EP0064456A1 - Heater using combustible granulated solids - Google Patents

Abstract

A solid fuel boiler in the form of aggregates comprises a) an automatic supply of fuel to the hearth by a piston system (6) back and forth forming a fire stop in the rest position and actuated by a low power motor (13) with linear movement , b) a lively combustion by supply of ventilated air and revived by the system for feeding the ash and combustion residues out of the burner (8) by the action of fingers (17) integral with the piston (8).

Description

The present invention relates to a hot water boiler using solid fuel in the form of aggregates: coal pellets, plugs, wafers or various briquettes of coal, wood, straw, sawdust, etc.

The boilers known in the prior art which can operate with this type of fuel pose problems of combustion, evacuation of the ashes and of the bottom ash, which results in poor calorific efficiency and frequent manual interventions.

In addition, the supply of these boilers is carried out by an expensive Archimedes screw system of manufacture and delicate operation which requires a relatively large motive power.

The object of the present invention is to provide a boiler which is free from the drawbacks indicated and which on the other hand has a whole series of advantages: simple design, calorific efficiency clearly superior to that of current boilers, combined with a supply system, 'activation of fire and automatic de_endering of great reliability and inexpensive implementation eliminating any manual intervention.

• a) une alimentation automatique du foyer en combustible par un système de piston va et vient formant coupe feu en potion repos et actionné par un moteur de faible puissance à mouvement linéaire.
• b) une combustion vive par apport d'air ventilé et ravivée par le système d'alimentation lui-même qui tisonne le foyer.
• c) une évacuation progressive et mécanique, hors du brûleur, des cendres et des résidus de combustion, tel que le machefer, par l'action de doigts solidaires du piston.

An object of the invention is to provide a boiler which comprises:

• a) an automatic supply of fuel to the hearth by a reciprocating piston system forming a fire break in the resting potion and actuated by a low power motor with linear movement.
• b) a lively combustion by supply of ventilated air and revived by the supply system itself which pokes the hearth.
• c) a gradual and mechanical evacuation, from the burner, of the ashes and combustion residues, such as clinker, by the action of fingers secured to the piston.

Another object of the invention is to provide a boiler which comprises an automatic feeding part of the burner from a hopper containing the fuel and by means of a double piston back and forth forming an integral fire stop in the rest position, and which is powered by a motor. electric linear motion cylinder type.

Another object of the invention is to provide a boiler which comprises a boiler body of the type with vertical tubular exchangers embedded in a water cylinder of conventional type but whose calorific efficiency is improved by a demountable domed deflector whose cavity can be filled with a load of refractory material in order to increase the heat inertia.

Another object of the invention is to provide a boiler in which combustion is improved by admission of air above the burner inlet by a deflector and a grid with high calorific inertia.

• Fig. 1 est une vue en coupe de la chaudière montrant à sa base le brûleur, la trémie de combustible et le dispositif à piston d'alimentation du brûleur et du conduit de ventilation activant le feu.
• Fig. 2 est une vue de dessus, avec coupe partielle, du foyer et du dispositif d'alimentation du brûleur et de décendrage de celui-ci.
• Fig. 3 est une vue en coupe de la trémie de combustible et du dispositif d'alimentation à double piston d'une variante de la chaudière précédente.
• Fig. 4 est une vue en coupe de la chaudière montrant notamment le brûleur et la grille supérieure du foyer d'une autre variante.

These characteristics and advantages of a boiler according to the invention, as well as others, will become more apparent on reading the detailed description of an exemplary embodiment, as well as on examining the corresponding appended drawings.

• Fig. 1 is a sectional view of the boiler showing at its base the burner, the fuel hopper and the piston device supplying the burner and the ventilation duct activating the fire.
• Fig. 2 is a top view, partly in section, of the hearth and of the burner supply and ash removal device.
• Fig. 3 is a sectional view of the fuel hopper and of the double piston supply device of a variant of the previous boiler.
• Fig. 4 is a sectional view of the boiler showing in particular the burner and the upper grate of the hearth of another variant.

as shown in Figures 1 and 2 a boiler according to the invention has the following separate parts: the automatic feed, the burner, the body of the boiler.

A - the automatic feed comprises, according to FIG. 1: the fuel storage hopper 1, the feed mechanism and the drive motor with its box or control members. This assembly mounted on a tubular frame with adjustable feet is connected to the boiler burner orifice by bolts or other fixing. The fuel storage hopper 1 in the form of a pyramid or cone throne ends at its base with a chute 2 of section adapted to the shape of this part of the hopper and comprises two baffles 3 and 4 limiting the action of the fuel charge column on the supply corridor. The baffle 3 is articulated at 5 and adjustable for closing the hopper and for adapting the fuel intake to the desired conditions. It is possible to provide that the other baffle 4 is also articulated, or that the two baffles are articulated.

The capacity of the hopper 1 can be increased by adding a raise to its upper part.

B - According to a feature of the invention, the supply of the hearth is carried out by a piston 6 circulating in a corridor 7 of roughly the same section and animated with a back and forth movement, which ensures the connection between the chute 2 and the burner inlet 8.

In the withdrawn position, the piston 6 discovers an opening 9 made in the upper part of the passage 7 at the base of the chute 2 and the fuel then enters the passage. The pushing movement of the piston 6 pushes the fuel towards the inlet of the burner 8; at the end of the stroke, the piston is positioned at the inlet of the burner and constitutes a fire protection element.

In order to avoid jamming of the piston, at the start of the thrust, in order to pass through the fuel column, a space 11 is provided between the top of the piston 6 and the vault of the corridor 7. For this purpose a horizontal shelf 10, of width equal to that of the corridor at this level extends the piston backwards over a length at least equal to the stroke of the piston.

During the thrust, a fuel blanket spreads out in the cavity 11 between the shelf 10 and the top of the corridor 7 thus eliminating the risk of jamming. A stop 12, fixed to the rear of the opening 9 gradually eliminates this mattress of fuel towards the front of the piston during the movement of withdrawal of the latter.

C - The feed mechanism is driven by a motor 13 of the known type electric actuator motor, that is to say that the rotary movement is transformed into linear movement by a two-way screw nut system of step which is advantageously controlled by any suitable electrical or electronic control and command device, the constituent elements of which are partly or wholly grouped together in a so-called control panel or box (not shown).

• - démarrage et arrêt programmé ou manuel,
• ^- - marche avec ou sans apport d'air ventilé dans le brûleur, etc....

This switchboard or control box advantageously includes all the appropriate safety control organs and for monitoring the stop or run state chosen and programmed for the desired operation of the boiler, for example: - Automatic run with power supply at intervals regular or variable, the duration of which may be linked to a thermostatic control determining the degree of heating of the boiler as a function of the need:

• - programmed or manual start and stop,
• ^- - works with or without ventilated air supply in the burner, etc ...

D - The burner 8 shown in section in Figure 1 and seen from above in Figure 2, is advantageously made of stainless steel or steel covered with a refractory lining or any other suitable material. Its inlet width is adapted to the width of the feed corridor 7. The burner then gradually widens towards the center of the boiler and its bottom is perforated to allow the admission of combustion air by means of a cavity 14 under the burner and connected to the outside to a fan 15 preferably fixed on the chassis of the hopper.

This air admitted to the burner can be, as desired, fresh air taken from the boiler, or air heated by passage through a box located under the burner.

In the burner inlet area, a guide piece 16 made of stainless steel, preferably, has grooves (three shown) in which fingers 17 of the same section slide, integral with the piston 6.

Each time the piston is fed, the fingers move over the bottom of the burner for about 4 / 5ths of its length; in their back and forth movement they break the product of combustion and fire the fire. The guide piece 16 prevents the embers, during the recoil, from entering the feed passage 7, while in the pushing movement the fingers revive the combustion and gradually drive the burnt residues out of the burner towards the ashtray.

The entire burner is fixed by stainless steel bolts 18 on the lower casing 19 of the boiler (Figure 2).

'C - According to Figure 1, the boiler is specially designed to make the best use of the advantages and features described above of the supply system and the burner.

It is of the known type with vertical tubular exchangers 20 made of steel, embedded in a water cylinder 21 placed above a circular hearth 22.

The heat exchanger tubes are fitted with smoke retarders 23.

A domed deflector 24 made of stainless steel, removable, the cavity of which can be filled with refractory materials to increase the heat inertia, is placed in the center of the hearth between the burner 8 and the inlet of the exchangers, which forces the flames to lick the vertical walls of the hearth and promotes the distribution of combustion gases in the exchangers. This new design of the deflector constitutes a particular feature of the invention.

The upper part of the exchangers opens into a smoke evacuation box, allowing an additional heat exchange above the water cylinder.

The lower box 19 contains the ashtray drawer 25. A large insulated door allows access to the ashtray and easy disassembly of the burner.

According to a first variant, illustrated by FIG. 3, the feed mechanism comprises, according to FIG. 3: an upper pre-feed passage 52, at the base of the hopper, inside which a pusher 53 circulates, which has a. conformation which provides a space between its upper face and the vault of the corridor 52, allowing it to pass through the column of fuel leaving the hopper, without jamming. The movement of the pusher 53 is transmitted by the introduction piston 6, the stroke of the pusher 53 being limited towards the front by stops 54. The front movement of the pusher delivers the fuel to a cavity 55 which communicates with the passage of introduction 7.

When the introduction piston 6 is in the rest position, ie end of travel, its horizontal shelf 10 serves as the bottom of the cavity 5 and receives the dose of fuel delivered by the pusher 53.

The section of the introduction piston 6 corresponds, apart from the operating clearance, to the section of the passage 7 in which it moves.

At the end of the stroke, the piston 6 is positioned at the inlet of the burner 8 and completely closes this orifice.

In the rear movement of the piston 6, the tablet 10 fully opens the base of the cavity 55. The dose of fuel contained in this cavity pours into the passage 7, in front of the piston, while the pusher 3 moves back to discover the orifice hopper.

In the forward movement of the piston 6, the latter discharges, towards the inlet of the burner, the fuel discharged into the passage 7. The forward movement of the pusher 3 begins to take place, by means of the front stop 4, when the tablet 10 has completely closed the base of the cavity 5. The pusher 3 again delivers a dose of fuel into this cavity.

All the constituent elements of the feed mechanism as well as the combustion activation fan 15 are mounted on a frame connecting to the orifice of the burner 8, by bolts or other fixing.

The hopper 1 is mounted on adjustable feet and its orifice adjusts in the upper opening of the corridor 2.

A second variant of the device described above concerns the improvement of combustion in the furnace hearth.

First, thanks to a horizontally ventilated air supply, on the burner inlet side, at its upper part, by a ventilation ramp 26 (FIG. 4), in connection with the air intake cavity 14, located under the burner, by vertical tubes 27 placed on either side of the burner inlet.

Then, by adding, under the deflector 24, placed at the top of the hearth, a grid with removable strips 28, made of steel, cast iron or any other suitable material, of high calorific inertia, through which the combustion gases circulate and continue to burn.

These two devices combined allow postcombustion of unburnt gases and fumes, they avoid polluting fumes, premature fouling of the boiler and improve its efficiency.

The boiler object of the invention can be used for central heating as for any domestic or industrial hot water production.

Claims (10)

1. Hot water boiler using solid fuel in the form of aggregates or various compacted materials, characterized in that it comprises: a) an automatic feeding part of the hearth from a hopper containing the fuel and by means of a reciprocating piston system forming a fire stop in the rest position and which is actuated by an electric motor with linear movement of the jack type. b) a lively combustion by supply of ventilated air and revived by the supply system itself which pokes the hearth. c) a progressive and mechanical evacuation, from the burner, of the ashes and combustion residues such as chewing it up by the action of fingers secured to the piston. 2. Boiler according to claim 1, characterized in that the fuel storage hopper in the form of a pyramid or cone throne ends at its base with a chute comprising two baffles, at least one of which is adjustable, the purpose of which is is to possibly close the outlet of the hopper and limit the action of the fuel charging column on a horizontal corridor for supplying the hearth in which a piston of the same section circulates, moving back and forth which, in the withdrawn position, discovers a fuel intake opening at the base of the hopper chute towards the passageway which, in its pushing movement, drives back towards the burner. 3. Boiler according to claim 1, characterized in that the configuration of the piston provides a space between its upper part and the vault of its passageway to avoid its jamming at the start of the thrust in order to pass through the fuel column and that the fuel mattress which is deposited in this space is eliminated by a stopper of the inlet opening of the chute when the piston is withdrawn. 4. Boiler according to claim 1, characterized in that the burner comprises at its inlet a guide piece with grooves in which slide fingers of the same section secured to the piston so that, at each piston feed movement, the fingers move over almost the entire length of the bottom of the burner so as to break the combustion product, fire the fire and push the burnt residue out of the burner towards the ashtray while, during the withdrawal movement, said piece guide retains the embers inside the fireplace. 5. Boiler according to claim 1, characterized in that the burner has an inlet length adapted to that of the supply corridor then it widens towards the center of the boiler and its bottom is perforated to allow admission d combustion air which is supplied to it by a ca vity which it comprises below, which is connected to a fan. 6. Hot water boiler using solid fuel in the form of aggregates or various compacted materials comprising: a) an automatic feeding part of the burner from a hopper containing the fuel and by means of a double piston back and forth forming an integral fire stop in the rest position, and which is actuated by an electric motor with linear movement of the kind cylinder. b) a lively combustion by supply of ventilated air at the base of the burner, revived by the supply system itself which pokes the hearth and improved by admission of air above the burner inlet. c) a progressive and mechanical evacuation, from the burner, of ash and combustion residues, such as clinker, by the action of fingers secured to the piston. 7. Boiler according to claim 6, characterized in that the fuel storage hopper, in the form of a pyramid or cone trunk, communicates at its base with a horizontal pre-feed passage in which a pusher circulates, the conformation of which provides for a space between its upper face and the vault of its evolution corridor, and which, animated by a back and forth movement, discovers, in the withdrawn position, the fuel intake opening, which it goes, in its pushing movement, pushing back towards an intermediate cavity communicating with the corridor for introduction into the burner. 8. Boiler according to claim 6, characterized in that the piston for introduction into the burner completely closing the inlet opening of the burner in the rest position, fully opens, in its recoil movement, the base of the cavity having collected the dose of pre-fueled fuel, which it will push back towards the burner, also allowing, by its mechanical connection with the pre-feed pusher, to reintroduce a dose of fuel into the above-mentioned cavity , after the base of this cavity has been closed. 9. Boiler according to claim 1 or 6, characterized in that the burner has an inlet width adapted to that of the introduction corridor, that its bottom is perforated to allow ventilation of combustion air, which it comprises , on the inlet side and at its upper part, a horizontal ventilation ramp, these air intakes being connected together by a cavity which it comprises below, which is connected to a fan. 10. Boiler according to claim 9, characterized in that the combustion of the gases is improved by their passage through a grid and around a deflector with high calorific inertia, placed at the top of the hearth.

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