the surrounding atmosphere, the free space provided between the two walls of this envelope constituting the heating body for the circulation of water.

 In accordance with a preferred embodiment of the above arrangement, the hearth portion proper is limited upwards by a pleating of the internal wall of the envelope, this pleating extending horizontally in the manner of a baffle to force the flames to lick it before escaping towards the quarry through the free space or collector formed between said pleating and the volte formed by the inner wall. This volte itself has a series of vertical hollow pleats which constitute a kind of heat exchanger with high calorific efficiency. It will also be noted that the part of the heating body disposed above the vault contains a coil for obtaining very hot water for domestic use.

Other remarkable characteristics of the boiler will emerge from the description which follows with reference to the appended drawing, which drawing, given by way of example, will make it possible to better understand the invention, the characteristics which it presents and the advantages which it is likely to provide
Figs. 1 and 2 of this drawing are schematic vertical sections of a boiler according to the invention, produced along the two perpendicular median axes.

 The boiler shown comprises an envelope open towards the bottom, formed by the assembly of two walls 1 and 2 arranged at a certain distance from each other so as to delimit a free space constituting the heating body for the circulation of water to heat. The external wall 1 of this double envelope 1-2 has five flat faces, the front face being cut out with an opening for the arrangement of an access door or porthole 3 and with a lower cutout for the passage of an ash drawer 4, suitably guided laterally. This external wall 1 is further coated with a layer 5 of a material ensuring thermal insulation (glass wool for example), said layer being protected by an outer skirt or carcass 6 It should be noted that the door or porthole 3 is designed to be wide enough to allow easy insertion of large logs of wood.

 The arrangement of the interior wall 2 is more complex. In the lower part is provided a horizontal pleating 7 to profile in rectangular plan, shaped so as to determine a central opening occupied by the grid 8 intended to support the logs of wood or coal. At an appropriate height above this grid 8 the internal wall 2 has a second hollow pleating 9 which is understood from back to front over the entire width of the heating body and which stops at a relatively reduced distance from the door or window 3; the flames and hot gases caused by the combustion are thus forced to lick this pleating 9 in order to pass into the upper part 10 acting as a collector, before being evacuated outside through the usual conduit 11.

 The vault of this part or collector 10 is formed by a series of vertical folds 12 of the internal wall 2, said folds being spaced apart to allow the passage of smoke and hot gases; a baffle 13 provides guidance thereof in front of the opening of the discharge duct 11. It will be noted that the latter contains, in the usual manner, an oscillating adjustment valve 14 capable of being controlled using a rod 15 accessible from the front part of the boiler; this valve 14 is further connected by an adjustable rod 16 to an additional valve 17 mounted to oscillate in the tube 18 formed in the lower part of the boiler for the admission of combustion air.

 Above the pleated vault 12, the walls 1 and 2 of the double envelope provide a free space 19 forming a housing for a coil 20 which two pipes 21 connect to the circulation of domestic hot water in the room. In this space 19 can also be mounted armored resistors 22, suitable for obtaining hot water in the coil 20 without the need to have recourse to the actual hearth of the boiler (summer periods) .

 The circulation of water in the heating body constitutes by the intermediate space defined by the walls 1 and 2 takes place through a lower inlet pipe 23 (corresponding to the return of the central heating installation) and a upper outlet pipe 24. The water to be heated thus passes through the entire heating body and it is understood that the heat given off by combustion (it may be either wood or charcoal which burns in the hearth located at above the grid 8, or fuel injected in gaseous form by a burner such as that shown diagrammatically in 25 in Fig. 2 and fixed against the door or porthole 3) is transferred to the water which fills the folds 7, 9 and 12 as well as the other parts of the heating body. The heat exchange coefficient is optimal, while the space requirement is reduced to a minimum and the presence of water against the internal wall 2 of the casing avoids any risk of deterioration of the sheet which forms said wall, said sheet does not po Before being brought to a temperature higher than 1000C.

The long service life of the boiler is thus ensured under excellent conditions.

 The folds 12 which form the exchanger are arranged so as to allow easy sweeping of the boiler through the window 3, it being noted that this operation can be carried out while the appliance is in operation, at least in the case where it acts as a fuel.

solid (wood or charcoal). The combustion of charcoal or wood is capable of being adjusted by the user by action on the linkage 15 associated with the valve 14, it being noted that the entry of air through the lower tube 18 is controlled as a function of the more or less pronounced throttling occurs at the outlet of hot fumes and gases. In the case where the fuel used by the boiler is a gas (town gas, butane or propane), the burner rail is capable of being placed at an appropriate height above the grate 8 or even immediately above pleating 9. For all-electric heating "one can be satisfied with the resistors 22 or else provide additional resistors at several appropriate points of the heating body.

 It should moreover be understood that the above description has been given only by way of example and that it in no way limits the field of the invention from which one would not depart by replacing the execution details described by all other equivalents. It is understood in particular that the upper part of the boiler is capable of being overcome, in the manner known per se, by a hot water preparation tank of the integrated type, with automatic regulation of the temperature supplied by the resistors 22, the coil 20 can then be removed.

Claims (8)

 1. Mixed boiler for the production of hot water, characterized in that it comprises a double-walled envelope which surrounds on all sides the central part forming a hearth, the free space provided between the walls constituting the heating body for circulation some water.  2. Boiler according to claim 1, characterized in that the external wall, provided with a smooth surface, of the envelope is coated with a layer of insulating material, protected by a metallic skirt.  3. Boiler according to any one of claims 1 and 2, characterized in that the hearth proper is comprised between a lower grid and a hollow horizontal pleating of the internal wall, which pleating forms baffle and delimits an upper part constituting collector for hot fumes and gases.  4. Boiler according to claim 3, characterized in that the collector contains an exchanger formed by a series of hollow pleats of the internal wall, said pleats being oriented vertically so as to be heard parallel to the horizontal axis of said collector.  5. Boiler according to any one of claims 1 to 4, characterized in that the heating body comprises an upper part in which is embedded a coil for the production of domestic hot water.  6. Boiler according to any one of claims 3 to 5, characterized in that the lower grid is supported by a hollow horizontal pleating of the internal wall, which pleating is profiled to define a central opening whose edge forms a support for the grid cited above.  7. Boiler according to any one of claims 1 to 6, characterized in that the smoke evacuation conduit contains, in the manner known per se, an adjustment valve connected by a linkage to an additional valve mounted in the pipe lower intended for the admission of the air in the hearth.  8. Boiler according to any one of claims 5 to 7, characterized in that the upper part of the heating body is equipped with electrical heating resistors.