RU2469244C1 - Water heating device - Google Patents

Abstract

FIELD: power industry.

SUBSTANCE: water heating device includes a tank with bottom and cover plate. In the above tank there installed is at least one vertical combustion chamber, liquid supply and discharge connection pipes, and discharge opening for combustion products, which is made in the cover plate. Device includes central cavity and intermediate cavity adjacent to side wall of the tank, cavities restricted with walls. Cavities are interconnected with liquid supply connection pipe. Spraying openings are located in upper part of walls of cavities. Combustion chamber has a gap between lower edge and bottom of the tank, concentrically between central cavity and cavity adjacent to the tank wall. Igniting through openings are located in lower part of the chamber wall, below initial water level in the tank. Burners are connected gas-dynamically to air and gas headers and uniformly built in upper edge of annular combustion chamber. Openings in upper part of walls of cavities, which are interconnected with liquid supply connection pipe, are directed towards external and internal walls of combustion chamber.

EFFECT: invention allows increasing specific heat removal from fuel combustion products at provision of smooth start-up.

3 cl, 2 dwg

Description

The invention relates to the field of efficient heat generating devices.

If it is necessary to decentralize heat supply, for example, for heating purposes using water or water-containing liquids, an important role can be played by submersible combustion apparatus (APG), widely used in the chemical industry, which together with instrumentation (regulation of air and gas supply, automatic control and safety) and air supply systems (fan with drive), as well as gas supply form a submersible combustion installation. An important element of this installation is a water heating device, in which bubbling (passing through a liquid) of the combustion products coming from the burners is carried out using tubular combustion chambers, lowered by an exit of 200-300 mm below the liquid level. This ensures direct contact of the combustion products with the heated fluid without the use of heat exchangers.

A device for submersible combustion (USSR author's certificate for the invention No. 1386216 of 04/28/1986) containing a tank with liquid, an immersion burner, and also a pipe for the release of combustion products in the upper part of the housing is known. The liquid in the tank is heated by the heat of the hot exhaust gases generated by the burner passing directly through it. However, the lack of a continuous flow of fluid through the tank does not allow the use of this device for the needs of heating.

A steam-gas water heater is known (RF Patent No. 2079796 dated 10.28.1991), containing a vertical tank with a liquid circulating through it, an immersion combustion chamber with a burner and a circulation pipe coaxially placed in the tank with annular gaps relative to each other, a gas outlet and a separation unit . This device allows you to heat the fluid with a continuous flow through the water heater and provides less loss of fluid leaving the exhaust gases. However, a noticeable increase in heat removal by water in the device, despite the introduced structural complications, is not to be expected due to the small size of the heat transfer surfaces from gas to liquid and the low rates of exhaust gas flow in the channels.

The closest in technical essence and the achieved result is a submersible combustion apparatus (RF Patent No. 325974 of 01/21/1969), adopted as a prototype, containing a tank with a liquid circulating through it, in which combustion chambers are vertically mounted with a gap between the lower edge and the bottom tank, bubbler, nozzles for fluid inlet and outlet and gas removal, an additional retaining grate and an additional fluid supply pipe, supplying liquid to the side opposite to its supply from the main pipe. An additional retaining grid is installed above the bubbler so that there is a sufficiently thick layer of liquid between them, with an additional nozzle located above the liquid level in the tank.

The technical solution of the prototype, although it allows to slightly increase the heat removal from the exhaust gas, but it still does not fully utilize the thermal potential of the combustible mixture due to insufficient mixing of the combustion products with the liquid. Moreover, due to the installation of an additional retaining lattice, the depth of the combustion chamber is substantially increased, which requires a corresponding increase in the pressure of air entering the combustion chamber, and, consequently, an increase in the power of the compressor or fan supplying air to the device. In addition, the increased depth of the combustion chamber makes it impossible to smoothly start the device without explosive pops.

To eliminate the disadvantages of the prototype and to solve problems of increasing the efficiency of the submersible combustion apparatus during start-up and operation, a water heating device is proposed with respect to water heating, which is based on the solution of the following problems:

- increase in specific heat removal from exhaust gases to liquid without additional external energy consumption,

- ensuring smooth, without explosive pops, device starts.

The tasks are solved in that the water heating device comprises a tank (for example, a cylindrical shape) with a bottom and a lid installed in the tank, at least one vertical combustion chamber (for example, an annular shape) with a gap between the bottom edge of the chamber and the bottom of the tank, filled above the lower edge of the chamber, liquid, nozzles for supplying and discharging liquid, a hole for discharging combustion products in the lid.

New in the invention is that the device further comprises a combustible gas line and an air line with valves, an air manifold, a gas manifold, burners, a central and an intermediate cavity adjacent to the side wall of the tank, bounded by the walls and communicating with the liquid supply pipe located in the upper parts of the walls of these cavities in annular rows of spray holes. The combustion chamber is located concentrically between the central and adjacent cavities to the wall of the tank and is provided with lower through holes in the lower part of the wall. These holes are located below the initial level of the water filled in the tank. The burners are connected gasdynamically to an air collector connected through a tap to the air line and to a gas collector connected through a tap to a combustible gas line. The burners are integrated uniformly around the circumference into the upper end face of the annular combustion chamber. Spray holes in the upper part of the walls of the cavity of the tank are directed towards the outer and inner walls of the combustion chamber.

With this design of a water heating device:

- a combustible gas line and an air line with cranes supply fuel components to the device to ensure the operation of the device.

- the air collector provides air supply, and the gas collector - combustible gas (for example, natural gas) in a predetermined ratio and with the same flow rate to each burner;

- the burner, mixing the incoming air and combustible gas, produces a homogeneous combustible mixture, which burns in the combustion chamber, forming a hot exhaust gas;

- the central and intermediate cavities with through holes (in the side walls bounding them) directed to the combustion chamber, provide, through the injection of liquid through the spray holes in the cavities adjacent to the combustion chamber, an increase in heat removal from exhaust gases;

- the use of a combustion chamber of the ring type allows to significantly increase the surface area of the exhaust gas in contact with water through the side walls, which also increases the heat transfer of exhaust gases to water;

- firing holes in the side wall of the combustion chamber, located between the lower cut of the combustion chamber and the initial level of the liquid, allow the device to be started at a lower overpressure in the combustion chamber due to less backpressure of the liquid at its lower cut. This makes it possible to reduce the initial volume of the combustible mixture in the combustion chamber and, accordingly, the pressure surges in it at startup; the gap between the lower edge of the combustion chamber and the bottom of the tank is necessary to facilitate the passage of exhaust gases from the combustion chamber into the water column in the tank and to improve heat transfer from gases to water due to the intensification of bubbling.

The burners in the combustion chamber can be located around the circumference at a distance of no more than 10-12 diameters of the outlet section of the burner from each other, which, as experience shows, ensures guaranteed stability of the flame front in the combustion chamber without the use of additional stabilizing structural elements.

The gap between the lower edge of the combustion chamber and the bottom of the tank is not less than the width of the output section of the combustion chamber, which provides, according to experimental data, the maximum heat transfer from hot gases to the liquid with minimal expenditure of power on the compression of the air entering the combustion chamber.

The location of the firing through holes in the wall of the combustion chamber can provide a depth below the initial liquid level in the tank 25-35% less than the depth of the lower edge of the combustion chamber. According to experimental data, this ensures a smooth start-up with virtually no decrease in heat removal from the exhaust gas passing through the ignition holes at the nominal operating mode of the device.

The water heating device may further comprise a mixer and a faucet outside the tank, which make it possible to create a combustible mixture not in each burner of the combustion chamber, but centrally in the mixer, the air line being connected to the air manifold in series through a tap and mixer, the combustible gas line is additionally connected to the mixer through a faucet that allows to supply a combustible mixture of exactly the same quality to all burners of the combustion chamber, simplifies the design of the burners and reduces the cost of the device wa.

Thus, the task of the invention is solved. A design diagram of a device was developed that provides heating of running water in a tank with an increased specific heat removal from exhaust gases without additional external energy consumption with a smooth, multiple-launch without explosive popping.

The present invention will be more clear after considering the following description of a water heating device with reference to the accompanying diagrams in FIGS. 1-2.

Figure 1 shows schematically a water heating device.

Figure 2 shows a diagram of a water heating device with a centralized supply of a combustible mixture.

The water heating device (see Fig. 1) comprises a tank 1, in particular of a cylindrical shape, with a bottom 2 and a cover 3, installed in the tank, at least one vertical combustion chamber 4, nozzles 5 and 6 for supplying and discharging liquid, respectively, and an opening 7 exhaust gases in the cover. New in the invention is that the device further comprises a combustible gas line 8 with a valve 9, an air line 10 with a valve 11, an air manifold 12, a gas manifold 13, a burner 14, central (for example, cylindrical) and intermediate (for example, annular), adjacent to the side wall of the tank 1 of the cavity 15 and 16, respectively, bounded by the walls located in the upper part of these walls of the annular rows of spray holes 17. The combustion chamber 4 can be made annular, with a gap between the bottom edge and the bottom 2 of the tank 1. The combustion chamber 4 is located concentrically between the central and adjacent to the wall of the tank cavities 15 and 16, respectively, and is equipped in the lower part of the wall with firing through holes 18. The firing holes 18 are located below the initial level of water filled in the tank 1. The burners 14 are connected gasdynamically to the air collector 12 and to the gas manifold 13, the air collector 12 is connected via a valve 11 to the air line 10. The gas collector 13 is connected through a valve 9 to the combustible gas line 8. The burners 14 are uniformly integrated around the circumference into the upper end of the combustion chamber 4. The spray holes 17 in the upper part of the walls of the cavities 15 and 16 are directed towards the inner and outer walls of the combustion chamber 4, respectively. Cavity 15 and 16 are in communication with the pipe 5 fluid supply.

The water heating device (see FIG. 2) may further comprise a mixer 19 and a faucet 20. The air line 10 is connected via a faucet 11 and the mixer 19 to an air manifold 12. A combustible gas line 8 is connected through a faucet 9 to a gas manifold 13 and further through a faucet 20 with mixer 19.

The operation of the device (see figure 1) is as follows. Before starting, the central and intermediate cavities 15 and 16 are filled using the fluid supply pipe 5, respectively, from where the liquid enters the tank 1 through the spray holes 17 in the walls of the cavities 15 and 16. From the tank 1, the fluid is discharged through the pipe 6 of the fluid outlet, which ensures such a flow liquid through the tank 1, at which the level of penetration of the combustion chamber 4 and the location of the ignition holes 18 below this liquid level, which is calculated for starting, is provided. When the device is started, combustible gas is supplied to the burners 14 from the combustible gas line 8 through the valve 9 and the gas manifold 13, and air is supplied from the air line 10 through the valve 11 and the air manifold 12 with a flow rate and pressure lower than calculated. In this case, the liquid level in the combustion chamber 4 decreases below the location of the ignition openings 18. In the burners 14, the gas and air are mixed and the resulting combustible mixture is ignited by an igniter (not shown). From the combustion of the mixture, hot exhaust gas is generated in the combustion chamber 4, which, passing through the ignition holes 18 and the liquid in the cavity of the tank 1, enters the opening 7 of the exhaust products in the lid 3. After starting the device, the nominal values of the flow rate of combustible gas and air are set, entering the burners 14. Significantly increases the formation of combustion products and their pressure in the combustion chamber 4. At the same time, the water level in the combustion chamber 4 decreases, and in the tank 1, respectively, increases. The increased exhaust gas flow cannot completely pass through the ignition openings 18, and its main quantity passes through the lower edge of the combustion chamber 4 into the liquid column 1. Passing through the liquid column, the exhaust gas intensively gives off part of its liquid heat and enters “super-liquid” area of the tank 1 and then through the hole 7 in the cover 3 of the tank 1 goes into the atmosphere. Liquid is also injected into the "super-fluid" cavities of the tank 1 through the spray holes 17 from the central and intermediate cavities 15 and 16, respectively, which leads to additional heat removal by the liquid from the exhaust gas.

During operation of the device of FIG. 2, at start-up, the valve 9 is closed, the valves 20 and 11 open, the combustible gas from the line 8 and the air from the line 10 enter the mixer 19, where gas and air are mixed to form a combustible mixture, which is then supplied through the air collector 12 in all burners 14 of the combustion chamber 4. Next, the operation of the device is the same as in the device of Fig.1.

Submersible heating of the liquid is widely used in the chemical industry for the evaporation of various solutions, as well as in heating boiler plants. Due to the passage of exhaust gas through the fluid from the combustion chamber immersed in it at 200-300 mm, the heat removal of the liquid is significantly higher than when using conventional heat exchangers. The introduction of liquid jets into the exhaust gas stream through the spray holes 17 further increases the heat transfer of the liquid, while the temperature of the exhaust gas is 40-45 ° C against the temperature value 130, which is typical for traditional boiler houses. This makes it possible to use the heat of combustion of fuel by 95-98% and increase environmental indicators for harmful emissions. In addition, the simplicity of the design of the device and the exclusion of the heat exchanger can reduce the cost of a water heating device by 30-40%. In this case, the intermediate cavity 16, in addition to increasing the heat exchange surface of the liquid with the exhaust gas, reduces the outflow of heat from the tank 1 due to the lower temperature of the liquid present in it compared to the temperature of the liquid entering the outlet 6. This further increases the efficiency of the device.

The efficiency of immersion heating of water used for heating needs is confirmed experimentally.

Claims (3)

1. A water heating device comprising a tank with a bottom and a lid installed in the tank, at least one vertical combustion chamber with a gap between the lower edge and the bottom of the tank, liquid filled above the lower edge of the chamber, nozzles for supplying and discharging liquid, an opening for exhausting combustion products in the lid, characterized in that the device further comprises a combustible gas line and an air line with taps, an air manifold, a gas manifold, burners, central and intermediate, adjacent to the side wall of the tank, p cavities bounded by walls and communicating with a fluid supply pipe located at the upper part of the walls of these cavities by spray holes, where the combustion chamber is concentrically between the central and adjacent cavities of the tank wall and provided with ignition through holes in the lower part of the wall located below the initial level liquid tank, burners are connected gasdynamically with an air collector connected through a tap to the air line and with a gas collector connected through the the backbone of combustible gas, the burner being uniformly embedded in the upper end of the combustion chamber, the openings in the upper part of the tank walls of the cavities are directed towards the outside and inside of the combustion chamber walls. 2. The device according to claim 1, characterized in that the burners in the combustion chamber are evenly spaced at a distance of not more than 10-12 diameters of the outlet section of the burner from each other, the gap between the lower edge of the combustion chamber and the bottom of the tank is not less than the width of the outlet section of the combustion chamber , the depth of the ignition through holes in the wall of the combustion chamber below the initial liquid level is 25-35% of the depth of the bottom edge of the combustion chamber. 3. The device according to claim 1, characterized in that it contains a mixer and a tap, the air line being connected to the air collector in series through a tap and a mixer, the combustible gas line is additionally connected to the mixer through a tap.

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