HEATING BOILER

Abstract: A heating boiler operating on solid, comparatively finely divided fuel, such as chips or peat, and which is used to produce hot water or steam. The boiler comprises a furnace (7), in which the grate consists of a shell-like burning basket (1), which can be placed in rotary motion about its substantially horizontal axis. The rotating of the burning basket (1) may be arranged by connecting to the basket a tubular arm (5) provided with a gear wheel and which is connected to a motor (24) placed outside the boiler. The arm (5) then simultaneously serves as duct through which the fuel is introduced into the burning basket (1). The purpose of the rotating burning basket (1) is to boost the combustion reaction so that comparatively wet fuel can be used in the boiler. The combustion may furthermore be boosted by placing the burning basket (1) in the furnace (7) in a housing (11) having as its extension a cyclone (12) constituting a helical exhaust duct for the flue gases, which sets the gases at high temperature into strongly turbulent motion.

Description: The present Invention concerns a h<>,itinr, hoi lor 1nten-ie-d for sol - fuel and comprising a furnace ani a feeding means to the purpose of feeding fuel onto the grate in the furnace. In prior art heating hoilprs using solid fuel such as peat or chips are known in which the feeding of fuel into the boiler furnace is with the ai of mechanical conveyors. The problem in using said fuels is however that they often contain a considerable amount of moisture, which retards the coπbustion. Tn some boilers, in an attempt to solve this prohlem, the fuel is dried with the aid of hot combustion gases conducted from the furnace. Tn that case the fuel feed ducts and the set of flue gas exhaust conduits have to be interconnected in a wav which renders the boiler comparatively comnlex of its construction. The object of the present invention is to nrovide a heatins boiler in which moist fuel can be burne , even green chins if required, without necessity to perform any drying of the fuel prior to its introduction into the boiler furnace. The invention is based on constructing the grate in the furnace in a way by which is achieved sufficient boosting of -the com¬ bustion reaction, and it is characterized in that the grate consists of a shell-like burning basket into which the fuel can be supplied and which can be set in rotary motion about its substantially horizontal axis. The rotating burning basket disperses the fuel over a wider area so that it is into the most efficient contact possible with the combustion air. By keening the burning basket in constant m o , one prevents the accum¬ ulation of fu«l on one spot, whereby further the. starting of rhe combus¬ tion reaction is 4pee<j≤4 «π» One embodiment of the heating boiler of the invention is characterized in that to the burning basket has been connected an arm parallelling the axis of the basket and connected over a gear wheel with the motor rotating the burning basket. Tt is to advantage in connection w h this probl m solu¬ tion to shape said arm to b° a hollow tube extending out from the boiler. In that case the mechanism rotating the burning basket constitutes no obstacle whatsoever to the feeding operation. Another embodiment of the heating boiler of the invention is characterized in that the burning basket consists of net-like material. The advantage is then that the fu * »l , which comes in a gr.nnulate—rese bl ing form, is caught in the net, which to a considerable extent prevents the sliding down of the fuel as the burning basket rotates. The net constitutes an ideal com¬ bustion base also in the respect that the fuel is all the time in com¬ pletely unobstructed contact with the combustion air. The invention may also he advantageousl applied so that the burning basket is encircled by a housing having as its extension a cyclone fitted with a helical flue gas exhaust duct. The heating boiler mav then be furnished with a duct through which the combustion air is blown into the housing, and the helical exhaust duct, where the combustion gases that are produced are set in rotary, accelerating motion, efficiently brings the combustion reaction to its completion and prevents ash from accumulating in the housing. The invention is described in detail in the following with the aid of an example and with reference to the attached drawing, wherein:- Fig. 1 presents the rotating burning basket and the arm thereto attached with its gear wheel; Fig. 2 shows, partlv sectioned, the furnace of the heating boiler, pro¬ vided with a burning basket as depicted in Fig. 1 and with a fuel dis¬ pensing apparatus; and Fig. 1 shows the section along line TTT-TTT in Fig. 2. In Fig.l has been depicted the rotating burning basket 1 constituting the grate of a heating boiler using mainly chins or milled peat, said burning basket comprising a cylindrical mantle 2 of metal netting, confined at both ends by a circular plate, or disk, " . One of said disks has an aper¬ ture 4, to which has been affixed a horizontal, tubular arm 5. Close to the end of the arm has been mounted a gear wheel fi, bv which the arm is connectable to the motor rotating the burning basket 1. In Fig. 2 is seen the furnace 7 of the heating boiler, its grate consist¬ ing of the rotating burning basket 1 above described. The furnace 7 is enclosed within a water jacket S, which absorbs the heat generated by the boiler, an ash hole 9 and tho initial end of the flue gas removing duct 1 having bean disposed on the bottom of the furnace. τ he rotating burning basket 1 has been encircled, in the furnace 7, with a cylindrical housing 11 having as its extension a cyclone 12, serving as exit path for the flue gases. The cyclone 12 comprises a gently converging inner cone 1 and a helical partition 14, which forms between the inner cone and the mantle of the cyclone a helical flue gas exhaust duct 15. This duct communicates by an aperture 16 with the housing 11 and it tapers down towards the end of the cyclone 12 in such manner that the speed of the departing flue gases increases in the duct. The inner cone 13 communicates with the housing 11, whereby its temperature rises to great height during the combustion pro¬ cess, and this ensures complete combustion in the turbulent gas flow taking place in the exhaust duct 15. Over the housing 11 an oil burner 17 has been disposed, communicating by the duct IS with the housing. The means supplying fuel into the furnace 7 consists of a conveyor l q , which has been disposed within the hollow, tubular arm 5 connecting with the burning basket 1 and extending out from the boiler. The conveyor 19 consists of an endless belt 21 provided with spikes 20, visible in sec¬ tion in Fig. 3. Between the conveyor 19 and the rotating arm 5, seals 22 have been fitted, as shown in Fig. 3. One end of the conveyor 19 has been connected to the fuel hopper 2.3, and the other end is placed adjacent to the aperture 4 in the disk 3 confining the burning basket, so that the fuel can fall down to the bottom of the burning basket. The motor 24 rotating the burning basket 1 over the arm 5 and the gear wheel *S has been placed outside the boiler, as shown in Fig. 2. The heating boiler just presented can he automated, in which case it operates as follows. The burner 17 is to begin with run with fuel oil, and the motor 24 rotating the burning basket 1 starts at this time. When these actions have been going on for a certain time, the motor of the con¬ veyor 19 starts.The conveyor now begins to transport fuel from the hopper 23 to the burning basket 1 , where it is ignited by the flame from the burner 17. The oil pump of the burner I 7 then becomes switched off so that the boiler ill thenceforwird operate exclusively on the solid fuel in¬ troduced by the convevor 1 and on oxvgen blown in through the duct 18. The speed of rotation of the conveyor motor 25 is controlled on the basis of the flue gas temperature sensed by the thermostat 2 , so that the motor °AD O speed is reduced by the control automatics when a given temperature limit is exceeded. As a result, the fuel introduction rat p goes down, and the flue gas temperature is correspondingly lowered. Tf on the other hand the flue gas temperature falls below a predetermined limiting value, the automatics increase the fuel introduction rate by increasing the speed of the motor. It is obvious to a person skilled in the art that different embodiments of the invention are not confined to the example presented above and that they may instead vary within the scope of the claims following below. For instance, it is possible to mount *hz,-burning basket and the tubular arm connecting therewith in a slightly inclined position, e.g. so that the arm slopes downward at an angle about 3 to 4 degrees, whereby the rotating arm serves as automatic fuel feeding means and no separate conveyor is needed. It is further possible to constrxict in the mantle of the cyclone serving as exit path ^or the flue gases, a preferably helical duct through which is conducted water which one desires, to heat. The duct runs in counter- direction to the gas flow, thus forming a heat exchanger operating ac¬ cording to the countercurrent principle and by the aid o which supei— heated steam may be generated. If the duct is provided with branch pipes and with check valves placeφ at the points where they branch off, super¬ heated steam may be drawn from the boiler as required, at different pres- sxires and temperatiires- Such a duct connected to the cyclone av even replace the entire water jacket encirc ng the furnace, as in the preced¬ ing example.

Claims: r> Cl aims ' 1. Heating boiler intended for solid fuel and comprising a furnace CM and a feeding means (19) for supplying fuel onto the grate in the furnace, characterized in that the grate consists of a shell-like burning basket (1 " ) into which the fuel can be supplied and which can be placed in rotary motion about its substantially horizontal axis. 2.Heating boiler according to claim 1, characterized in that to the burn¬ ing basket 1) has heen connected an arm ( 5) parallelling the axis of the basket and connected over a gear wheel (6) with a motor (24) rotating the burning basket. 3. Heating boiler according to claim 2, characterized in that the arm (5 " ) of the burning basket extends to the outside of the boiler. 4. Heating boiler according to claim 3, characterized in that the gear wheel (6) rotating the arm (5^ and the motor (24) are located outside the boiler. 5. Heating boiler according to any one of claims 2-4, characterized in that the arm ( > of the burning basket (1) consists of a hollow tube, through which the fuel can he introduced into the burning basket. n. Heating boiler according to anv one of the preceding claims, charac¬ terized in that the burning basket (1) consists of net-like material. 7. Heating boiler according to any one of the preceding claims, charac¬ terized in that the burning basket is encircled bv a housing (11) having as its extension a cvclone (12) pro ^e^ with a. helical flue gas exhaust duct (1 1 (

Inventors: AUTERE I
Applicants: AUTERE I
Application year: 1981
Main classification: F23H9
IPC codes: F23B30, F23H9, F24H1, F24H9