GB2129915A

GB2129915A - A gas operated boiler

Info

Publication number: GB2129915A
Application number: GB08232669A
Authority: GB
Inventors: James Dutfield; Philip Paul Wilson
Original assignee: Baxi Partnership Ltd
Current assignee: Baxi Partnership Ltd
Priority date: 1982-11-16
Filing date: 1982-11-16
Publication date: 1984-05-23

Abstract

A gas operated boiler (1) for heating water circulating in a heating load (6), comprising a gas burner (2), a first water/gas heat exchanger (7) and a flue (3) for conducting exhaust gases away from the boiler (1). The said first heat exchanger (7) is connected in series with the water input side of the heating load (6) and is positioned in the immediate vicinity of the gas burner (2) to absorb a major proportion of the energy released therefrom. In addition, a second water/gas heat exchanger (8) is connected to the first mentioned heat exchanger (7) and to the water return side of the load, which second heat exchanger (8) is positioned in the path of the exhaust gases away from the boiler (1) to absorb at least some of the residual energy contained therein. <IMAGE>

Description

SPECIFICATION A gas operated boiler The present invention relates to an improved gas operated boiler.

Sources of energy are becoming increasingly more expensive, both to locate and to supply to the consumer. Accordingly, it is essential that they are utilised with the maximum degree of efficiency. Such is the case with gas operated boilers which find wide application, especially in central heating systems, and which consume a large proportion of gas supplies.

When gas is burnt large quantities of water vapour are produced as a product of combustion.

In a gas operated boiler most of this water vapour is removed via the boiler exhaust. However, some of the water can and does condense within the boiler. This accumulating water condensate within the boiler results in corrosion of the boiler and is therefore highiy undesirabie.

It is an object of the present invention to provide a gas operated boiler in which the efficiency thereof is increased over conventional gas operated boilers, and further, in which water condensate within the boiler is conveniently removed.

According to the present invention there is provided a gas operated boiler for heating water circulating in a heating load, comprising a gas burner, a water/gas heat exchanger and a flue for conducting exhaust gases away from the boiler, the heat exchanger being connectable in series with the water input side of the heating load and positioned in the immediate vicinity of the gas burner to absorb a major proportion of the energy released therefrom the boiler being characterised by the provision of a second water/gas heat exchanger connected to the first-mentioned heat exchanger and connectable to the water return side of the load and positioned in the path of the exhaust gases away from the boiler to absorb at least some of the residual energy contained therein.

Preferably, the drainage means is associated with the second heat exchanger, to collect condensate from the latter.

Preferably, said drainage means comprises a collection vessel located beneath said second heat exchanger.

Preferably, said drainage means further comprises a gutter in said exhaust flue into which condensate forming therein can run and be carried therefrom.

Preferably, said gutter runs into the said collection vessel which comprises means for draining the condensate accumulated therein away from the boiler.

An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which: Fig. 1 shows a schematic view of a gas operated boiler embodying the present invention, and Fig. 2 shows a perspective view of the balanced flue of the boiler of Fig. 1.

Referring to Fig. 1 of the accompanying drawings, there is shown a gas operated boiler 1 comprising a gas burner 2 and a telescopic balanced flue 3, through the air inlet side 4 of which fresh air is supplied to the burner and through the exhaust outlet side 5 of which exhaust gases are vented.

The burner 2 operates to heat a heating load 6, which may, for example, comprise the radiators of a central heating system. Transfer of heat from the burner 2 to the load 6 is effected by circulating water through a heat exchange arrangement comprised of heat exchangers 7 and 8 and the load 6. Heat exchanger 7 is positioned as is conventional directly over the gas burner 2 and consequently water circulating through it to the load 6 absorbs the major part of the energy released by combustion of the gas. However, some of the energy released passes the heat exchanger 7 to the exhaust outlet 5 through the intermediary of the exhaust gases.In order to make use of this, otherwise wasted, energy, and thereby improve the efficiency of the boiler 1, heat exchanger 8 is positioned between the heat exchanger 7 and the entrance to the exhaust outlet 5 and is connected into the return side of the water circulating through the heat exchangers 7 and 8, and the load 6. It will be realised that as a result of circulating through the load 6 the water entering heat exchanger 8 is cooled considerably from when it left heat exchanger 7. In consequence a degree of heat transfer from the hot exhaust gases, passing to the exhaust outlet 5, to the water in the heat exchanger 8 occurs, and as a result the water entering heat exchanger 7 is slightly warmed, thereby improving the efficiency of the boiler.Whilst the degree of heat transfer to the water in heat exchanger 8 is by no means great, it is sufficient to increase the efficiency of the boiler by several per cent. This can result in considerable savings in fuel consumption.

When gas is burnt large quantities of water vapour are produced as a by-product of combustion which, in the main, are exhausted from the boiler 1 through the exhaust outlet 5.

However, some of this water vapour may condense within the boiler, particularly where it strikes a cold surface of the boiler such as the exit surface of the exhaust outlet 5 and in the boiler described hereinabove, the heat exchanger 8. In order to facilitate the removal of this condensate from the boiler 1 a water collection vessel 9 is provided directly below the heat exchanger 8, which vessel 9 is also connected to a gutter 14 (see Fig. 2) in the lower surface 10 of the exhaust outlet 5, which gutter 14 is inclined down towards the collection vessel 9. By this arrangement, any water condensing in the exhaust outlet 5 runs back into the collection vessel 9, and any water condensing onto the heat exchanger 8 simply drips off into the collection vessel 9 thereunder.A drain is provided from the collection vessel 9 to a point conveniently removed from the boiler 1 via a suitable 'U' trap.

In order to ensure that in the balanced flue of the gas boiler described hereinabove, the exhaust gases from the exhaust outlet 5 are not returned to the gas burner 2 through the fresh air inlet 4, the actual exit of the exhaust outlet 5 is staggered beyond the actual entrance of the fresh air inlet 4, to ensure that the exhaust gases are carried well beyond the fresh air inlet 4. In addition, the end face 11 of the exhaust outlet 5 comprises panels 1 5 (see Fig. 2) inclined outwardly from the exhaust duct 12 of the exhaust/outlet 5 so as to direct the exhaust gas through grills 1 3 provided in the sides of the balanced flue 3 and away therefrom.

The provision of the outwardly inclined panels 1 5 means that the exhaust gases from the boiler will carry away from the exhaust outlet 5 without it being necessary to provide a combustion fan to give them sufficient velocity to pass through grills 1 3.

Finally, it will be appreciated that the gas operated boiler of the present invention is not restricted to gas operated boilers comprising balanced flues.

Claims

1. A gas operated boiler for heating water circulating in a heating load, comprising a gas burner, a first water/gas heat exchanger, and a flue for conducting exhaust gases away from the boiler, the said first heat exchanger being connectable in series with the water input side of the heating load and positioned in the immediate vicinity of the gas burner to absorb a major proportion of the energy released therefrom, the boiler being characterised by the provision of a second water/gas heat exchanger connected to the first mentioned heat exchanger and connectable to the water return side of the load, which second heat exchanger is positioned in the path of the exhaust gases away from the boiler to absorb at least some of the residual energy contained therein.

2. A gas operated boiler according to claim 1, wherein drainage means are provided to collect condensate from the second heat exchanger.

3. A gas operated boiler according to claim 2, wherein said drainage means comprises a collection vessel located beneath said second heat exchanger.

4. A gas operated boiler according to claim 2 or 3, wherein said drainage means further comprises a gutter in said exhaust flue into which condensate forming therein can run and be carried therefrom.

5. A gas operated boiler according to claim 4, wherein said gutter runs into the said collection vessel which comprises means for draining the condensate accumulated therein away from the boiler.

6. A gas operated boiler substantially as hereinbefore described with reference to the accompanying drawings.