FURNACE INSTALLATION

Abstract: Furnace installation designed for solid fuels and exhibiting a fire grate receiving the fuel from a fuel feeding device. The grate comprises a disc (3, 21) of substantially circular circumference, which cooperates with at least one distribution means (15, 36) connected with the fuel feeding device (14, 26, 29), which is rotatably arranged in relation to the disc (3, 21), said distribution means being designed to secure that the desired thickness of the layer of fuel deposited on the grate during the relative rotation of the same is maintained.

Description: Furnace installation The present invention relates to a furnace installation designed for solid fuels and exhibiting a fire grate receiving the fuel from a fuel feeding device. It is a principal object of the invention to provide a furnace of the kind mentioned above, by means of which it is made possible that the fuel, which by the feed¬ ing device is deposited on the grate, will be evenly distri buted over the same in a layer of desired thickness. Said object is obtained by means of a furnac according to the present invention, which is substantially characterized by the grate comprising a disc of substan¬ tially circular circumference, which grate co-operates with at least one distribution means connected with the fuel feeding device, which is rotatably arranged in relation to the disc, said distribution means being designed to. secure that the desired thickness of the layer of fuel deposited on the grate during the relative rotation of the same is maintained. The invention will now be described in the following, reference being made to the accompanying draw¬ ings, in which Fig. 1 is a partly sectional view of a first example of embodiment of a furnace made according to the invention, Fig. 2 is a view of a second example of em¬ bodiment of a furnace made according to the invention like¬ wise shown in a partly sectional view, Fig. 3 is a fuel feeding device and a means for spreading shown in a partly sectional view and seen in side elevation, Fig. 4 is a cross-sectional view of the in¬ stallation and the means respectively illustrated in Fig. 3, Fig. 5 is a view of a discharging device de¬ signed to rake out burnt residues from the furnace grate, an Fig. 6 is a cross-sectional view of the discharging device illustrated in Fig. 5. The furnace installation illustrated in the accompanying drawings is designed to be used as a boiler in residential housing units, but its size can of course be adapted to sui ' any heating requirements, and it can for example be designed for use as a combustion plant in a big industrial installation. The furnace is designed for solid fuels, by way of example such as wood chips, sawdust and peat. The body of the furnace installation in the examples shown comprises a closed part of cylindrical shape, in the drawings indicated with 1. The bottom portion of the f rnace is provided with supporting legs indicated with 2. The space in the body 1 of the installation is divided up in a high and a low chamber by means of a disc of substan¬ tially circular circumference. The disc is in Fig. 1 indi¬ cated with 3. The disc in question, which in the illustrated examples exhibits radially disposed openings 4 for the flow of air, forms the grate of the furnace installation. In the first example of embodiment illustrated in Fig. 1 this grate 3 exhibits the form of the mantle of a cone with its pointed end facing in upwards direction, and the top side 3A of this grate 3 is designed to receive fuel for its combustion on the same. The grate 3 is rotatably mounted on a vertical shaft 5 located at its centre and penetrat¬ ing the bottom 6 of the furnace installation 1, which shaft 5 can be driven by a motor 7. This driving motor 7 can be connected with a sensor (not shown in the drawings) , which senses the load of the furnace and regulates the rotation of the grate 3 accordingly. The grate 3 is designed to, after a completed revolution of the same, only carry the cinders at its discharging point, and the driving shaft 5 can be connected with a rotatable raking device for the removal of cinders (not shown in the drawings) and located at the bottom 6 of the furnace 1, said raking device during OMP its rotation and the rotation of the shaft 5 removing cinders from the bottom 6 and for example conducting them to a worm conveyor located in a chute. A connecting pipe 8 for hot air debouches in a hole in the jacket 9 of the furnace installation 1 and more specifically in the chamber, where the combustion takes place, and is designed to conduct hot air from the furnace 1 to the spaces, which are desired to be heated up. The jacket 9 also supports blowers 10 provided to blow in air in the furnace 1 for the combustion. As is evident from the drawings, a baffle plate 11 of annular shape and located between said blowers 10 divides up the air intake part of the furnace 1 under the grate disc 3 in two spaces for air intake, and air is supplied to said spaces by means of each respective blower 10. A fuel supply pipe 14 slightly laterally dis¬ placed relative to the centre of the grate disc 3 and ex¬ tending through the upper portion 12 of the furnace 1 to the combustion chamber 13 of the furnace supports a raking device 15 extending in transversal direction to the direct¬ ion of rotation of the grate disc 3. This pipe 14 together with the raking device 15 are mounted in such a manner that they can be displaced in the axial direction of the furnace installation, so that they can adjust the thickness of the layer of fuel deposited on the grate disc 3 through the supply pipe 14. The fuel is made level during the rotation movement of the grate disc 3, and the direction of rotation is the one indicated with an arrow in Fig. 1. The thickness of the layer of fuel is adjusted by lifting up the raking device 15 from and lowering it down to the grate disc 3 respectively depending upon the desired thickness. A discharging means for cinders is provided in the space in front of the raking device 15, as seen in the direction of rotation of the disc 3. This means in the embodiment illustrated in Fig. 1 comprises a wedge-shaped rake 16 with its pointed portion facing against the direc- tion of rotation, said rake 16 at one end by means of slewing brackets 17 being .connected with a driving motor 18 in order to produce vibrations in said discharging rake 16. The fuel, which by means of the raking device 15 is levelled on the grate 3, and which during .the rotation of said grate 3 is burnt according to the rotation of the same, is owing to the adjustment of the revolutions of the grate 3 by means of the driving motor 7 substantially comp¬ letely burnt, when it arrives at the discharging rake 16. The cinders are then raked out from the surface 3A of the grate by means of the discharging rake 16, and on account of the vibrations of the same, the cinders are discharged in the longitudinal direction of said rake 16 landing in a discharging shaft 19 mounted on the outside of the jacket 9 of the furnace 1 and debouching in a discharging chute 20 for cinders. In the embodiment according to Fig. 2 the rotating grate is formed by an annular part 21 with a cent¬ rally located discharging hole 22 for burnt material. This discharging opening 22, as is evident from Fig. 2, is close¬ ly connected to a tubular shaft 23 located under the grate 21 and extending downwards in vertical direction through the lower part of the furnace 1. The annular grate 21, which exhibits a conical shape, its pointed portion facing down- wards towards the discharging opening, is on its underside along its circumference supported by motor driven support¬ ing and driving rollers 24. These rollers 24 are preferably made with teeth, and in such a case they co-operate with a driving gear ring 25 mounted on the underside of the annular grate 21. In the space formed under this ringshaped and also with air vents 41 provided grate 21 there are a similar air separating baffle wall 11' and blowers 10' res¬ pectively as in the previously described first example of embodiment. The function of these parts is the same in both embodiments, in which they form a first zone of combustion on one side of the baffle wall 11* and a second zone of combustion on the other side of the baffle wall 11'. The fuel feeding device in the second em¬ bodiment shown in Fig. 2 comprises an opening 26 made in the jacket 9' in the area above the peripherical portion of the annular grate 21, -through which opening fuel is arranged to be fed from a hopper 27 located on the outside of the furnace onto the peripherical upper surface portion 21A of the annular grate 21 by means of a worm conveyor rotatably mounted and driven in a transportation tube 28. The fuel, which by means of the worm conveyor is fed onto the grate 21, on account of the inclination of the grate 21 falls down towards the discharge opening 22 and in connec¬ tion therewith forms a layer of fuel of uniform thickness, the material discharged through the discharging opening 22 and the tubular shaft 23 because of the adjusted rotation of the grate 21 being practically completely burnt. A levelling rake and a discharging rake si¬ milar to the ones of the first example of embodiment can also be used in this second example of embodiment, but the discharging means must then of course be designed in such a manner that the cinders are fed out through the discharg¬ ing opening 22 at the centre of the grate 21. 'The fuel supply means 29, which is illustrat- ed in Figs. 3 and 4, and which can be applied at least to the furnace installation according to the first example of embodiment, comprises a worm conveyor 33 rotatably mounted in a transportation tube 30 and driven by a motor 31. The front portion of this transportation tube 30 at its end extending inside the furnace 1 blends into a hopper 36 pro¬ vided with lateral walls 34, 35, which hopper, as seen in the direction of rotation of the grate, extends across the same along substantially the whole width of said surface 3 of the grate. Fuel 37 stored in a hopper 38 located at the rear end of the tube 30 is by means of the worm conveyor 33 fed through the tube 30 to said hopper 36. During the rota- o. ' .g-i " tion of the grate 3 a layer of material is fed onto the surface 3A of the grate, the thickness of this layer being adjusted by at least the walls 34, 35 of the hopper 36 per¬ mitting a setting in vertical direction relative to the grate surface 3A. If by way of example a thicker layer of fuel is desired, the walls 34, 35 are, thus, lifted up in direction away from the grate 3, and in order to reduce the thickness of the fuel layer, said walls are lowered down. The discharging means for cinders, which is illustrated in Figs. 5 and 6, and which is preferably app¬ lied to the embodiment according to the first example, comprises a wedge-shaped chute 39 mounted with its pointed end facing against the direction of rotation of the grate 3. The upper portion 39A of this chute 39 co-operates with the peripherical portion of a worm conveyor 40, which is rotat¬ ably mounted in the chute 39. When the grate is rotating in the direction of the arrow, cinde ' rs are raked from the surface 3A of the grate 3 landing in the chute 39, from where they are fed out by means of the worm conveyor 40 in the direction indicated by the arrow away from the grate 3 and the furnace 1. The invention is not limited to the examples of embodiment illustrated in the drawings and described above, but can be varied within the scope of the following claims. It can by way of example be mentioned that the sub¬ stantially circular grate disc can be designed in a number of different ways. The disc can for example be designed as a multi-stage grate or as a plane substantially horizontal grate. The fuel feeding device and the levelling rake as well as preferably also the discharging rake can be designed to perform a movement along the circumferential direction of the grate relative to the grate, if the latter one is designed as a fixed component. The discharging rake must in this case, as seen in the direction of movement, be pla¬ ced ahead of the feeding-in portion and the levelling rake. The grate can for example be provided with portions, which can be opened up, so that after a complete turn of rotation of the grate, said portions by means of for example a pivoting movement open up in such a manner that the cinders fall down in the space under the grate. The discharging rake 16, which is shown in Fig. 1, and the worm conveyor 40 shown in Fig. 5, can preferably be provided with an air supply duct, which is designed to supply air to the fuel residues reaching con- tact with said discharging means, so that the fuel will be completely burnt.

Claims: C l i s 1. Furnace installation designed for solid fuels and exhibiting a fire grate (3, 21) receiving the fuel from a fuel feeding device (14, 26, 29), c h a r a c ¬ t e r i z e d b y the grate comprising a disc (3, 21) of substantially circular circumference, which grate co¬ operates with at least one distribution means (15, 36) connected with the fuel feeding device (14, 26, 29), which is rotatably arranged in relation to the disc, said distribution means being designed to secure that the desired thickness of the layer of fuel deposited on the grate during the relative rotation of the same is maintained. 2. Furnace installation according to claim 1, c h a r a c t e r i z e d b y the grate (3) exhibiting the form of a conical mantle (3).- 3. Furnace installation according to anyone of the preceding claims, c h a r a c t e r i z e d b y the grate being formed by an annular part (21) with a discharge opening (22) of central location for burnt ate- rial. 4. Furnace installation according to anyone of the preceding claims, c h a r a c t e r i z e d b y the grate (21) in a manner permitting its drive being supported by a supporting and driving means preferably co-operating with the underside of said grate, which pre¬ ferably comprises toothed wheels (24) , which can engage a gear ring (25) . 5. Furnace installation according to anyone of the claims 1-3, c h a r a c t e r i z e d b y the grate (3) in a manner permitting its drive being supported by a shaft (5) , which itself can be driven and is located at the centre of the grate (3) . 6. Furnace installation according to anyone of the preceding claims, c h a r a c t e r i z e d b y the fuel feeding device (14, 29) debouching at a levelling rake (15, 36) extending crosswise to the direction of'move¬ ment of the grate (3) , said rake forming said distributing means and occupying a position at such a distance of height above the top surface (3A), of the grate (3-) that a desired thickness of the layer of fuel deposited on the grate will be obtained after said-fuel has passed by the rake (15, 36) 7. Furnace installation according to claim 6, c h a r a c t e r i z e d b y said levelling rake (36) being formed by a laterally covered chute-like hopper (35) , in the upper portion of which a conveyor device (30, 33) for the fuel feed debouches, said conveyor device preferab¬ ly comprising a worm conveyor (30, 33) . 8. Furnace installation according to anyone of the claims 1-6, c h a r a c t e r i z e d b y said fuel feeding device exhibiting an intake opening (26) located at the periphery or centre of the grate (21) , the distribut ing means being formed by said intake opening in co-opera¬ tion with the grate (21) , which is movable in relation to the same. 9. Furnace installation according to anyone of the preceding claims, c h a r a c t e r i z e d b y ex¬ hibiting a discharging rake (16, 39) , which, as seen in the direction of movement of the grate (3) , occupies a position in the area ahead of a fuel levelling rake (15, 36) , said discharging rake preferably being made to vibrate or co¬ operate with a discharging worm conveyor (40) , which is rotatable in the direction of discharge. 10. Furnace installation according to anyone of the claims 1-8, and wherein the grate (21) comprises an annular part exhibiting the form of the mantle of a cone inclining in direction towards its centre, c h a r a c ¬ t e r i z e d b y the centric portion (22) of the grate debouching in a discharging duct (23) extending in a direc- tion out of the furnace installation (1) .

Inventors: JOHANSSON S
Applicants: JOHANSSON S
Application year: 1981
Main classification: F23K3
IPC codes: F23K3