GB2436869A

GB2436869A - Multifuel stove with combined secondary and tertiary air inlet

Info

Publication number: GB2436869A
Application number: GB0606853A
Authority: GB
Inventors: Stephen Philip Tripp
Original assignee: Individual
Current assignee: Individual
Priority date: 2006-04-05
Filing date: 2006-04-05
Publication date: 2007-10-10
Anticipated expiration: 2026-04-05
Also published as: CN101050868A; IES20070032A2; GB0606853D0; CN100523620C; GB2436869B

Abstract

A multi-fuel stove 1 supplies both secondary air 11, to keep the window 12 clean, and tertiary air 26, to increase flame height and efficiency, from a combined inlet chamber 36 fed by vents 38. Airflow into the secondary conduit (72, fig. 3) and tertiary conduit 40 is independently controlled via knobs 52 and 58 (fig. 4) on the front of the stove, improving access without compromising appearance. The secondary conduit's tapered exit (70, fig. 3) prevents smoke entering the room via inlet vents 38, as does the tertiary conduit's upwards inclination 40.

Description

2436869

A multi fuel stove

Field of the Application.

The present application to solid fuel stoves for the heating of a living room using wood, coal and/or other 5 solid fuels.

Background

Solid fuel stoves are becoming popular in homes. The 10 stoves 1, as shown in figure 1, typically comprise a burning chamber 3 having a grate 2 therein. Fuel 4, including for example wood, coal and turf, may be placed on the grate and burnt. The grate is situated over an underlying ash drawer 18 in which ash from the burning 15 fuel collects. Fuel may be added to the burning chamber through a door 12 in the front. A handle 14 on the door allows the door to closed and locked or opened as required. The ash drawer 18 may be removed after opening a lower door 16. Commonly, the main door and lower door 20 are combined into a single door. Traditionally, these stoves were intended primarily as a source of heat. However, stoves are now also used to provide a decorative function. As a result, modern stoves tend to be designed with an aesthetic appearance, including a window (not 25 shown) that is provided in the door 12 at the front of the stove to allow the fire inside to be viewed. An advantage of combining the two doors into a single larger door is that window in the front may extend down the door to substantially the level of the grate thus providing a 30 better view of the fire. The stoves may be manufactured using any suitable material but are typically cast iron.

v

To facilitate combustion in the chamber a supply of air is required. This air supply is primarily provided by a primary air supply, which is supplied through a lower intake opening 6, which feeds air 8 to the area under the 5 grate 2, which supports the fuel. The primary air 8 is effectively sucked into the fuel pile as the heated air and smoke in the pile rises to exit through a flue 22, which is connected to a flue outlet 20 at the top of the burning chamber. The primary air is typically supplied 10 through an adjustable baffle or damper (not shown), which allows a user to manually regulate the supply of air to the fire. Commonly the adjustable baffle or damper comprises one or more rotateable caps, which may be rotated in one direction to increase the flow of air and 15 in the opposite to decrease the flow of air. By closing the damper, the supply of air can be cut-off and the fire effectively extinguished. Opening the damper increases the flow of primary air and thus the intensity of the fire. The primary air damper may also be adjusted to give 20 the best possible results when burning different fuels.

A known problem with these types of stoves is that soot deposits on the window obscuring the view of the fire, necessitating the regular cleaning of the window. A known 25 solution to this problem is to have an air inlet 9 providing a source of secondary air 11 above the door 14. This secondary air is typically supplied through inlets in the front of the stove through a conduit 10 and out a number of exit ports (not shown) provided in the conduit 30 above the door. The purpose of this conduit 10 is to direct the incoming secondary air 11 downwards along the window. As the air exiting from the chamber is colder than the heated air rising from the fuel pile it falls along the inner surface, i.e. the window, of the door.

The falling secondary air keeps the rising smoke rising from the fuel pile away from the window. The secondary air effectively provides a barrier keeping the window clean and reducing the need for regular cleaning of the 5 window. The secondary air after falling down along the face of the window provides for moderate feeding of the fire. Depending on the fuel used and the configuration of the conduit, the efficiency of the fire may be improved by appropriate adjustment of the flow of secondary air. 10 Accordingly, a damper, e.g. a movable baffle, is typically provided on the chamber side of the air inlets for reducing the effective size of the air inlets 9 to the chamber 10 and thus adjust the flow of secondary air.

15 A further air supply, sometimes referred to as a tertiary air supply may also be provided. This air 26 is supplied to the upper region of the combustion chamber. This tertiary air supply facilitates secondary combustion, whereby combustible gases rising from the fuel pile 20 ignite providing a dramatic increase in the flame height, which is aesthetically pleasing to users of the stoves. The secondary combustion caused by the tertiary air also improves the heat efficiency of the fire. A further advantage of the secondary combustion is that the overall 25 combustion process is cleaner with reduced emission of carbon monoxide and other combustible gases. The tertiary air supply is typically supplied from an inlet 24 at the rear of the stove, typically near the bottom. The air is fed to the upper part of the burning chamber by suitable 30 pipe work 30, 28. As with the primary and secondary air supplies, a damper may be provided at the inlet to adjust the flow of tertiary air.

3

The present application is directed at stoves, which comprise a primary, secondary and tertiary air supplies.

Summary

5

The inventor of the present invention has identified that a problem with the existing stoves is that the controls for the tertiary air supply are typically provided at or beside the bottom rear side of the stove. 10 As these types of stove are intended for placement in a fireplace, a user may have difficulty in gaining unrestricted access to the control for the tertiary air supply. As a result, users may have difficulty in operating the tertiary air supply control.

15

The present application addresses this concern by providing a tertiary air supply, which may be controlled from the front of the stove. Moving the controls for the damper for the tertiary air supply is not a 20 straightforward task since providing linkages within the fire chamber is problematic, whereas providing linkages on the exterior of the stove is unlikely to be aesthetically pleasing. The present application overcomes these problems by combining the tertiary and secondary 25 air supplies together in one unit.

In particular, a first embodiment provides a multi fuel stove comprising a base, a top, a wall structure joining the base and top, the base, top and wall structure 30 defining an burning chamber, a grate provided in the burning chamber for supporting fuel and allowing ash to fall there through, a door provided in the wall structure for allowing fuel to be added to the burning chamber, a window provided in the door for external viewing of the

CP

burning chamber, a first vent means in fluid communication with an area below the grate for supplying primary air to the burning chamber, a second vent means, provided in the wall structure at the front of the stove 5 above the door, in fluid communication with an intermediate chamber provided on the interior surface of the wall, the intermediate chamber having a downward opening providing a low of secondary air to the chamber along the window, wherein a further opening is provided 10 from the intermediate chamber to provide a tertiary air supply to the upper part of the burning chamber.

A second embodiment provides a multi fuel stove comprising:

15 a burning chamber, a door providing access to the burning chamber, a window provided in the door, a vent provided above the door in fluid communication with an intermediate chamber provided within the burning chamber, the intermediate chamber supplying both secondary and 20 tertiary air to the burning chamber.

Other embodiments, features and advantages will become apparent from the description and claims which follow.

25 Brief Description of The Drawings

The present invention will now be described with reference to the accompanying drawings in which:

Figure 1 is a simplified side profile view of a multi 30 fuel stove known from the prior art,

Figure 2 is a simplified side profile view of an exemplary multi fuel stove according to the invention, Figure 3 is a more detailed side profile representation of a part of the stove of Figure 2, and

Figure 4 is an exemplary front view of the air inlet section for the stove of Figure 2.

Detailed Description

5

The present invention is directed at replacing the manner of supply of the tertiary air to the burning chamber of a stove and in particular to combining the features that provide the secondary air with those 10 features supplying the tertiary air supply. As shown in Figure 2, a multi fuel stove is provided comprising a base, a top, a wall structure joining the base and top. The base, top and wall structure define an enclosed burning chamber 3. A grate 2 is provided in the burning 15 chamber for supporting fuel and allowing ash to fall there through. A door 12 is provided at the front of the stove 1 corresponding to an opening (not shown) provided in the front wall structure. Fuel may be added to the burning chamber 3 through the opening. The door frame 20 surrounds a window which allows for external viewing of the burning chamber. As with previous stoves, a first vent means is provided in fluid communication with an area below the grate for supplying primary air to the burning chamber. In the exemplary embodiment shown this 25 comprises an air inlet in the front of the stove below the level of the grate.

Those features common to the prior art are numbered similarly and no specific additional description is 30 provided herein. Combining the means for supplying the tertiary and secondary air supplies allows the controls for the tertiary air supply to be positioned on the front of the stove without complicated linkages in the interior

G

of the stove or without interrupting the aesthetics of the device.

It will be appreciated that combining the means for 5 supplying the tertiary and secondary air is not an obvious solution since the tertiary air supply would be seen as likely to interrupt the secondary air supply and could lead to smoke exiting the air inlet, which would be completely undesirable. Additionally, it is desirable 10 that the control of the supply of tertiary air be completely independent of the control of the supply of secondary air.

15 The supply of tertiary and secondary air and the controls therefore will now be discussed in greater detail with reference to the more detailed representation of Figure 3 in which a second vent means is provided in the wall structure at the front of the stove above the door 12. 20 The vent means comprises an inlet or series of inlets 38 is defined in the front of the stove above the door 12. The inlets provide an opening into and fluid communication with a small intermediate chamber 36 in the stove. The intermediate chamber is suitable fixed to or 25 built into the inner portion of the front wall. The intermediate chamber has a downward opening providing a flow of secondary air to the chamber along the window. Additionally, the intermediate chamber provide a outlet for supplying tertiary air supply to the upper part of 30 the burning chamber.

In contrast to the prior art, there is no baffle or damper for controlling the air through the inlets into the chamber 36. A first opening 44 provided in the base

1

of the intermediate chamber provides an entrance to a conduit 72 which has an exit 70 directed at the top of the door 12. The exit 70 from the conduit may comprise one or more apertures. The combination of the inlets 38, intermediate chamber 36 and conduit 72 provides a path for secondary air to enter the intermediate chamber 36 and pass through the conduit and be directed downward along the surface of the door. The conduit 72 is shaped to taper toward the exit and be directed to the front of the stove so that smoke is prevented from entering the conduit and intermediate chamber 36 and exiting from the inlets 38. The entrance from the intermediate chamber to the conduit suitably comprises one or more apertures defined in the base of the chamber. Preferably, a damper 48 is provided to control the flow of secondary air from the chamber. Suitably, the damper comprises a movable baffle resting on the base of the chamber, which is movable from a first position where the apertures in the base of the chamber are covered to a second position where the apertures are uncovered. The baffle 48 may be moved to any position between the two extremes so as to provide full control of the supply of secondary air 70. The baffle is linked by a short vertical linkage 74 to a shorter horizontal linkage, which extends through a first linkage opening 60 in the front of the stove. A first actuating mechanism, for example a small control knob 52 is provided at the end of the linkage to allow a user to operate it. The first linkage opening 60 is shaped to allow for horizontal movement of the linkage by a user moving the knob, but is sized to prevent the knob 52 from passing through the opening or vertical movement.

A second opening or second series of openings 42 provide an entrance to a second conduit 40, which has one or more

exits 37, 39 directed into the upper section of the burning chamber. The second conduit provides a path for tertiary air to enter the burning chamber 3. The second opening may be provided in the roof of the chamber 36 (as 5 shown) or in a rear or side wall of the chamber. Preferably, a damper 46 is provided to control the flow of tertiary air from the chamber. Suitably, the damper comprises a second movable baffle. In the exemplary embodiment shown, this second baffle abuts the roof of 10 the chamber and is movable from a first position where the apertures in the roof of the chamber are covered to a second position where the apertures are uncovered. The baffle 46 may be moved to any position between the two extremes so as to provide full control of the supply of 15 tertiary air 26. Supports (not shown) may be provided to maintain the baffle against the roof of the chamber. The second baffle is linked by a short vertical linkage 75 to a shorter horizontal linkage 54, which extends through a second linkage opening 62 in the front of the stove. This 20 second linkage opening is suitably at the opposite side of the air inlets 38 to the first linkage. A second actuating mechanism, for example a second small control knob 58 is provided at the end of the second horizontal linkage 54 to allow a user to operate the linkage. 25 Similar to the first linkage opening, the second linkage opening 62 is shaped to allow for horizontal movement of the linkage by a user moving the knob, but is sized to prevent the knob 58 from passing through the opening or vertical movement. Although, the exemplary embodiment 30 shown provides the baffle and opening for the tertiary air supply in the roof of the intermediate chamber, it may be more convenient for servicing of the unit if these are supplied in the rear wall of the intermediate chamber.

1

To prevent smoke entering the tertiary air supply conduit 40 and exiting through the chamber 36 and air inlet 38, the designed path for the tertiary air through 5 the chamber and conduit is selected to be such that tertiary air is pulled upwards from the chamber through the conduit and then downwards into the chamber. In this regard, the conduit 40 may be inclined upwards from the front of the stove into the burning chamber.

10

A significant advantage of the present invention is that the external appearance of the stove is substantially unchanged to a user, as the prior art previously may have had two knobs on either side of the 15 air inlets for controlling the secondary air. In this regard, it will be appreciated that one of the knobs may have been redundant but having two improved the aesthetic appearance of the stove by providing symmetry. It will be appreciated that a ariety of alternatives may be 20 provided. Thus whilst the exemplary embodiment discloses a unitary intermediate chamber providing two air flows, an alternative would be the provision of a split chamber with one half of the chamber providing tertiary air and the second half secondary air. However, it is believed 25 that such an arrangement would be more problematic for assembly and servicing. Nonetheless, such embodiments and alternatives are to be taken as being within the scope of the present invention, which it is intended should only be limited by the claims which follow.

30

It will be appreciated that a significant benefit provided by the above stove is that the user operable controls for the primary, secondary and tertiary air supplies are all provided at the front of the stove,

(O

which allows for easy operation of the stove particularly where the stove is installed in a location where it is difficult to reach the sides or rear of the chamber, e.g. in a small fireplace.

5

The words comprises/comprising when used in this specification are to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other 10 features, integers, steps, components or groups thereof.

K

Claims

A multi fuel stove comprising:

a burning chamber, a door providing access to the burning chamber, a window provided in the door, a vent means provided above the door supplying both secondary air to keep the window clean and tertiary air to the burning chamber.

A multi fuel stove according to claim 1 where the burning chamber comprises a base, a top, a wall structure joining the base and top, the base, top and wall structure defining an burning chamber, a grate provided in the burning chamber for supporting fuel and allowing ash to fall there through.

A multi fuel stove according to claim 2 further comprising a primary air vent means in fluid communication with an area below the grate for supplying primary air to the burning chamber, and where the vent means comprises a secondary air vent means, provided in the wall structure at the front of the stove above the door, in fluid communication with an intermediate chamber provided on the interior surface of the wall, the intermediate chamber having a downward opening providing a flow of secondary air to the chamber along the window, wherein a further opening is provided from the intermediate chamber to provide a tertiary air supply to the upper part of the burning chamber.

A multi fuel stove according to claim 3, wherein a first control means is provided for altering the flow of secondary air.

[I

5. A multi fuel stove according to claim 4, wherein a second control means is provided for altering the flow of tertiary air.

5 6. A multifuel stove according to claim 5, wherein the first and second control means are independently operable.

7. A multifuel stove according to claim 6, wherein an

10 first actuating mechanism for the first control means is provided at the front of the stove.

8. A multifuel stove according to claim 7, wherein a second actuating mechanism for the second control

15 means is provided at the front of the stove.

9. A multifuel stove according to claim 7, wherein the first and second actuating mechanisms are provided on opposite side of the secondary air vent means.

20

10. A multi fuel stove according to claim 4, wherein the first control means for altering the flow of secondary air comprises a movable baffle.

25 11. A multi fuel stove according to claim 5,

wherein the first control means for altering the flow of secondary air comprises a movable baffle.

30 12. A multi fuel stove comprising a base, a top, a wall structure joining the base and top, the base, top and wall structure defining an burning chamber, a grate provided in the burning chamber for supporting fuel and allowing ash to fall there

13

through, a door provided in the wall structure for allowing fuel to be added to the burning chamber, a window provided in the door for external viewing of the burning chamber, a first vent means in fluid 5 communication with an area below the grate for supplying primary air to the burning chamber, a second vent means, provided in the wall structure at the front of the stove above the door, in fluid communication with an intermediate chamber provided 10 on the interior surface of the wall, the intermediate chamber having a downward opening providing a flow of secondary air to the chamber along the window, wherein a further opening is provided from the intermediate chamber to provide a 15 tertiary air supply to the upper part of the burning chamber.

13. A multi fuel stove according to claim 12, wherein a first control means is provided for

20 altering the flow of secondary air.

14. A multi fuel stove according to claim 13, wherein a second control means is provided for altering the flow of tertiary air.

25

15. A multifuel stove according to claim 14,

wherein the first and second control means are independently operable.

30 16. A multifuel stove according to claim 15,

wherein an first actuating mechanism for the first control means is provided at the front of the stove.

W

17. A multifuel stove according to claim 16,

wherein a second actuating mechanism for the second control means is provided at the front of the stove.

5 18. A multifuel stove according to claim 17,

wherein the first and second actuating mechanisms are provided on opposite side of the second vent means.

10 19. A multi fuel wherein the first flow of secondary

20. A multi fuel 15 wherein the first flow of secondary stove according to claim 13, control means for altering the air comprises a movable baffle.

stove according to claim 14, control means for altering the air comprises a movable baffle.

21. A multi fuel stove comprising:

a burning chamber, a door providing access to the 20 burning chamber, a window provided in the door, a vent provided above the door in fluid communication with an intermediate chamber provided within the burning chamber, the intermediate chamber supplying both secondary and tertiary air to the burning 25 chamber.

if

Amendments to the claims have been filed as follows

Claims

1. A multi fuel stove comprising:

a burning chamber, a door providing access to the burning chamber, a window provided in the door, a vent means supplying both secondary air to keep the window clean and tertiary air to the burning chamber,

where the burning chamber comprises a base, a top, a wall structure joining the base and top,

a grate provided in the burning chamber for supporting fuel and allowing ash to fall there through, wherein the vent means comprises at least one inlet provided in the wall structure above the door a first control means for altering the flow of secondary air,

a second control means for altering the flow of tertiary air, wherein the first and second control means are independently operable.

2. A multi fuel stove according to claim 1 further comprising a primary air vent means in fluid communication with an area below the grate for supplying primary air to the burning chamber, and where the vent means comprises a secondary air vent means, provided in the wall structure at the front of the stove above the door, in fluid communication with an intermediate chamber provided on the interior surface of the wall, the intermediate chamber having a downward opening providing a flow of secondary air to the chamber along the window, wherein a further opening is provided from the intermediate chamber to provide a tertiary air

I b

supply to the upper part of the burning chamber.

10

3. A multifuel stove according to claim 2, wherein an first actuating mechanism for the first control means is provided at the front of the stove.

4. A multifuel stove according to claim 3, wherein a second actuating mechanism for the second control means is provided at the front of the stove.

5. A multifuel stove according to claim 4, wherein the first and second actuating mechanisms are provided on opposite side of the secondary air vent means.

15 6. A multi fuel stove according to claim 4, wherein the first control means for altering the flow of secondary air comprises a movable baffle.

7. A multi fuel stove according to claim 5, wherein the 20 second control means for altering the flow of tertiary air comprises a movable baffle.

in