CA1046370A - Space heaters - Google Patents

Abstract

ABSTRACT

A space heater having 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 may incorporate a water boiler and/or 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.

Description

:10~370 This invention relates to a space heat-~r.
According to the present invention there is provided a space heater comprising a combustion appliance which includes combustion chamber having a burner and a flue open to atmosphere, the combustion chamber having one or more hollow side cheeks operatively associated with air control means and provided with one or more openings for the supply of air from the hollow side cheeks into the combustion chamber at a level above the burner.
Preferably the space heater is operated on solid fuel, e.g. ~ -coke or coal, and the burner comprises a conventional firebed with fire bars, refractory bricks and an ash pit. The flue is open to the area below the fire bars and to the top of the combustion chamber, when a damper provided in the top of the com-bustion chamber is open. When the damper is closed the flow of combustion products is through the fire bars to the flue. A
.
secondary air supply i8 preferably allowed, the secondary air `
, supply being fed to the firebed from below the fire bars.
In one embodiment of the invention the heater incorporates a water boiler arranged to be heated by combustion products in ~ the flue. In a second embodiment of the invention, two flues are provided and the heater comprises a water boiler and a coo~er unit which are arranged to be heated by respective flues, each flue having a separate damper whereby the flow of combustion products through each may be controlled. In each case, the space heater is provided with a plurality of fins on its exterior surface to give efficient heating of air for space heating purposes.
Embodiments of the invention will now be described by way of example, with reference to the accompanying drawings, in ~30 which:
. . .:
--1-- .
- - ~fi '' ', ' , 104~ 0 Fig. 1 is a side view in vertical section, of a first embodiment of the invention, Fig. 2 is a front view, in vertical section, of a second embodiment of the invention, and Fig. 3 is a diagrammatic representation of a system of dampers used in the heater of Fig. 2.
Referring to Fig. 1 of the drawings, the space 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. The heater comprises a cast iron combustion chamber 10 having hollow side cheeks 11 with a plurality of openings 12 into the combustion chamber. A firebed 13 is provided having fire bars 14 and a refractory brick lining 15. 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 flue 18 open to atmosphere is provided which is open at its bottom end 19 to the ash pit area beneath the fire bars 14.

The flue 18 also connects to the top of the combustion chamber 10 via a damper 20 pivotally mounted on a bracket 20a. When the damper is in the raised or open position - as shown in the drawing, the flow of combustion products from the combustion chamber 10 is directly past the damper 20 into the flue 18. When the damper 20 is closed the flow of combustion products is through the firebed to the ash pit area to the bottom 19 of the flue 18.
A fuelling lid 21 is provided at the top of the combustion chamber 10. Further, 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 10~70 1 plurality of cooling fins 26 which serve to heat air for space heating purposes.
An adjustable air control 25 is provided which allows air into the hollow side cheeks 11 and hence following heating in said side cheeks 11, into the combustion chamber 10.
It will be readily understood that under normal working conditions the supply of air - primary air - from the hollow side cheeks 11 enters the combustion chamber 10 above the firebed, and .
due to the location of the openings 12 the distribution of the primary air is radially around the combustion chamber 10. The interior surfaces of the combustion.chamber 10 may be ribbed and/
or striated to achieve mixing o the primary air at different levels in or above the firebed 13.
A secondary air supply is available to the said firebed 13 under natural draught from the ash pit area. It is to be under-stood, 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 action of the damper 20 controls the flow of combustion products to the flue 18 as previously described and hence controls the heat available to the boiler 22 and the fins 26.
The combustion chamber of the above embodiment operates on the principle of down-firing, wherein volatile materials resulting : :
from the incomplete combustion of fuel may be prevented from escaping from the combustion chamber, by way of a conventional upwardly located chimney, by means of the damper arrangement 20.
Instead, the volatile materials must leave the combustion chamber . by way of the firebed and ash pit area and thence to the flue and accordingly are more extensively combusted, thereby resulting in -.. :

.

.
, . : . .

104~70 1 a more efficient use of the fuel employed in the combustion chamber. This system of combustion permits a greater depth of fuel above the firebed 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 radially and at different levels within the combustion chamber.
A second embodiment of the invention will now be described with reference to Figs. 2 and 3, in which the combustion appliance is adapted to heat air for supplying heat to a cooker unit, in addition to heating a water boiler to provide a hot water supply and to heating air for space heating.
As before, the heater incorporates a combustion appliance which comprises a cast iron combustion chamber 10 having hollow side cheeks 11 with a plurality of openings 12 leading into the combustion chamber 10. A fire bed 13 is provided having fire bars 14 and a refractory brick lining 15. A conventional ash pit area 16 is provided beneath the fire bars 14. A flue 18 is provided at the rear of the combustion chamber 10 and is open to atmosphere at its upper end and is open to the ash pit area 16 at its bottom end. These parts are similar to those parts of Fig. 1 having the same reference numerals.
Gas flow in the flue 18 is controlled by means of a boiler damper 27 mounted in a smokehood 28. The boiler damper 27 has a permanently open area to prevent full closure of the flue 18. An oven flue 29 is provided at one side of the combustion chamber 10, the oven flue 29 being open at its bottom end 30 to the ash pit area 16.

An oven/hotplate assembly indicated generally at 31 is located adjacent the flue 29 and comprises a base plate 32 with 3~0 1 an upstand which is adapted to receive and enclose 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 perimeter for the oven flue 29, similarly an oven top plate 38 extends sideways to enclose the oven flue 29 and is provided with a rectangular opening 40, approximately 11" x 2 1/2", which, in use, admits hot gases to the underside of the front of the hotplate 39, the hotplate 39 resting on the oven top plate 38. A 3/8"
gap between the hotplate 39 and a cooker top plate 41 is sealed by woven asbestos rope. A 2 1/2" space 42 between the oven top plate 38 and the hotplate 39 is closed all round by a vertical wall except for a gas outlet 43 which gives access to the smokehood 28.
A similar vertical wall 44 divides the space 42 into two sections along most of its major axis. A cleaning plug is pro-vided at 45 where the wall 44 terminates and where, in use, the gases change direction through 180. The cooker top plate 41 encloses 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 insulated and is provided with a thermometer. The front plate is extended at one side to enclose the front of the ' ~04~'70 1 oven flue 29 and to form a joint with the combustion chamber.
The part of the front plate which encloses the oven flue 29 is provided with a layer of suitable rigid insulating material.
The external side of the combustion chamber 10 consists of a steel metal plate which has a 1" layer of mineral fibre insulating material adjacent thereto. A 1/2" layer of rigid insulating material is provided between the layer of mineral fibre and the inner wall 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 insulating material. A steel boiler is welded at the rear of the combustion chamber 10 by means of base and top castings provided on said combustion chamber 10.
The smokehood 28 is mounted on the combustion chamber 10 at its top plate 47. A rear section 48 of the smokehood 28 surmounts the boiler flue 18 and the boiler damper 27 is situated in the opening of said flue 18 and rotates about the major axis of the opening. A front section 49 of the smokehood 28 surmounts the oven flue 29 and is separated from the rear section 48 thereof by a vertical wall 50. A rotary oven damper 51 mounted in the smokehood 28 controls the flow of gases in the oven flue 29. A sliding damper 52 situated below the rotary oven damper 51 controls up- and down- firing in the combustion chamber 10.
The smokehood 28 has a short extension at the side nearest the oven/hotplate assembly 31, said extension connects with the gas outlet 43. Bolting this extension to the cooker top plate 41 together with one connecting bolt or clip at the base plate 32 secures the combustion chamber 10 and the oven/hotplate assembly together.

~C~4~370 1 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 center of the main oven 36 is heated. Hot gases in the flue 29 then rise through the opening 40 and pass under the hotplate 39 and over the top plate 38 returning through 180 about the wall 44 to be discharged into the smokehood 28 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 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 amount of heat to the boiler may be control-led by virtue of the rotary damper 27, however this damper 27 may not be completely closed. 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 tempera-tures 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.

Claims (6)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A space heater comprising, in combination, a solid fuel combustion appliance, a water boiler and a cooker unit, said combustion appliance comprising an upwardly elongated combustion chamber having firebars 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 said first flue for transferring heat to said cooker unit; said flues having upstream ends positioned below said firebars; said combustion chamber communicating with the upstream end of said flues by paths, 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 said fire bed to a position below said firebars, first and second dampers operable to control the flow of the gaseous products of combustion through said first and second flues, respectively; said combustion chamber having at least one upwardly elongated hollow side wall provided with an adjustable natural draft air inlet and with at least one downwardly directed air outlet for discharging heated air downwardly into said combustion chamber above said fire bed.

2. A space heater according to claim 1, in which said first and second flues have respective downstream ends dis-charging, respectively, into first and second sections of a common smokebox, said first and second sections being separated from each other by a partition.

3. A space heater according to claim 2, in which said combustion chamber has a top wall formed with an opening communicating with said second section of said smokebox;
and a third damper controlling said opening.

4. A space heater according to claim 1, including means for supplying air to said position below said firebars.

5. A space heater according to claim 1, formed with heat-radiating fins on its outer surface.

6. A space heater according to claim 1, in which said cooker unit comprises at least one oven and a hot plate.