MODE AND APPARATUS FOR SHIFTING OF FUEL IN A FURNACE

Abstract: A mode for, in a furnace, carrying forward and moving fuel made of combustible materials by cutting, crushing, compressing or by a similar method, such as wood, peat, straw, etc., e.g., in the form of chips, briquettes or pellets. The fuel is fed from the fuel container into the furnace through an opening in the furnace wall by means of a tube (2, 3) placed outside the furnace, connected to the opening, and by means of a spiral (5) that is rotated in the said tube. The fuel ends up on a trough (8) open at the top and placed in the furnace and air is blown through holes (7) provided in the walls of the trough into the fuel. The burning fuel is shifted forwards in the trough (8) initially preferably as pushed by the new fuel entering into the furnace from outside, without any agitating means being provided among the fuel at this part of the trough. At least towards the end of the trough, among the partly burnt and still burning fuel with a higher content of ashes, e.g., a rod-shaped agitator (9) twisted to a spiral shape and attached to the shaft at relatively few points is rotated so as to stir the fuel and the ashes as well as to reduce the drawbacks of caking of the ashes and to shift the fuel forwards.

Description: Mode and apparatus for shifting of fuel in a furnace The present invention relates to a mode for, in a furnace, carrying forward and moving fuel made of combustible materials by cutting, crushing, compressing or by a similar method, such as wood, peat, straw, etc., e.g., in the form of chips, briquettes or pellets, the said fuel being fed from the fuel container into the furnace through an opening in the furnace wall by means of a tube placed outside the furnace, connected to the opening, and by means of a spiral that is rotated in the said tube, whereat the fuel ends up on a trough open at the top and placed in the furnace and air is blown through holes provided in the walls of the trough into t the fuel. The invention is in particular characterized in that the burning fuel is shifted forwards in the trough initially preferably as pushed by the new fuel entering into the furnace from outside, without any agitating means being provided among the fuel at this part of the trough, and at least towards the end of the trough, among the partly burnt and still burning fuel with a higher content of ashes, e.g., a rod-shaped agitator twisted to a spiral shape and attached to the shaft at relatively few points is rotated so as to stir the fuel and the ashes and to shift them orwards as well as in order to reduce the drawbacks resulting from caking of the ashes. An embodiment of the equipment in accordance with the present invention will be illustrated by means of the attached, partly schematical drawing, wherein Figure.1 shows the equipment as a side view, as a vertical section, Figure 2 shows a section of the above along line A-A, Figure 3 likewise shows a section,along Figure 4 likewise shows a section, along line C-C , and Figure 5 likewise shows a section, along line D-D. In the sectional views, in order to make them clearer, some components located behind the section plane have not been drawn. The furnace proper is outlined only partly by means of a broken line 1. Its lef vertical wall is provided with an opening large enough so that the tube 2 just fits into it and fills it. Inside the tube 2, there is another, concentric tube 3. To a shaft 4 placed inside the said tube, a screw-shaped spiral sheet 5 is connected, which is drawn only schematically. The spiral ends outside the furnace at 6. When the shaft is rotated, the spiral shifts fuel out of the fuel container (not shown in the drawing) through the tube 3 into the -furnace. The shaft may be rotated by jerks, at appropriate time intervals. The times and speeds of rotation of the shaft are regulated by means of a thermostat (not shown in the drawing) , which from time to time starts the motor rotating the shaft 4 so that an appropriate quantity of fuel per unit of time burns and maintains the desired temperature in the furnace and, e.g. , in the water heated by the furnace, whereat the thermostat may be located in the said water. Air is blown into the space between the tubes 2 and 3 from an appropriate point (not shown in the figure) . The tubes 2 and 3, as tubes proper, end _ approximately at the wall of the furnace. On the con¬ trary, the bottom portions of the tubes continue in the way shown in Figures 3 to 5 inside the furnace as a trough 8 open at the top. The air blown between the tubes 2 and 3 into this hollow trough flows out through the holes 7 into the fuel placed in the trough 8, thus maintaining the burning. As the spiral 5 pushes new fuel batchwise into the furnace and onto the trough, the new fuel pushes the already burning fuel ahead of it in the trough further. Towards the end of the trough, the trough is provided with slots 13, shown in Fig. 4, through which the ashes can fall down off the trough onto the furnace bottom and into the spaces for the ashes. At the end portion of the trough, the shaft is also joined by a spiral-shaped rod 9 by means of radial arms 10. The slots 13 extend in the longitudinal direction of the trough at the end portion of the trough approximately equally far as the spiral 9 extends over the trough. According to a preferred embodiment, between the spiral rod 9 and the left vertical wall of the furnace, the shaft 4 incorporates no member shifting the fuel. In this part of the trough, viz., initially the dry-distillation of the new fuel takes place, then its ignition. In order that the fuel should catch fire readily and start burning all right, it is important that the relative positions of the fuel particles in relation to each other are not shifted extensively, in order that the initially tiny flames were able to grow in the passages between the fuel particles in which they started. An excessive stirring of the firewood, e.g., in an ordinary domestic fireplace immediately after kindling will extinguish the fire. A corresponding phenomenon in the apparatus in accordance with the invention is avoided thereby that, at the initial part of the trough, there is no apparatus changing the rela¬ tive positions of the fuel particles, but the layer of fuel that is about to catch fire is shifted forwards as such along the trough as pushed by the material entering from behind. Also, a continuation of the spiral sheet 5 out of the tube 3 into the furnace among the burning fuel and the fuel that is about to catch fire would • —•" - cause its drawbacks. Thereby, in the initial part of the trough, the fuel would be divided in a way into com¬ partments between the spirals of the spiral sheet, and the fire could thus not spread itself from compartment to compartment. At the end portion of the trough, it is important that the fuel on the trough is stirred to some extent and thereby gently shifted forwards by means of the spiral 9. In this part of the trough, the burning has already reached such an advanced stage that such stirring promotes the burning, owing to the burning, air has better access into the fuel and the ashes fall down through the slots 13 more readily. An important effect obtained by means of the spiral 9 is that the abundant ashes produced out of some fuels, such as some compressed peat blocks, can then not melt to a major extent and be caked into larger slag clods .or to blocks' that could no longer pass through the ash slots 13. Even the little quantity of slag clods that may be produced despite the effect of the spiral 9 is removed at point 11. The outer end of the spiral has been designed as a hook 12, which throws the slag clods or blocks over the edge of the trough. In prior-art burners of corresponding type with no spiral rod 9, when certain fuels are used, molten ashes caked into clods and blocks are gathered at the final end of the burning base as a constantly increasing layer. The new fuel is then pushed onto this slag layer, where it does not obtain a sufficient ■ quantity of air, and the burning there is disturbed or totally prevented. This is quite a detrimental drawback, which is experienced especially when certain species of peat and plants are burnt. The ashes of plants mainly consist of silicates, phosphates, sulphates and carbonates of potassium, sodium, calcium, magnesium and iron. The relative proportions of these substances, however, vary to a great extent depending on the species of plant, and so do the ash contents as well as the melting points and the caking tendencies. By means of the apparatus in accordance with the invention, it is, however, readily possible to burn any of the above- fuel sorts. The apparatus is also suitable for use in various existing furnaces. For example, out of an oil-burning furnace, the oil burner proper may. be removed and replaced by an apparatus in accordance with the present invention, burning solid fuel particles in the way described above, together with the necessary accessories.

Claims: AMENDED CLAIMS (received by the International Bureau on 31 January 1983 (31.01.83)) 1. (amended). A mode for, in a furnace,carrying forward and moving fuel made of combustible materials by cutting, crushing, compressing or by a similar method, such as ' wood, peat, straw, etc., e.g., in the form, of chips, briquettes or pellets, the said fuel being fed from the fuel container into the furnace through an opening in the furnace wall by means of a tube (2, 31 placed outside the furnace, connected to the opening, and by means of a spiral (5) that is rotated in the said tube, whereat the fuel ends up on a trough (8) open at the top and placed in the furnace and air is blown trough, holes (7) pro¬ vided in the walls of the through into the fuel, c h a r a c t e r i z e d in that the burning fuel is shifted forwards in the trough (8) initially as pushed by the ne., r fuel entering into the furnace from outside, without any agitating means being provided among the fuel at this part of the trough, and towards the end of the trough among the partly burnt and still burning fuel with a higher content of ashes, e.g., a rodshaped agitator (9) twisted to a spiral shape and attached to the shaft at reltively few points is rotated so as to stir the fuel and the ashes and to shift them forwards as well as in order to reduce the drawbacks of slag formatio . 2. (amended) . An apparatus for the application of the mode as claimed in claim 1, which apparatus comprises two concentric tubes (2, 3), between which air for burning is passed into the furnace and inside which inner tube (3) , by means of a rotatable spiral (5) resembling a screw spiral, fuel is fed into the furnace and which tubes are in the furnace converted to a hollow trough (8) open at the top, in which trough burning material is pushed forwards in the logitudinal direction of the trough until it is practically burnt out, and w erebv the air for burning comes through the holes (7) f-rom the hollow trough (8) into the burning material, c h a r a c t e r i z e d in that, at the initial portion of the trough, the shaft (4) of the spiral (5) continues without any additional projections and that, at the end portions of the trough, an agitator member or agitator members are attached to the shaft by means of radially projecting arms (10), e.g. a rod (9) bent to spiral form con¬ centrically with the shaft (4) , the said rod being placed at a distance determined by the length of the said arms (10) from the shaft (4) and, at its bottom part, at an appropriate distance from the trough (8) . 3. An apparatus as claimed in claim 2, c h a r a c t e r i z e d in that at the end portion (11) of the spiral, its radius is longer than elsewhere, whereat a cam (12) moving near the inside wall of the trough is formed at the final end, which cam lifts ashes and pieces of slag off the trough over its side wall, and that toothings or equivalent, radially pro- jecting from the spiral, have been possibly attached to other parts of the spiral. 4. An apparatus as claimed in claim 3, c h a r a c t e r i z e d in that the agitator means consist of curved pin portions or equivalent objects, which are attached to the outer ends of the arms (10) and which are placed at a distance from the inside . wall of the trough (8) . OMPI

Inventors: PAEMPPI TOPI, PAEMPPI, TOPI
Applicants: PAEMPPI TOPI, PAEMPPI, TOPI
Application year: 1982
Main classification: F23B1
IPC codes: F23K3