CA1166911A - Furnace - Google Patents
FurnaceInfo
- Publication number
- CA1166911A CA1166911A CA000377744A CA377744A CA1166911A CA 1166911 A CA1166911 A CA 1166911A CA 000377744 A CA000377744 A CA 000377744A CA 377744 A CA377744 A CA 377744A CA 1166911 A CA1166911 A CA 1166911A
- Authority
- CA
- Canada
- Prior art keywords
- combustion chamber
- firebox
- inlet means
- chamber
- air
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24B—DOMESTIC STOVES OR RANGES FOR SOLID FUELS; IMPLEMENTS FOR USE IN CONNECTION WITH STOVES OR RANGES
- F24B5/00—Combustion-air or flue-gas circulation in or around stoves or ranges
- F24B5/02—Combustion-air or flue-gas circulation in or around stoves or ranges in or around stoves
- F24B5/021—Combustion-air or flue-gas circulation in or around stoves or ranges in or around stoves combustion-air circulation
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24B—DOMESTIC STOVES OR RANGES FOR SOLID FUELS; IMPLEMENTS FOR USE IN CONNECTION WITH STOVES OR RANGES
- F24B1/00—Stoves or ranges
- F24B1/02—Closed stoves
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Air Supply (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A firebox for a furnace comprising a casing having a combustion chamber with an opening for charging fuel; first inlet means from the combustion chamber for a flue passage, said first inlet means being adjacent the top of the combustion chamber;
second inlet means from the combustion chamber for a flue passage, said second inlet means being disposed lower than said first inlet means; and supply passage means for combustion air to said combus-tion chamber having an entry opening to said combustion chamber that is higher than said second inlet means for said flue passage.
A firebox for a furnace comprising a casing having a combustion chamber with an opening for charging fuel; first inlet means from the combustion chamber for a flue passage, said first inlet means being adjacent the top of the combustion chamber;
second inlet means from the combustion chamber for a flue passage, said second inlet means being disposed lower than said first inlet means; and supply passage means for combustion air to said combus-tion chamber having an entry opening to said combustion chamber that is higher than said second inlet means for said flue passage.
Description
This invention relates to a hot air furnace that has a firebox with an improved combustion air circulating system.
The improved firebox of this invention is especially suit-ed for use with a furnace for heating room air in a situation where it is mounted in the room to be heated although it is not intended that the scope of the invention be restricted to such furnaces.
Furnace designs are legion. Basically, most of them were devices to achieve the objectives of good capacity and good efficiency.
The purpose of this invention is to provide an improved firebox whereby to achieve these objectives.
The furnace with a firebox of this invention achieves good efficiency, good heating capacity for its size, and is economic to build. It is unique in respect of the design of the combustion air circulating system that it incorporates, a feature that gives ; it special advantage in achieving its objectives in use.
A furnace according to the invention comprises a firebox for a furnace comprising a casing ha~Ting a combustion chamber with an opening fox charging fuel; first inlet means from the combustion chamber for a flue passage, said first inlet means being adjacent the top of the combustion chamber; second inlet means from the com-bustion chamber for a flue passage, said second inlet means being disposed lower than said first inlet means; and suppl~ passage means for combustion air to said combustion chamber having an~ntry open-ing to said combustion chamber that is higher than said second in let means for said flue passage. The invention will be clearly understood after reference to the following detailed specification read in conj~nction with the drawings.
,
The improved firebox of this invention is especially suit-ed for use with a furnace for heating room air in a situation where it is mounted in the room to be heated although it is not intended that the scope of the invention be restricted to such furnaces.
Furnace designs are legion. Basically, most of them were devices to achieve the objectives of good capacity and good efficiency.
The purpose of this invention is to provide an improved firebox whereby to achieve these objectives.
The furnace with a firebox of this invention achieves good efficiency, good heating capacity for its size, and is economic to build. It is unique in respect of the design of the combustion air circulating system that it incorporates, a feature that gives ; it special advantage in achieving its objectives in use.
A furnace according to the invention comprises a firebox for a furnace comprising a casing ha~Ting a combustion chamber with an opening fox charging fuel; first inlet means from the combustion chamber for a flue passage, said first inlet means being adjacent the top of the combustion chamber; second inlet means from the com-bustion chamber for a flue passage, said second inlet means being disposed lower than said first inlet means; and suppl~ passage means for combustion air to said combustion chamber having an~ntry open-ing to said combustion chamber that is higher than said second in let means for said flue passage. The invention will be clearly understood after reference to the following detailed specification read in conj~nction with the drawings.
,
-2~
~ .
In the drawings:
Figure 1 is a view of a furnace showing the exterior cabinet and the location of the firebox therein in broken lines;
Figure 2 is an illustration of the firebox, partly broken away to show construction, with the cabinet in broken lines; and Figure 3 is a view along the line 3-3 of Figure 1.
The furnace illustrated has an exterior cabinet 10 within which is mounted a firehox 12. The general operation of the furnace is similar to all furnaces of its general type. Air to be heated is admitted to the space between the cabinet and the firebox;
becomes heated by reason of its heat exchange relation with the firebox within which a fire is maintained; and leaves the space in heated condition.
In the furnace illustrated air is admitted to the space either through openings like cabinet opening 14 or through openings like the grill openings 16. Openings like opening 14 are designed for connection to a cold air pipe for conducting air tc be heated from a more remote location. Openinqs like opening 16 take in room air from the immediate area of the furnace. Heated air leaves ~0 the inter-cabinet firebox space through grill openings 18. No fan forcing of the heated air is necessary in the embodiment of the invention illustrated but it could be incorporated.
The circulation of air to be heated through a hot air furnace is capable of wide variation and those versed in the art will be able to vary the means shown. Further or more detailed reference will not be made to it in this application because the novelty o~ the invention resides in the firebox.
~ .
In the drawings:
Figure 1 is a view of a furnace showing the exterior cabinet and the location of the firebox therein in broken lines;
Figure 2 is an illustration of the firebox, partly broken away to show construction, with the cabinet in broken lines; and Figure 3 is a view along the line 3-3 of Figure 1.
The furnace illustrated has an exterior cabinet 10 within which is mounted a firehox 12. The general operation of the furnace is similar to all furnaces of its general type. Air to be heated is admitted to the space between the cabinet and the firebox;
becomes heated by reason of its heat exchange relation with the firebox within which a fire is maintained; and leaves the space in heated condition.
In the furnace illustrated air is admitted to the space either through openings like cabinet opening 14 or through openings like the grill openings 16. Openings like opening 14 are designed for connection to a cold air pipe for conducting air tc be heated from a more remote location. Openinqs like opening 16 take in room air from the immediate area of the furnace. Heated air leaves ~0 the inter-cabinet firebox space through grill openings 18. No fan forcing of the heated air is necessary in the embodiment of the invention illustrated but it could be incorporated.
The circulation of air to be heated through a hot air furnace is capable of wide variation and those versed in the art will be able to vary the means shown. Further or more detailed reference will not be made to it in this application because the novelty o~ the invention resides in the firebox.
-3-.. . .
~ ~ 6~3~ ~
The invention is more concerned with the circulation of the combustion air and the design of the firebox 12 to achieve it.
The casing 12 is fabricated from stainless steel and has a combustion chamber 20 to which combustion air is admitted through air supply openings 22, and from which the gaseous products of com-bustion are evacuated through a flue 24 that has a first inlet open-ing 2~ and second inlet means comprising two openings 28.
~ ombustion air is admitted to chamber 20 through openings 22 by way of a series of baffles and ducts that preheat it prior to admission. Air from underneath the cabinet travels through open-ing 30 in the bottom of the cabinet and firebox; towards the front of the firebox between the base plate of the firebox and baffle 32;
upwardly through openings 34 in baffle 30, towards the rear of the firebox between baffle 32 and baffle 36 through openings 3~ in baffle 36; towards the front and across the firebox betw~en baffle 36 and the firebox bottom to the inlets of vertical ducts 40;
across horizontal duct 42 ancl out openings 22 into the co~ustion chamber~ When there is a fire malntained in the firebox the air becomes preheated prior to its delivery to the combustion chamber as it travels this path.
The location of the air entry port on the bottom of the firebox and the extent of the tortuous preheating path is variable and would be varied from model to model to achieve proper air entry under operating conditions. These things are capable of variation by a person skilled in the art.
The location of the flue inlets in the firebox is signif-icant. Inlet 26 is at the top of the fire chamber and of itself , ~ , .
t ~ S6~ 1 1 is conventionally located. However/ it is combined with inlets 28 which are located below inlet 26 and below air inlets 22.
Flue 24 has a damper 44 operable within the flue by means of a rotatable handle 46 that is journalled in link member 48. By rotating the handle the damper can be operated between the open position of Figure 1 and the closed position of Figure 2. The handle can also be raised and lowered within the guide brackets 50 to cause the free end of link 52 to engage in slots 54 in the doors 56 to lock the doors in a closed position.
Doors 56 are hinged to a moulding around the door opening of the cabinet as at 58.
The firebox will commonly burn wood and to load the fire-box and ignite it one opens the doors, loads the firebox, sets the dampers, lights the fire and closes the doors. In the begin-ning one would adjust damper 44 fully open to get maximum draft on fire start-up.
As the fire gains in intensity and the firebox becomes hotter, damper 44 is closed gradually. On full fire it will, under many draft conditions, be fully closed. As damper 44 is gradually moved towards the closed position a ~reater percentage of the flue gases leave through ducts 280 The combustion air enters the fire-box through inlet 22, is burned in the firebox as it travels down-wardly and the products of combustion leave through the ducts 28 the inlets to which are below the level of the air inlet 22. This circulation of preheated air can be maintained and results in a very efficient unit. The unit illustrated has a 30 inch firebox and has a heating range of between 30,000 and 100,000 BTU's depend-~-J 5-~ 3 ~6~ t t ing on the fuel loading and damper operation. The highest ~ire operation will be with damper 44 open because this would give maxi-mum drat. The lowest fire operation would be with damper 44 closed.
The height of the ducts 28 from the bottom o~ the firebox is variable Erom about 4 inches from the bottom to almost the top o~ the firebo~ but it has been found that best efficiencies in the 30 inch fi~ebox illustrated are achieved when the height is about 6 inches from the bottom of the firebox. The top of the pile of wood being burned is usually higher than the level of th~ bottom of the duct openings 28.
The design of the combustion air supply passage will vary and must have a resistance to flow that will provide for an adequate supply of air to chamber 20 with the vent 26 closed to maintain a low fire. The size from model to model will vary.
The firebox is illwstrated in a cabinet but it is contem-plated that the firebox may be used without the cabinet. It could, for example, be incorporated into the masonry of a fireplace either with or without doors to the fire chamber.
The air to be heated in the embodiment illustrated is supplied through opening 14 or openings 16 depending upon operation, but in most cases it would not be supplied through ~oth openings.
In many cases air supplied through opening 14 would be supplied through a duct leading from outside of the building. Thus, the heated air in each case would be outside air. If openings 16 are used for air to be heated, openings 14 would be closed and visa versa.
Similarly, the combustion air that enters through the open-ings 30 in the bottom of the firebox can be taken from the room ~ 3 ~6~ ~ ~
or from outside of the building. It is preferable to take combus-tion air from outside the building.
Embodiments of the invention other than the one illus-trated will be apparent to those skilled in the art.
~ ~ 6~3~ ~
The invention is more concerned with the circulation of the combustion air and the design of the firebox 12 to achieve it.
The casing 12 is fabricated from stainless steel and has a combustion chamber 20 to which combustion air is admitted through air supply openings 22, and from which the gaseous products of com-bustion are evacuated through a flue 24 that has a first inlet open-ing 2~ and second inlet means comprising two openings 28.
~ ombustion air is admitted to chamber 20 through openings 22 by way of a series of baffles and ducts that preheat it prior to admission. Air from underneath the cabinet travels through open-ing 30 in the bottom of the cabinet and firebox; towards the front of the firebox between the base plate of the firebox and baffle 32;
upwardly through openings 34 in baffle 30, towards the rear of the firebox between baffle 32 and baffle 36 through openings 3~ in baffle 36; towards the front and across the firebox betw~en baffle 36 and the firebox bottom to the inlets of vertical ducts 40;
across horizontal duct 42 ancl out openings 22 into the co~ustion chamber~ When there is a fire malntained in the firebox the air becomes preheated prior to its delivery to the combustion chamber as it travels this path.
The location of the air entry port on the bottom of the firebox and the extent of the tortuous preheating path is variable and would be varied from model to model to achieve proper air entry under operating conditions. These things are capable of variation by a person skilled in the art.
The location of the flue inlets in the firebox is signif-icant. Inlet 26 is at the top of the fire chamber and of itself , ~ , .
t ~ S6~ 1 1 is conventionally located. However/ it is combined with inlets 28 which are located below inlet 26 and below air inlets 22.
Flue 24 has a damper 44 operable within the flue by means of a rotatable handle 46 that is journalled in link member 48. By rotating the handle the damper can be operated between the open position of Figure 1 and the closed position of Figure 2. The handle can also be raised and lowered within the guide brackets 50 to cause the free end of link 52 to engage in slots 54 in the doors 56 to lock the doors in a closed position.
Doors 56 are hinged to a moulding around the door opening of the cabinet as at 58.
The firebox will commonly burn wood and to load the fire-box and ignite it one opens the doors, loads the firebox, sets the dampers, lights the fire and closes the doors. In the begin-ning one would adjust damper 44 fully open to get maximum draft on fire start-up.
As the fire gains in intensity and the firebox becomes hotter, damper 44 is closed gradually. On full fire it will, under many draft conditions, be fully closed. As damper 44 is gradually moved towards the closed position a ~reater percentage of the flue gases leave through ducts 280 The combustion air enters the fire-box through inlet 22, is burned in the firebox as it travels down-wardly and the products of combustion leave through the ducts 28 the inlets to which are below the level of the air inlet 22. This circulation of preheated air can be maintained and results in a very efficient unit. The unit illustrated has a 30 inch firebox and has a heating range of between 30,000 and 100,000 BTU's depend-~-J 5-~ 3 ~6~ t t ing on the fuel loading and damper operation. The highest ~ire operation will be with damper 44 open because this would give maxi-mum drat. The lowest fire operation would be with damper 44 closed.
The height of the ducts 28 from the bottom o~ the firebox is variable Erom about 4 inches from the bottom to almost the top o~ the firebo~ but it has been found that best efficiencies in the 30 inch fi~ebox illustrated are achieved when the height is about 6 inches from the bottom of the firebox. The top of the pile of wood being burned is usually higher than the level of th~ bottom of the duct openings 28.
The design of the combustion air supply passage will vary and must have a resistance to flow that will provide for an adequate supply of air to chamber 20 with the vent 26 closed to maintain a low fire. The size from model to model will vary.
The firebox is illwstrated in a cabinet but it is contem-plated that the firebox may be used without the cabinet. It could, for example, be incorporated into the masonry of a fireplace either with or without doors to the fire chamber.
The air to be heated in the embodiment illustrated is supplied through opening 14 or openings 16 depending upon operation, but in most cases it would not be supplied through ~oth openings.
In many cases air supplied through opening 14 would be supplied through a duct leading from outside of the building. Thus, the heated air in each case would be outside air. If openings 16 are used for air to be heated, openings 14 would be closed and visa versa.
Similarly, the combustion air that enters through the open-ings 30 in the bottom of the firebox can be taken from the room ~ 3 ~6~ ~ ~
or from outside of the building. It is preferable to take combus-tion air from outside the building.
Embodiments of the invention other than the one illus-trated will be apparent to those skilled in the art.
Claims (4)
1. A firebox for a furnace comprising a casing having:
a combustion chamber with an opening for charging fuel;
a flue passage from said combustion chamber;
said flue passage having first inlet means from said com-bustion chamber disposed adjacent the top of said combustion chamber;
means for damping flow of flue gas through said first in-let means;
said flue passage having second inlet means from said combustion chamber disposed lower than said first inlet means;
supply passage means for combustion air to said combus-tion chamber having an entry opening to said combustion chamber higher than said second inlet means to said flue;
said supply passage means for combustion air being in heat exchange relation to the combustion chamber in use whereby to preheat combustion air prior to its entry to the combustion chamber in use;
said supply passage commencing under the combustion chamber and traversing the underside of the fire chamber.
a combustion chamber with an opening for charging fuel;
a flue passage from said combustion chamber;
said flue passage having first inlet means from said com-bustion chamber disposed adjacent the top of said combustion chamber;
means for damping flow of flue gas through said first in-let means;
said flue passage having second inlet means from said combustion chamber disposed lower than said first inlet means;
supply passage means for combustion air to said combus-tion chamber having an entry opening to said combustion chamber higher than said second inlet means to said flue;
said supply passage means for combustion air being in heat exchange relation to the combustion chamber in use whereby to preheat combustion air prior to its entry to the combustion chamber in use;
said supply passage commencing under the combustion chamber and traversing the underside of the fire chamber.
2. A firebox for a furnace as claimed in Claim 1 having a cabinet, said firebox being mounted within the cabinet in spaced relation thereto, and means for circulating air to be heated through the space between the cabinet and firebox in heat exchange relation to the firebox.
3. A firebox as claimed in Claim 1 having a door for said opening in said firebox.
4. A firebox for a furnace comprising a casing having a combustion chamber with an opening for charging fuel;
first inlet means from the combustion chamber for a flue passage, said first inlet means being adjacent the top of the com-bustion chamber;
second inlet means from the combustion chamber for a flue passage, said second inlet means being disposed lower than said first inlet means;
supply passage means for combustion air to said combustion chamber having an entry opening to said combustion chamber that is higher than said second inlet means for said flue passage;
said supply passage means for combustion air being in heat exchange relation to the combustion chamber in use whereby to preheat combustion air prior to its entry to the combustion chamber in use;
said supply passage commencing under the combustion chamber and traversing the underside of said fire chamber.
first inlet means from the combustion chamber for a flue passage, said first inlet means being adjacent the top of the com-bustion chamber;
second inlet means from the combustion chamber for a flue passage, said second inlet means being disposed lower than said first inlet means;
supply passage means for combustion air to said combustion chamber having an entry opening to said combustion chamber that is higher than said second inlet means for said flue passage;
said supply passage means for combustion air being in heat exchange relation to the combustion chamber in use whereby to preheat combustion air prior to its entry to the combustion chamber in use;
said supply passage commencing under the combustion chamber and traversing the underside of said fire chamber.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000377744A CA1166911A (en) | 1981-05-15 | 1981-05-15 | Furnace |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000377744A CA1166911A (en) | 1981-05-15 | 1981-05-15 | Furnace |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1166911A true CA1166911A (en) | 1984-05-08 |
Family
ID=4119973
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000377744A Expired CA1166911A (en) | 1981-05-15 | 1981-05-15 | Furnace |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1166911A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4621610A (en) * | 1985-01-31 | 1986-11-11 | Tomooka Walter K | Solid fuel heating apparatus |
| WO1992014972A1 (en) * | 1991-02-14 | 1992-09-03 | Jonathan Greenall | A solid fuel heating stove |
| US5657742A (en) * | 1993-03-05 | 1997-08-19 | Greenall; Jonathan | Solid fuel heating device |
-
1981
- 1981-05-15 CA CA000377744A patent/CA1166911A/en not_active Expired
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4621610A (en) * | 1985-01-31 | 1986-11-11 | Tomooka Walter K | Solid fuel heating apparatus |
| WO1992014972A1 (en) * | 1991-02-14 | 1992-09-03 | Jonathan Greenall | A solid fuel heating stove |
| AU661673B2 (en) * | 1991-02-14 | 1995-08-03 | Jonathan Greenall | A solid fuel heating stove |
| US5469836A (en) * | 1991-02-14 | 1995-11-28 | Greenall; Jonathan | Solid fuel heating appliance |
| US5657742A (en) * | 1993-03-05 | 1997-08-19 | Greenall; Jonathan | Solid fuel heating device |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |