WO2007101874A1

WO2007101874A1 - Combustion chamber.

Info

Publication number: WO2007101874A1
Application number: PCT/EP2007/052158
Authority: WO
Inventors: Sandro Brigo
Original assignee: B & B Elevators Srl
Current assignee: B & B Elevators Srl
Priority date: 2006-03-08
Filing date: 2007-03-07
Publication date: 2007-09-13
Anticipated expiration: 2008-09-08
Also published as: ITVI20060060A1; EP1994333A1; EP1994333B1; ATE540264T1

Abstract

Combustion chamber (1) for heating systems (A) of the type comprising a container body (2) provided with an opening (3) for the supply of the fuel (C) and an area (4) for collecting the combustion product (R), between which there is a fire area (6) for burning the fuel (C). The fire area (6) comprises two rotating bodies (7) with opposite rotation directions, arranged side by side and defining longitudinal development axes (X, X') that are substantially parallel to each other, whose perimetric surfaces (7a) define a combustion bed (8) for the fuel (C) when facing the supply opening (3), and a cooling surface for detaching the combustion product (R) through gravity when facing the collection area (4).

Description

"COMBUSTION CHAMBER". DESCRIPTION

The present invention concerns a combustion chamber particularly suitable for use in combustion heating systems. It is known that, especially in recent years, many steps forward have been made in the exploitation of and research into new sources of energy, in particular renewable and clean energy.

In particular, in the last years the market has seen the progressive introduction of heating systems like boilers or radiators that use new energy sources such as biomass and pellets for heating rooms.

In this case, the heating systems used are combustion systems and they are generally equivalent, if not exactly equal to the known boilers that use wood as a fuel. It is also known that the new energy sources increasingly often include maize in addition to biomass and pellets.

Maize, in fact, offers a higher energy output than the other sources and develops the same quantity of heat with much lower costs than diesel oil. Furthermore, while biomass and pellets are obtained through proper processing of the relevant raw materials, maize needs no previous processing. Maize grains are introduced directly into the combustion chamber and furthermore its combustion product does not generate particulate matter or soot.

The combustion chambers of the known type, though operating correctly with wood, biomass, pellets or other substances, present a recognized drawback when the fuel used is exclusively maize.

In particular, since maize grains contain an oily substance, after burning each of them releases a solid combustion product that at high temperatures combines with the combustion product of the other grains and tends to form a uniform mass that is deposited on the combustion bed, thus clogging it. In this case it is necessary to periodically stop the heating system in order to remove the combustion product from the combustion chamber. In order to overcome this drawback, several different types of combustion chamber have been designed, all characterized in that to allow the combustion product to be removed from the combustion bed, the fire must be moved. These solutions, though eliminating the inconvenience represented by the - 7 -

clogging of the combustion bed, present the drawback of being rather bulky.

In fact, since the temperatures reached near the fire are very high, the fire must be moved at a considerable distance.

A further drawback is represented by the fact that moving the fire is rather difficult and complex, since the flame must be kept alive.

The object of the present invention is to overcome all the aforementioned drawbacks presented by the known combustion chambers when the fuel used is constituted by maize or other vegetable products with a partially oily content.

In particular, one of the aims of the present invention is to carry out a combustion chamber that allows the combustion product to be removed from the combustion bed with no need to move the fire.

It is a further aim of the present invention to carry out a combustion chamber that allows said combustion product originating from the burning of maize to be removed with no need to put out the fire. It is a further aim of the present invention to carry out a combustion chamber whose overall dimensions are substantially equivalent to the overall dimensions of the known combustion chambers and suited to be fuelled with wood or similar materials.

These and other aims have been achieved through the implementation of a combustion chamber carried out according to the contents of the main claim, to which reference is made for the sake of brevity; the successive secondary claims describe the details of the invention.

To advantage, since the combustion bed is constituted by the portion of the surface of the rotating bodies that is directed towards the fuel supply opening, the rotation of the rotating bodies removes the combustion product from the combustion bed without involving the fire and, above all, without requiring the fire to be put out.

In fact, at high temperatures the combustion product of maize sticks to the surface of the rotating bodies and their rotation moves it away from the combustion bed.

Still to advantage, the motion of the rotating bodies causes the mixing of the fuel, so that it burns completely before the combustion product is discharged.

This obviously improves the output and efficiency of the combustion chamber.

The aforesaid objects and advantages, and others that are described below, will be highlighted in greater detail in the description of preferred embodiments of the invention, provided here as non-restrictive examples, with reference to the attached drawings, wherein:

- Figure 1 shows an axonometric view of the combustion chamber that is the subject of the invention; - Figure 2 shows a detail of the combustion chamber of the invention;

Figure 3 shows a heating system equipped with the combustion chamber of the invention.

The combustion chamber 1 for heating systems A, which is the subject of the invention, is shown in Figure 1 , where it is possible to see that it comprises a container body 2 provided with an opening 3 for the supply of the fuel C and an area 4 for collection of the combustion product R, between which there is a fire area 6 for burning the fuel C.

According to the invention, the fire area 6 comprises two or more rotating bodies 7 with opposite rotation directions, arranged side by side and defining longitudinal development axes X, X' substantially parallel to each other, whose perimetric surfaces 7a define a combustion bed 8 for the fuel C when facing the supply opening 3, and a cooling surface for detaching the combustion product R through gravity when facing the collection area 4. According to the preferred embodiment of the invention described herein, the combustion chamber comprises counteracting means arranged beside the rotating bodies and generally constituted by its walls.

According to different embodiments of the invention, the counteracting means may be constituted by partitions inserted in the combustion chamber or by other rotating bodies. The rotating bodies 7 are two and are set rotating so that, as can be seen in the detail of Figure 2, the vector V of the tangential velocity of any point 7b, which can be identified on one of the rotating bodies 7 and belongs to the combustion bed 8, has a projection V on the axis Z that joins the centres of the rotating bodies 7, said projection V being opposite to and diverging from the projection U' of the vector U of the tangential velocity of any point 7c of the combustion bed 8 that can be identified on the other rotating body 7 and belongs to the combustion bed 8.

Said embodiment is described only as an example and does not represent a limitation for other embodiments in which the rotating bodies may be present, for example, in a number different from two. As regards the rotating bodies 7, according to the preferred embodiment of the invention described herein they are drums and are operatively connected to moving means 10 that set them rotating around their longitudinal development axes X and X'. In particular, the moving means 10 comprise at least one gear motor 11 that is associated with both the rotating bodies 7 via a mechanism 12 generally constituted by a plurality of pinions and gears.

As regards the fuel C, it is preferably constituted by maize, for the use of which the combustion chamber 1 has been particularly designed. It can be observed, however, that according to the invention the same chamber 1 can allow the use of different types of products characterized in that they contain an oily substance and release a solid combustion product.

In order to facilitate the combustion of the fuel C, the combustion chamber 1 has been designed in such a way as to comprise an air feed channel 15. According to different embodiments of the invention that are not represented herein, the feed duct may comprise air conveying means suited to convey the air uniformly to the combustion bed, which may be constituted, for example, by a duct provided with a plurality of through holes.

Finally, the combustion chamber also includes at least one opening that gives access to the area 4 for collection of the combustion product R in order to allow said combustion product to be manually extracted.

According to different embodiments of the invention, extraction of the combustion product may be carried out automatically through mechanic extraction means that may be constituted, for example, by an auger. From an operational point of view, the combustion chamber 1 that is the subject of the invention is generally included in a heating system 20 similar to the one shown in Figure 3.

The heating system 20 comprises, in addition to the combustion chamber 1 of the invention, means 21 for feeding air into the combustion chamber 1 through the air feed duct 15, and a space 22 for containing the fuel C, generally constituted by a silo.

During operation, the fuel C passes from the silo 22 into the combustion chamber 1 through the supply opening 3.

The combustion product generated after burning maize is a solid oily product consisting of grains having the same dimensions as the maize grains. Said burnt grains tend to combine with one another forming solid masses and said masses tend to deposit permanently on the combustion bed 8 constituted by the upper surface of the rotating bodies 7 due to the high temperatures reached. Following time intervals fixed in advance, which may be, for example, of ten minutes each, the rotating bodies 7 turn around their longitudinal axes X and X' due to the action of the driving means.

Said separate rotation phases follow one another, so that the combustion product R comes to be positioned on the lower surface of the revolving bodies 7 that also corresponds to the surface that is furthest from the combustion bed 8.

In those points, the temperature of the surface 7a of the rotating bodies 7 is lower than it was when the surface 7a formed the combustion bed 8 and is such as to allow the combustion product R to come off the surface 7a and fall, due to gravity, in the collection area 4.

In this way, therefore, the combustion product R can be removed from the combustion bed 8 without moving the fire and without modifying its intensity. According to a different embodiment of the invention, the motion of the rotating bodies may be continuous and the speed depends on the dimensions of the combustion chamber as well as on the quantity of fuel introduced therein.

It should also be observed that the rotary motion of the rotating bodies not only allows the combustion product to be extracted from the combustion chamber, but also allows the combustion of the fuel introduced in the combustion chamber to be improved. In fact, the rotary motion tends to move the fuel that is still burning towards the lateral areas of the combustion chamber, where it rests against the side walls of the chamber.

In this way, therefore, the fuel is mixed during combustion and this offers the advantage of improving the combustion output and ensuring the constant intensity of the fire.

Furthermore, said mixing action prevents the completely burnt fuel from combining and forming solid blocks.

During mixing, when the burnt fuel comes in contact with the rotating bodies it sticks to them and is transported towards the collection area, in which it falls due to gravity, as already explained. It should also be observed that in different embodiments of the invention the side walls of the combustion chamber, which counteract the mixing movement of the fuel, can be replaced by further rotating bodies that, besides performing the above mentioned counteracting action, would advantageously increase the mixing action itself.

For the reasons explained above, the combustion chamber that is the subject of the invention achieves all the set aims.

In particular, by exploiting the adhesion of the maize combustion product to the rotating bodies due to the heat present on the combustion bed, the product is removed from the area where the fire is positioned without affecting the fire itself, thus allowing the combustion bed to be cleaned without involving or affecting the combustion process, not even to a minimum extent. The invention also achieves the aim to carry out a combustion chamber particularly suited to use maize as a fuel and that makes it possible to extract the maize combustion product with no need to put out the fire.

The invention also achieves the aim to carry out a combustion chamber particularly suited to the use of maize as a fuel and whose overall dimensions are substantially equivalent to the overall dimensions of the combustion chambers of the known type that are suited to use wood or similar materials as a fuel.

Upon implementation, further changes may be made and further construction variants of the combustion chamber may be developed, which are all to be considered protected by the present invention, provided that they fall within the scope of the claims expressed below. Where technical features mentioned in any claim are followed by reference signs, those reference sings have been included for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims

1 ) Combustion chamber (1 ) for heating systems (A) of the type comprising a container body (2) provided with an opening (3) for the supply of the fuel (C) and an area (4) for collecting the combustion product (R), between which there is a fire area (6) for burning said fuel (C), characterized in that said fire area (6) comprises two or more rotating bodies (7) with opposite rotation directions, arranged side by side and defining longitudinal development axes (X, X') that are substantially parallel to each other, whose perimetric surfaces (7a) define a combustion bed (8) for said fuel (C) when facing said supply opening (3), and a cooling surface for detaching said combustion product (R) through gravity when facing said collection area (4).

2) Combustion chamber (1 ) according to claim 1), characterized in that it comprises counteracting means (9) arranged beside said rotating bodies (7). 3) Combustion chamber (1 ) according to claim 2), characterized in that said counteracting means (9) are the walls of said combustion chamber (1 ).

4) Combustion chamber according to claim 2), characterized in that said counteracting means are partitions inserted in said combustion chamber. 5) Combustion chamber according to claim 2), characterized in that said counteracting means are rotating bodies.

6) Combustion chamber (1 ) according to claim 1), characterized in that said rotating bodies (7) are two.

7) Combustion chamber (1 ) according to claim 6), characterized in that the vector (V) of the tangential velocity of any point (7b) of said combustion bed (8) belonging to one of said rotating bodies (7) has a projection (V) on the axis (Z) that joins the centres of said rotating bodies (7), said projection being opposite to and diverging from the projection (U') of the vector (U) of the tangential velocity of any point (7c) of said combustion bed (8) belonging to the other of said rotating bodies (7).

8) Combustion chamber (1 ) according to claim 1), characterized in that said rotating bodies (7) are drums.

9) Combustion chamber (1 ) according to claim 1), characterized in that said rotating bodies (7) are operatively connected to moving means (10) suited to set them rotating around their longitudinal development axes (X, X'). 10) Combustion chamber (1 ) according to claim 9), characterized in that said moving means (10) comprise at least one gear motor (11 ).

11 ) Combustion chamber (1 ) according to claim 1), characterized in that it comprises at least one air feed duct (15) for conveying air in said combustion chamber (1 ).

12) Combustion chamber (1 ) according to claim 1), characterized in that it comprises at least one opening (23) that gives access to said collection area (4) for extracting said combustion product (R).

13) Combustion chamber according to claim 1), characterized in that it comprises mechanical means for extracting said combustion product from said collection area.

14) Combustion chamber according to claim 13), characterized in that said mechanical means comprise at least one auger.

15) Combustion chamber (1 ) according to claim 1), characterized in that said fuel (C) is maize.

16) Combustion heating system (20) of the type comprising a combustion chamber (1 ) having a container body (2) provided with an opening (3) for the supply of fuel (C) and an area (4) for collecting the combustion product (R), between which there is a fire area (6) for burning said fuel (C), characterized in that said fire area (6) comprises two or more rotating bodies (7) with opposite rotation directions, arranged side by side and defining longitudinal development axes (X, X') substantially parallel to each other, whose perimetric surfaces (7a) define a combustion bed (8) for said fuel (C) when facing said supply opening (3), and a cooling surface for detaching said combustion product (R) through gravity when facing said collection area (4).

17) Method for cleaning through removal of the combustion product (R) from a combustion bed (8) of a combustion chamber (1) for heating systems (A), of the type comprising a container body (2) provided with an opening (3) for supplying fuel (C) and an area (4) for collecting the combustion product (R), between which a fire area (6) is interposed for burning said fuel (C), said fire area (6) comprising two or more rotating bodies (7) with opposite rotation directions, arranged side by side and defining longitudinal development axes (X, X') substantially parallel to each other, whose perimetric surfaces (7a) define, in the sections facing said supply opening (3), said combustion bed (8) for said fuel (C), characterized in that it comprises at least the following stages:

- supplying said fuel (C) to said combustion chamber (1 ) through said supply opening (3);

- burning said fuel (C) until it changes into said combustion product (R) associated with said combustion bed (8);

- rotating said rotating bodies (7) at preset intervals, so that said combustion bed (8) with said combustion product (R) faces said collection area (4).