Title:
Apparatus for generating heat through burning of solid fuel and method of controlling such an apparatus
Kind Code:
A1


Abstract:
An apparatus for generating heat and consisting of: a) a firebox; b) a combustor assembly; c) a fuel inlet; d) an air inlet through which air is delivered to a combustion location; e) an outlet for releasing heated air; f) an outlet damper assembly; and g) an inlet damper assembly. The inlet and outlet damper assemblies are constructed to both be placed or maintained in safety states in response to the apparatus being placed in certain predetermined states to thereby prevent, or smother, combustion of solid fuel within the apparatus.



Inventors:
Guzorek, Steven E. (Kinston, NC, US)
Application Number:
12/316107
Publication Date:
06/10/2010
Filing Date:
12/09/2008
Primary Class:
Other Classes:
126/99R
International Classes:
F23N5/22; F24H3/00
View Patent Images:



Foreign References:
JPH05223348A1993-08-31
Primary Examiner:
PEREIRO, JORGE ANDRES
Attorney, Agent or Firm:
BGL (CHICAGO, IL, US)
Claims:
1. An apparatus for generating heat in an environmental space, the apparatus comprising: a firebox bounding a space; a combustor assembly for burning solid fuel at a combustion location; a fuel inlet through which solid fuel is delivered from a supply to the combustion location, solid fuel delivered through the solid fuel inlet to the combustion location burned to generate heat in the firebox space; an air inlet through which air is delivered from the environmental space to the combustion location; an outlet for releasing air heated in the firebox space for delivery to the environmental space; an outlet damper assembly having first and second states wherein the outlet damper assembly respectively: a) permits movement of air from the firebox continuously through the outlet for delivery to the environmental space; and b) substantially blocks movement of air from the firebox through the outlet for delivery to the environmental space; an inlet damper assembly having first and second states wherein the inlet damper assembly respectively: a) permits movement of air from the environmental space continuously through the air inlet to the combustion location; and b) substantially blocks movement of air from the environmental space through the air inlet to the combustion location, the inlet and outlet damper assemblies constructed to both be placed or maintained in their second states in response to the apparatus being placed in certain predetermined states to thereby prevent or smother combustion of solid fuel within the apparatus.

2. An apparatus for generating heat in an environmental space according to claim 1 further comprising a control assembly for detecting the certain predetermined states for the apparatus and, as an incident thereof, changing the state of either of the inlet and outlet damper assemblies that is in its first state into its second state.

3. The apparatus for generating heat in an environmental space according to claim 1 in combination with a fuel delivery assembly capable of storing a supply of solid fuel that is delivered through the solid fuel inlet to the combustion chamber.

4. The apparatus for generating heat in an environmental space according to claim 3 wherein at least one of the apparatus and fuel delivery assembly comprises at least one auger for conveying solid fuel from the solid fuel supply towards the combustion location.

5. The apparatus for generating heat in an environmental space according to claim 1 wherein there is a first powered assembly for changing the outlet damper assembly between its first and second states and in the event that power to the apparatus is terminated, the outlet damper assembly is: a) maintained in its second state if the outlet damper assembly is in its second state when power to the apparatus is terminated; and b) changed from its first state into its second state if the outlet damper assembly is in its first state when power to the apparatus is terminated.

6. The apparatus for generating heat in an environmental space according to claim 5 wherein there is a second powered assembly for changing the inlet damper assembly between its first and second states and in the event that power to the apparatus is terminated, the inlet damper assembly is: a) maintained in its second state if the inlet damper assembly is in its second state when power to the apparatus is terminated; and b) changed from its first state into its second state if the inlet damper assembly is in its first state when power to the apparatus is terminated.

7. The apparatus for generating heat in an environmental space according to claim 2 wherein the apparatus further comprises an air flow inducer for causing air to be delivered under pressure to the combustion location and the control assembly causes each of the inlet and outlet damper assemblies to be changed into or maintained in their second states as an incident of detecting that the air flow inducer is either: a) not operating; or b) not causing air to be delivered in at least a predetermined volume to the combustion location.

8. The apparatus for generating heat in an environmental space according to claim 2 wherein the control assembly causes each of the inlet and outlet damper assemblies to be changed into or maintained in their second states as an incident of detecting that the combustor assembly is either: a) not operating; or b) operating below a predetermined capacity.

9. The apparatus for generating heat in an environmental space according to claim 2 wherein there is a first powered assembly for changing the outlet damper assembly between its first and second states and the control assembly causes each of the inlet and outlet damper assemblies to be changed into or maintained in their second states as an incident of detecting that the first powered assembly is not functioning properly.

10. The apparatus for generating heat in an environmental space according to claim 1 wherein the apparatus further comprises an air flow inducer for inducing flow of heated air from the firebox space to and through the outlet.

11. The apparatus for generating heat in an environmental space according to claim 2 wherein the apparatus further comprises an air flow inducer for inducing flow of heated air from the firebox space to and through the outlet and the control assembly causes each of the inlet and outlet damper assemblies to be changed into or maintained in their second states as an incident of detecting that the air flow inducer is either: a) not operating; or b) not causing at least a predetermined volume of heated air to flow from the firebox space to and through the outlet.

12. The apparatus for generating heat in an environmental space according to claim 2 wherein the combustion assembly has on and off states and can be operated at different heat generating levels and the control assembly causes at least one of: a) each of the inlet and outlet damper assemblies to be changed into or maintained in their second states; and b) the combustion assembly to be either: i) changed into its off state; or ii) changed to operate at a different heat generating level as an incident of detecting that a temperature of heated air in the firebox is at least at a predetermined level.

13. The apparatus for generating heat in an environmental space according to claim 3 wherein there is a supply of solid fuel in the fuel delivery assembly that is one of: a) wood; b) corn kernels; and c) pellets.

14. A method of controlling operating of an apparatus for generating heat in an environmental space, the method comprising the steps of: a) providing an apparatus comprising: a firebox; a combustor assembly for burning a solid fuel at a combustion location; an inlet damper assembly having different states; an outlet damper assembly having different states; and a control assembly; and b) configuring the control assembly so that the control assembly causes the inlet and outlet damper assemblies to be placed or maintained in a safety state wherein the outlet damper assembly blocks movement of air heated through combustion of solid fuel from the apparatus and the inlet damper assembly blocks movement of air from the environmental space to the combustion location so as to thereby prevent or smother combustion of solid fuel within the apparatus upon detection of the apparatus being placed in certain predetermined states wherein there is a danger of: i) emission of harmful combustion byproducts from the apparatus to the environmental space due to a slow burning condition; ii) unwanted combustion of solid fuel at a location upstream of where solid fuel is delivered to the combustion location; or iii) overheating of the apparatus.

15. The method of controlling operation of an apparatus for generating heat in an environmental space according to claim 14 wherein the step of configuring the control assembly comprises configuring the control assembly so that the inlet and outlet damper assemblies are caused to be placed in their safety states as an incident of detecting that there is insufficient air delivered to the combustion location for adequate combustion.

16. The method of controlling operation of an apparatus for generating heat in an environmental space according to claim 14 wherein the step of configuring the control assembly comprises configuring the control assembly so that the inlet and outlet damper assemblies are caused to be placed in their safety states as an incident of detecting that operating power to the apparatus has been interrupted or otherwise altered.

17. The method of controlling operation of an apparatus for generating heat in an environmental space according to claim 14 wherein the step of configuring the control assembly comprises configuring the control assembly so that the inlet and outlet damper assemblies are caused to be placed in their safety states as an incident of detecting that a component on the apparatus is malfunctioning.

18. The method of controlling operation of an apparatus for generating heat in an environmental space according to claim 14 wherein the step of configuring the control assembly comprises configuring the control assembly so that the inlet and outlet damper assemblies are caused to be placed in their safety states as an incident of detecting that flow volume of heated air away from the apparatus is below a predetermined amount.

19. The method of controlling operation of an apparatus for generating heat in an environmental space according to claim 14 wherein the step of configuring the control assembly comprises configuring the control assembly so that the inlet and outlet damper assemblies are caused to be placed in their safety states as an incident of detecting that the combustor assembly is either: a) not operating; or b) operating below a predetermined capacity.

20. The method of controlling operation of an apparatus for generating heat in an environmental space according to claim 14 wherein the step of configuring the, control assembly comprises configuring the control assembly so that the inlet and outlet damper assemblies are caused to be placed in their safety states as an incident of detecting that a temperature of air heated in the firebox is at least at a predetermined level.

Description:

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to an apparatus that generates heat through the combustion of a fuel arid, more particularly, to an apparatus that is operated using a solid fuel.

2. Background Art

Solid fuel-burning apparatus are commonly used for purposes of generating heat to control a temperature in a work or living space. Different solid fuels are used for this purpose. As examples, wood chips, corn kernels, pellets, etc. are commonly used as fuels.

In one such apparatus, a firebox bounds a space within which the solid fuel is combusted. Solid fuel from a supply is delivered, as by an auger, to a combustion location within the firebox. Combustion air is delivered under pressure at an appropriate volume to optimize the combustion of the fuel. As the fuel is burned, heat is generated in the firebox from where it is delivered through an appropriate conduit system to the space to be treated.

When there is a call for heat, the fuel is continuously delivered at a volume whereby complete combustion occurs at the combustion location in the firebox. The delivery of the fuel is ideally controlled so that there is no significant ignition of the fuel upstream of the combustion location, as in a conduit through which the auger advances the fuel to the combustion location.

Through an appropriate damper assembly, the heat generated in the firebox space is released to the delivery conduit system either continuously or once there has been an appropriate, predetermined temperature rise in the firebox space.

The individual components that operate and reconfigure during system operation are normally electrically operated, as are any controls used to dictate the sequence and coordination of component operation. So long as all components are operational and supplied with power, a properly constructed and operating system will confine combustion of the solid fuel to the combustion location in the firebox and effect delivery of the heated air only after complete combustion. This assures that harmful byproducts of combustion, such as smoke and CO gas, do not migrate into the living or work space. However, failure of one or more components, or total power failure, may cause dangerous conditions with systems of the above type that burn solid fuel.

In the event of a total power failure, with most conventional systems, a limited amount of air may be continuously delivered by convection to the firebox space that is adequate to continue combustion resulting in a slow burn of the solid fuel. Combustion of the fuel under these conditions may generate smoke and CO gas that is both offensive and potentially dangerous if it migrates into the living or work space. This problem may not be as significant in the event that the damper assembly controlling outflow of heated air from the firebox is closed and effectively sealed in a no power state.

However, this slow burn condition may cause combustion of the static supply of solid fuel which is upstream of the combustion location. Depending upon the nature and density of the fuel at such locations, such as in delivery conduits, the combustion may detrimentally spread, in a worse case potentially even to a hopper, or the like, in which there is a bulk supply of the solid fuel. Such a condition could cause damage to the hopper and/or supply system and, in a worse case, represent a fire hazard.

In the event that there is a failure of the component assembly that delivers intake air to the firebox space for combustion, the slow burn condition may occur. The inefficient partial combustion of the fuel may generate smoke and dangerous byproducts that are allowed to be delivered to the work or living space.

In the event that the component assembly that assists the delivery of heated air to the work or living space fails, there exists a risk that excessive heat may be generated in the firebox space. Such a condition could potentially damage the apparatus and/or present a fire hazard in an extreme case.

Another dangerous condition that may occur results potentially from the failure of the solid fuel combustor assembly with the apparatus in a state wherein the heated air may convey continuously from the apparatus to the environmental space. Not only is there a resulting potential for delivery of smoke and harmful byproducts to the environmental space, but there exists the possibility that burning of the solid fuel may be accelerated upstream of where it is delivered to the combustion location. Again, this condition is such that the apparatus, or components delivering solid fuel thereto, may become damaged. In a worse case, a fire hazard is presented.

While the burning of solid fuels has a significant up side from the standpoint of cost and the environment, it has a number of inherent limitations, such as those noted above. While the industry has addressed a number of these issues, not all of the above problems have been adequately addressed, as a consequence of which risks remain with the operation of such apparatus.

SUMMARY OF THE INVENTION

In one form, the invention is directed to an apparatus for generating heat in an environmental space. The apparatus consists of: a) a firebox bounding a space; b) a combustor assembly for burning solid fuel at a combustion location; c) a fuel inlet through which solid fuel is delivered from a supply to the combustion location, the solid fuel delivered through the solid fuel inlet to the combustion location burned to generate heat in the firebox space; d) an air inlet through which air is delivered from the environmental space to the combustion location; e) an outlet for releasing air heated in the firebox space for delivery to the environmental space; f) an outlet damper assembly having first and second states wherein the outlet damper assembly respectively: i) permits movement of air from the firebox continuously through the outlet for delivery to the environmental space; and ii) substantially blocks movement of air from the firebox through the outlet for delivery to the environmental space; and g) an inlet damper assembly having first and second states wherein the inlet damper assembly respectively: i) permits movement of air from the environmental space continuously through the air inlet to the combustion location; and ii) substantially blocks movement of air from the environmental space through the air inlet to the combustion location. The inlet and outlet damper assemblies are constructed to both be placed or maintained in their second states in response to the apparatus being placed in certain predetermined states to thereby prevent or smother combustion of solid fuel within the apparatus.

In one form, a control assembly is provided for detecting the certain predetermined states for the apparatus and, as an incident thereof, changing the state of either of the inlet and outlet damper assemblies that is in its first state into its second state.

In one form, the apparatus is provided with a fuel delivery assembly capable of storing a supply of solid fuel that is delivered through the solid fuel inlet to the combustion chamber.

In one form, at least one of the apparatus and fuel delivery assembly has at least one auger for conveying solid fuel from the solid fuel supply towards the combustion location.

In one form, there is a first powered assembly for changing the outlet damper assembly between its first and second states and in the event that power to the apparatus is terminated, the outlet damper assembly is: a) maintained in its second state if the outlet damper assembly is in its second state when power to the apparatus is terminated; and b) changed from its first state into its second state if the outlet damper assembly is in its first state when power to the apparatus is terminated.

In one form, there is a second powered assembly for changing the inlet damper assembly between its first and second states and, in the event that power to the apparatus is terminated, the inlet damper assembly is: a) maintained in its second state if the inlet damper assembly is in its second state when power to the apparatus is terminated; and b) changed from its first state into its second state if the inlet damper assembly is in its first state when power to the apparatus is terminated.

In one form, the apparatus further has an air flow inducer for causing air to be delivered under pressure to the combustion location. The control assembly causes each of the inlet and outlet damper assemblies to be changed into or maintained in their second states as an incident of detecting that the air flow inducer is either: a) not operating; or b) not causing air to be delivered in at least a predetermined volume to the combustion location.

In one form, the control assembly causes each of the inlet and outlet damper assemblies to be changed into or maintained in their second states as an incident of detecting that the combustor assembly is either: a) not operating; or b) operating below a predetermined capacity.

In one form, there is a first powered assembly for changing the outlet damper assembly between its first and second states and the control assembly causes each of the inlet and outlet damper assemblies to be changed into or maintained in their second states as an incident of detecting that the first powered assembly is not functioning properly.

In one form, the apparatus further has an air flow inducer for inducing flow of heated air from the firebox space to and through the outlet.

In one form, the apparatus further has an air flow inducer for inducing flow of heated air from the firebox space to and through the outlet. The control assembly causes each of the inlet and outlet damper assemblies to be changed into or maintained in their second states as an incident of detecting that the air flow inducer is either: a) not operating; or b) not causing at least a predetermined volume of heated air to flow from the firebox space to and through the outlet.

In one form, the combustion assembly has on and off states and can be operated at different heat generating levels. The control assembly causes at least one of: a) each of the inlet and outlet damper assemblies to be changed into or maintained in their second states; and b) the combustion assembly to be either: i) changed into its off state; or ii) changed to operate at a different heat generating level as an incident of detecting that a temperature of heated air in the firebox is at least at a predetermined level.

In one form, there is a supply of solid fuel in the fuel delivery assembly that is one of: a) wood; b) corn kernels; and c) pellets.

The invention is also directed to a method of controlling operating of an apparatus for generating heat in an environmental space. The method includes the steps of: a) providing an apparatus having: a firebox; a combustor assembly for burning a solid fuel at a combustion location; an inlet damper assembly having different states; an outlet damper assembly having different states; and a control assembly; and b) configuring the control assembly so that the control assembly causes the inlet and outlet damper assemblies to be placed or maintained in a safety state wherein the outlet damper assembly blocks movement of air heated through combustion of solid fuel from the apparatus and the inlet damper assembly blocks movement of air from the environmental space to the combustion location so as to thereby prevent or smother combustion of solid fuel within the apparatus upon detection of the apparatus being placed in certain predetermined states wherein there is a danger of: i) emission of harmful combustion byproducts from the apparatus to the environmental space due to a slow burning condition; ii) unwanted combustion of solid fuel at a location upstream of where solid fuel is delivered to the combustion location; and/or iii) overheating of the apparatus.

In one form, the step of configuring the control assembly involves configuring the control assembly so that the inlet and outlet damper assemblies are caused to be placed in their safety states as an incident of detecting that there is insufficient air delivered to the combustion location for adequate combustion.

In one form, the step of configuring the control assembly involves configuring the control assembly so that the inlet and outlet damper assemblies are caused to be placed in their safety states as an incident of detecting that operating power to the apparatus has been interrupted or otherwise altered.

In one form, the step of configuring the control assembly involves configuring the control assembly so that the inlet and outlet damper assemblies are caused to be placed in their safety states as an incident of detecting that a component on the apparatus is malfunctioning.

In one form, the step of configuring the control assembly involves configuring the control assembly so that the inlet and outlet damper assemblies are caused to be placed in their safety states as an incident of detecting that flow volume of heated air away from the apparatus is below a predetermined amount.

In one form, the step of configuring the control assembly involves configuring the control assembly so that the inlet and outlet damper assemblies are caused to be placed in their safety states as an incident of detecting that the combustor assembly is either: a) not operating; or b) operating below a predetermined capacity.

In one form, the step of configuring the control assembly involves configuring the control assembly so that the inlet and outlet damper assemblies are caused to be placed in their safety states as an incident of detecting that a temperature of air heated in the firebox is at least at a predetermined level.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic representation of an apparatus for generating heat in an environmental space, according to the present invention, and including a fuel delivery assembly; and

FIG. 2 is a flow diagram representation of a method of controlling operation of an apparatus for generating heat in an environmental space, according to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In FIG. 1, an apparatus is shown at 10 for generating heat in an environmental space. The apparatus 10 is shown in schematic form as it is intended to encompass virtually a limitless number of different variations of components, in terms of their type, construction, interaction, and overall operation.

Typically, the apparatus 10 resides in a living or work environmental space 12 and has an external housing 14 within which some, or all, of the various operating components are integrated and combined. A firebox 16 bounds a space/chamber. A combustor assembly 18 is operable to burn solid fuel 20 supplied from a fuel delivery assembly at 22 wherein a supply of the solid fuel 20 is stored. The fuel delivery assembly 22 may be considered part of the apparatus 10 or a separate assembly that is combined to operate therewith. For purposes of the disclosure herein, this distinction is not critical. The combustor assembly 18 causes the solid fuel 20 to be burned at a combustion location 24 that is either adjacent to or within the space bounded by the firebox 16.

Solid fuel 20 is delivered from a supply thereof in a hopper 26, on the fuel delivery assembly 22, through a fuel inlet 28 to the combustion location 24. The fuel delivery assembly 22 additionally has a solid fuel moving assembly 30 that causes continuous conveyance of solid fuel 20 during operation from the hopper 26 to the fuel inlet 28 and therefrom to the combustion location 24. The fuel moving assembly 30 may typically incorporate one auger or a series of cooperating augers provided on one or both of the apparatus 10 and the fuel delivery assembly 22.

An air inlet 32 is provided through which air is delivered from the environmental space 12 to the combustion location 24. The environmental space 12, from which intake air can be drawn, is considered to be any enclosed space within which the apparatus 10 is located, and airspace externally thereof.

An airflow inducer 34 causes air from the environmental space 12 to be delivered under pressure to the combustion location 24.

An air flow inducer 36 may induce flow of heated air from the firebox space to and through a heated air outlet 37 to the environmental space 12, as through an appropriate conduit or system of conduits.

An outlet damper assembly 38, through which heated air flows from the apparatus 10, has first and second states. In the first state, the outlet damper assembly 38 permits movement of heated air from the firebox space continuously through a heated air outlet 37 for delivery to the environmental space 12. In the second state, the outlet damper assembly 38 substantially blocks movement of air from the firebox space through the outlet 37 for delivery to the environmental space 12. A powered assembly 40 is operable to change the outlet damper assembly 38 between the first and second states.

An inlet damper assembly 42 likewise has first and second states. In the first state, the inlet damper assembly 42 permits movement of air from the environmental space 12 continuously through the air inlet 32 to the combustion location 24. In the second state, the inlet damper assembly 42 substantially blocks movement of air from the environmental space 12 through the air inlet 32 to the combustion location 24. A separate powered assembly 44 is operable to change the inlet damper assembly 42 between its first and second states.

A control assembly 50 is operable to control the various system components. The control assembly 50 is also constructed to detect when the apparatus 10 is placed in certain predetermined states to thereby prevent, or “smother”, combustion of solid fuel within the apparatus 10. This smothering occurs with both of the inlet damper assembly 42 and outlet damper assembly 38 in their second states which represents their safety states. Upon detecting the predetermined states for the apparatus 10, some of which will be described below, the control assembly 50 causes either of the inlet damper assembly 42 and outlet damper assembly 38 that is in its first state to be changed into its second state. The control assembly 50, upon detecting the certain predetermined states for the apparatus 10, may cause the change in state of one or both of the inlet damper assembly 42 and outlet damper assembly 38, as through its associated powered assembly 44, 40, respectively. The powered assemblies 44, 40 may actively change the states or cause a disengagement whereby through a fail safe mechanism, the inlet and outlet damper assemblies 42, 38 assume on their own the safety states. As one example, each of the damper assemblies 42, 38 may be normally spring biased towards its second/safety state.

In normal operation, a supply of the solid fuel 20 is introduced to the hopper 26. With the combustor assembly 18 operational, the fuel moving assembly 30 is operated to continuously convey solid fuel through the fuel inlet 28 to the combustion location 24 at which the combustor assembly 18 initiates burning. The burning is augmented by intake air that flows through the air inlet 32 to the combustion location 24, with the flow volume enhanced by the air flow inducer 34.

With the heat of combustion reaching a predetermined level, the heated air in the firebox space is directed through the outlet 37, with flow volume increased by the air flow inducer 36. Alternatively, there may be a continuous flow of air from the firebox space without a delay for heat buildup, as at startup. The heated air may flow directly into the environmental space 12 or from the heated air outlet 37 to a conduit system for strategic discharge at one or more locations in the environmental space 12. With the apparatus thus operating, the outlet damper assembly 38 and inlet damper assembly 42 are in their first states, within which potentially a range of volumes of air flow is permitted.

The control assembly 50 is designed to detect one system state wherein there is a termination of power to the apparatus 10, to potentially include the fuel delivery assembly 22. Once there is detection that power to the apparatus 10 is terminated, the outlet damper assembly 38 is: a) maintained in the second state if the outlet damper assembly 38 was in the second state when power to the apparatus 10 was terminated; and b) changed from the first state into the second state if the outlet damper assembly 38 was in the first state when power to the apparatus was terminated.

At the same time, upon detection of power termination, the inlet damper assembly 42 is: a) maintained in its second state if the inlet damper assembly 42 is in its second state when power to the apparatus 10 was terminated; and b) changed from its first state into its second state if the inlet damper assembly 38 was in its first state when power to the apparatus 10 was terminated.

In the absence of the inlet and outlet damper assemblies 42, 38 being maintained in their second/safety states so as to smother combustion, incomplete combustion of the solid fuel 20 may occur at the combustion location 24, whereupon smoke and potentially harmful combustion byproducts, such as CO, might migrate into the environmental space 12. This may be a result of the fact that the combustor assembly 18 does not operate in a no power state and/or because there is inadequate intake air to cause complete or adequate combustion.

In the absence of smothering combustion in the no power state, the solid fuel 20 may “slow burn” upstream of the combustion location 24 whereat the solid fuel 20 is staged for conveyance to the combustion location 24.

The smothering action caused by the placing/maintaining of the inlet and outlet damper assemblies 42, 38 in their second/safety states may also be caused upon the control assembly 50 detecting that the air flow inducer 34 is either: a) not operating; or b) not causing air to be delivered in at least a predetermined volume to the combustion location 24 necessary for full combustion. Inadequate intake air may cause incomplete combustion that allows the slow burn condition, potentially resulting in the generation of smoke and CO that migrates into the environmental space.

Aside from the fact that the inlet and outlet damper assemblies 42, 38 effectively close the space within which combustion might occur when in their second states, the inlet and outlet damper assemblies 42, 38 also preferably seal this space adequately to block flow of any significant volume of heated air, in which combustion byproducts are entrained, to the environmental space 12. Typically, smothering of the burning occurs by reducing outflow of heated air from the apparatus 10 by 80-90%. Ideally, each of the damper assemblies 42, 38 would effect complete sealing.

The smothering action may be caused through the control assembly 50 also in the event that the combustor assembly 18 is either: a) not operating; or b) operating below a predetermined capacity, even though there may be power supplied to the apparatus.

The smothering action may be caused additionally in the event that there is detection that the powered assembly 40 or air flow inducer 36 are not functioning properly. The latter condition may be detected in the event that the air flow inducer 36 is either: a) not operating; or b) not causing adequate heated air flow volume from the firebox space to and through the heated air outlet 37. To comply with certain industry standards, the system may be required to be designed so that detection of either failure of, or inadequate flow movement caused by, the flow inducer 36 triggers a shut down of the combustion assembly 18, with the consequences as set forth herein.

The control assembly 50 may further detect an overheating condition in the firebox space, as through a temperature probe 52. In addition to causing the smothering action to occur in the event that a temperature of heated air in the firebox space is at least at a predetermined level, the control assembly 50 may further cause the combustor assembly 18 to be either changed from an on state into an off state or changed to operate at a different heat generating level.

As shown schematically in FIG. 2, heat can be generated for delivery to the environmental space by carrying out the inventive method, including the step of providing an apparatus with a firebox, combustor assembly for burning solid fuel at a combustion location, an outlet damper assembly, an inlet damper assembly, and a control unit, as shown at block 70. As shown at block 72, the control assembly is configured so that the control assembly causes the inlet and outlet damper assemblies to be placed or maintained in safety states wherein: a) the outlet damper assembly blocks movement of air heated through the combustion of solid fuel from the apparatus; and b) the inlet damper assembly blocks movement of air from the environmental space to the combustion location so as to thereby prevent or smother combustion of solid fuel within the apparatus, by detection of the apparatus being placed in certain predetermined states. These predetermined states are any ones wherein there is a danger of: i) emission of harmful combustion byproducts from the apparatus to the environmental space due to a slow burning condition; ii) unwanted combustion of solid fuel at a location upstream of where solid fuel is delivered to the combustion location; or iii) overheating of the apparatus.

More specifically, the inlet and outlet damper assemblies are caused to be placed in their safety states as an incident of there being insufficient air delivered to the combustion location for adequate combustion. Other such conditions are when: a) power to the apparatus has been interrupted or otherwise altered; b) a component on the apparatus is not functioning; c) the volume of heated air directed away from the apparatus is below a predetermined amount; d) the combustor assembly is either not operating or operating below a predetermined capacity; and/or e) the temperature of air heated in the firebox is at least at a predetermined level.

The foregoing disclosure of specific embodiments is intended to be illustrative of the broad concepts comprehended by the invention.