Self-recuperative burner

Abstract

A self-recuperative burner comprising: a burner body having an exchanger; said exchanger comprises a first duct for the combustion air and a second duct for the flue gases: at least one first flue gas discharge pipe; characterized in that it comprises an air inlet duct leading to a first annular chamber concentric to said at least one first flue gas discharge pipe; said first annular chamber being connected also to a Venturi tube positioned inside said at least one first flue gas discharge pipe.

Claims

1. A self-recuperative burner comprising: a burner body having an exchanger; said exchanger comprises a first duct for the combustion air and a second duct for the flue gases: at least one first flue gas discharge pipe and an air inlet duct leading to a first annular chamber concentric to said at least one first flue gas discharge pipe; said first annular chamber being connected also to a Venturi tube positioned inside said at least one first flue gas discharge pipe; wherein the burner comprises a second flue gas discharge pipe connected to an end of said first flue gas discharge pipe downstream of said Venturi tube, and the burner comprises a third flue gas exhaust pipe connected to an end of said first flue gas exhaust pipe upstream of said Venturi tube.

2. The burner according to claim 1 characterized in that said first annular chamber is connected to a second annular chamber concentric to said exchanger.

3. The burner according to claim 1 characterized in that said second annular chamber communicates with a first passage in contact with said exchanger; said first passage is positioned between said exchanger and a first pipe coaxial with said exchanger and internal thereto.

4. The burner according to claim 1 characterized in that it comprises a second passage in contact with said exchanger for the return flue gases; said second passage is positioned between said exchanger and a second pipe coaxial with said exchanger and external thereto.

5. The burner according to claim 1 characterized in that said first annular chamber exchanges heat with said at least one first flue gas discharge pipe.

6. The burner according to claim 2, characterized in that said first annular chamber and said second annular chamber are both composed of an outer shell and an inner shell which partially surrounds the exchanger.

7. The burner according to claim 6 characterised in that said outer shell is made of aluminium or cast iron and said inner shell is made of steel.

8. The burner according to claim 6 characterized in that the burner comprises an insulating material thermally adhered to said outer shell.

Description

BRIEF DESCRIPTION OF THE DRAWING FIGURES

(1) The characteristics and advantages of the present invention will become evident from the following detailed description of a practical embodiment thereof, illustrated by way of non-limiting example in the accompanying drawings, in which:

(2) FIG. 1 shows a self-recuperative burner, seen laterally and in section, according to the present invention;

(3) FIG. 2 shows a self-recuperative burner, from below and in section, according to the present invention;

(4) FIG. 3 shows a self-recuperative burner, seen from the rear and in section, according to the present invention;

(5) FIG. 4 shows a Venturi tube of a self-recuperative burner, seen laterally and in section, according to the present invention;

(6) FIG. 5 shows a Venturi tube, in an alternative embodiment, of a self-recuperative burner, seen laterally and in section, according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

(7) Referring to the attached figures, a self-recuperative burner according to the present invention comprises a burner body 10 comprising an exchanger 11, and having inside it a gas supply pipe 12, and terminates in a burner head 13.

(8) At the rear it comprises a block 14 which comprises the gas inlet and supports the exchanger 11 and the gas supply pipe 12.

(9) Near the beginning of the exchanger 11 a flue gas discharge pipe 15 extends upwards; inside said pipe is a Venturi tube 16, and outside is an air intake 17, which can be positioned on the right or the left, with respect to the exchanger 11, since two opposite inlets are provided which can be used alternatively.

(10) The air intake 17 is connected to a first annular chamber 20 which surrounds a first flue gas discharge pipe 21. The first annular chamber 20 is directly connected to the inlet of the Venturi tube 16.

(11) The air intake 17 and the first annular chamber 20 are made in one single piece 22 which surrounds the first pipe 21.

(12) Opposite the inlet of the Venturi tube 16, a valve 23 is provided which regulates the inflow of air into the Venturi tube 16.

(13) The first annular chamber 20, descending towards the exchanger 11, is connected to a second annular chamber 24 (to the first pipe 21) which joins a third annular chamber 25 around the exchanger 11.

(14) The second annular chamber 24 and the third annular chamber 25 are composed of an outer shell 26 and an inner shell 27 which initially and partially surrounds the exchanger 11.

(15) The outer shell 26 is made of aluminium or cast iron and the inner shell 27 is made of steel or in any case heat-resistant material.

(16) An insulator 30 is positioned adhering to the outer shell 26; said insulator delimits (externally) the third annular chamber 25, to guarantee external temperatures of around 50° C.

(17) The first pipe 21 is fixed to the inner shell 27 by means of a coupling with washer.

(18) A second upper pipe 31 is screw-fitted to the end of the first pipe 21.

(19) The third annular chamber 25 comprises a passage 32 perpendicular to the exchanger 11 and communicates with a passage 33 which is in contact with the exchanger 11, positioned between it and a pipe 34 coaxial to the exchanger and internal to it.

(20) The flue gases returning from the head 13 pass through a passage 40 external to and in contact with the exchanger 11, delimited externally by a further pipe 41. When the flue gases reach the vicinity of the flue gas discharge pipe 15, they pass into an annular chamber 42, which communicates with the first pipe 21, and alongside the Venturi tube 16 to reach the second pipe 31.

(21) In an alternative embodiment of the Venturi tube 16, the first annular chamber 20, instead of being directly connected to the inlet of the Venturi tube 16, is connected to a further annular chamber 50, positioned inside the first pipe 21. The annular chamber 50 has at the top a narrowing in volume and forms a vertical and circular opening 51 which then leads into the second pipe 31, which substitutes and acts as the Venturi tube 16.

(22) The flue gases coming from the annular chamber 42 pass inside the annular chamber 50, which is inside the first pipe 21, and proceed towards the second pipe 31.

(23) In the first case the Venturi tube 16 is internal and the flue gases flow outside it, in the second case the corresponding Venturi tube 51 is external and the flue gases flow inside it.

(24) The combustion air inlet, being concentric to the flue gas discharge, will already allow energy recovery at the air inlet on the valve body. Furthermore this solution also allows insertion at a height of another exchanger pipe if necessary, before the Venturi tube, thus elongating the heat exchange and increasing the burner efficiency.

(25) The quantity of combustion air is regulated by means of an external valve not shown.

(26) Any materials and dimensions can be used for the self-recuperative burner according to any one of the requirements and the state of the art.

(27) The burner thus conceived is subject to numerous modifications and variations, all falling within the ambit of the inventive concept; furthermore all the details can be replaced by technically equivalent elements.