COAL FURNACE

Abstract: Coal furnaces for space heating are usually adapted for functioning according to the principle of thorough combustion. The optimum combustion is achieved by adequate regulation of the proportion between primary and secondary air. This is often difficult and necessitates a supervision of the combustion. By arranging furnaces with a perforated air pipe (7) in the middle of the combustion chamber (4) an automatic regulation of the proportion between the primary and secondary air is achieved. The air pipe (7) is detachably mounted in a hole (6) at the bottom of the combustion chamber (4) through which hole (6, 4) an air channel (9) is connected to an adjustable air valve (3) at the front of the furnace.

Description: COAL FURNACE The present invention relates to a coal furnace for spaceheating and of the kind which has a lined, fire¬ proof combustion chamber, a firing door, and a valve for the supply of combustion air. Coal is often fired in furnaces or boilers which func¬ tion according to the principle of thorough combus¬ tion. However, the kind of boilers are also used which function according to the principle of under- combustion, but they are rather complicated and most¬ ly used in big plants. The necessary primary oxygen supply for the combustion takes place by means of a- * valve at the bottom of the combustion chamber of the furnace, while secondary air is supplied through an air valve over the combustion chamber. It is often difficult to adjust the proportion between primary and secondary air in such a way that optimum combus¬ tion is achieved at any time. This problem can be remedied by supervision and manual regulation when it is about big boiler plants, while small furnaces mostly burn without supervision after the lighting, often resulting in an uncomplete combustion. The purpose of the invention is to show a furnace for coal burning, which is adjusted in such a way that primary and secondary air at any time is supplied automatically in the right proportion. This purpose is fulfilled by adjusting the combus- tion chamber with means for supply of combustion air in the total thickness of the coal measure. According to claim 2 the coal furnace is character¬ ized in that the air supply takes place hole at the bottom of the combustion chamber, in which hole a detachable air pipe with holes of principally the same length as the height of the combustion cham¬ ber is inserted, the air pipe being connected through a channel to an adjustable air valve. This embodiment is especially appropriate. The necessary primary air is supplied through those holes in the air pipe which are situated in and immediately under the burning coal measure, while secondary air is supplied through holes at the top of the pipe and through the detached holes at the sides of the pipe. When the cinder is to be removed the pipe is dismounted, whereafter the cin¬ der is either shovelled up through the firing door or poked down into an ashpan in the air channel. According to claim 3 the coal furnace can be cha- _ racterized in that the air supply takes place through a number of holes at the sides of the combustion cham¬ ber, which holes through a channel are connected to an adjustable air valve. This embodiment is approp¬ riate for furnaces with a relatively small and low combustion chamber. Finally, according to claim 4 the furnace can be cha- racterized in that the combustion chamber includes a liner of a fireproof material with a vent at the bottom -at which is mounted a detachable air pipe with vents, the air pipe being principally of the same length as the height of the liner. In this way furn- aces can in a simple way be adjusted for coal burn¬ ing. The invention is further explained with reference to the drawing, where Fig. 1 shows a preferred embodiment according to _ OMPI * IPO the invention,, shown from the side and as a cross section, and Fig. 2 a liner according to the invention mounted in a furnace, shown from the side and as a cross section. Fig, 1 shows a coal furnace with a smoke pipe 1, a firing door 2, and an adjustable valve 3. The combus- tion chamber 4 is worked out as a pot of lined, fire¬ proof material 5. At the bottom of the combustion cham¬ ber 4 is adapted a vent β with a sleeve, in which a pipe 7 is mounted with a number of holes 8 at the sides and detachable at the top. The pipe 7 can if necessary be perforated at the side and at the top. The vent β runs at the bottom into an air channel 9 which leads to the air valve 3 at*, the front of the furnace. The furnace is further arranged with a generally known circulation draught device which consists of a number of pipes 10 passing from the bottom of the furnace through the fireproof material 5 behind the combustion chamber 4 and to the front, where they run out above the firing door 2. Fig, 2 shows a furnace 11 in which is mounted a fire¬ proof liner 12 with vent 13 at the bottom, at which is mounted a detachable perforated air pipe 14. The vent 13 in the liner 12 is through a hole at the bottom of the furnace 11 connected to an air channel 15 which runs out at the front of the furnace through an adjust¬ able valve lβ. The air channel 15 is mounted on the furnace like the liner 12, the furnace 11 being first provided with a hole at the bottom, at which is attached a sleeve 17 for the air pipe 14.

Claims: C L A I M S 1. Coal furnace for spaceheating and of the kind which has a lined, fireproof combustion chamber, a firing door, and a valve for the supply of combustion air, c h a r a c t e r i z e d i n that the combustion chamber (4) is adapted with means (3 3 6, 7, 8) for the supply of combustion air in the total thickness of the coal measure. 2. Coal furnace according to claim 1, c h a - r a c t e r i z e d i n that the air supply takes place through a hole (6) at the bottom of the combus¬ tion chamber (4) in which hole (β) a detachable air pipe (7) with holes (8) and of principally the same length as the height of the combustion chamber (4) has been inserted, the air pipe (7) being connected through a channel (9) to an adjustable air valve (3). 3. Coal furnace according to claim ^ c h a ¬ r a c t e r i z e d i n that the air supply takes place through a number of holes at the sides of the combustion chamber, which holes through a channel are connected to an adjustable air valve. 4. Coal furnace according to claims 1 and 2, c h a - r a c t e r i z e d i n that the combustion chamber includes a liner (12)of a fireproof material with a vent (13) at the bottom, in which is mounted a detach¬ able air pipe (14) with vents, the air pipe (14) having principally the same length as the height of the liner (12).

Inventors: NIELSEN K, NIELSEN M
Applicants: NIELSEN K, NIELSEN M
Application year: 1981
Main classification: F24B5
IPC codes: F24B5, F24B13