RU2767418C1 - Water-tube boiler with forced circulation - Google Patents

Abstract

FIELD: heat engineering.

SUBSTANCE: invention relates to the field of heat engineering and can be used in the creation of steam and hot water boilers for heat and steam generation. A water-tube boiler with forced circulation includes a furnace chamber made of two halves. Each of the halves contains smooth U-shaped pipes located in the transverse plane of the mentioned furnace chamber, partially finned U-shaped pipes, heat exchange pipes made in the form of a snake and placed inside the furnace chamber mostly along its side wall. Each of the halves also contains a transverse collector, an additional transverse collector, upper and lower longitudinal collectors having terminal sections. The upper and lower longitudinal manifolds are interconnected by means of partially finned U-shaped pipes and smooth U-shaped pipes. The transverse collector is located near the end sections of the upper and lower longitudinal collectors. The transverse collector is connected to an additional transverse collector by means of the mentioned heat exchange pipes.

EFFECT: given the same power, the boiler’s metal consumption and dimensions can be reduced simultaneously with a decrease in the number of welding and assembly operations.

10 cl, 13 dwg

Description

FIELD OF TECHNOLOGY

The invention relates to the field of heat engineering and can be used to create steam and hot water boilers to produce heat and steam.

BACKGROUND OF THE INVENTION

Known water-tube boiler with forced circulation, containing a combustion chamber and a convective part located behind it, made of several parallel packages, characterized in that each package is composed of two sections, each containing a pair of adjacent collectors, interconnected by U-shaped pipes, distributed in height with a gap relative to each other with the possibility of placing U-shaped pipes of one section in the gap of another section, and at the top and bottom each package is closed by membrane pipes connected by the corresponding section collectors, adjacent collectors of adjacent packages located on one side are connected to each other by external adapters with the formation of a single water path (RF patent for invention No. 2722493).

The disadvantage of the known boiler is its large dimensions and complexity of manufacturing, due to the location of the large-sized convective part behind the furnace part of the boiler, and the complexity of welding the convective part due to the large number of small welded elements and, accordingly, the need for intermediate control of welding in the process of manufacturing the heat exchanger, the complexity of control and correction of errors after each subsequent stage in the manufacture of boiler elements.

DISCLOSURE OF THE INVENTION

The objective of the invention is to eliminate the above disadvantages, to create a water-tube boiler with forced circulation, which has the following combination of properties (superior to analogues with a separate convective and combustion zones):

- elimination or reduction of distortions and stresses in the structure during operation and start/stop;

- downsizing;

- improving the ratio between the metal content of the boiler and the heat transfer surface at the same heat output;

- reducing the amount of welding;

- improved maintainability;

- reduction in the number of different types of parts used for the production and repair of the boiler.

The technical result to which the present invention is directed lies in the fact that at the same power, the metal consumption and dimensions of the boiler can be reduced simultaneously with a decrease in the number of welding and assembly operations.

The features of the forced circulation water tube boiler are described below, due to which the solution of the above problem and the achievement of the above technical result are provided. Other features of forced circulation boilers that are known to those skilled in the art to ensure their normal operation, as well as features that provide additional benefits, will be described separately.

The proposed water-tube boiler with forced circulation contains a combustion chamber (1) made of two halves, which are combined into one water path by various collectors. This allows the production of two separate halves at the same time, reducing the production time. It also simplifies access to all elements during assembly and welding, improves maintainability.

As can be clearly seen in FIG. 1 and 2, in contrast to the prototype, the convective and furnace parts of the proposed boiler are combined into one, due to which the dimensions of the boiler are significantly reduced and the efficiency of all heat exchange pipes is increased by obtaining heat from the burner flame in the form of radiation and convection.

In this case, each half of the combustion chamber (1) of the boiler is formed by the upper (2) and lower (3) longitudinal collectors, and at least one transverse collector is placed near their end sections (i.e. at the end of the combustion chamber (1)) (4). The transverse manifold (4) may be welded to the longitudinal manifolds (2, 3) or secured in any other suitable manner near their end portions.

The presence of a transverse collector (4) allows, after the passage of the coolant through the U-shaped pipes (6, 7) welded to the longitudinal collectors (2, 3), through the upper or lower longitudinal collectors (this depends on the number of turns) to go into the transverse collector ( 4) for further movement along the heat exchange pipes (8). This solution makes it possible to solve the problem of optimal and consistent circulation of the coolant through the heat exchange pipes (8) of the boiler as simply as possible and with small dimensions.

The upper (2) and lower (3) longitudinal collectors are interconnected by groups of at least partially ribbed U-shaped pipes (6) and U-shaped smooth pipes (7) located in the transverse plane of the combustion chamber.

The presence of U-shaped finned tubes (6) welded to the longitudinal collectors (2, 3) allows you to maximize the removal of heat from the burnt gases due to the fins and metal figured plates (17) located on it, which regulate the output of the burnt gases through each U-shaped finned tube (6), without the risk of stress in the heat exchange tubes (8) due to elongation due to heating. The coolant sequentially moves through several U-shaped pipes (6) from the lower to the upper manifold or vice versa.

The number of pipes (6) through which the coolant moves and their diameter can be increased and decreased. Thus, it is possible to regulate the speed of movement of the coolant through the U-shaped pipes (6).

Smooth U-shaped pipes without fins (7) are mainly needed for welding membranes to them to form a gas-tight zone where the finned U-shaped pipes (6) are located. Gas-tight membranes also provide the possibility of welding fasteners for the boiler frame and transportation. Through the gas-tight zone, the burnt gases move to the collectors of the gas ducts (15) and are subsequently removed into the chimney.

All U-shaped pipes (6, 7) carry the function of the boiler frame and their vertical arrangement contributes to the rigidity of the structure on which most of the boiler elements are located.

Each half of the combustion chamber (1) is equipped with an additional transverse collector (5), while one transverse collector (4) is connected to the other transverse collector (5) using several heat exchange pipes (8) in the form of a snake, placed inside the combustion chamber for the most part along its side wall in such a way that one end of each heat exchange tube (8) is connected to one transverse manifold (4), and the other end of the same heat exchange tube (8) is connected to another transverse manifold (5).

The presence of two transverse collectors (4, 5) is necessary to ensure the flow of the heat carrier through the heat exchange pipes (8) in the form of a snake. First, the coolant enters the heat exchange pipes (8) from one end welded to one transverse collector (4), passes through the pipe (8), being heated by the heat of the burnt gases and radiation from the burner flame (16), and then enters the other transverse collector (5 ) from which it moves to the supply manifold (if it is necessary to reduce the amount of condensate, the manifolds can be interchanged).

In one of the preferred embodiments of the boiler, the aforementioned heat exchange tubes (8) are located essentially horizontally, and the aforementioned transverse manifold (4) and the additional transverse manifold (5) are essentially vertical. This allows you to effectively remove air from pipes and manifolds,

The design and mutual arrangement of U-shaped pipes (5, 6), heat exchange pipes (8) and collectors, described above, provides a number of advantages:

- the heat exchange tubes (8) in the form of a snake can have a maximum length, while no stresses arise in them due to heating,

- by varying the number of heat exchange pipes (8) welded to the transverse collectors and coils of a snake, it is possible to regulate the speed of the heat carrier in a wide range, which is an important factor in heat transfer and reliability of the boiler,

- with this design, it became possible to place the heat exchange pipes (8) as close as possible in the form of a snake to the U-shaped pipes (6) in one or two rows, which makes it possible, with small dimensions, to obtain a large heat transfer surface without greatly increasing the dimensions of the boiler,

- the presence of heat exchange pipes (8) located inside the furnace (1) and U-shaped pipes (6) located after the heat exchange pipes (8) and also the sequential flow of the heat carrier from the U-shaped pipes (6) to the heat exchange pipes (8) (or vice versa if necessary, reduce condensate) allows you to remove heat from the burnt gases with maximum efficiency,

- with this design, heat exchange pipes (8) in the form of a snake and U-shaped pipes (6) receive heat from radiation and convection obtained from the combustion of gases in the burner,

- with this design, all heat exchange pipes (8) are available for inspection and repair, unlike the prototype,

In particular embodiments of the boiler described above, additional advantages may be provided.

In one of the preferred embodiments of the boiler described above, the smooth U-shaped tubes (7) are provided with steel plates forming a membrane surface.

In another preferred embodiment, the aforementioned smooth U-shaped pipes (7) are provided with screen pipes (9, 10) located in the plane of the smooth U-shaped pipes (7).

Additional collector (5) can be located in various ways.

In an embodiment of the boiler described above, an additional transverse collector (5) can be located near the end sections of the upper (2) and lower (3) longitudinal collectors. This allows you to create boilers with different dimensions for the tasks of the customer. In this case, the boiler is slightly larger in size, but easier to manufacture.

In an alternative embodiment of the boiler described above, an additional cross manifold can be located outside the combustion chamber (1). With this arrangement of the additional transverse collector (5), the boiler is a little more compact, but there are additional costs in manufacturing.

In one of the preferred embodiments of the boiler described above, the heat exchange pipes (8) connected into transverse collectors are made of several parts, where at least two parts of the pipe, connected to each other by bends, are located along the combustion chamber (1).

The heat exchange tubes (8) may differ slightly in their configuration and the serpentine may be formed from two or more pipes connected to each other by bends (i.e. the serpentine may have one or more U-shaped coils).

In one of the preferred embodiments of the boiler described above, the heat exchange pipes (8) located inside the combustion chamber (1) can be additionally equipped with fins or studs.

In another preferred embodiment of the boiler described above, the two halves of the combustion chamber (1) are interconnected by return (11) and supply (12) collectors to form a single water path. Combining the two halves into common supply (12) and return (11) manifolds in parallel allows the two halves of the combustion chamber (1) to work with an equally distributed load without distortions.

In one of the particularly preferred embodiments of the above-described boiler, shaped metal plates (17) can be located on the outside of the finned part of the U-shaped pipes (6). The plates (17) serve to distribute the burnt gases in such a way that the flow is in full contact with the front and rear surfaces of the finned part of the pipes (6). Also figured plates allow to direct the burnt gases as evenly as possible to that part of the boiler which is loaded less or, conversely, if necessary, reduce the flow of hot gases.

Below, some particular embodiments of the boiler will be illustrated and described in detail with reference to the figures of the drawings.

BRIEF DESCRIPTION OF THE FIGURES OF THE DRAWINGS

In FIG. 1 shows a perspective view of the complete combustion chamber, front view;

in fig. 2 - the same, rear view;

in fig. 3 - axonometric half of the combustion chamber, front view;

in fig. 4 - the same, rear view;

in fig. 5 - perspective view of a U-shaped tube with a finned part;

in fig. 6 - axonometric view of a heat exchange tube (in the form of a snake) of two tubes with a U-shaped connection;

in fig. 7 - axonometric view of a heat exchange tube (in the form of a snake) of four tubes with tubes connected in the form of a spiral.

in fig. 8 - axonometric view of a half of the combustion chamber with an additional transverse collector taken out of the furnace, rear view;

in fig. 9 - section of the combustion chamber, front view;

in fig. 10 - view B;

in fig. 11 - view A;

in fig. 12 - figured metal plate.

in fig. 13 shows the course of movement of the coolant inside the pipes and collectors of the boiler.

In FIG. 1-13, the following notation is adopted:

1 - combustion chamber,

2 - upper longitudinal collectors,

3 - lower longitudinal collectors,

4 - cross collector,

5 - additional cross collector,

6 - at least partially ribbed U-shaped tubes,

7 - smooth U-shaped pipes,

8 - heat exchange horizontal pipes in the form of a snake,

9 - front screen pipes,

10 - rear screen pipes,

11 - return manifold,

12 - supply manifold,

13 - air vents,

14 - drainages,

15 - gas ducts,

16 - burner,

17 - figured metal plates,

18 - partitions.

IMPLEMENTATION OF THE INVENTION

As shown in FIG. 1-13, a forced circulation water tube boiler comprises a combustion chamber (1), longitudinal horizontal collectors (2) located at the top, longitudinal horizontal collectors (3) located at the bottom, a transverse collector (4) located vertically at the rear of the combustion chamber ( 1), an additional transverse collector (5) located vertically in the rear part of the combustion chamber (1), U-shaped pipes with a lateral finned part (6), smooth U-shaped pipes (7), heat exchange pipes (8) in the form of a snake horizontal, screen pipes (9) at the front, screen pipes (10) at the back, return manifold (11), supply manifold (12), air vents (13), drains (14) and gas ducts (15).

Boiler with forced circulation as part of the boiler plant (not shown) operates as follows.

Fuel and air are fed through the burner (16) into the combustion chamber (1), where the fuel burns with heat release.

The combustion products are cooled in the heat exchanger, giving off heat through the body and the fins of the heat exchange pipes (8), also due to the lower (lower sections of the U-shaped pipes (6)), ceiling (upper sections of the U-shaped pipes (6)), front (9 ) and rear (10) screen pipes with membranes, manifolds (2, 3, 4, 5).

Then the exhaust gases pass through the side finned sections of the U-shaped pipes (6), outside of which figured metal plates (17) are fixed, which regulate the amount of gas passing through each pipe with maximum heat transfer from the burnt gases.

Then, through the gas ducts (15), the exhaust gases are removed into the chimney (not shown).

The heat obtained during the combustion of fuel is perceived by water through the heating surfaces.

As shown in FIG. 13, the coolant through the return manifold (11), enters the longitudinal upper manifolds (2), in which partitions (18) are installed and, along the rows of parallel U-shaped tubes (6), descends into the lower longitudinal manifolds (3), and then moves along those the same collectors and, resting against the partition (18), rises along the rows of parallel U-shaped tubes (6) to the upper collector (2) and, according to the same principle, the coolant turns in the upper collector (2) and goes down until it reaches the extreme rows parallel U-shaped pipes (6) at the rear of the combustion chamber (1).

From the upper (2) or lower (3) collectors, the coolant enters the vertical collector (4), from which it moves along the horizontal heat exchange pipes (8), turning 180 degrees once or twice, depending on the number of U-shaped bends (see Fig. 6 and 7) and then enters the additional transverse manifold (5), and then through the nozzles in the additional transverse manifold (5) - into the supply manifold (12), from which the coolant is sent to the consumer. When moving through the pipes (6, 8), the coolant is gradually heated to a predetermined temperature.

This design allows you to equalize the speed of water in different parts of the boiler, regardless of its size and power.

Optimal speeds of water movement allow avoiding overheating of water and metal.

During operation, after the boiler is stopped, drains (14) open to empty it, and when it is filled with water, air vents (13) open (with closed drains (14)).

Due to the fact that the combustion chamber (1) consists of two halves, its assembly and welding on the conductor has been simplified.

Due to the fact that in the furnace part the surface of the U-shaped tubes (6) has fins, the amount of time-consuming welding of the membranes has decreased.

Heat exchange tubes (8) in the form of a serpentine with a smooth or additional heat exchange surface (finned, studded, etc.) located next to the outer vertical finned tubes are longer in comparison with the heat exchange tubes of the prototype, which reduces the number of welds in the product when the same heat output.

Thus, the use in the proposed boiler of a certain design of heat exchange pipes (8) and combustion chamber collectors allows maximum removal of heat from the burnt gases and makes it possible to have an optimal hydraulic circuit of the boiler, simplifies the design and manufacture through the use of simple and similar elements, reduces the metal consumption of the boiler and improves reliability and economy.

Due to the good accessibility of all elements of the boiler design, the maintainability during operation significantly increases in comparison with the prototype, it makes it possible to create many options for the same type of boilers of various capacities.

Claims (20)

1. Water tube boiler with forced circulation, including a combustion chamber (1) made of two halves, each of which contains: smooth U-shaped pipes (7) located in the transverse plane of said combustion chamber (1), at least partially ribbed U-shaped tubes (6), heat exchange pipes (8), made in the form of a snake and placed inside the mentioned combustion chamber (1) mostly along its side wall, cross collector (4), additional cross collector (5), upper (2) and lower (3) longitudinal collectors having end sections; in which: said upper (2) and lower (3) longitudinal manifolds are interconnected by said at least partially finned U-shaped tubes (6) and said smooth U-shaped tubes (7); said transverse manifold (4) is located near the end sections of said upper (2) and lower (3) longitudinal manifolds, said transverse collector (4) is connected to said additional transverse collector (5) by means of said heat exchange pipes (8). 2. The boiler according to claim 1, in which the aforementioned smooth U-shaped tubes (7) are provided with steel plates forming a membrane surface. 3. Boiler according to any one of claims 1 or 2, in which the aforementioned smooth U-shaped pipes (7) are equipped with screen pipes (9, 10) located in the plane of the smooth U-shaped pipes (7). 4. Boiler according to claim 1, in which the aforementioned additional transverse collector (5) is located near the aforementioned end sections of the upper (2) and lower (3) longitudinal collectors. 5. Boiler according to any one of claims 1 or 4, in which the aforementioned additional transverse collector (5) is located outside the aforementioned combustion chamber (1). 6. Boiler according to claim 1, in which the aforementioned heat exchange pipes (8) connected in transverse collectors are made of several parts, where at least two parts of the pipe (8) connected to each other by bends are located along the combustion chamber. 7. The boiler according to claim 1, in which the aforementioned heat exchange pipes (8) located inside the combustion chamber (1) can be additionally equipped with fins or studs. 8. The boiler according to claim 1, in which the two halves of the aforementioned combustion chamber (1) are interconnected by return (11) and supply (12) collectors to form a single water path. 9. The boiler according to claim 1, in which on the outer side of the finned part of the above-mentioned U-shaped pipes (6) there are figured metal plates (17). 10. Boiler according to claim 1, in which the aforementioned heat exchange tubes (8) are arranged essentially horizontally, and the aforementioned transverse manifold (4) and the additional transverse manifold (5) are arranged essentially vertically.

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