GB2262336A

GB2262336A - A gas burner

Info

Publication number: GB2262336A
Application number: GB9225439A
Authority: GB
Inventors: Aldo Polidoro
Original assignee: Individual
Current assignee: Individual
Priority date: 1991-12-06
Filing date: 1992-12-04
Publication date: 1993-06-16
Anticipated expiration: 2012-12-04
Also published as: NL9202112A; NL194447C; GB9225439D0; FR2684747B3; GB2262336B; ITVI910105V0; FR2684747A3; ITVI910105U1; ES1023152U; NL194447B; DE9216605U1; IT226008Y1; ES1023152Y

Abstract

The invention provides a gas burner of the "ramp" type, provided with a cooling circuit through which flows water from a boiler circuit, the burner having a body (5) made of material with a high coefficient of thermal conductivity; and having a head (1) provided with apertures (2); the head (1) being made from heat-resistant material; the cooling circuit comprising pipes (6) which are placed at a distance from the head (1) such as to produce thereon the temperature necessary and sufficient for calcination of atmospheric dust coming from at least one "venturi" tube placed upstream of the burner. The apertures may take various formations, Figs 1 and 6-8 (not shown). <IMAGE>

Description

A GAS BURNER The present invention concerns a gas burner of the so-called "ramp" type, fitted with a cooling unit which uses the water from the boiler circuit.

The term "ramp" burner as used herein means an assembly which comprises a plurality of flanking linear elements, in each of which are arranged slots through which a combustible-gas/primary-comburent-air mixture is discharged, the mixture being supplied to each element via a shaped pipe which forms a venturi tube; the combustible gas coming from a common collector which feeds individual nozzles provided to correspond to each of the ramps.

Such a construction is described in Italian Patent Application No. 85507/A/84, by the same applicant, which provides for the "ramps" to be so close together as to prevent the passage of secondary air to feed the flame; in this way complete combustion is reliant upon the primary comburent air which is in excess with regard to the stoichiometric quantity, in a percentage varying from 20 to 40%, in order to reduce the quantities of nitrous products (NO,), contained in the combustion product.

Still with the aim of reducing the quantities of nitrous products in the combustion product, burners have been deigned which are fitted with cooling units for the purpose of preventing excessive heating of the head of the burner which, it will be noted, can cause flash-back with ignition of the gas at the nozzles, thus compromising the functioning of the burner.

In order to overcome such problems, boiler circuit water has been used as the cooling fluid for the burner.

An object of the present invention is to create a "ramp"-type burner of the atmospheric type, i.e. of the type which takes air directly from the surroundings without the aid of fans or suchlike, and, which is capable of providing combustion of the hyperstoichiometric type, whilst at the same time providing a burner which is of uncomplicated structure and mode of operation.

These aspects are achieved by configuring the burner so that its body is made of material with a high coefficient of thermal conduction and, furthermore, by making it so that its head, on which are arranged the apertures for discharging the combustible gas, is made of heat-resistant material.

Morever, provision is made for the pipes of the cooling circuit to be placed at a distance from the head such as to produce thereon the temperature necessary and sufficient for calcination of the atmospheric dust which would settle on the head, coming from the pipes discharging the mixture placed upstream of the burner.

Accordingly, the invention provides a gas burner of the ramp type, provided with a cooling circuit through which flows water from a boiler circuit, the burner having a body made of material with a high coefficient of thermal conductivity; and having a head provided with apertures, the head being made from heat-resistant material; the cooling circuit comprising pipes which are placed at a distance from the head such as to produce thereon the temperature necessary and sufficient for calcination of atmospheric dust coming from at least one venturi tube placed upstream of the burner.

The invention will now be illustrated, but not limited, with reference to the particular embodiment as shown in the drawings, of which: Figures 1, 2 and 3 represent respectively a plan view of the unit from above, a side view and a front view of the device according to the design; Figure 4 shows a diagramatic view of a possible use of the device according to the design; Figure 5 shows a front view of a possible form of construction of the burner according to the design; and Figures 6, 7 and 8 represent three possible forms of construction of the slot made in the head of the burner according to the design.

In Figures 1, 2 and 3 it will be seen that the burner according to the invention is of the so-called "ramp type, comprising a series of linear elements 1, in each of which are arranged slots 2 or apertures from which the combustible gas/air mixture is discharged. Primary comburent air is supplied to each element from at least one venturi tube 3 which is supplied in turn by air coming from a single collector, as well as by the combustible gas coming from a nozzle 4 (Figure 2).

One fundamental characterstic of the device according to the invention is that the body 5 of the burner is made from material with a high coefficient of thermal conductivity, for example, copper. As may be seen from the attached Figures, the burner is fitted with a cooling unit comprising in particular a tubular pipe 6, which runs transversely through the bodies of the burner either on one side or the other, following a substantially U-shaped route.

Water from the boiler runs through pipe 6 thereby avoiding the need to provide a subsequent independent cooling unit.

A further fundamental characteristic of the device according to the invention is that the head of the burner is made of heat-resistant material. Furthermore it is arranged so that the pipe 6 of the cooling circuit is placed at a distance from the head of the burner so as to produce thereon the temperature necessary and sufficient for calcination of atmospheric dust coming from the venturi(s) 3 which would otherwise settle on the head causing a reduction in the rate of aeration.

It will be noted that where pipe 6 is arranged perpendicularly to the body of the burner (as illustrated in the drawings), the same is of a modular type, in the sense that it is possible to provide a plurality of flanking "ramps" of an indefinite number.

The fixing of the pipes to the edges of the holes made in the body of the ramp can easily be done by welding; however, fixing could advantageously be done by mechanical interference fitting with particular advantages from the constructional point of view.

As shown in Figure 1, advantageously the slots 2 have a narrowing 2' corresponding to their central part, which determines the stabilization of the flame.

Preferably the narrowed part has a width of 0.7mm.

In Figures 6, 7 and 8 further solutions are shown relating to the shape and arrangement of the slots 2. In particular these can be grouped into groups 11 of slots of variable number, centres 12 between slots and reciprocal distance 13, to prevent disjunctions of the flame, which allows combustion to be regulated.

In particular, in Figure 6 are shown rows of holes 10 between the rows of adjoining pairs of slots.

In Figure 5 may be seen a particular form of construction of the burner in which the "venturi" 3 is placed asymmetrically with regard to the head of the burner thereby reducing the overall size of the burner.

In Figure 4 it may be seen that the burner according to the invention may usefully be inserted level with the bottom of a boiler 7 with a heat exchanger 8 being fitted level with the top of the boiler.

In using the burner according to the invention in a traditional type of boiler, it is found that whilst there is a 25% excess of primary air when it is operating at 100% of its capacity, when on the contrary it operates at 50% capacity, the combustion can be imperfect giving rise to an excess of CO in the combustion product. So as to eliminate this inconvenience, apertures 9 are made in the side walls of the boiler 7; in this way even with capacity reduced to 50% the excess air is 30% and the rate of CO is kept within the limits laid down by law.

In addition, the rise in thermal output of the boiler is impeded, avoiding condensation of water vapour at the heat exchanger, which would be potentially extremely detrimental to the burner in the event of the water starting to drip onto its head and which would corrode the exchanger.

As will be apparent from the foregoing description, the burner according to the invention is extremely simple from the point of view of both construction and ease of use.

Tests carried out on the burner of the invention have shown the quantities of nitrous products, CO and other noxious gases, produced by the burner are strictly within the limits of the most rigorous and stringent laws.

An advantageous aspect of the burner of the invention is that it is capable of operating with equal efficiency with all gases in domestic use, whether natural or other types.

Claims

1. A gas burner of the ramp type, provided with a cooling circuit through which flows water from a boiler circuit, the burner having a body made of material with a high coefficient of thermal conductivity; and having a head provided with apertures, the head being made from heatresistant material; the cooling circuit comprising pipes which are placed at a distance from the head such as to produce thereon the temperature necessary and sufficient for calcination of atmospheric dust coming from at least one "venturi" tube placed upstream of the burner.

2. A burner according to claim 1, characterised in that the pipes are arranged perpendicularly with regard to the body of the burner, passing through suitable holes made in the same.

3. A burner according to claim 1 or claim 2, characterised in that the connection between the pipes and the body of the burner is made by welding.

4. A burner according to claim 1 or claim 2, characterised in that the connection between the pipes of the body of the burner is made by interference fitting between the pipes and the holes made in the head of the burner in which they are inserted.

5. A burner according to claim 1, characterised in that it is used as a bottom element in a boiler, in relation to at least one of whose walls there is at least one aperture providing communication between the inside of the boiler with the outside ambient air.

6. A burner according to claim 1, characterised in that its head has in it slots which have a narrowing in relation to their central part.

7. A burner according to claim 1, characterised in that the head is provided with rows of holes placed between rows of pairs of adjoining slots.

8. A burner according to claim 1, characterised in that the "venturi" tubes are placed asymmetrically with respect to the head of the burner.

9. A burner according to claim 1, characterised in that on the head of the burner there are disposed slots arranged into groups of variable number, centres between slots and reciprocal distance in order to prevent disjunction of the flame and to allow regulation of combustion.

10. A burner substantially as described herein with reference to the accompanying drawings.