RU2239750C1 - Method of burning solid fuel in domestic stoves - Google Patents

Abstract

FIELD: methods of burning solid fuel in domestic stoves.

SUBSTANCE: proposed method includes loading fuel on fire grate, forming draft in working space, lighting-up and burning of fuel at removal of combustion products into atmosphere, control of draft and amount of combustible products removed from stove by slightly opening the wind box and chimney dampers. Process of burning of fuel charged in stove is divided into several phases including lighting-up and obtaining intensive burning; after temperature of stove walls reaches required level, burning is automatically discontinued by synchronous and tight closing of wind box and chimney dampers. Lighting-up in second and subsequent phases is performed automatically by charging fuel into stove space and igniting it with the air of electric arc igniter.

EFFECT: enhanced efficiency; saving of fuel.

2 cl, 2 dwg

Description

The invention relates to the field of heating furnace technology, in particular, to the processes of burning solid fuel in domestic heating furnaces.

Widespread methods of burning solid fuel in domestic heating furnaces are known, including loading it on the grate of the furnace firebox, creating traction in its working space by opening the blower doors and chimney dampers, igniting and burning fuel with the removal of its combustion products through chimneys and flue pipe into the atmosphere, heat accumulation in the working space of the stove by closing the blower doors and chimney flaps after complete combustion of the fuel (see, for example, Fireplaces, stoves , heating of houses, baths, greenhouses. - M., 1997, p. 81-82; Fireplaces and stoves. - M., 2002, p. 416).

When heating by these methods, the heat enters the room unevenly, and an unsteady thermal regime is observed in it.

The greatest heat transfer of the furnace occurs at the end of the furnace, when the temperature of the walls of the furnace reaches a maximum, the lowest heat transfer refers to the time before the start of the next furnace. In addition, the existing heating regimes of domestic solid fuel heating furnaces lead to significant heat losses with flue gases and entrainment of unburned fuel particles with them, which reduces the efficiency of furnaces and increases fuel consumption per unit time of operation of the furnace.

A significant disadvantage of the known methods of domestic furnace heating is also the need for periodic loading of subsequent portions of fuel into the furnace.

In the case of using metal stoves during their overheating, warping of the metal casing of the stove is possible, which reduces its service life (Fireplaces, stoves, heating homes, baths, greenhouses. - M., 1997, p. 94).

Existing combustion devices of domestic heating furnaces do not have the means of mechanization and automation of solid fuel combustion modes, which necessitates the use of personnel carrying out the manual combustion process and controlling the process of burning fuel in the furnace throughout its duration.

The problem to which the invention is directed is to increase the efficiency of the furnace, reduce heat loss with flue gases, save fuel, increase the service life of furnaces, create maximum amenities for their maintenance, reduce the number of furnaces during the day and the entire heating season.

The solution of this problem is achieved by the fact that the combustion process of all the fuel loaded into the furnace is divided into a number of separate successive periods, in each of which the fuel is re-ignited, brought to the intensive combustion mode, and after the furnace wall temperature reaches the set value, the combustion process is automatically transferred in the mode of attenuation of fuel combustion by synchronously and tightly (in relation to the room) closing the damper blast and chimney; in this case, the fuel is ignited in the second and subsequent periods automatically by feeding liquid or gaseous fuel ignited by, for example, an electric spark igniter, into the working space of the furnace firebox.

Moreover, in the last period, the fuel combustion process is carried out until it is completely burned.

The proposed method is illustrated by graphical material, which schematically shows one of the possible options for the device for its implementation, as well as graphs of changes in temperature in the furnace during its operation on the existing and proposed methods.

Figure 1 shows a longitudinal section of a household furnace operating on solid fuel according to the proposed method; figure 2 - graphs of temperature changes in the furnace during its operation on the existing and proposed methods.

The following symbols are used on graphic materials: 1 - tank with liquid fuel; 2 - mini-compressor; 3 - drive a mini-compressor; 4 - the working space of the furnace firebox; 5 - firebox door; 6 - burners; 7 - chimney; 8 - chimney; 9 - chimney damper; 10 - chimney damper actuator; 11 - a temperature regulator; 12 - temperature sensor; 13 - pipeline supplying liquid fuel to the firing mini-burner; 14 - blower damper drive; 15 - base; 16 - firing mini-burner; 17 - control unit igniter; 18 - electric spark igniter; 19 - solid fuel; 20 - grate; 21 - the working space blew; 22 - a choke blew.

The letters indicate the functional relationships of the temperature sensor, thermostat and actuators in the proposed mode of automatic control of the processes of ignition and attenuation of fuel combustion.

Figure 2: I is a graph of the temperature of the exhaust gases before the chimney flap during operation of the furnace according to the existing method; II is a graph of the temperature of the exhaust gases in front of the chimney flap during operation of the furnace according to the proposed method; III is a graph of changes in the temperature of the walls of the furnace during its operation according to the existing method; IV is a graph of changes in the temperature of the walls of the furnace during its operation by the proposed method.

The proposed method is as follows.

With the shutters 22 and 9 open (see FIG. 1), the daily or daily portion of solid fuel 19 (firewood, coal, etc.) is loaded onto the grate 20 and the fuel is ignited in the usual manner.

After reaching the regime of intensive combustion of fuel and increasing the temperature of the exhaust gases and the walls of the furnace above a predetermined value, the temperature sensor 12 installed in the chimney 8 sends a signal proportional to the temperature change above the specified value to the thermostat 11, which simultaneously gives the command to put the stove into operation And, indicated by the arrows in FIG. 1, which attenuates the combustion of the fuel and puts the furnace in “heat accumulator” mode with the maximum heat transfer by the walls of the furnace to the surrounding wednesday. At the same time, automatically, with the help of electric drives 10 and 14, synchronously and hermetically, the shutters 9 of the chimney and 22 of the blower are closed.

The damper 9 has a series of holes with a diameter of 3 mm (not shown in the figure), which, after closing the damper, maintains the set value of the flue gas pressure in the furnace working space after simultaneously closing the damper 9 and 22. The damper 22 closes and is completely sealed, which eliminates the ingress of carbon monoxide from the products of fuel combustion into the atmosphere of the room.

After lowering the temperature of the exhaust gases and the walls of the furnace to a predetermined value (Fig. 2, curves II and IV), the temperature sensor 12 sends a signal to the thermostat II, which simultaneously gives the command to switch the furnace to mode B, which resumes the combustion process of the fuel in the furnace . At the same time, the following operations are carried out:

1. Automatically and synchronously with the help of electric drives 10 and 14, the shutters 9 and 22 open, creating traction in the furnace.

2. Using the electric drive 3, the mini-compressor 2 is turned on, which provides the supply of liquid fuel from the tank 1 through the pipe 13 to the ignition mini-burner 16.

3. A command arrives at the control unit 17, including the electric spark igniter 18.

Using the portion of liquid fuel supplied to the burner 13 and the igniter 18, the process of ignition of the solid fuel located on the grate is carried out.

After ignition of the fuel and reaching the regime of its intense burning, the above operations are repeated.

The alternation of successive modes A and B provides automatic control and maintenance of the temperature of the exhaust gases and the walls of the furnace within the specified limits (see curves II and IV in figure 2).

Such operating modes of the furnace are carried out until complete combustion of the fuel on the grate.

Compared with existing, the proposed method of burning solid fuel in domestic heating furnaces provides the following advantages:

1. Significantly reduced the number of bookmarks in the fuel furnace.

2. The amount of ash is reduced.

3. By stopping the combustion process, fuel is saved.

4. The number of starts and stops of the device occurs automatically depending on the room temperature.

5. The time of use of one fuel tab increases 3-5 times.

6. About the same amount of heat loss with flue gases is reduced.

7. When using metal furnaces, the service life of the metal casing of the furnaces is increased, because the mode of stepwise combustion of fuel eliminates overheating of the walls of the furnace.

8. The method allows for a much more uniform heating of the room during the day and, thus, to establish a stationary thermal regime.

9. The system of automatic regulation of the furnace eliminates the need for the constant presence of staff near it.

10. The most economical mode of fuel consumption is achieved. Practical implementation of the proposed method does not require large expenditures, because involves the use of relatively small, non-deficient elements of automation (temperature sensor, temperature controller, etc.), as well as auxiliary devices and equipment (electric drives, a tank for liquid fuel, a pipeline).

Claims (2)

1. A method of burning solid fuel in domestic heating furnaces, including loading it onto the grate of the furnace, creating traction in its working space, igniting and burning fuel with the removal of combustion products into the atmosphere, regulating traction and the amount of fuel combustion products removed from the furnace by opening the dampers a blower and a chimney, characterized in that the combustion process of all the fuel loaded into the furnace is divided into a number of separate periods, in each of which the fuel is re-ignited, brought to the intensive mode continuous combustion and after reaching the temperature of the furnace walls the set value, the fuel combustion process is automatically set to damping by synchronously and tightly closing the damper and chimney flaps with respect to the room, moreover, the fuel is ignited in the second and subsequent periods automatically by feeding the furnace firebox into the working space liquid or gaseous fuel ignited by an electric spark igniter. 2. The method according to claim 1, characterized in that in the last period the process of burning fuel is carried out until it is completely burned.

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