EP1731831A1

EP1731831A1 - High efficiency burner

Info

Publication number: EP1731831A1
Application number: EP05425482A
Authority: EP
Inventors: Emilio Manenti
Original assignee: Jolly-Mec Caminetti SpA
Current assignee: Jolly-Mec Caminetti SpA
Priority date: 2005-06-06
Filing date: 2005-07-07
Publication date: 2006-12-13
Also published as: ITBG20050035A1

Abstract

A burner with a dispenser part (1) and a combustion part (2), said dispenser part comprising an inlet opening (6) for the fuel, said burner being characterised by comprising a drum (8) which in its interior contains flame arrester walls (10) fixed to a flame arrester shaft (9) rotating about its axis, under said drum (8) there being disposed a secondary screw shaft (11) for feeding fuel from the dispenser part (1) to a basket (12) iocated within the combustion part (2), said burner further comprising a primary screw shaft (7) positioned upstream of said drum (8) to feed the fuel to said inlet opening (6), said flame arrester shaft (9), said secondary shaft 11) and said primary shaft (7) being driven synchronously by a transmission member driven by a gearmotor (17).

Description

The present invention relates to a burner in accordance with the introduction to the main claim.
The state of the art includes burners which use ecological fuel generally crushed into small-dimension pieces known as pellets. This fuel is conveyed to the burner, to which an air stream is also fed for the combustion reaction.
The fuel is currently dispensed by a plate of controlled inclination which also behaves as a flame arrester to prevent the combustion reaction passing to the fuel reserve upstream of the plate.
Ideally, the fuel and combustion air should be in stoichiometric ratio to achieve optimum combustion. However the fuel is currently unable to be accurately dispensed so that it enters the burner in excess and does not participate completely in the combustion reaction. This results in a reduced burner efficiency and fuel wastage. Moreover, to achieve good mixing between the air and fuel, this latter is dropped from above with the result that a part is dispersed by convective movements without contributing to the combustion.
The object of the present invention is therefore to provide a burner which enables the stated drawback to be overcome, and in particular a burner able to accurately dispense the fed fuel, in order to achieve higher efficiency.
Said object is attained by a burner the inventive characteristics of which are defined by the accompanying claims.
The invention will be more apparent from the following detailed description of a preferred embodiment thereof, provided by way of non-limiting example with reference to the accompanying drawings, in which:

Figure 1 is a side view of the burner according to the invention;
Figure 2 is a view of the burner of the invention taken from above;
Figure 3 is a longitudinal section through the burner of the invention;
Figure 4 is a cross-section through the burner on the plane 4-4 of Figure 1.

With reference to the figures, the burner according to the invention comprises a dispenser part 1 connected to a combustion part 2 via a feed section 3. To the side of the dispenser part 1 there is a gear-type transmission member 4 driven by a gearmotor 17. An air blower 5 is disposed external to the dispenser part 1. The dispenser part 1 also presents an inlet opening 6 for fuel entry.
With reference to Figures 3 and 4, it can be seen that in the interior of the dispenser part 1 a primary screw shaft 7 is provided, rotated at predetermined speed. Below the primary shaft there is a fixed drum 8 internally carrying a rotating shaft 9 to which flame arrester and smoke arrester walls 10 are fixed, they dividing the drum into four sectors to form a rotary valve. The drum 8 laterally presents two openings, one upper and one lower, for fuel passage. A secondary screw shaft 11 is disposed below the drum 8 and extends through the feed section 3 to reach a basket 12 which is disposed within the combustion part 2 and is extractable therefrom. The basket 12, raised from the floor by suitable supports, not shown, presents small holes 15 in its sides and base to allow air passage, and a lateral hole of greater dimensions to allow entry of the fuel conveyed by the secondary screw shaft 11. The feed section 3 upperly comprises a channel 13 enabling the air originating from the blower 5 to enter the basket 12 through the area external to the basket 12 and the small holes 15 in the basket 12. An igniter 14 is positioned close to the basket 12.
The primary shaft 7 is of smaller dimensions than the secondary shaft 11, its screw being likewise of smaller pitch than that of the secondary shaft 11, to achieve accurate fuel dispensing.
During operation, the fuel, the path of which is indicated by the arrows of Figures 3 and 4, enters the burner through the inlet opening 6 and is dispensed with accuracy by the primary screw shaft 7, to enter the drum 8 divided into sectors. Rotation of the rotary shaft 9 causes the sectors formed by the flame arrester walls 10 to rotate, to pour the fuel onto the secondary shaft 11 which is also provided with a screw. The movement of the secondary shaft 11, driven by the transmission member 4, feeds the fuel into the basket 12. At the same time the blower 5 feeds air under pressure into the channel 13 from which it passes into the combustion part 2 to enter the basket 12. Air and fuel then mix in the basket 12 in which the combustion reaction takes place, when triggered.
As the basket 12 is extractable, the combustion residues can be advantageously eliminated by extracting the basket 12.
Because of the presence of the primary shaft 7, which is provided with a screw, the fuel can be accurately dispensed to obtain an optimum air-fuel ratio, enabling maximized fuel efficiency to be obtained without fuel wastage.
The transmission member 4 enables the three elements of the dispenser part 1, i.e. the primary shaft 7, the rotary valve 9 and the secondary shaft 11 to be synchronized. The fuel feed is increased or decreased depending on the heat quantity required.
The air flow from the blower 5 is also suitably regulated by an electrical/electronic control circuit, not shown.
Because of the presence of small holes 15 in the sides and base of the basket 12, the air mixes well with the fuel, which can be fed into the bottom of the basket 12, so avoiding the need for the fuel to fall from above.

Claims

A burner with a dispenser part (1) and a combustion part (2), said dispenser part comprising an inlet opening (6) for the fuel, said burner being characterised by comprising a drum (8) which in its interior contains flame arrester walls (10) fixed to a flame arrester shaft (9) rotating about its axis, under said drum (8) there being disposed a secondary screw shaft (11) for feeding fuel from the dispenser pan (1) to a basket (12) located within the combustion part (2), said burner further comprising a primary screw shaft (7) positioned upstream of said drum (8) to feed the fuel to said inlet opening (6), said flame arrester shaft (9), said secondary shaft 11) and said primary shaft (7) being driven synchronously by a transmission member driven by a gearmotor (17).
A burner as claimed in claim 1, characterised by further comprising a blower (5) for feeding air into the basket (12).
A burner as claimed in claim 1, characterised in that said primary screw shaft (7) is disposed within the dispenser part (1).
A burner as claimed in claim 1, characterised in that said primary shaft (7) has smaller dimensions than the secondary shaft (11).
A burner as claimed in claim 1, characterised in that the pitch of the screw on said primary shaft (7) is less than that of the screw on the secondary shaft (11).
A burner as claimed in claim 1, characterised by comprising holes (15) provided in the basket (12) for air feed.
A burner as claimed in claim 5, characterised in that said holes (15) are provided in the base of the basket (12).
A burner as claimed in claim 5, characterised in that said holes (15) are provided in the side walls of the basket (12).
A burner as claimed in claim 5, characterised in that said basket (12) comprises a lateral hole (16) for fuel feed.
A burner as claimed in claim 8, characterised in that said lateral hole (16) is located in proximity to the basket base.