WO1983001672A1

WO1983001672A1 - Automated wood combustion apparatus

Info

Publication number: WO1983001672A1
Application number: PCT/US1982/001550
Authority: WO
Inventors: Harvester Corporation Heat; Werner Martin; Daniel R. Koenigshofer
Original assignee: Heat Harvester Corp
Priority date: 1981-10-30
Filing date: 1982-11-01
Publication date: 1983-05-11
Also published as: EP0092585A1

Abstract

A tunnel fuel burner (10) in which wood pellets/chips (16) may be burned in which longitudinal outer (34) and inner (35) concentric cylindrical housings form a longitudinal annular air preheating chamber (46) for supplying combustion air to a combustion chamber (45) formed by the inner concentric cylindrical housing (35) and in which fuel in the form of wood pellets/chips (16) are supplied to one end of the combustion chamber (45) through an inlet feed nozzle (42) with the wood pellets/chips being preheated by the incoming preheated air and combustion products to drive off moisture and volatile matter preliminary to combustion of the fuel.

Description

AUTOMATED WOOD COMBUSTION APPARATUS

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the drawings and particularly Figure 1, there is illus¬ trated a tunnel fuel burner 10 mounted on a vertical furnace housing 11 that is supported on the furnace base 12 on which furnace the stack 13 is mounted for discharging the flue and any fly ash and other emissions. A fuel hopper 14 mounted on the base 15 contains wood pellets 16 which are fed through the fuel supply tube 17 that is connected to an opening (not shown) in the side wall 18 of the hopper 14 through which the wood chips 16 may pass by means of a revolving auger (not shown) that is rotated by means of the motor 19 which drives the auger-mounted pulley 20 through the drive belt 21. A rheostat 22 is provided to control ash and other emis- sions. A fuel hopper 14 mounted on the base 15 contains wood pellets/ chips 16 which are fed through the fuel supply tube 17 that is connected to an opening (not shown) in the side wall 18 of the hopper 14 through which the wood pellets/chips 16 may pass by means of a revolving auger 47, shown in Figure 3, that is rotated by means of the motor 19 which drives the auger-mounted pulley 20 through the drive chain 21. A rheostat 22 is provided to control the speed of the motor 19.

Upper and lower forced air centrifugal fans 23-and 24 are securely mounted to the projecting air inlet ducts 25 and 25' on the outer cylin¬ drical horizontal housing 26 of the tunnel burner 10. The forward or discharge end 27 of the burner 10 has a c'ircular flange 28 that seals the forward end of the annular chamber 46 and is secured to the plate 29 that is mounted on the projecting rectangular furnace door flange 30.

An ash removal duct 31 extends downwardly from the tunnel burner 10 to receive the ashes from within the combustion chamber and to be dis¬ charged through the diverging lower.portion 32 into an ash collecting chamber (not shown).

A start-up access port 33 extends vertically through the tunnel burner to provide access to the combustion chamber for igniting the wood chips to be burned with the upper end being provided with a cover plate (not shown) during operation.

In Figure 2, the tunnel burner is illustrated with the flange 28 mounted on the outer horizontal cylindrical housing 34 with the inner horizontal cylindrical combustion chamber 35 projecting therefrom to the right. The downwardly extending ash removal sleeve 36 extends through an

SU S5? S?" w*e-r»- rcj_-c sct=_ c-s-ssrE*-?^** r OMPI arcuate opening 37 in the outer housing 34. The upper air inlet duct 25 is secured to the outer housing 34 while the start-up port or nipple 33 extends through the circular opening 38 in the outer housing 34 for attachment to the inner horizontal cylindrical combustion chamber housing 35. A rear flange 39 is secured to the outer and inner housings 34 and 35, and with the flange 28 being secured to the outer and inner housings, and an annular longitudinal chamber 46 is provided between the inner and outer housings 34. and 35 as shown in Figures 3 and 4. The tunnel burner 10 is secured to the plate 29 on the furnace by means of the bolts 40 that pass through the openings 41 provided in flange 28. Removal of the bolts 40 from threaded engagement with the plate 29 will facilitate removal of the tunnel burner from connection to the furnace.

A fuel inlet tube or passage 42 is securely supported by the fuel nozzle supporting plate 43 which plate 43 is securely fastened by suitable bolts (not shown) to the rear plate 39 permitting the fuel discharge nozzle 44 to be positioned eccentrically in the combustion chamber 45 within the inner housing 35 as more clearly shown in Figure 3.

Figure 3 illustrates, in transverse sectional view, the assembled tunnel burner with any external insulation 54 and but with the fuel injection nozzle 44 in position and eccentrically mounted within the combustion chamber 45 of the inner combustion housing 35. Plates 39 and 43 are fastened together. The air supply ducts 25 and 25' extend diametri¬ cally opposite each other in close proximity to the discharge nozzle 44 of the fuel inlet line 42 with air being forced into the annular longi¬ tudinal chamber 46 in which incoming air for combustion will be preheated and circulated rotatably and longitudinally through chamber 46 before entry into combustion chamber 45 through a plurality of longitudinally and circumferentially-spaced openings 48 as illustrated in Figure 4.

The annular chamber 46 is closed at opposite ends by flange 28 and plate 39. The start-up port 33 is shown connected to the inner combustion housing 35 and projects through the outer housing 34. The ash removal sleeve 36 is connected also to the inner combustion housing 35 to remove any ash deposited within the combustion chamber 45. A longitudinally- extending auger 47 extends through the fuel supply tube 17 into the fuel supply inlet line 42 to deliver wood pellets/chips into the combustion chamber 45 upon discharge from the nozzle 44.

^TJ?. The plurality of longitudinally and circumferentially spaced air inlet openings 48 provided through the inner combustion housing 35 lead directly to the combustion chamber 45 from the annular chamber 46. Air circulating through the annular chamber 46 from the inlet openings 25 and 25' will be preheated and supplied as combustion air upon entering into the combustion chamber 45 to support combustion with the wood pellets/ chips.

The fuel injection nozzle 50 illustrated in Figure 5, shown as 44 in Figures 2 and 3, is mounted on the plate 51 in which the outlet end 52 is chamfered or machined at an angle, similar to the end of nozzle 44 in Figures 2 and 3, and is provided with a series of longitudinally and circu ferentially-spaced openings or ports 53 through which air entering the combustion chamber 45 from the openings 48 leading to the annular chamber 46 may be introduced and gas exchange can take place in order to drive off moisture and volatile matter out of the fuel and to preheat the products of combustion entering through the nozzle 50 before being dispensed into the combustion chamber. The heated air from the annular chamber 46 will be directed downwardly through openings 48 into the openings 53 in nozzle 50.

The tunnel burner of this invention may be readily disassembled and reassembled with a minimum number of parts that are maintenance free. It will be readily apparent to those skilled in the art that the amount of combustion air may be regulated by the fan speeds, adjusting the openings 25 and 25', modifying the air inlet openings on the fans 23 and 24 and providing the desired number of openings in the combustion chamber or adjusting them by size and quantity depending upon design requirements.

SUBSTITUTE SHEET

Claims

1. A tunnel fuel burner comprising; an outer horizontal cylin¬ drical housing and a concentric inner cylindrical housing having a common axis, said inner cylindrical housing forming a longitudinally extending combustion chamber, said outer housing and said inner housing forming an annular chamber therebetween, combustion air supply means connected to said outer housing to force air into said annular chamber, said inner housing having a plurality of spaced circumferential and longitudinally- spaced openings to admit air from said annular chamber through said openings into said longitudinal combustion chamber, and fuel inlet means projecting into said combustion chamber for supplying wood chips and other solid combustible matter into said chamber at one end thereof, and means for sealing one end of said combustion chamber adjacent to the fuel inlet supply.

2. A tunnel fuel burner as claimed in Claim 1, said combustion air supply means including centrifugal blowers for supplying combustion air to said annular chamber for introduction into said combustion chamber, said supply combustion air circulating around said annular chamber and enters into satd combustion chamber through said openings.

3. A tunnel fuel burner as claimed in Claim 1, an ash cleanout member communicating with said combustion chamber for gravity ash removal.

4. A tunnel fuel burner as claimed in Claim 1, an auger means in said fuel inlet means for supplying solid particles including wood pellets for combustion into said combustion chamber.

5. A tunnel fuel burner as claimed in Claim 4, a fuel supply hopper mounted adjacent to said burner for supplying solid particles including wood pellets to said combustion chamber through said fuel inlet means, said auger means supplying wood pellets from said hopper to said fuel inlet means.

6. A tunnel fuel burner as claimed in Claim 1, and a furnace having a housing, said tunnel fuel burner being mounted on said furnace housing for receiving within said furnace the energy discharged from said combustion chamber.

7. A tunnel fuel burner as claimed in Claim 1, and insulation supported on the exterior of said outer horizontal cylindrical housing.

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