Space heaters

A space heater has a combustion chamber provided with hollow cheeks adapted for providing a supply of air into the combustion chamber at a level above the burner. The space heater incorporates a water boiler and a cooker unit which are arranged to be heated by combustion products in respective flues, each flue having a separate damper, whereby the flow of combustion products through each may be controlled individually.

FIELD AND SUMMARY OF THE INVENTION 
This invention relates to a space heater. 
According to the present invention there is provided a space heater with a 
water boiler and a cooking unit comprising, a solid fuel combustion 
appliance including an upwardly elongated combustion chamber having fire 
bars at its lower end, for supporting a fire bed, a first flue for 
transferring heat to the water boiler and a second flue, in parallel with 
and adjacent to the first flue and the elongated combustion chamber for 
transferring heat to the cooking unit. The flues both have upstream ends 
positioned below the fire bars with the combustion chamber communicating 
with the upstream end of the flues by transverse paths in an ash pit area 
below the fire bars. The paths are provided for the gaseous products of 
combustion, along which, in normal use of the space heater, the gaseous 
products of combustion flow from the combustion chamber downwardly through 
the fire bed to a position below the fire bars. First and second dampers 
are operable to control the flow of the gaseous products of combustion 
through the first and second flues, respectively. The combustion chamber 
comprises upwardly elongated hollow side walls provided with an adjustable 
natural draft air inlet and with a plurality of downwardly directed spaced 
air outlets for discharging heated air downwardly and evenly into the 
combustion chamber above the fire bed offset from the natural air draft 
inlet. 
The space heater is operated on solid fuel, e.g. coke or coal, and the 
lower part of the combustion chamber is lined with, refractory bricks and 
an ash pit is provided below the combustion chamber. A secondary air 
supply is preferably provided which is fed to a space below the fire bars. 
For an understanding of the principles of the invention, reference will now 
be made to a typical embodiment thereof as illustrated in the accompanying 
drawings.

Referring to the drawings, the combination heater there shown incorporates 
a combustion appliance which is adapted to heat a water boiler to provide 
a hot water supply as well as to heat air for space heating and for 
cooking. The heater comprises a cast iron combustion chamber having hollow 
side cheeks or upwardly elongated hollow side walls 11 with a plurality of 
openings or downwardly directed air outlets 12 into the combustion 
chamber. The lower part of the combustion chamber 10 is provided with fire 
bars 14 and a refractory brick lining 15 supporting a fire bed 13. A 
conventional ash pit bin 16 is provided beneath the fire bars 14 and 
access to the ash pit bin 16 is provided through an ash pit door 17. 
A first flue 18 open to atmosphere is provided which is open at its bottom 
or upstream end 19 to the ash pit area beneath the fire bars 14. 
A fueling lid 21 is provided at the top of the combustion chamber 10. A 
water boiler 22 is provided beside the flue 18, the boiler 22 having 
conventional tappings 23 and 24. On the exterior surface of the heater 
there is provided a plurality of cooling fins 26 which serve to heat air 
for space heating purposes. 
An adjustable air inlet 25 is provided which allows air to flow in a 
controlled manner into the hollow side cheeks 11 and thence, following 
heating in said side cheeks 11, to flow into the combustion chamber 10. 
It will be readily understood that the supply of air--primary air--from the 
hollow side cheeks 11 enters the combustion chamber 10 above the firebed 
13, and due to the location of the openings 12 the distribution of the 
primary air is dispersed around the sides of the combustion chamber 10. 
The interior surfaces of the combustion chamber 10 may be ribbed and/or 
grooved to improve mixing of the primary air at different levels in or 
above the firebed 13. 
A secondary air supply is available to the firebed 13 under natural draught 
from the ash pit area. The secondary air supply comprises one or more air 
inlets 17a in the perimeter of the ash pit area. It is to be understood, 
however, that in this construction of space heater the primary air control 
means 25 allows air only into the hollow side cheeks 11 and hence to the 
combustion chamber 10 through the openings 12. 
The flue 18 which is located at the rear of the combustion chamber 10 is 
open to atmosphere at its upper end and is open to the ash pit area 16 at 
its bottom end. 
Gas flow in the flue 18 is controlled by means of a boiler or first damper 
27 mounted in a smokehood 28. The boiler damper 27 has a cut-out portion 
to prevent full closure of the flue 18. An oven or second flue 29 is 
provided at one side of the combustion chamber 10, the oven flue 29 being 
open at its bottom or upstream end 30 to the ash pit area 16. 
The cooker unit comprises an oven/hotplate assembly indicated generally at 
31 and is located adjacent the flue 29. This assembly 31 comprises a base 
plate 32 with an upstanding edge which is adapted to receive and locate a 
front plate and a rear plate (not shown) and side plates 34 and 35 of the 
oven/hotplate assembly 31. The oven/hotplate assembly 31 comprises a main 
oven 36, a smaller lower oven 37 and a hotplate 39. The rear plate is 
extended sideways to form a rear ball for the oven flue 29 and separate it 
from flue 18. Similarly an oven top plate 38 extends sideways to enclose 
the oven flue 29 and is provided with a rectangular opening 40, 
approximately 11".times.21/2", which, in use, admits hot gases to the 
front section of a space 42 at the underside of the hot plate 39. The hot 
plate 39 is disposed over the oven top plate 38. As described below, the 
front section is defined on one side by a vertical wall 44. A 3/8" gap 
between the hotplate 39 and a cooker top plate 41 is sealed by woven 
asbestos rope. The space 42 between the oven top plate 38 and the hotplate 
39 is 21/2" deep and is closed all round by a vertical wall except for a 
gas outlet 43 which gives access to the smokehood 28. 
The vertical wall 44 divides the space 42 into two sections, a front 
section and a rear section, along most of its major axis. A cleaning plug 
is provided at 45 in the hotplate where the wall 44 terminates and where, 
in use, the gases change direction through 180.degree. and return through 
the rear section. The cooker top plate 41 locates and secures the top 
edges of the front plate, the rear plate and the side plates 34 and 35 of 
the oven/hotplate assembly 31. A metal closure plate (not shown) is 
provided and is hinged in conventional manner to the cooker top plate 41 
at its rear, the metal closure plate being adapted to enclose the entire 
top of the oven/hotplate assembly 31 and to serve as a splash-back when 
open. When open the metal closure plate may be held in an upright position 
by means of a detent fitted to the smokehood 28. The front plate carries 
two oven doors, of which the upper is thermally insulated and is provided 
with a thermometer. The front plate is extended at one side to enclose the 
front of the oven flue 29 and to form a joint with the combustion chamber 
10. The part of the front plate which encloses the oven flue 29 is 
provided with a layer of suitable rigid thermally insulating material. 
The left-hand side of the combustion chamber 10 as viewed in FIG. 2 
consists of a steel plate which has a 1" layer of mineral fibre thermally 
insulating material adjacent the inwardly-facing surfaces of the steel 
plate. A 1/2" layer of rigid insulating material is provided between the 
layer of mineral fibre and the steel plate of the combustion chamber 10. 
The side of the combustion chamber 10 adjoining the oven/hotplate assembly 
31 is also provided with a 1/2" layer of rigid thermally insulating 
material. 
The smokehood 28 is mounted on the combustion chamber 10 above its top 
plate 47 and has a rear section 48 and a front section 49 separated from 
each other by a vertical wall 50. A rear section 48 of the smokehood 28 
surmounts the boiler flue 18 and the boiler damper 27 is situated in the 
section 48 and rotates about the major axis of the section. The front 
section 49 of the smokehood 28 communicates with outlet 43 and the opening 
10a. A rotary oven or second damper 51 mounted in the smokehood 28 
controls the flow of gases in the oven flue 29. A sliding damper 52 
controls the opening 10a and determines whether the gases from the 
combustion chamber 10 pass directly into the front section 49 or whether 
the gases pass downwardly through the fire bed in the flues 18 and 29. 
Normally, the damper 52 is closed as shown in FIG. 3. 
The smokehood 28 has a short extension at the side nearest the 
oven/hotplate assembly 31, which extension connects with the gas outlet 43 
from the hotplate 39. By bolting this extension to the cooker top plate 41 
and by using one connecting bolt or clip at the level of the base plate 32 
secures the combustion chamber 10 and the oven/hotplate assembly are 
secured together. 
In operation with the sliding damper 52 in its closed position and the 
dampers 27 and 51 open, down-firing occurs in the combustion chamber 10. 
Hot gases pass from the chamber 10 into the flues 18 and 29. Hot gases in 
the oven flue 29 heat the small lower oven 37 by limited conduction. Hot 
gases heat cheeks 53 located in the side plate 34 of the main oven 36, by 
conduction. Within the oven 36, hot air, heated by convection, circulates 
by way of a plurality of openings 54 and in this way the centre of the 
main oven 36 is heated. Hot gases in the flue 29 then rise through the 
opening 40 and pass through the front section of space 42 between the 
hotplate 39 and the top plate 38, turn through 180.degree. at the end of 
the wall 44, and then return through the rear section of the space 42 to 
be discharged into the smokehood 28, upstream of the dampers 1 by way of 
the gas outlet 43. When the sliding damper 52 and the oven damper 51 are 
closed, hot gases enter the boiler flue 18 preferentially. The fact that 
the oven damper 51 may be completely closed, coupled with the presence of 
rigid thermally insulating material at the side of the combustion chamber 
10 nearest the oven/hotplate assembly, means that the aforesaid assembly 
31 may be virtually cut off from the source of heat. The flow of hot gases 
to the boiler may be controlled by virtue of the rotary damper 27, however 
this damper 27 cannot completely close the section 48 since it has a 
cut-out portion. Hence boiler output will always be sufficient to maintain 
a supply of domestic hot water. 
The advantages of this arrangement include the capacity to reduce boiler 
output to the minimum required for domestic hot water while maintaining 
satisfactory oven and hotplate temperatures and the capacity to use the 
boiler independently of the oven/hotplate assembly, such that full boiler 
output may be attained as desired without necessarily supplying heat to 
the oven/hotplate assembly. 
The combination heater also has the great advantage that the combustion 
chamber of the above embodiment normally operates on the principle of 
downfiring, wherein volatile materials resulting from the incomplete 
combustion of fuel may be prevented from escaping from the combustion 
chamber 10 directly into the flue through the opening 10a. Instead, by 
closing the damper 52 the volatile materials must leave the combustion 
chamber by way of the fire bed and ash pit area and then pass to the flue 
18 and/or flue 29 and into the smoke box 28 and accordingly are more 
extensively burned, thereby resulting in a more efficient use of the fuel 
employed in the combustion chamber. This system of combustion permits a 
greater depth of fuel above the barebars 14 in addition to bringing about 
a more efficient use of the fuel. Down-firing in the combustion chamber is 
assisted and improved by the pre-heating of primary air within the hollow 
side cheeks 11 which distribute the air around and at different levels 
within the combustion chamber, by means of the downwardly inclined 
openings 12. 
While a specific embodiment of the invention has been shown and described 
in detail to illustrate the application of the principles of the 
invention, it should be understood that the invention may be embodied 
otherwise without departing from such principles.