GB2241567A

GB2241567A - Burners

Info

Publication number: GB2241567A
Application number: GB9103434A
Authority: GB
Inventors: Nicco Polidoro
Original assignee: Individual
Current assignee: Individual
Priority date: 1990-02-26
Filing date: 1991-02-19
Publication date: 1991-09-04
Also published as: IT9064235V0; IT9064235U1; DE9102176U1; GB9103434D0; IT223115Z2; FR2658901B3; FR2658901A3

Abstract

A gas burner is composed of independently fed linear elements 1, each supplied with gas/air mixture through a duct and each comprising a box structure 3 with a perforated base, surmounted by a perforated flat box top 5 and two arched concentric perforated sheets of metal 6 and 7. The lower arched sheet 6 is bounded by vertical side members 8, so that the burner above the flat box top 5 is divided into a central zone in which gas/air mixture passes through perforations in the arched sheets 6 and 7 and flanking zones in which it passes through the upper arched sheet 7 only. <IMAGE>

Description

Small Ramps Burners This invention relates to small ramps burners. In the field of burners a unit is defined as being a small ramps" burner when it is composed of a certain number of adjacent linear elements, within each of which there are slits allowing the outflow of the primary combustant fuelair mixture which is supplied to each element through a shaped duct preceded by a Venturi tube, supplied in turn by forced air coming from a single fan and passing through a (single) manifold, and by fuel gas also fed through a common manifold which in turn supplies the individual nozzles of the "small ramps".

In terms of technology this kind of burner is well known. In one particular example of it, described in Italian Application for a Patent for Industrial Invention No. 85.507/a/84 submitted by the same applicant, the small ramps are arranged very close together so as to prevent the passage of secondary air which fuels the flames, whereby the entire combustion process is fuelled only by the prinmary combustant air, which exceeds the stoichiometric quantity by a percentage of between 20 and 40%, for the precise purpose of reducing the percentage of nitrous products (NOx) contained in the products of combustion.

This invention relates to a particular kind of small ramps burner in which combustion is of the hyperstoichiometric kind and which is considerably simple in constructions and operation.

This is achieved, according to the invention, by providing a small ramps burner with hyperstoichiometric combustion as hereinabove defined wherein, from each one of the small ramps, a mushroom shaped structure rises upwards which includes a box structure at the bottom, the bottom of which is perforated, in which the ramp is installed, the top of the box structure being composed of a perforated baffle, the central part of which is covered by a perforated curved sheet of metal, the box structure being covered by a further curved and perforated sheet of metal the central part of which is placed over the first sheet of metal, the structure also having two baffles which rise in essentially perpendicular fashion from the top of the box structure, outside the first perforated sheet of metal, so as to define the boundaries of two side areas of the burner, the tops of which are defined by sections of the secondary perforated sheet of metal into which the pilot holes of the burner have been drilled.

By way of example, a burner is illustrated in one of its applications in the attached plates of drawings, wherein Figure 1 is a side view of a burner incorporating the invention; Figure 2 is a plan view of the burner of Figure 1; Figure 3 is a side view of the. burner after it has been inserted into a boiler.

The attached illustrations show that the burner is of the small ramps kind, which is composed of a series of linear elements (1), within each one of which there are slits, through which flows the primary combustant fuel-air mixture supplied by each element, through the shaped duct 1' from the Venturi tube 1", fuelled in turn by the forced air coming from the fan and by the fuel gas coming from the nozzle.

From each one of these ramps a mushroom shaped structure (2) stretches upwards. This is composed of a box shaped component (3) at the bottom, with holes (4) to allow air to enter and within which ramp is installed.

At the top of this box structure is a baffle which is also perforated.

The central part of this baffle is covered by a curved and perforated sheet of metal (6) and the entire box structure is covered by a further perforated sheet of metal (7), which is also curved and central part of which is placed over the first of these curved sheets. From the top (5) of this structure, there rise vertically two baffles (8) which are placed outside the first perforated sheet and which define the boundaries of the two side areas of the burnner, together with sections of the top (5) and sections of the secondary perforated sheet metal (7).

In these sections, the pilots of the burner have been drilled, and these are fed by the holes in the underlying sections of the top (5). The central holes of the secondary perforated sheet of metal (6) are vice versa the ones at which the main combustion takes place.

As can be seen more clearly in Figure 2, the curved sheet of metal (7), placed above the curved sheet (6), has sets of closely drilled slits, whilst the lower sheet of metal (6) has few holes.

The ratio between the total diameter of the holes in the upper sheet may be ten times greater than the total diameter of the holes in the lower sheet.

It should be stressed that the holes in both the sheets of metal may be of a different shape from those illustrated in Figure 2.

The burner in the invention will be placed in a boiler, the side panels of which will cover the sides of the mushroom shaped structure.

The burner will operate with forced air channelled through a fan which is preferrably placed before the burner.

The function of the chamber within the box structure is to allow the further enrichment of the air in the combustant air-fuel gas mixture subject to combustion so as to make it hyperstiochiometric, in order to reduce to a minimum the percentage of NOx contained in the products of combustion.

It will be appreciated that the foregoing is merely exemplary of small ramps burners in accordance with the invention and that modifications can readily be made thereto without departing from the true scope of the invention.

Claims

1. A small ramps burner with hyperstoichiometric combustion as hereinabove defined wherein, from each one of the small ramps, a mushroom shaped structure rises upwards which includes a box structure at the bottom, the bottom of which is perforated, in which the ramp is installed, the top of the box structure being composed of a perforated baffle, the central part of which is covered by a perforated curved sheet of metal, the box structure being covered by a further curved and perforated sheet of metal the central part of which is placed over the first sheet of metal, the structure also having two baffles which rie in essentially perpendicular fashion. from the top of the box structure, outside the first perforated sheet of metal, so as to define the boundaries of two side areas of the burner, the tops of which are defined by sections of the secondary perforated sheet of metal into which the pilot holes of the burner have been drilled.

2. A burner according to Claim 1, wherein the sides of the mushroom shaped structure are open and placed against the side panels of a boiler into which it is inserted.

3. A burner according to Claims 1 or 2, wherein the upper curved sheet of metal has holes of a much greater total diameter than the total diameter of the holes in the lower sheet of metal.