EP1970623A2

EP1970623A2 - Solid fuel boiler

Info

Publication number: EP1970623A2
Application number: EP08152357A
Authority: EP
Inventors: Michele Cavallini
Original assignee: Arca Srl
Current assignee: Arca Srl
Priority date: 2007-03-14
Filing date: 2008-03-06
Publication date: 2008-09-17
Also published as: EP1970623A3; ITMN20070006A1

Abstract

A solid fuel boiler (1), comprising a wall (3) provided with an interspace (4) for containing a fluid to be heated, which is adapted to delimit a portion of space which comprises a burner (5) provided with a grille (6) which divides the portion of space into an upper region (8) for containing the fuel and a lower region which comprises a combustion chamber (9) and heat exchange surfaces (10), a protection shield (14) being provided which is located directly above the grille (6) of the burner (5) at a suitable distance therefrom.

Description

The present invention relates to a solid fuel boiler.
Solid fuel boilers are known which comprise a wall provided with an interspace for containing the fluid to be heated, very commonly constituted by water, which delimits a portion of space which comprises a burner provided with a grille which divides such portion of space into an upper region, which is designed to contain the fuel, and a lower region, which comprises the combustion chamber and heat exchange surfaces which are designed to be struck by the products of the combustion before being sent to the stack.
These boilers work according to the principle of gasification of the fuel, which, arranged in the upper region, in contact with the embers that are present on the grille of the burner, generates gases which combine with the primary oxidizing air, creating a combustible mix.
This mix is aspirated through the openings of the grille of the burner, where it receives an addition of secondary air and passes into the lower region, where the characteristic inverted flame is generated in the combustion chamber, generating combustion products which strike surfaces which are assigned appropriately to the transmission of heat to the fluid contained in the interspace of the wall, and are then sent to the stack.
The aim of the present invention is to provide a boiler of the type described above which is capable of burning solid fuels constituted equally by small wood logs or by granular biomasses of any size.
This aim is achieved by a solid fuel boiler according to the invention, comprising a wall provided with an interspace for containing a fluid to be heated, which is adapted to delimit a portion of space which comprises a burner provided with a grille which divides said portion of space into an upper region, which is designed to contain the fuel, and a lower region, which comprises a combustion chamber and heat exchange surfaces which are designed to be struck by the products of combustion before conveyance to the stack, characterized by the presence of a protection shield located directly above the grille of the burner at a suitable distance therefrom.
Further characteristics and advantages of the invention will become better apparent from the description of a preferred but not exclusive embodiment thereof, illustrated by way of non-limiting example in the accompanying drawings, wherein:

Figure 1 is a perspective view of the boiler according to the invention;
Figure 2 is a sectional view, taken along the line II-II of Figure 1;
Figures 3 and 4 are sectional views of the boiler operating with two different types of fuel.

With reference to the figures, the reference numeral 1 generally designates the boiler provided with an outer casing 2 and comprising a wall 3 provided with an interspace 4 which contains the water to be heated.
The portion of space delimited by the wall 3 comprises a burner 5, which comprises a cast iron grille 6 which rests on a block of refractory material 7, and the burner divides the portion of space into two regions: an upper region 8, which is designed to contain the fuel, and a lower region, which comprises a combustion chamber 9, in which the inverted flame visible in Figures 3 and 4 is generated, the flame being obtained from the mixture produced by the gasification of the fuel combined with the primary oxidizing air and with the addition of secondary air through ducts 6a; the products of combustion then strike, before being sent to the stack, heat exchange surfaces 10, thus transmitting heat to the water to be heated.
An important feature of the invention resides in that the upper region 8 is provided both with a door 11 for loading the fuel in the form of small wood logs and with a tube 12 for feeding fuel in the form of granular biomasses with an underlying igniter constituted by a glow bar 13, and moreover in that there is a protection shield 14 directly above the grille 6 of the burner and suitably spaced therefrom, in order to allow the passage of the fuel mix, by means of feet 15.
It is thus possible to burn in the boiler according to the invention both small wood logs, as shown in Figure 3, and granular fuel, as shown in Figure 4, without running the risk of said fuel passing through the openings of the grille without burning or without burning completely.
The access of the fuel to the combustion region is optimized by the presence of a hopper 16.
The described invention is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims; all the details may further be replaced with other technically equivalent elements.
The disclosures in Italian Patent Application No. MN2007A000006 from which this application claims priority are incorporated herein by reference.
Where technical features mentioned in any claim are followed by reference signs, those reference signs 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

A solid fuel boiler (1), comprising a wall (3) provided with an interspace (4) for containing a fluid to be heated, which is adapted to delimit a portion of space which comprises a burner (5) provided with a grille (6) which divides said portion of space into an upper region (8), which is designed to contain the fuel, and a lower region, which comprises a combustion chamber (9) and heat exchange surfaces (10) which are designed to be struck by the products of combustion before conveyance to the stack, characterized by the presence of a protection shield (14) located directly above the grille (6) of the burner at a suitable distance therefrom.
The boiler according to claim 1, characterized by the presence, within the region arranged above the burner in the portion of space delimited by the wall (3) provided with an interspace (4), of a door (11) for loading the fuel in the form of small wood logs and of a tube (12) for feeding fuel in the form of granular biomasses.
The boiler according to one or more of the preceding claims, characterized by the presence of an igniter (13) in a position below the tube (12) for feeding the fuel in the form of granular biomasses.
The boiler according to one or more of the preceding claims, characterized by the presence, within the region located above the burner in the portion of space delimited by the wall (3) provided with an interspace (4), of a hopper (16) for containing the fuel, which is adapted to convey said fuel so that it falls at said protection shield (14).