RU2263851C2 - Heating boiler - Google Patents

Abstract

FIELD: boilers for heating heat transfer agent, possibly for heating rooms.

SUBSTANCE: boiler includes housing in the form of water jacket inside which hollow heat exchange horizontally placed members are arranged. Said members form together with cavity of water jacket closed circuit for heat transfer medium. Central members having lateral surface area S_cm = (70 - 80)N cm² are mounted in different levels symmetrically relative to lengthwise axis of cross section of boiler, horizontally and mutually in parallel; their end sides are joined with opposite sides of jacket. Two lateral heat exchange members with lateral surface area S_lm = (35 - 40)N cm² are mounted between central members at the same level diametrically opposite in such a way that lengthwise lateral side of each member adjacent to inner lateral wall of boiler is joined with end sides of respective member by means of jacket. Between other free lengthwise sides of those heat exchange members there is window for passing gaseous products of fuel combustion. Said window has cross section area S_l = (5 - 9)N cm². Between lateral surfaces of central heat exchange members at two sides and inner wall of jacket, between upper surface of central heat exchange member and inner wall of jacket, between lateral and central heat exchange members there are ducts with cross section area S₂ = (2.5 - 4.5)N cm² where N - power of boiler, kWt.

EFFECT: enhanced efficiency, lowered size of boiler.

2 dwg

Description

The invention relates to thermal engineering and can be used for heating residential, industrial premises, individual greenhouses and other premises.

Known hot water boiler [1, 2], designed for heating and hot water supply, containing a firebox framed by a water jacket, connected to a window for the exit of combustion products. In the upper part of the furnace there are guide partitions, one of which is located transversely at a distance from the side wall of the furnace with the formation of a passage for combustion products, and the other partition is made in the form of a vertical open shell. It is installed between the transverse partition and the upper wall of the furnace, and the open section of the shell faces in the opposite direction to the passage mentioned above.

To increase the efficiency of heat transfer, the boiler is equipped with additional partitions, one of which is installed transversely between the windows for the exit of combustion products, and the second is located longitudinally.

A disadvantage of the known hot water boiler is that it does not take full advantage of the possibilities for increasing the efficiency of heat exchange between the partitions and the water filling the water jacket, since it only increases the path of the combustion products and their residence time in the furnace space, and the heat exchange area remains unchanged .

The heat transfer efficiency increases slightly only due to heat removal from the metal partitions to the walls of the water jacket in the upper part of the boiler. This type of heat transfer does not contribute to the intensity of water circulation in the heating system.

Of the known heating boilers, the closest in technical essence and the achieved results is a heating boiler [3], containing a casing in the form of a water jacket framing the furnace and gas duct, equipped with 2-4 hollow partitions installed horizontally and diametrically opposite at different heights with overlapping each other in the gas duct and connected with the cavity of the water jacket and forming a labyrinth gas channel in the gas duct.

A disadvantage of the known boiler is that an increase in the number of heat exchange elements of more than two gives a small increase in turbulization of the flow of gaseous products of fuel combustion and a slight increase in efficiency, which is economically and technically not rational, and also leads to a worsening of the conditions for removal of soot from the horizontal surfaces of the heating elements . The design of the boiler is sensitive to sudden changes in air velocity, which can lead to the extinction of the pilot and main burners.

The invention is aimed at increasing the efficiency and intensity of heat transfer between the products of combustion of fuel and heat transfer elements of the boiler design by increasing the area of convective heat transfer and turbulizing the flow of gaseous products of combustion of fuel; reduction of the overall dimensions of the boiler per unit of power.

This is achieved by the fact that in a known heating boiler containing a casing in the form of a water jacket framing the furnace and flue spaces, with four hollow heat-exchange elements inserted horizontally into the boiler’s interior, forming a closed coolant circuit with the cavity of the water jacket, and also forming in the gas passage space there is a labyrinth gas channel, while two of the mentioned heat-exchange elements are central, and two are lateral. The central elements with the side surface area S _ce = (70 ÷ 80) N cm ^{2 are} installed at different height levels, symmetrically along the longitudinal axis of the transverse internal section of the boiler, horizontally and parallel to each other, and their end faces are connected to the opposite sides of the framing shirt and form a closed coolant circulation circuit, where - N boiler power, kW.

Two lateral heat-exchange elements with a side surface area S _be = (35 ÷ 40) N cm ^{2 are} installed between the central ones at the same level and diametrically opposite so that the longitudinal side of each element adjacent to the inner side wall of the boiler and their end sides (parts ) are connected to the framing jacket and form a closed loop of the circulation of the coolant. A window with a cross section S ₁ = (5 ÷ 9) N cm ^{2 is} formed between other free longitudinal sides of the side heat-exchange elements for the passage of gaseous products of fuel combustion. Between the lateral surfaces of the central heat-exchange elements on both sides and the inner wall of the framing shirt, between the upper surface of the central heat-exchange element and the inner wall of the framing shirt, as well as between the side and central heat-exchange elements, channels with a cross section S ₂ = (2.5 ÷ 4, 5) N cm ² for the passage of gaseous products of combustion of fuel.

In this case, the gas burner device is installed across the longitudinal axes of the heat exchange elements.

The invention is illustrated by drawings, where figure 1 shows a cross section of a heating boiler; figure 2 is a longitudinal section of a heating boiler along section AA.

The positions in the drawings indicate:

1 - boiler body in the form of a framing shirt;

2 - the inner wall of the framing shirt of the boiler body;

3 - the outer wall of the framing shirt of the boiler body;

4 - heat transfer medium;

5 - element hollow heat exchange, side;

6 - a hollow heat-exchange element, central;

7 - end faces of the hollow heat exchange central element;

8 - side surface of the heat exchange element;

9 - the lower surface of the heat exchange element;

10 - the upper surface of the heat exchange element;

11 - a window for the passage of gaseous products of combustion of fuel between the side surfaces of the side heat exchange elements with a section S ₁ ;

12 - windows between the inner wall of the framing shirt and the side surfaces of the central heat exchange elements with a cross section of S ₂ ;

13 - furnace furnace space;

14 - channel of the gas duct of the boiler with a section S ₂ ;

15 - gas burner device with an automation system;

16 - a stream of gaseous products of fuel combustion;

17 - chimney;

18 - draft regulator (vacuum);

19 - pipe outlet from the boiler coolant;

20 - pipe input into the boiler coolant;

21 - the upper cavity of the gas duct of the boiler;

22 - end sides of the hollow heat exchange side element;

23 - burner.

To improve the technical parameters and properties of the heat transfer process into the inner cavity of the boiler, containing a casing in the form of a water jacket 1 with inner 2 and outer 3 walls, framing the furnace 13 and gas duct 14 spaces (see figure 1 and figure 2), four hollow heat exchange elements: two central 6 and two side 5. Central heat exchange elements 6 with the side surface area S _ce = (70 ÷ 80) N cm ^{2 are} installed at different height levels, symmetrically along the longitudinal axis of the transverse internal section of the boiler 1 (Fig. 1) , g horizontally and parallel to each other. The end sides 7 of the heat exchange elements 6 are connected to opposite sides of the inner wall 2 of the framing shirt of the boiler body 1 and form a closed loop of the circulation of the heat transfer medium 4.

Lateral heat exchange elements 5 with a side surface area S _be = (35 ÷ 40) N cm ² in the amount of two pieces are installed between the central heat exchange elements 6 at the same level diametrically opposite. Moreover, the longitudinal side of each element 5 adjacent to the inner wall of the framing shirt 2 of the boiler 1 is connected by its end faces 22 to the framing jacket and forms a closed circulation loop of the heat transfer medium 4. Between the other free longitudinal side surfaces 8 of the heat exchange elements 5 in the gas passage a window 11 with a cross section S ₁ = (5 ÷ 9) N cm ² for the passage of gaseous products of fuel combustion. Between the side surfaces 8 of the central heat exchange elements 6 on two sides and the inner wall of the framing shirt 2, between the upper surface 10 of the central heat exchange element 6 and the inner wall of the framing shirt 2, and also between the lower surfaces 9 and the upper surfaces 10 of the side 5 and central 6 heat exchange elements made channels 14 of the gas passage with a cross section S ₂ = (2.5 ÷ 4.5) N cm ² for the passage of gaseous products of fuel combustion 16.

The proposed arrangement of heat exchange elements 5 and 6, windows 11 and 12 with a cross section S ₁ and S ₂ and the space between the upper 10 and lower 9 surfaces of the central 6 and side 5 heat exchange elements, the inner wall 2 of the framing jacket of the furnace furnace space create two labyrinth channels 14 for passing the flow of gaseous products of combustion of fuel 16. The presence of two labyrinth channels in the boiler lengthens the path of passage of gaseous products of combustion of fuel 16, increases their turbulization, improves convective heat transfer to the heating elements of the boiler and the heat transfer medium. The proposed technical solution contributes to a more efficient use of combustible fuel and increase the efficiency of the boiler.

The cross-sectional area S _{1 of the} window 11 and S _{2 of the} channel 14 for the passage of gaseous products of fuel combustion is determined by the power of the heating boiler. If the cross-sectional area S _{1 of the} window 11 and S _{2 of the} channel 14 for the passage of the gaseous products of fuel combustion is greater than that indicated for a certain boiler capacity, then there will be a decrease in heat transfer from the gaseous products of fuel combustion to the heat exchange elements of the boiler. Part of the heat from the combustion chamber will be emitted into the chimney 17, which will lead to a significant reduction in boiler efficiency. If the cross-sectional areas S _{1 of the} window 11 and S _{2 of the} channel 14 for the passage of gaseous products of fuel combustion are less than indicated, then incomplete combustion of the fuel will occur, the concentration of carbon monoxide and nitrogen oxides will increase, as well as the release of soot substances that settle on the surfaces of the heat exchange elements 5, 6 and the inner wall of the framing shirt 2, form a layer of soot. This reduces the heat transfer to the coolant and reduces the cross sections S ₁ and S ₂ for the passage of gaseous products of combustion of fuel. At the same time, the operating conditions of the boiler deteriorate. All this leads to a significant reduction in the efficiency of the heating boiler.

The area S _ce = (70 ÷ 80) N cm ^{2 of the} side surface of the central heat exchange elements 6 and the side surface S _be = (35 ÷ 40) N cm ^{2 of the} side heat exchange elements 5 are also determined by the power of the heating boiler. If the areas _Sce and _Sbe will be less than indicated for a certain boiler capacity, then there will be a decrease in heat transfer from the gaseous products of fuel combustion to the heat exchange elements of the boiler. Part of the heat from the combustion chamber will be emitted into the chimney 17, which will lead to a significant reduction in boiler efficiency.

If the areas _Sce and _Sbe are greater than the specified, then the temperature of the exhaust gases will significantly decrease, which will lead to the formation and sedimentation of water condensate in the chimneys, as well as to an increase in the overall dimensions of the boiler.

The proposed design of the heating boiler provides more efficient heat transfer in the heat exchange elements by increasing the heat transfer area while reducing the overall dimensions of the boiler; optimal reduction of the temperature of the exhaust gases; reduction in their content of carbon monoxide and nitrogen oxides.

The heating boiler operates as follows. The pre-heating system connected to the nozzle for introducing the coolant medium 20 into the boiler and the nozzle for the outlet of the coolant from the boiler 19 is filled with the coolant 4. Then, the supply of gaseous fuel to the gas burner device 15. An air-gas mixture is formed in the gas burner device 15. The resulting gas-air mixture is ignited on the burner 23. The combustion process begins and the formation of a gaseous stream of fuel combustion products 16. The stream of fuel combustion products 16 in the furnace space washes the inner wall of the framing jacket 2, the lower surface 9 of the heat exchange element of the central 6 and is divided into two parts. One part of the stream 16 passes through the window 12 to the left along the side surface 8 of the heat exchange element of the central 6 and the inner wall of the framing shirt 2 and abuts against the lower surface 9 of the heat exchange element of the side 5. This part of the stream 16 is turned ninety degrees and moves along the channel 14 formed by the upper surface 10 of the heat exchange element of the central 6 lower and lower surface 9 of the heat exchange element of the side 5, washes the surface 10 and 9 of the heat exchange elements 6 and 5. At the same time, the second part of the stream 16 passes through the window 12 to the right of the heat exchange element of the central 6 and is directed towards the part of the stream 16 to the left. Parts of the stream 16 are found in the central longitudinal section of the boiler, are combined and, passing through the window 11, wash the side surfaces 8 of the heat exchange elements of the side 5. When leaving the window 11, the gaseous stream of fuel combustion products 16 abuts against the lower surface 9 of the upper heat exchange element of the central 6 and again divided into two parts. One part of the stream 16 is directed to the left into the channel formed by the upper surface 10 of the heat exchange element of the side 5 and the lower surface 9 of the heat exchange element of the central 6, and then into the window 12, washing the side surface 8 of the heat exchange element of the central 6 and the inner wall of the framing shirt 2. After the flow exits from the window 12 it enters the upper cavity of the gas passage of the boiler 21, formed by the upper surface 10 of the heat exchange element of the central 6 and the inner wall of the framing shirt 2. At the same time, the analog adic second part flow 16 passes right through the window 12 of the central heat exchange element 6 and is guided into the upper space 21 of the boiler flue gas space flow toward the part 16, moving to the left. The flow of fuel combustion products 16, transferring the bulk of the heat to the heat exchange elements 6 and 5 of the boiler, goes into the upper cavity 21 of the boiler, combines and through the draft (rarefaction) 18 goes into the chimney 17.

The most efficient heat transfer occurs in the heat exchange elements 5 and 6. The heat-transfer medium 4 enclosed in them is heated more intensively due to the relatively small volume, which leads to its rapid thermal expansion, increase in pressure differences at the inlet 20 to the heat-transfer medium boiler and at the outlet 19 and directed its course. This leads to an increase in the speed of movement of the coolant in a closed heating system.

This design of the boiler and its operation provide the most efficient heat transfer from the combustion products of the fuel to the coolant.

The use of new elements in the boiler for heating compares favorably with the proposed boiler, as it allows:

- intensify heat transfer in the furnace and flue spaces by improving the conditions of heat transfer from the combustion products to the heating elements;

- increase the circulation rate of the coolant by increasing the heating rate in the heat exchange elements;

- increase the degree of turbulization of the flow of fuel combustion products;

- to reduce the dimensions and consumption of materials per unit capacity of the heating boiler by creating a complex labyrinth of movement of fuel combustion products, increasing the path of their passage and the washing area of the heat exchanging elements of the boiler;

- increase the efficiency of the heating boiler;

- to increase the reliability of the boiler by reducing the possibility of blowing the ignition burner during sudden changes in the flow of atmospheric air;

- improve the conditions for servicing the boiler during operation.

Sources of information

1. Copyright certificate No. 1820156, A 1 F 24 H 1/26, F 23 M 9/06, BI No. 21.1993.

2. Copyright certificate No. 1733867, A 1 F 24 H 1/40, No. 18, 1992.

3. RF patent No. 2122688 F 24 H 1/00, BI No. 33, 1998.

Claims (1)

A heating boiler for heating residential, industrial premises, comprising a casing in the form of a water jacket framing the furnace and flue spaces, with four hollow heat-exchange elements inserted into the internal volume of the boiler, installed horizontally, forming a closed loop of the heat-transfer medium with the cavity of the water jacket, and also forming gas passage labyrinth gas channel, characterized in that two of the above heat-exchange elements are central, and two are lateral, while neutral elements with lateral surface area S _ce = (70-80) N cm ^{2 are} installed at different height levels, symmetrically along the longitudinal axis of the transverse internal section of the boiler, horizontally and parallel to each other, and their end faces are connected to opposite sides of the framing shirt and form a closed the circulation medium of the heat-transfer medium, two lateral heat-exchange elements with the side surface area S _BE = (35-40) N cm ^{2 are} installed at the same level between them, diametrically opposite so that the longitudinal side the cylinder of each element adjacent to the inner side wall of the boiler, and their end sides (parts) are connected to the framing jacket and form a closed loop of circulation of the heat-transfer medium, and a window with a cross section S ₁ = (5- 9) N cm ² for the passage of gaseous combustion products, while between the side surfaces of the central heat exchange elements on both sides and the inner wall framing shirts, between the upper surfaces w central heat exchange element and the inner wall framing shirts, as well as between the side and central channels of the heat exchange elements are made with cross-section S ₂ = (2,5-4,5) N cm ² for the passage of gaseous combustion products, gas-burning unit is installed along the longitudinal axes of heat exchange elements, while N is the boiler power, kW.

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