RU2780178C1 - Bathhouse furnace - Google Patents

Abstract

FIELD: heating systems.

SUBSTANCE: invention relates to thermal power engineering, namely to furnace heating systems based on solid fuel furnaces, and can be used to create bath furnaces with improved technical and operational characteristics. The bath furnace contains a housing containing a firebox with an ignition door and a grate, under which an ash collector with an ash box and an ash box tunnel are located, a heat exchange cavity with a chimney and a stove inside, with a door for loading stones and a device for generating steam. The housing contains a hopper placed on the bottom with the formation of a firebox in the lower part. The hopper in the upper part contains a loading door, and from below in the rear part of the furnace there is a gas window to which a heat exchange cavity is connected through a transition tunnel. In the transition tunnel, a secondary air duct with metering holes and an afterburning chamber are sequentially located. The secondary air duct communicates through an opening in the bottom with the sub-grate cavity. In the upper part of the hopper there is a smoke extraction flap with a drive and a position lock for connection by means of a gas channel with a chimney located in the upper part of the heat exchange cavity for the removal of flue gases from the furnace. A transverse plate with a hole for controlling the inlet air flow is installed on the ash box near the front wall between the side walls.

EFFECT: increase in the duration of the furnace operation from one fuel load, an increase in combustion efficiency and an increase in the stability of thermal power generation during furnace operation.

7 cl, 1 dwg

Description

The invention relates to thermal power engineering, namely to furnace heating systems based on solid fuel furnaces and can be used to create sauna stoves with improved technical and operational characteristics.

It is known that bath stoves are a special kind of heating appliances and have a long history of development. However, the disadvantage of all known designs of solid fuel sauna stoves is the short operating time from one fuel load. This is due to the fact that bath stoves operate mainly in the maximum power mode, and the operating time is limited by the amount of fuel placed in the combustion chamber. Since almost the entire volume of fuel burns in the bath furnace at the same time, its increase leads to an increase in the generated power and does not significantly affect the duration of the furnace. If, at the same time, the heat exchange surface of the furnace is not increased, this will lead to a decrease in the efficiency of the furnace, since excess heat energy will be carried away by flue gases and the service life of the furnace will be reduced due to overheating of the metal of the casing. In addition, in the process of fuel combustion, the generated thermal energy changes over a wide range (including due to the low accuracy of controlling the flow of inlet air), as a result of which a significant fluctuation in air temperature occurs in the heated room. The consequence of these shortcomings of bath stoves is the need for frequent addition of fuel to the furnace to prevent temperature fluctuations in the steam room, which reduces the performance of bath stoves and makes it difficult to carry out high-quality bath procedures.

The bath stoves are known (Patents RU2737626 C1 2020, RU2347980 C1 2009, Finland Patent No. F1865046 1988, SU1633233 A1 1991, SU1813994 A1 1993, RU22281433 C2, 2004487, and RUU27587, and RU27587. U1, RU116606 U1, RU145166 U1, RU47494 U1), with a collapsible and all-metal body, the main elements of which are a combustion chamber with a loading door and a chimney, a grate and an ash box. Auxiliary elements of these stoves can be a heater, a water tank, a steam generator, a steam gun, a heat exchanger, etc. The principle of operation of sauna stoves is based on the combustion of solid fuel in the combustion chamber and the radiative and convective heat transfer of thermal energy to surrounding objects and air in the heated room. The regulation of the intensity of combustion is usually carried out by changing the volume of air supplied to the combustion chamber by changing the position of the ash box.

The disadvantages of these furnaces are the short burning time, low accuracy of combustion intensity control, the need for frequent reloading of fuel and large temperature fluctuations in the room.

Known bath stove (RU2076277C1), selected as a prototype, contains a body with a firebox, a loading door, a grate, an ash box, a heat exchange cavity with a chimney. Inside the heat exchange cavity there is a heater with a door for loading stones and a device for generating steam.

The disadvantages of the known design are:

- short duration of combustion, due to the relatively limited amount of fuel in the combustion chamber;

- insufficient stability of thermal power generation, due to the low accuracy of adjustment by the ash box of the passage section for the inlet air flow;

- the need for frequent reloading of fuel and relatively large temperature fluctuations in the room, which is associated with a significant change in the generated power of the furnace.

In addition, the specified furnace has a low fuel utilization rate, which is due to incomplete combustion of pyrolysis gases and fuel particles due to insufficient temperature in the peripheral areas for their combustion and a short gas path.

The technical result consists in increasing the duration of operation of the furnace from one load of fuel, by increasing its volume and increasing the efficiency of combustion, increasing the stability of heat power generation during the operation of the furnace, by increasing the accuracy of controlling the inlet air flow, and improving the performance of the furnace.

The technical result is achieved by the fact that the sauna stove, containing a body in which the firebox is located, with an ignition door and a grate, under which there is an ash pan with an ash box and an ash box tunnel, a heat exchange cavity with a chimney and a heater inside, with a door for loading stones and with a device for generating steam, the body contains a bunker placed on the bottom with the formation of a furnace in the lower part, while the bunker in the upper part contains a loading door, and at the bottom in the rear part of the furnace there is a gas window, to which a heat exchange cavity is connected through a transition tunnel, with In this case, the secondary air duct with dosing holes and the afterburner chamber are sequentially located in the transition tunnel, and the secondary air duct communicates through the hole in the bottom with the grate cavity, moreover, in the upper part of the bunker there is a smoke exhaust damper with a drive and a position lock for connection through a gas channel with a chimney, located in the upper part of the heat exchange cavity for removing flue gases from the furnace, while on the ash box near the front wall between the side walls there is a transverse plate with a hole for controlling the inlet air flow.

The sauna stove may also contain a steam generator with a device for supplying water and discharging steam, a heat exchanger, a door with glass installed on the back of the heat exchange cavity under the heater, and the door on the inside communicates with the grate cavity through an air channel.

The essence of the invention is illustrated in Fig. 1, which shows a simplified view of the furnace in longitudinal section and indicated: 1 - body, 2 - hopper, 3 - heat exchange cavity, 4 - bottom, 5 - ignition door, 6 - loading door, 7 - furnace, 8 - grate, 9 - ash box, 10 - ash box tunnel, 11 - ash pan, 12 - cross plate with a box opening 9, 13 - gas sealing plate, 14 - grate cavity, 15 - gas window, 16 - transition tunnel, 17 - secondary air duct, 18 - dosing holes, 19 - holes for the secondary air duct, 20 - afterburner, 21 - fireclay plates, 22 - turbulence plates, 23 - heater, 24 - heater door, 25 - steam generator, 26 - steam generator, 27 - heat exchanger , 28 - a door with glass, 29 - an air supply duct for blowing a door with glass, 30 - a metering hole for blowing a door with glass, 31 - a chimney, 32 - a gas channel, 33 - a smoke exhaust damper, 34 - a smoke exhaust damper drive, 35 - position lock. The furnace body 1 with its parts and assemblies (and other elements of the furnace) is made of steel with the required wall thickness and heat resistance to ensure the required service life of the furnace. A metal casing (not shown in the figure) or a brick lining can be mounted around the furnace with an air gap. Hopper 2 is designed for laying fuel into the furnace, first through the ignition door 5, and then through the loading door 6. Hopper 2 is placed on the bottom 4, and its lower part at the level of the gas window 15 forms a furnace 7. At the base of the furnace 7 on the bottom 4 is placed grate 8, under which there is a grate cavity 14, an ash pan 11 with an ash box 9. On the bottom 4, through a transitional tunnel 16, a heat exchange cavity 3 is placed, which serves to transfer thermal energy from flue gases to the environment. To improve heat transfer on the inner walls of the heat exchange cavity 3, terbulizing elements can be installed in the gas channels on three sides near the heater 23. In the heat exchange cavity 3 there is a heater 23 with a door 24 and a device for obtaining steam 25, consisting of a funnel and a tube that supplies water to the most heated stones. The heat exchange cavity 3 is equipped with a chimney 31 for removing flue gases from the furnace. To prevent an uncontrolled volume of air from entering the furnace, doors 5 and 6 are sealed with a sealing cord. For more precise control of the inlet air flow near the front wall of the ash drawer 9, between its side walls there is a plate 12 with a hole, for example, of a triangular shape. In this case, one of the tops of the hole is adjacent to the front wall of the ash box 9, and the side opposite from this top is located on the edge of the plate 12. On the side and top walls of the tunnel 10 there is a flexible gas sealing plate 13, consisting of three parts. The secondary air duct 17 can be made of a square or rectangular U-shaped pipe. The secondary air duct 17 is placed in the transitional tunnel 16 behind the gas window 15 of the hopper 2 with open ends on the holes 19 in the bottom 4. On the inner walls of the duct 17 there are dosing holes 18, the area of which is approximately 20-25% of the area of the flow section of the grate 8. Tunnel 16 in the form of a U-shaped plate, placed on the bottom 4, may have a different length, depending on the characteristics of the room and the conditions for placing the furnace in it. An afterburner 20 in the form of a gas channel, for example, of rectangular cross section, is located in the transition tunnel 16 behind the air duct 17 and partially in the lower part of the heat exchange cavity 3. The inner walls of the chamber can be thermally insulated, for example, with fireclay plates 21. To further improve the conditions for combustion of pyrolysis gases , fuel particles in the liquid and solid phases, turbulence plates 22 can be installed between the fireclay plates. They protrude by several millimeters relative to the fireclay plates 21 and provide swirling and mixing of the gas flow. To expand the functionality of the furnace, it can be equipped with a high-temperature steam generator 26, a hot water heat exchanger 27 and a door with glass 28 for observing fire in the afterburner chamber 20 and furnace 7. The steam generator 26 can be equipped with a device for drip or jet water supply and steam output to steam room (not shown in the figure). The heat exchanger 27 may be made from a piece of pipe connected to a water tank. To reduce soot deposits on the glass of the door 28, air is supplied to it from the grate cavity 14 through the air supply duct 29 and through the metering hole 30. The door with glass 28 can be equipped with additional protective glass to increase safety. Chimney 31 has no features and is used for its intended purpose. The gas channel 32 is designed to drain flue gases from the hopper 2 directly into the chimney 31 when the smoke exhaust damper 33 is opened before additional loading of fuel through the loading door 6. The smoke exhaust damper 33 can be made of a flat plate that closes the hole in the upper wall of the hopper 2. The damper 33 is controlled drive 34 (for example, in the form of a round rod welded to the edge of the plate). To fix the damper 33 in the closed position, the position lock 35 is used. The lock 35 can be made in the form of a rectangular plate fixed on the drive 34 and engaged with an oblique plate (not shown in the figure) on the door 6. At the same time, the loading door is blocked 6, which prevents its accidental opening without prior ventilation of the hopper 2 from flue gases.

The bath oven works as follows. Through the open door for ignition 5, splinter and small firewood are placed on the grate 8. Then, through the loading door 6, the main volume of fuel (firewood, sawdust briquettes) is loaded. After fuel is loaded into the furnace, door 6 closes. The smoke exhaust damper 33 is also closed by turning the damper actuator 34 using the latch 35. In this position, the latch 35 blocks the door 6, preventing the possibility of its accidental opening without ventilation of the hopper 2. The fuel is ignited through the door 5 and it closes. The ash box 9 extends so as to open a hole in the plate 12. Through this hole, the combustion air enters through the grate 8 to the fuel, and through the holes 19 in the bottom 4, into the secondary air duct 17 and the metering holes 18 into the afterburner chamber 20. Due to Since the grate 8 occupies a large part of the bottom of the hopper 2, the air is distributed over it relatively evenly, which ensures its better mixing with the decomposition products of the fuel and the exothermic reaction. However, due to the presence of peripheral low-temperature zones, non-uniform combustion of various sections of the volume of simultaneously burning fuel, in the flue gases there is a significant percentage of unburned pyrolysis gases and particles of decomposition products in the liquid and solid phases, the ignition temperature of which is lower than required (more than 600 ° C is required) . Therefore, secondary air is supplied to the afterburner 20 together with flue gases through holes 19 and 18. Due to the limited cross section of the chamber 20, the thermal insulation of its walls and the required length, quite efficient combustion of unburned particles occurs in it. This is also facilitated by the placement of 20 turbulence plates 22 in the afterburner chamber, which provide mixing of air oxygen and previously unburned fuel particles. At the same time, temperatures above 1000° C. can develop at the outlet of chamber 20, which ensures sufficiently efficient combustion of unburned pyrolysis gases and fuel particles entering chamber 20. This allows you to extract additional energy from the fuel and thereby increase the duration of the furnace. The gas flow from the chamber 20, due to the rarefaction in the furnace, is carried upwards along the walls of the heat exchange cavity 3 to the chimney 31, giving off thermal energy to its walls. At the same time, the gas flow, passing along the walls of the steam generator 26, the heat exchanger 27 and the heater 23, transfers heat energy to them. Placement of the steam generator 26 in the zone of the highest temperatures makes it possible to obtain finely dispersed steam with a higher temperature than in the heater 23, since the stones in the heater are heated to a lower temperature. The presence of two different devices for obtaining steam expands the functionality of the oven to meet the various needs of consumers. The combustion intensity of the fuel is controlled by the ash box 9. Since the area of the triangular hole in the plate 12 is much smaller than the area of the plate itself and air is supplied only through this hole (due to the mechanical sealing of the ash box 9), a fairly high accuracy of controlling the volume of air entering the furnace is achieved. and hence the generated power of the furnace. Changing the area of the hole in the plate by shifting the ash drawer 9 allows you to regulate the generated power within a fairly wide range, depending on the mode of operation of the furnace (heating the room, maintaining the set temperature in it). High accuracy of power control in this furnace is necessary to ensure its stable operation over a long period of time. The fact is that a volume of fuel is loaded into the furnace that is much larger than the volume of burning fuel, which is located in the furnace 7 between the ignition door 5 and the gas window 15. Therefore, it is necessary to supply a limited amount of air to the furnace to ensure the generation of a given power. As the fuel located on the grate 8 burns out, the overlying layers of fuel fall down under the action of gravity and combustion continues in a stable mode. Small, short-term fluctuations in power can occur when the fuel is not lowered evenly and its fractionation is different, but this does not significantly affect the temperature in the room due to the large thermal inertia of the furnace. Due to the fact that the volume of fuel loaded into the furnace is many times greater than the volume of simultaneously burning fuel, the operating time of the furnace from one fuel loading is multiplied compared to the prototype and other technical solutions. In the experimental sample of the furnace, the burning time was about 10 hours.

If it is necessary to reload the furnace until the end of its operation, the air supply to the furnace is cut off by sliding the ash drawer 9 into the ash pan 11 until it stops. Then, with the position lock 35, the smoke exhaust damper 33 is set to the open position. After ventilating the bunker for one or two minutes, the loading door 6 opens and fuel is loaded. After fuel is loaded, door 6 closes. The smoke exhaust damper 33 is also closed by turning the position lock 35 until it is fixed on the oblique plate on the door 6. At the end of the fuel reloading process, the ash box 9 extends to the distance it was before reloading. However, depending on the quality of the loaded fuel (humidity, fractionation, etc.), it may be necessary to correct the position of the ash drawer 9.

Thus, in the proposed design of the bath furnace, in comparison with the prototype and other analogues, a multiple increase in the duration of the furnace operation from one fuel filling is provided, by increasing its volume and increasing the efficiency of the gradual combustion of a large volume of fuel. In the proposed bath furnace, the stability of thermal energy generation during the operation of the furnace is increased by increasing the accuracy of controlling the volume of inlet air and organizing the gradual supply of fuel to the furnace. The consequence of the increase in the duration of the furnace on one tab of fuel and the stability of the generation of thermal energy is to improve the performance of the furnace, since there is no need for periodic reloading of the furnace and adjustment of the generated heat power during bath procedures, and the possibilities for implementing an expanded range of functionality of the proposed design are improved. In addition, the presence of a door with glass in the steam room creates an inimitable atmosphere of visual images of fire, which increases the emotional pleasure from bath procedures.

The level of development, after experimental verification of the performance and efficiency of the proposed design, is at the stage of organizing mass production of a model range of sauna stoves with different thermal power.

Claims (7)

1. A sauna stove containing a body in which a firebox with an ignition door and a grate is located, under which there is an ash pan with an ash box and an ash box tunnel, a heat exchange cavity with a chimney and a heater inside, with a door for loading stones and with a device for generating steam , characterized in that the body contains a bunker placed on the bottom, with the formation of a furnace in the lower part, while the bunker in the upper part contains a loading door, and at the bottom in the rear part of the furnace there is a gas window, to which a heat exchange cavity is connected through a transition tunnel, with In this case, the secondary air duct with dosing holes and the afterburner chamber are sequentially located in the transition tunnel, and the secondary air duct communicates through the hole in the bottom with the grate cavity, moreover, in the upper part of the bunker there is a smoke exhaust damper with a drive and a position lock for connection through a gas channel with a chimney, located at the top of the a seal-exchange cavity for removing flue gases from the furnace, while a transverse plate with a hole for controlling the inlet air flow is installed on the ash box near the front wall between the side walls. 2. Sauna stove according to claim 1, characterized in that the afterburner chamber is made of rectangular cross-section of fireclay plates. 3. Sauna stove according to claim 2, characterized in that turbulence plates are installed between fireclay plates. 4. Sauna stove according to claim. 1, characterized in that it contains a door with glass installed on the back of the heat exchange cavity under the heater, and the door on the inside communicates through the air channel with the grate cavity. 5. Sauna stove according to claim 1, characterized in that a steam generator with a device for supplying water and discharging steam is placed under the heater. 6. Sauna stove according to claim 1, characterized in that a heat exchanger is placed under the heater. 7. Sauna stove according to claim 1, characterized in that the hole in the transverse plate of the ash box is made of a triangular shape, facing one of the corners to the front wall of the ash box, and in the tunnel of the ash box on the front side, gas sealing flexible plates are installed on the side and top walls .

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