COMBUSTION UNIT

The invention belongs to heating appliances, namely solid fuel boilers.

The closest prior art described in Patent Application No 5731, TPKK: F 23 B 10/00 published in the official bulletin of the State Patent Bureau "Inventions, design, trademarks" No 2, 201 1 consists of a fuel-stocking shaft installed inside the housing, a combustion chamber installed in the fuel- stocking shaft, a gas combustion chamber with a burner, an ash box, a smoke extract and a heat exchanger. The housing of the burner is double-walled, each wall has an opening: an inlet for supplying secondary air into the space between the walls of the burner, and an outlet for releasing heated secondary air into the combustible gas mixture formation and combustion channel.

The known technical solution does not secure generation of optimal heat amounts, sufficient formation of combustible gas mixture and its combustion at a high temperature.

The objective of the invention is to increase the amount of generated heat by accelerating the formation of combustible gas mixture and its combustion at a high temperature.

To achieve the objective of the invention, a stainless steel reflection partition wall is installed in the lower part of the first combustion chamber - the fuel-stocking shaft of the boiler - and an external air inlet tube is placed above the ash box. The tube is connected to a tube-shaped accelerator that supplies preheated air and accelerates the delivery of combustible gas to the combustible gas mixture formation and combustion channel in the universal gas combustion unit installed in the second double-wall combustion chamber. Furthermore, the metal cone-shaped gas combustion unit consists of an air supply and preheating channel, which is located between the walls of the double-wall housing of the unit and connected to the air preheating channels with a hinged lid of the unit. The unit contains a double - internal and external - metal core with a lid installed inside the housing, a hot air distribution and supply channel between the external core and the internal wall of the housing, designed to distribute and supply hot air into the combustible gas mixture formation and combustion channel between the external and internal cores. Furthermore, to achieve the objective of the invention, the core and the lid have openings, the ash box has a removable partition dividing the box into two vertical parts, a control panel is designed to monitor the combustion process, the upper part of the fuel-stocking shaft has an additional opening for fuel supply into the fuel-stocking shaft, and metal plates are fixed to the heat exchanger.

The invention is illustrated by drawings.

Fig. 1 - principal scheme of the solid fuel gasification boiler, where 1 - housing of the boiler, 2 -load door, 3 - ignition door, 4 - smoke extract, 5 - forced draft fan, 6 - fuel-stocking shaft (first combustion chamber), 7 - stainless steel reflection partition wall, 8 - ash box, 9 - grating of the fuel- stocking shaft, 10 - partition of the ash box, 1 1 - air supply tube, 12 - accelerator, 13 - second double- wall combustion chamber, 14 - universal gas combustion unit, 21 - heat exchanger. Fig. 2 -principal scheme of the universal gas combustion unit, where 15 - hinged lid of the unit, 16 - air supply and preheating channel, 17 - internal core, 18 - external core, 19 - hot air distribution-supply channel, 20 - combustible gas mixture formation and combustion channel. The metal housing of the solid fuel gasification boiler 1 has double walls. A load door 2 is installed at the top and an ignition door 3 with a manually or automatically operated valve is located at the bottom of the boiler 1. A smoke extract 4 is installed for the discharge of combustion products from the upper part of the boiler. The upper part of the boiler is fitted with a forced draft fan 5. A fuel-stocking shaft, the first combustion chamber 6, with an inclined front wall to prevent fuel from attaching is placed in the housing 1. A stainless steel reflection partition wall 7, which reflects the heat back to the fuel-stocking shaft, the first combustion chamber 6, is installed in the lower part of the fuel- stocking shaft 6. An ash box 8 is installed under the reflection partition wall 7 and a grating of the fuel-stocking shaft 9 is placed over the ash box 8. The ash box 8 is vertically divided by a removable partition 10, which enables to speed up moisture evaporation from the fuel.

The partition 10 is necessary to maintain stronger draft when fuel with high moisture content is burned in the fuel-stocking shaft - the first combustion chamber 6. An air preheating tube 11 designed to preheat the supplied external air and a gas velocity accelerator 12 are installed under the grating 9 of the fuel-stocking shaft, the first combustion chamber 6. Next to the fuel-stocking shaft, the first combustion chamber 6, there is the second double-wall combustion chamber 13 containing a universal cone-shaped double-wall gas combustion unit 14 with a hinged lid for combustible gas mixture formation and combustion. The hinged lid 15 is composed of air-preheating channels connected to the air supply and preheating channel 16 between the walls of the housing. A double cone-shaped core - internal 17 and lidded external 18 - is installed in the central part of the housing 14. The walls of the core and the lid have openings. A hot air distribution-supply channel 19 for supplying hot air into the combustible gas mixture formation and combustion channel 20 is designed between the external core 18 and the internal wall of the housing 14. The combustible gas mixture formation and combustion channel 20 is located between the internal 17 and external 18 cores. The boiler is connected to the heat exchanger (heating system) 21 with inlet and outlet nipples. Metal plates are welded to the heat exchanger 21 for a more efficient heat transfer.

Operation of the solid fuel gasification boiler with the universal gas combustion unit.

Load solid fuel, such as wood, wood waste or billets, through the load door 2, open the ignition door 3 of the fuel-stocking shaft, the first combustion chamber 6, and light the fuel if the required air draft is achieved. Burning of bulky or fine solid fuel in the fuel-stocking shaft, the first combustion chamber 6, results in formation of combustible gas. The gas goes from the fuel-stocking shaft, the first combustion chamber 6, into the second combustion chamber 13. The gas velocity towards the second combustion chamber 13 and consequently the universal gas combustion unit 14 is stimulated by preheated air supplied by the accelerator 12; the preheated air reaches the accelerator through the air supply tube 11. The air-preheating tube 1 1 heats up itself from embers. After the combustible gas gets into the combustible gas mixture formation and combustion channel 20, it mixes with the hot air, which is further heated by the channels of the unit, supplied by the hot air distribution-supply channel 18. Additional heating increases the air temperature and consequently the hot air facilitates fast and qualitative formation of the combustible gas mixture and its efficient combustion. Therefore, the combustible gas mixture formed in the universal gas combustion unit 14 in the aforesaid manner burns to generate a considerable amount of heat, which is transferred by the heat exchangers with fixed plates. The reflection partition wall 7 keeps the heat in the fuel-stocking shaft, the first combustion chamber 6, and prevents it from dispersing. Furthermore, the proper design of the universal gas combustion unit installed in the second combustion chamber provides for even dissipation of heat that is moving upwards and transfer of an optimal heat amount by the heat exchanger 21 with the fixed plates. Combustion products also move up to the top part of the boiler where they are removed through the smoke extract.

To create optimal conditions for combustible gas mixture formation and combustion, a forced draft fan controls the air intake. According to the readings of the lambda probe (a sensor used to monitor the level of unburned oxygen in the exhaust gases of an engine), a valve and a draft fan can be used to automatically control the air intake.

The operation of the boiler is automated.

The technical solution of the claimed boiler provides optimum conditions for a qualitative formation of the combustible gas mixture and its complete and cost-efficient combustion at a high temperature of 1200-2000°C and consequently to generate of a large amount of heat. The stainless steel reflection partition wall and the double-wall second combustion chamber play a significant role in total heat retention and maintaining a high temperature. A pre-set programme, which is used to operate and control the boiler, and the universal gas combustion unit installed in the second combustion chamber, provide for an easier control of the combustion process, cutting-down the boiler maintenance time, and achieving a high coefficient of boiler performance.