GB2114726A

GB2114726A - Improvements in or relating to gas-fired space heaters

Info

Publication number: GB2114726A
Application number: GB08138315A
Authority: GB
Inventors: Dennis Norman Brown
Original assignee: TI Domestic Appliances Ltd
Current assignee: TI Domestic Appliances Ltd
Priority date: 1981-12-18
Filing date: 1981-12-18
Publication date: 1983-08-24
Also published as: GB2114726B

Abstract

A gas-fired, space heater has a flueway (10) for conveying products of combustion from gas burners (7) to a heat exchanger (12) and a downdraught diverter (13). The heat exchanger is located in a first passageway (17) which conveys ambient air over the heat exchanger (12). The diverter (13) is located in a second passageway through which ambient air also passes. The second passageway is connected to the first passageway via an aperture (25) in a back plate (22). <IMAGE>

Description

SPECIFICATION Improvements in or relating to gas-fired, space heaters This invention relates to gas-fired, spacer heaters and has particular reference to such heaters for domestic use.

Conventionally, the combustion products from the gas burner or burners of the appliance pass through a heat exchanger at the rear of the appliance before entering a draught diverter located adjacent the exit of the heat exchanger.

From the draught diverter, the combustion products enter a flue which discharges the products to atmosphere. The appliance has a casing with an internal air flow passage that conveys ambient air to the heat exchanger and thence out of the casing into the space surrounding the appliance. In this way usable heat is extracted from the combustion products and the efficiency of the appliance is increased.

However, it is found that a considerable amount of heat is radiated by the draught diverter and from the rear of the appliance and this heat is wasted.

According to the present invention, a gas-fired space heater comprises a flue way for conveying products of combustion from a combustion space bounded in part by a back wall to a heat exchanger and thence to a draught diverter, and an air flow path open at both ends to atmosphere conveying ambient air over at least the lower part of the back wall and over the heat exchanger and draught diverter.

The air flow path may comprise a first passageway open at both ends to atmosphere conveying ambient air over at least the lower part of the back wall and the heat exchanger.

The air flow path may also comprise a second passageway open at both ends to atmosphere conveying ambient air over at least the lower part of the back wall and the draught diverter.

The first and second passageways may be separated at least in part by a rear wall of the heater, ambient air flow through the passageways also flowing over the rear wall.

Preferably, the second passageway joins the first passageway at a point downstream (in the direction of air flow through the first passageway) of the heat exchanger.

By way of example only, a domestic gas fire embodying the invention will now be described in greater detail with reference to the accompanying drawing which is a schematic elevation of the fire.

The fire comprises a base 1 on which is mounted a chamber 2 at the lower part of which is located an inclined bed 3 of simulated fuel briquettes 4. The fuel 4 is supported upon a grid 5 below which is a combustion space 6 into which fires a gas burner indicated schematically at 7.

The front and back walls 8, 9 of the chamber 2 converge upwardly to a parallel-sided flueway 10 with an exit 11 connected to a plate-type heat exchanger 12. Part at least of the front wall 8 is of heat-resistant glass which, whilst confining the products of combustion, exposes the bed 3 to view.

A draught diverter of conventional form indicated schematically at 1 3 is connected between the exit 14 of the heat exchanger 1 2 and a short length 1 5 of outlet flue 1 6 which conveys the products of combustion to a chimney (not shown) or other form of flue that discharges the products to atmosphere.

The heat exchanger 12 is located in a first passageway 1 7 located behind the chamber 2 and open at its lower end as indicated at 18 and at its upper end at 19. The upper open end 19 is aligned with a decorative grille 20 in the upper part of a canopy 21 that extends across the upper front of the fire.

The passageway 1 7 has a rear transverse wall 22 that extends across the rear of the fire and supports the down draught diverter 13. The wall 22 constitutes the rear wall of the appliance and is, when the fire is mounted in position against a chimney breast indicated at 23, separated from the latter by a decorative spacer with a top wall 24 that extends across the full width of the fire and side walls that extend downwardly from the top wall 24 to the leve of the base 1. The spacer thus conceals and isolates the draught diverter 1 3 and the length 15 of fiue.

The side walls of the spacer are apertured at least over their lower parts thereby admitting air both to the space enclosed by the space and to the lower open end 1 8 of the first passageway 1 7. The wall 22 has a transverse aperture 25 across its full width above the draught diverter whereby air admitted to the space exits into the first passageway 1 7 at a point downstream of the heat exchanger. A transverse, upwardly inclined partition wall 26 directs air towards the aperture 25. In effect, the down draught diverter is thus located in a second passageway.

Associated with the fuel burner 7 are the conventional controls and safety devices but these are not shown in the drawing.

In operation, air for combustion of gaseous fuel supplied to the burner 7 enters the combustion space 6 through inlet apertures not shown. The combusting fuel raises the fuel 4 to incandescence and the resultant products of combustion enter the flueway 10 and pass via the heat exchanger 12, draught diverter 13 and length 15 of flue into the chimney. Heat is extracted from the products of combustion by the heat exchanger 12 and imparted to ambient air entering the first passageway 1 7 via the apertures in the lower parts of the side walls of the spacer and the inlet 1 8. The heated ambient air exits via the upper open end 1 9 of the first passageway and the decorative grille 20 so passing into the room occupied by the fire.

Some of the ambient air entering the space within the spacer also flows through the second passageway and over the draught diverter 13 and part of the flue 1 5 and thereby further heat is extracted from the combustion products. Air flowing through the second passageway is directed by the inclined wall 26 through the aperture 25 where the air joins air flowing through the first passageway.

In the drawing the air flows through the first and second passageways as indicated by the arrows 27. The flow of combustion products is indicated by the arrows 28.

It will be appreciated that air entering the space flows over the back wall of the combustion zone 6 thereby cooling the wall. In addition, the flow of ambient air through the first passageway 1 7 cools the back wall 9, whilst the flow of ambient air through the second passageway cools the rear wall 22.

The construction described above has the advantage that a greater proportion of heat is extracted from the products of combustion than is the case with known constructions and in this way, the efficiency of the appliance is improved.

Down draught entering the length 15 of flue is prevented from entering the chamber 2 by the diverter 1 3 which acts to vent the down draught through the open lower aend 29 of the diverter.

It will be appreciated that the concept described above is applicable to other forms of gas-fired space heaters than that shown in the drawings. For example, the inclined bed of fuel could be replaced by upright radiants of ceramic material that, in use, are heated to incandescence by gas burners beneath the radiants.

It will also be appreciated that the heat exchanger and draught diverter may be supported by suitable brackets or other support means instead of the rear wall 22 describd above. In such a case, the first and second passageways merge into a common air flow path exiting to atmosphere via the end 1 9 and the decorative grille 20 referred to above.

Claims

1. A gas-fired space heater comprising a flueway for conveying combustion products from a combustion space bounded in part by a back wall to a heat exchanger and thence to a draught diverter, and an air flow path open at both ends to atmosphere conveying ambient air over at least the lower part of the back wall and over the heat exchanger and draught diverter.

2. A heater as claimed in claim 1 in which the air flow path comprises a first passageway open at both ends to atmosphere conveying ambient air over at least the lower part of the back wall and the heat exchanger.

3. A heater as claimed in claim 2 in which the air flow path further comprises a second passageway open at both ends to atmosphere conveying ambient air over at least the lower part of the back wall and the draught diverter.

4. A heater as claimed in claim 3 in which the first and second passageways are separated at least in part by a rear wall of the heater, ambient air flow through the passageways also flowing over the rear wall.

5. A heater as claimed in claim 3 or 4 in which the second passageway exits into the first passageway.

6. A heater as claimed in claim 5 in which the second passageway exits into the first passageway at a point downstream (in the direction of air flow through the second passageway) of the heat exchanger.

7. A heater as claimed in any one of claims 1-6 in which the second passageway is defined, at least in part, by the rear wall of the heater and a spacer fitted to the rear of the heater.

8. A heater as claimed in claim 7 in which the wall has an aperture through which the second passageway exits into the first passageway and in which an inclined wall is provided for directing air flow in the second passageway through the aperture.

9. A gas-fired, spaced heater substantially as herein described with reference to and as illustrated by the accompanying drawing.