Title:
Clean burning furnace method and apparatus
Kind Code:
A1


Abstract:
A furnace includes a primary and secondary combustion chamber. Heated air from the secondary combustion chamber travels through a vertically-oriented set of flues, and two horizontally-oriented sets of flues before exiting through a chimney.



Inventors:
Plett, Delmer (Arborg, CA)
Application Number:
12/322853
Publication Date:
01/28/2010
Filing Date:
02/05/2009
Primary Class:
Other Classes:
110/210
International Classes:
F23B10/00
View Patent Images:



Primary Examiner:
CORBOY, WILLIAM
Attorney, Agent or Firm:
LOWE GRAHAM JONES, PLLC (SEATTLE, WA, US)
Claims:
We/I claim:

1. A furnace comprising: a housing having a front wall, a rear wall and two side walls; and a primary combustion chamber positioned within the housing; a secondary combustion chamber disposed beneath the primary combustion chamber within the housing, the secondary combustion chamber arranged to enable the combustion of gases and other combustion products from the primary combustion chamber; a heat exchanger positioned within the housing, the heat exchanger including: a plurality of vertically-oriented flues configured to form a vertical heat exchange path, the vertically-oriented flues arranged to carry heated air from the secondary combustion chamber towards a top of the housing; a first plurality of horizontally-oriented flues configured to form a first horizontal heat exchange path, the first plurality of horizontally-oriented flues fluidly coupled to the vertically-oriented flues and arranged to carry the heated air from proximate the rear wall of the housing to proximate the front wall; a second plurality of horizontally-oriented flues configured to form a second horizontal heat exchange path, the second plurality of horizontally-oriented flues fluidly coupled to the first plurality of horizontally-oriented flues and arranged to carry the heated air from proximate the front wall of the housing to proximate the front wall; and one or more liquid conduits positioned along the vertical heat exchange path, the first horizontal heat exchange path, and the second horizontal heat exchange path, the liquid conduits configured and dimensioned to enable a heat exchange between the heated air and liquids carried by the liquid conduits; and a chimney fluidly coupled to the second plurality of horizontally-oriented flues.

Description:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the apparatus;

FIG. 2 is a schematic diagram of the heat transfer;

FIG. 3 is a perspective view of the rear door of the apparatus;

FIG. 4 is a perspective cut away view of the apparatus;

FIG. 5 is a furnace properties table;

FIG. 6 is a front elevational view of the apparatus;

FIG. 7 is a rear perspective view of the apparatus detailing the blower;

FIG. 8 is a schematic elevational view of a typical installation in a home or shop environment;

FIG. 9 is a schematic perspective view of a closed-circuit installation;

FIG. 10 is a second furnace properties table;

FIG. 11 is a perspective schematic view of one embodiment the firebrick layout;

FIG. 12 is an exploded perspective view of the apparatus showing the rear panel;

FIG. 13 is an exploded perspective view of the apparatus showing the front loading door;

FIG. 14A is a front elevational view of the apparatus;

FIG. 14B is a side elevational view of the apparatus;

FIG. 14C is a rear elevational view of the apparatus;

FIG. 14D is a detail view of a clean-out door;

FIG. 15 is an exploded perspective view of a first embodiment of the firebrick insulation;

FIG. 16 is an assembled perspective view of the first embodiment of the firebrick insulation;

FIG. 17 is a front elevational view of a first embodiment the firebrick;

FIG. 18 is a front elevational view of the first embodiment of the firebrick insulation;

FIG. 19 is a front elevational view of a second embodiment the firebrick;

FIG. 20 is a perspective view of the firebrick in a second embodiment;

FIG. 21 is an exploded perspective view of the firebrick in a second embodiment;

FIG. 22 is a perspective view of a first embodiment of the firebrick;

FIG. 23 is an exploded perspective view of a first embodiment of the firebrick with airgap brick spacers;

FIG. 24 to 31 are photographic perspective drawings of a series of maintenance steps;

FIGS. 32 to 35 are photographic perspective drawings of a series of maintenance steps that the rear panel;

FIGS. 36 to 39 are additional photographic perspective drawings of a series of maintenance steps at the rear panel;

FIGS. 40 to 42 are additional photographic perspective drawings of a series of maintenance steps at the rear panel;

FIGS. 43 to 46 are additional photographic perspective drawings of a series of maintenance steps at the rear panel;

FIGS. 47 to 50 are additional photographic perspective drawings of a series of maintenance steps at the rare panel;

FIGS. 51 to 53 are photographic perspective drawings of an apparatus trailer.

EMBODIMENTS

Referring to FIG. 1, a discussion of the present embodiment will now be provided. The present embodiment is a clean burning furnace 10 which burns off gases and other emissions that a conventional furnace would release into the atmosphere. The present embodiment, utilizes a wood gasification process to produce highly efficient combustion in the present embodiment's dual fuel burn chambers. Generally speaking, the fuel or wood in the firebox burns from the bottom up, drying the top layer of wood in the firebox and forcing gases and exhaust into the lower burn chamber. In the brick lined lower chamber, these volatile gases are burned at temperatures as high as 2000° F. The firebrick lining in both burn chambers absorbs the heat and maintains burn chamber temperatures for consistent gas combustion. This high temperature gas combustion significantly lowers emissions, prevents creosote buildup, and minimizes ash buildup in the unit. After passing through the burn chamber, the excess air escapes through multiple flues running through a water jacket, which heats the water quickly and efficiently. The excess cools as it passes through the flues and as the exhaust leaves the chimney, temperatures of the gas exhaust have generally fallen to approximately 300° F.

The present embodiment includes a roof 12, which covers the top portion of the furnace 10, the furnace has a front wall 14, two equal but opposite parallel side walls 16, a back wall 18, and a light 28 which extends below the eve of the roof 12. A pressurized sealed locking door 24 is provided, the locking door 24 providing access to the upper burn chamber to be discussed further below. Also on the front wall 14 is a clean out door 26, for access to the lower ash chamber to be discussed below. Supporting the entire structure are anchor feet 22 which maintain the structure above grade. For transportation and moving, a plurality of forklifts sleeves 20 are arranged on the bottom floor of the furnace 10. Generally speaking, the furnace is arranged along and axial system 11, the axial system having a vertical axis 5, arranged in the substantially vertical direction, and a transverse axis 9 arranged substantially 90 degrees away from the vertical axis, a longitudinal axis 7 arranged in the longitudinal direction at a 90° angle to the vertical and transverse axes respectively.

Return FIG. 2, a brief discussion of the inner chamber regions and burn/gasification process 40 will now be provided. In the burn/gasification process 40, the user will load the wood/fuel 42 into the firebox 44 through the pressurized sealed locking door 24 located at the front wall 14. For full efficiency, the entire firebox chamber 44 will be filled with wood fuel 42. In one embodiment, the firebox chamber 44 may be considered a primary combustion chamber. The wood, burns from the bottom up, drying the upper layers and the outer layers of the wood first. The wood fuel 42 is maintained on an upper chamber firebrick seat 202 (FIG. 11) to be discussed below. The firebrick seat is made of a firebrick lining 46, and as the burn progresses in the firebox 44, gases from the hottest part of the fire exhaust into the brick lined lower chamber 45. The gases pass through the firebrick lining 46 and further combustion occurs within the lower burn chamber 45, which may be considered a secondary combustion chamber. The combustion temperatures in the lower burn chamber reach approximately 2000° F. As the fire progresses, the firebrick lining in both the firebox chamber 44 and the lower burn chamber 45 absorb the heat help to maintain constant burn temperature within the respective chambers.

Superheated exhaust air 48 exits through multiple boiler tube openings which run through the center of the water tank or water jacket 52. These multiple boiler tubes or multiple flues 50, are approximately ½″ in diameter, but may be maintained at a smaller diameter or a larger diameter depending upon the particular design. Furthermore, the flues may not be cylindrical tubes, but may be other cross-sectional geometric configurations such as a rectilinear configuration, square configuration, oval configuration and the like. Also, the tubes may vary in number from a single tube, to multiple small flues. In another embodiment, this arrangement may be “reversed,” such that the water is carried in tubes, and the flues 50 for carrying the superheated exhaust air 48 occupy the space surrounding these tubes. In different embodiments, one or more liquid conduits (e.g., tubes, jackets, tanks, etc.) may be positioned along the heat exchange path(s) of the flues 50 and may be configured and dimensioned to enable a heat exchange between the heated air 48 traveling through the flues 50 and liquids carried by the liquid conduits. Although described as water, the liquids carried within such liquid conduits may be any of a variety of liquids having substantial heat capacity.

The superheated exhaust air 48 then travels through the multiple boiler flues 50 first along a vertical path, second along a forward looking longitudinally aligned horizontal path, then makes a 180° turn to travel along a third longitudinally aligned rearward looking horizontal path, then makes a 90° turn through the flue area 120 (FIG. 7) to travel along a vertical path up through the chimney. The water jacket 52 encompasses the first vertical path and the second and third horizontal paths. Heat transfer occurs throughout this elongated exhaust travel path providing for increased heat transfer efficiency.

Now referring to FIGS. 3 and 4, the clean burning furnace 10 has a rear door panel 19 located on the back wall 18. A blower 21 regulates the amount of intake air which feeds the firebox 44 providing for the needed oxygen to maintain the superheated combustion process. Furthermore, although not shown in this particular embodiment, a water heater sensor interoperates with a control panel, to maintain a temperature range of approximately 150° Fahrenheit to 180° F. or a 30° differential.

When the heat sensor in the water jacket 52 determines that the water temperature has fallen below its desired temperature range, the control panel sends a signal to the blower 21 to provide additional air intake oxygen to the fuel chamber or firebox 44. Additionally, when the desired temperature range exceeds the 180° F. or a predetermined upper range, the control panel can send a signal to the blower to turn off all air intake into the firebox 44 thus lowering the burn rate and the corresponding heat transfer to the water jacket 52. Referring to FIG. 4, a front cutaway view 60 of the furnace 10 shows a cross-sectional view of the lower burn chamber 45, the firebox 44, and the horizontally aligned second and third travel paths for the superheated exhaust along the flues 50.

Presently, two embodiments are provided. Referring to FIG. 5, the first embodiment 72 as seen in the furnace property table 70 has a maximum furnace output per BTU/hour 75 of approximately 175,000 BTUs per hour. A second embodiment, 74, has approximately 350,000 BTUs per hour of maximum furnace output 75. These outputs correspond to various physical design parameters 71 shown in the furnace property table 70 including the maximum feeding area 76, total weight 78, body width 80, total depth 82, body depth 84, total height 86, chimney size 88, door size 90, and firebox volume 92.

A more detailed discussion of the poetry on the front wall 14 of the furnace 10 will now be provided as seen in FIG. 6. During units, the lights 28 will be on to warrant any potential users opening the pressure is to seal loading door 24 that's the furnace system in operation. When a user opens the loading door 24, a smoke curtain 58 is provided to keep flames from jumping outset of the furnace until the loading door 24 passes a certain opening degree, for sample 30°. On the inside face of the loading door 24 is a removable inner door panel 106. That the upper right hand corner of the front wall 14 is a control panel 104. The control panel enables the user to monitor the water temperature and level in the water jacket 52 by providing any aqua Stat readout 102, also a lights damper switch 100 is provided.

Also during cleanup, an automatic smoke exit lid 110 is provided, enabling the user to access the 180° bend and empty the ash collecting in this bend, enabling cleanout procedures for the flues 50. At the lower portion of the front wall 14 is an ash cleanout door 108. This gives access to the secondary burn chamber 45 and enables the user to remove the final ash deposits after the superheated gasification process. Referring to FIG. 7, a more detailed discussion of the rear panel or back wall 18 will now be provided.

The back wall can be opened through a rear access door 132. This enables the users to access the blower 138, as well as the flue fly ash cleanout cover 122, the various drains 134 and supply ports 128 as well as the return ports 126 and the ash cleanout tray 124. The ash cleanout tray 124 is located behind the cleanout cover 122 and collects the ash which is carried by the exhaust process and deposited in the flue area 120. The user removes the cleanout cover 122, and then removes the ash cleanout tray 124 with the ash deposits on the tray. The flues 50 also known as heat exchangers 136 exit into the flue area 120. The remaining heat exhaust exits vertically through the chimney 32. Also, the blower 138 is arranged to cooperate with a solenoid 142 and a damper lid 140. The temperature probe 135 is also accessible at the back cover or access door 132.

Now, a brief discussion of the furnace operation as used in either an in-house environment or workshop environment will be provided. The circulation of the heated water within the water jacket 52 is shown as seen in FIGS. 8 and 9. A furnace 10 can be utilized to provide hot water to a house 152 or for example a shop 154. The heated water is circulated through recirculation water lines 156. A recirculation line 160 is shown with an insulated supply line 162 feeding to a filter 164. Impurities are filtered out and a pump 168 forces the water into the hot water tank 168. An optional sidearm heat exchanger 170 is utilized. Water then exits through the hot water tank 168 and is transferred to the heat exchanger 172 or existing furnace 174 which can utilize the heat in a forced air scenario to heat a home. The hot water line can also be circulated to a plurality of parallel floor heating pipes 180, with the water being recalculated back to the furnace through a recirculation line 182 which returns the cool water to the furnace 10 for reheating inside of the water jacket 52.

A brief discussion of the first 72 and second 74 embodiments as seen in a second furnace table 182 provides additional information with regard to the physical design parameters 71. Additional physical design parameters include the maximum average outputs in BTUs per hour of a full load of wood burning duration 184, maximum log length 186, furnace width 188, furnace length 190, water capacity 192, and shipping weight 194.

Referring to FIGS. 12 and 13, a discussion of the assembly of the front and rear panel's will now be provided. FIG. 12 shows a rear panel assembly 230 where the insulated door panel 232 is shown in exploded view. Similarly, FIG. 13 shows a front panel wall assembly 240 where the insulated front door panel 242 is shown in exploded view. Referring now to FIG. 14A, a furnace front elevation 215 is shown, and FIG. 14B shows a furnace side elevation 260. FIG. 14C shows a furnace or rear elevation 270 with a back panel hidden door detail 280 as seen in FIG. 14D.

As previously discussed, the firebrick configuration within the upper chamber or firebox 44 and the lower chamber 45 enables the downdraft to occur while also maintaining a specific level of heat for prolonged periods of time. The firebrick's act as heat sinks to maintain a more level temperature, as well as provide the structural support for the wood fuel within the firebox 44 and also provide the structural support and configuration for the lower burn chamber. Because of the need for specialized downdraft venting, the present embodiments utilize strategically placed downdraft brick flues enabling for a more efficient burn and combustion to occur. Furthermore, an efficient configuration for collecting the ash removes the ash particulate from the burn zone and creates a free and clear burn cavity for constant and consistent combustion.

Referring to FIG. 11, a discussion of the general arrangement of the firebrick 200 will be provided. The wood fuel is maintained on an upper chamber firebox seat 202. Generally, the firebox seat 202 is conFig.d with outwardly slopping firebox sidewall bricks 204 and transversely aligned brick grading which runs longitudinally along on-edge along the length of the firebox. The outwardly sloping firebox sidewall bricks 204 lay flat and the slope provides for settling of the burned fuel to the bottom seat of the firebox 202. The transversely aligned brick grading 210 arranged along the longitudinal axis 7 is spaced with a plurality of equidistant downdraft brick flues 208. The downdraft brick flues 208 provide for the transfer of the exhaust into the lower burn chamber 45.

The lower burn chamber 45 is defined by longitudinally aligned sailor standing sidewall bricks 212, a front wall 213, and a bottom slope ash channel series of longitudinally aligned bricks 224. These ash channel bricks 224 define the front ash chamber 226. At the rear end of the firebrick arrangements 200 is a rear ash chamber 214. This is defined by a rear ash chamber back wall 220, rare ash chamber sidewalls 218, and the extension of the bottom slope Channel ash bricks 224. An ash chamber front wall 216 is also provided. In the present configuration, for shipping, transportation stabilization blocks 222 are provided spanning from sidewall to sidewall in the lower chamber to maintain stability of the sailor standing brick sidewall during transportation.

To maintain the heat within the furnace, insulation panels are provided on the outside face of the firebrick to reflect and insulate the heat within the firebox.

Referring to FIGS. 15 and 16, a firebrick insulated panel arrangement in an exploded view 290 is shown in FIG. 15, and a firebrick insulated panel assembled position 320 shown in FIG. 16. The insulated panel's follow the same outside slope lines of the firebrick arrangement 200 as seen in FIG. 11. In the upper chamber region, two equal but opposite longitudinally aligned insulating slope walls 300 support the sloped sidewall brick 204 of the firebox.

Running vertically are two front ash chamber insulating sidewalls 302 which are seated on two longitudinally aligned front ash chamber sloped insulating front walls 310 which terminate at a front ash chamber insulating bottom wall 212. Along the top vertical edge of the front ash chamber side walls 302 are placed grate rails 296 supported by a rail posts 298.

The transversely aligned brick grating 210, FIG. 11, rests on the grate rails 296. The rear ash chamber is insulated by a rear ash chamber back wall 304, two equal but opposite rear ash chamber side walls 306, and a rear ash chamber sloped bottom wall 308 terminating at the front ash chamber bottom wall 312. Also, a rear ash chamber front wall 314 is provided.

A front insulating panel 292 is positioned to close the front edge of the lower burn chamber 45, and has an ash chamber cleanout port 294 through which the ash can be removed.

Discussing a first embodiment arrangement of the firebrick and brick insulation, as seen in FIGS. 17 and 18, a firebrick front elevation 330 is provided with two sloped sidewalls 204 resting on a transversely aligned brick grating 210. A lower combustion chamber sailor brick walls 212 frame the lower combustion chamber. A lower combustion chamber front wall 211 is seated below at the end grating unit 210 and the supported by the bottom sloping ash channel bricks 224.

The first embodiments of the firebrick front elevation 330 is suitable within the first embodiment of the firebrick insulation for elevation 340.

Referring to FIGS. 19, 20, and 21, a second embodiment of the firebrick arrangement is shown as seen in front elevation 350 FIG. 19, and assembled perspective view 350 as seen in FIG. 20, and in exploded perspective view 360 as seen in FIG. 21.

Here in the second embodiment of the firebox seat 352 utilizes the same general configuration as the first embodiment, and has a rear ash chamber 354. Referring to FIG. 21, to maintain equidistant spacing between the brick grating 210, flue brick air gap spacers 362 and 364 are placed between the transversely aligned bricks 210 to create the air transfer space for the downdraft of the exhaust. The lower burn chamber 45 is divided into two regions, an upper gas combustion region 366, and a lower ash chamber 226. The upper gas combustion region 366 in this second embodiment, is flanked by two inwardly leaning longitudinally aligned brick side walls 361.

Referring to FIGS. 22 and 23, and discussing the first embodiment of the firebox as seen in perspective view 370, FIG. 22, and exploded perspective view 380 as seen in FIG. 23, the first embodiment of the firebox seat 372 provides for the seating of the fuel wood in the lower region of the firebox or first burn chamber. A plurality of flue brick air gap spacers 382 and 384 are provided between the brick grating 210 to provide for the previously mentioned airflow from the firebox chamber into the lower burn chamber 45. The previously mentioned sailor standing side walls 212 flank the burn chamber and stand on the front lower ash chamber 388. The lower burn chamber 45 is also composed of an upper gas combustion region 386 and the front lower ash chamber 388.

FIGS. 24 to 31 show a user 394 accessing the ash cleanout door 108 of the furnace 10 and performing a cleanout process 390. The user 394 utilizes an ash cleanout bucket 392 and an ash hoe 396. The ash hoe has a hoe shoe 402 which is conFig.d to the same trapezoidal shape as the lower ash chamber 388. The ash 398 is easily removed from the lower ash chamber. This process occurs once every two weeks.

FIGS. 32 through 50 shown the user 394 accessing the flue cleanout panel 408 to perform cleanout maintenance on the horizontally aligned to flue tubes 50. In FIG. 48, the user utilizes a wire brush and flexible drive drill 500 to cleanout the flew tubes 50. Lastly in FIGS. 51 through 53, a furnace trailer 510 is provided for transportation of the furnace when used in multiple locations.