EP0131585B1 - Moveable hearth boiler with internal combustion and ajustable draught - Google Patents

Abstract

Moveable hearth boiler device with internal combustion using fluids as heat conveying medium and with automatic draught regulation. It is comprised in its visible part of a boiler body (12), two supply pipes (2 and 3), a slide suspension (fig. 3), an articulated bracket (fig. 2), two holes pipes (17) for the connection to the central heating plant, two sealed hydraulic connections of the so-called fast type (18). In its invisible part, the boiler device comprises combustion chambers (9), a fluid (10), baffles (16), a draught device (20), a purging cock (5), a safety valve (7), a fume collector (6), a thermostatic probe (8). Among the most interesting applications of the invention, it may be mentioned the utilisation as the main boiler for the central heating or as an auxiliary boiler in an existing plant, and the facility for producing sanitary hot water through a boiler water drum.

Description

The present invention relates to a hearth boiler of the type comprising a body intended to be disposed above an open hearth and in which a heat transfer fluid circulates, this body having heat exchange surfaces between said fluid and said hearth, and being connected to supply and evacuation pipes for said fluid, themselves linked to an external central heating circuit and / or a domestic hot water circuit.

Document FR-A-2 475 695 already describes such a boiler, but in which the surfaces for exchange between the flames and the combustion gases emanating from the hearth and the heat transfer fluid are relatively reduced, since they are limited to the lateral surfaces, essentially the bottom surface of the boiler. As a result, the efficiency of such a boiler is relatively limited, a major part of the calories produced by the hearth not being transferred to the heat transfer fluid, but being lost in the chimney.

The object of the present invention is essentially to remedy this drawback of known boilers and to considerably increase the heat exchange surfaces between on the one hand the flames and the combustion gases emanating from the hearth and on the other hand the heat transfer fluid. , and this without increasing the external dimensions of the boiler.

To this end, a hearth boiler according to the present invention is essentially characterized in that said body is equipped with internal combustion chambers capable of being traversed by flames and combustion gases emanating from said hearth, and the walls of which constitute said heat exchange surfaces, the spaces delimited between said chambers constituting an internal circulation circuit for said heat transfer fluid, and in that it is mobile, removable, provided with its own drawing device and with a smoke collector, the draft is adjusted automatically by a key controlled by a thermostatic probe or is manually actuated by a joystick, the upper part of the boiler being removed, constituting an inspection hatch giving access to the smoke collector, the combustion chambers, a automatic air vent and a safety valve.

Thus, all the walls of the internal combustion chambers constitute heat exchange surfaces, which explains why one can very considerably increase these surfaces compared to boilers of the prior art.

Furthermore, the external space requirement of the hearth boiler is not increased, since, as has just been specified, these are walls of chambers internal to the boiler.

The boiler object of the invention has the following characteristics and advantages: it is an open hearth boiler using fluids as heat transfer agent. Internal combustion takes place in the numerous combustion chambers whose open downward shape can be conical to brake the combustion gases and hot fumes, forcing them to lick their internal wall, thus enhancing combustion and increasing the exchange caloric.

The bottom of the boiler can be characterized by its parabolic shape, thus designed to collect. channel and concentrate the combustion gases, flames and hot fumes inside the boiler, where the heat exchange takes place.

The exchange is done by fluid according to a forced circuit by baffles through the whole body of the boiler around multiple combustion chambers, which makes it possible to obtain a large caloric surface compared to the diameter of the boiler. The combustion chambers open into a smoke collector located at the top of the boiler. In its rear part, the collector is provided with a drawing device with automatic adjustment by a spiral type thermostat which, when expanding, acts on the drawing key located above the device. This setting promotes rational fuel consumption. A manual position allows, thanks to the complete closure of the draft, the use of the chimney in continuous fire.

The technical study of the shapes (bottom of the boiler, combustion chambers, smoke evacuation duct towards the bottom of the hearth) allows to significantly improve the defective draft of certain chimneys.

The upper part of the boiler constitutes an inspection hatch giving access to the automatic and manual draft device, the smoke collector, the combustion chambers, an automatic vent valve and a safety valve.

A suspension device, integral with the boiler, allows the latter to position itself automatically, as close as possible and directly above the heat source by gravity according to the evolution of the fire in the fireplace.

This sliding suspension device is compensated by a spring which reduces the vertical pressure of the boiler on the logs. It conceals the connection pipes. It has an interlock which keeps the boiler in the high position for fuel supply to the hearth.

An articulated bracket supports the sliding suspension device, secured to the boiler by its supply pipes. It is fixed to the back wall of the chimney in the upper part of the hood. The articulation of this bracket allows lateral movement of the boiler, which offers the user the possibility of better following the horizontal evolution of the wood fire or clearing part of the hearth for other purposes (rotisserie , grill ....). These horizontal and vertical movements of the boiler are possible because it is connected to the central heating circuit by means of flexible pipes tested under the conditions of heat and pressure. The connection of these hoses is made by means of watertight hydraulic connections called rapid type, which allows the immediate removal and replacement of the boiler and its suspension device, providing the following advantages: clearing of the hearth for the use of a grill, rotisserie, sweeping, use of the same boiler in various chimneys previously equipped with the same connection device (second homes).

• la figure 1 représente en demi-coupe et demi- élévation la chaudière suivant l'invention ;
• la figure 2 représente en perspective la potence articulée ;
• la figure 3 représente en vue de face le dispositif de suspension ;
• la figure 4 représente en vue de dessous la chaudière suivant l'invention ;
• la figure 5 représente en vue de gauche le dispositif complet positionné dans l'âtre ; et la figure 6 représente en vue de dessous la trappe de visite à la partie supérieure de la chaudière.

According to a preferred embodiment:

• Figure 1 shows in half-section and half-elevation the boiler according to the invention;
• Figure 2 shows in perspective the articulated bracket;
• Figure 3 shows a front view of the suspension device;
• Figure 4 shows a bottom view of the boiler according to the invention;
• Figure 5 shows in left view the complete device positioned in the hearth; and Figure 6 shows a bottom view of the inspection hatch at the top of the boiler.

According to a preferred embodiment, FIG. 1 shows the boiler characterized by the curved lateral body 12, the specially studied shape of which offers the following particularity: the part below the axis AB makes it possible to recover the calories by exchange in contact with the flames, while the upper part of this axis returns these calories by radiation in the room.

The bottom of the boiler 11 of parabolic shape opening onto multiple conical vertical combustion chambers 9, connected to each other, vertically by baffles 16 forcing the fluid 10 through the boiler. These combustion chambers open into a smoke collector 6 regulating its flow rate by a draft key 20 actuated either by a thermostatic probe 8 or by a lever 19. The upper part of the boiler (FIG. 1) receives an automatic vent valve 7 and a valve. 5. The upper part of the boiler constitutes an inspection hatch 4.

The boiler is suspended by its own cold 2 and hot 3 supply pipes, extended by hoses 17 and fittings 18, on a sliding device (Figure 3) provided with a locking system 14 and a compensating spring 13; this device is attached by a ring 15 to an articulated bracket 21 (Figure 2).

The device according to the invention constitutes with the hearth fire a real boiler which covers, captures and stores the flames and the gases in the vertical combustion chambers 9 around which the exchange with the fluid 10 takes place, the circuit of which is forced by baffles 16 welded vertically between the combustion chambers.

This boiler, whose body represents the shape of a pot, can be made of copper, whose conductivity and radiation properties are excellent.

The evacuation of the burnt gases is controlled by a drawing key with automatic and manual adjustment (Figure 6) closing the evacuation duct located in the upper part of the boiler on its rear face.

To follow the evolution of the wood fire in the chimney, the boiler was designed mobile by means of a sliding suspension (Figure 3) made of wrought iron with a spring 13 to control the pressure of the boiler on the logs. A locking system 14 keeps the boiler in the high position for supplying the fire with fuel.

The boiler is made integral with this device by the supply pipes, recommended in brass, and fixed by flanges on the back of the device, which conceals them.

An articulated bracket (figure 2) fixed to the back wall of the chimney by means of two screws, to which the boiler-suspension assembly is hung, allows lateral movement of the boiler.

This vertical and horizontal mobility of the boiler is made possible by the use of proven stainless steel hoses.

The removability of the assembly is obtained instantly by means of quick hydraulic couplings 18.

The technical characteristics of the device according to the invention make it a full-fledged high performance boiler, justifying its use as a main boiler. It can also be used as a replacement for an existing boiler.

The high temperatures obtained inside the combustion chambers mean that the boiler is self-cleaning and does not require any maintenance.

The design of the boiler allows it to operate as a thermosyphon; however, its high efficiency justifies the use of a circulator.

Domestic hot water is obtained from a tank independent of the device according to the invention.

Claims (10)

1. An open-hearth boiler of the kind comprising a body (12) adapted to be placed above an open fire and flowed through by a fluid heat vehicle and having surfaces for heat exchange between the heat vehicle and the fire and being connected to return and flow ducts (2, 3 respectively) for the heat vehicle, the ducts being connected to an external central heating circuit and/or a hot water service, characterised in that the body (12) has inner combustion chambers (9) adapted to be passed through by the flames and combustion gases from the fire, the chamber walls being the heat exchange surfaces, the gaps (10) between the chambers (9) being operative as an internal flow circuit (10) for the fluid heat vehicle ; and the boiler is portable and releasable and has its own draught device and a smoke manifold (6) whose draught is controlled automatically by a damper controlled by a thermostatic probe (8) or is operated manually by a handle (19), the top part of the boiler being removable and being an inspection door (4) giving access to the smoke manifold (6), combustion chambers (9), an automatic bleeding valve (7) and a safety valve (5).

2. A boiler according to claim 1, characterised in that the inner combustion chambers (9) extend through the body (12) between the base (11) thereof, the base being adapted to make contact with the fire, and a top part devised as a smoke manifold (6) communicating with the outside by way of a discharge aperture.

3. A boiler according to claim 2, characterised in that the walls of the inner chambers (9) are in the form of surfaces of revolution whose axis is substantially vertical.

4. A boiler according to claim 3, characterised in that the surfaces of revolution are conical surfaces.

5. A boiler according to any of claims 2-4, characterised in that the base (11) of the body (12) is in shape at least approximately parabolic.

6. A boiler according to any of the previous claims, characterised in that the inner flow circuit (10) is bounded between the chambers (9) by the walls thereof, by the base (11), by a top wall of the body (12), the chambers (9) extending into the latter wall, and by baffle plates (16) each interconnecting two adjacent chambers (9) and disposed in the gaps (10), the baffle plates (16) together forming a substantially spiral internal flow circuit (10) between the return and flow ducts (2, 3 respectively).

7. A boiler according to any of the previous claims, characterised in that the body (12) is suspended, by way of the return and flow ducts (2. 3 resoectivelvl. on a slidina susoension device adapted to adjust the height of the body (12) relatively to the fire.

8. A boiler according to claim 7, characterised in that the suspension device comprises a compensating spring (13) to which a system (1) for securing the lines (2, 3) is secured, the spring (13) providing automatic control of the height of the body (12) relatively to the fire.

9. A boiler according to claim 7 or 8, characterised in that the suspension device is sustained by articulated gallows (21) providing adjustment of the lateral position of the body (12) relatively to the fire.

10. A boiler according to any of the previous claims, characterised in that the return and flow lines (2, 3 respectively) are connected to the external central heating circuit and/or hot water service by way of flexible pipes (17) and rapid hydraulic connections (18).

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