RU2585331C1 - Air heater of mixing type, gas heat generator - Google Patents

Abstract

FIELD: energy.

SUBSTANCE: invention relates to heat engineering and can be used for air heating. Air heater mixer comprises housing, air chambers, combustion chamber made of two conical shells with specified aperture angle, and adjustment of burning modes can be performed by means of rotary gate valve built into burner. Gas chamber can be made of solid-drawn pipe, and combustion chamber is welded thereto by spot welding.

EFFECT: by varying gate opening angle, size of flame and degree of excess oxygen is controlled to obtain optimum fuel combustion at minimum emissions of unburnt hydrocarbons and minimum amount of harmful substances (CO and NO_x) in exhaust gases.

1 cl, 1 dwg

Description

The present invention relates to a power system, and in particular to gas heat generators with forced air supply, and can be used for heating air.

The technical result of the invention is the ability to adjust the power of the gas heat generator, reduce harmful emissions, reduce pressure losses in the air path, reduce noise, increase reliability, simplify the design and installation of the burner.

The gas heat generator contains a cylindrical body, inside of which are two cylindrical and two conical shells located coaxially. Two conical shells form a combustion chamber. The housing and the first inner cylindrical shell form an external air chamber. The inner cylindrical shell forms an inner air chamber. At its entrance are the gates of the gate device for regulating the air flow. Both conical shells are welded to a ring made of a seamless pipe. A gas pipe with gas equipment is connected to this pipe. In the annular pipe from the side located between the conical shells, holes have been made through which gas is supplied into the space between the shells. Holes were made in the walls of the shells. The number, location, size and shape of these holes were obtained by calculation, confirmed by experiments.

Known burner (RF patent No. 2052174 F23D 14/62) containing an external diffuser, coaxially located in it the middle and inner diffusers, forming a conical annular fuel manifold, to the top of which a fuel pipe is connected, while the outer and middle diffusers form each other confuser, ring, air channel. The mixer is additionally equipped with an external confuser, the base of which is interfaced with the base of the external diffuser, and inside the specified diffuser an internal confuser is coaxially located, forming the diffuser ring air-fuel channel with the latter. At the same time, the bases of the middle diffuser and the internal confuser are interconnected, and holes are made on the wall portion of the internal diffuser adjacent to the indicated interface, communicating the annular fuel manifold with the diffuser air duct at a right angle, and the external confuser holds the middle with ribs made in the form guides.

The closest to the claimed gas heat source for a combination of essential features is a gas burner (RF patent No. 2213299 F23D 14/20) with forced air supply, containing a chamber for supplying air, a chamber for supplying gas, in the end walls of which a number of opposed openings are made, mixing tubes with an annular row of holes in the side walls and a flame tube, according to the invention, a gas supply chamber is installed between the air supply chamber and the flame tube to form an annular gap between its side cylindrical wall and the flame tube, while the mixing tubes are hermetically installed in the holes in the end walls of the gas supply chamber, in the side cylindrical wall of which an annular row of radial holes is made, and the holes in the side walls of the mixing tubes are located inside the gas supply chamber.

However, this burner is very sensitive to pressure differences between gas and air, there is a danger of a sharp increase in the content of nitrogen oxides (NO _x ), or it is difficult to smoothly ignite the burner. Another disadvantage of this design is the manufacturing complexity - a large number of welded, sealed joints connecting parts that operate at high temperature gradients, which crack during prolonged operation, and the gas chamber is lost and the integrity of the product is impaired.

The proposed device tried to avoid these disadvantages.

The air heater contains a cylindrical body (1), inside of which are two cylindrical (2), (3) and two conical (4), (5) shells located coaxially. Two conical shells form a combustion chamber (14). The housing and the first inner cylindrical shell form an external air chamber (6). Two cylindrical shells form an air chamber (8). At the entrance to the chamber (8) a filter mesh (11) is placed to protect the combustion chamber from the ingress of foreign particles into it.

The inner cylindrical shell forms an inner air chamber (7). At its entrance are the gates of the slide gate device (10) for regulating the air flow. The space formed by the conical shells is a combustion chamber (14). The cone opening angle α = 4 ÷ 12 °. Both conical shells are welded to a ring made of a seamless pipe (9), which is a gas chamber. A gas pipeline pipe with gas equipment (12) is connected to this pipe. In the annular pipe from the side located between the conical shells, holes (13) were made with a diameter of 1.5 mm, the area of the holes is 3 ÷ 3.5 times smaller than the area of the hole in the gas supply pipe. Through the holes, gas is supplied to the combustion chamber. Holes (15) were made in the walls of the shells, through which air enters the chamber. The diameters of the holes are from 2.5 mm to 5 mm. The total area of the holes is 20 ÷ 30 times the area of the holes for gas.

The combustion chamber, consisting of two diverging conical shells, is welded to the gas chamber, a seamless pipe, using spot welding. The resulting design is not afraid of warping during uneven heating of its individual parts.

According to the operating conditions, the combustion chamber is subjected to uneven heating, that is, the side of the chamber in which the holes are made, from which the gas escapes, is in the thermal zone at high temperature. The opposite side of the gas chamber is heated to a lower temperature, as it is constantly blown with cold air. As a result, a temperature difference occurs, which leads to an uneven expansion of the chamber metal. If the combustion chamber is made of individual parts by welding, then welding should be carried out by a continuous tight seam along the entire length. Uneven heating of the chamber and, accordingly, expansion leads to high stresses in the metal. Welds in these places must be performed by very carefully qualified welders, which is not always possible. A rather large length of these seams leads to an increase in the production time, an increase in the cost of the structure, to its manufacture in special equipment. In addition, the welded structure is, by definition, weaker than solid metal and, accordingly, its service life is shorter.

The combustion chamber is made of two conical shells, in which holes are made for the intake of air into the chamber. Since air enters the chamber through special openings, there is no need to achieve tightness at the place of welding of these shells to the gas chamber (seamless pipe), the inflow of a small amount of air through leaks in the welds will not significantly change the gas-air ratio. In this case, the connection of the parts can be carried out by spot welding and, as a result, the stresses arising during welding with a continuous seam can be avoided. This simplifies and reduces the cost of burner manufacturing.

The design of the combustion chamber, made of two conical shells, allows air to enter the chamber without large aerodynamic drag. Air smoothly enters the chamber, which reduces the occurrence of turbulence in the inlet flow and reduces the occurrence of sound waves (noise). The air jets passing through the conical shells located at an angle spread over the inside of the chamber to a greater distance, the intensity of mixing of gas media (internal - natural gas from the outside - atmospheric air) increases and, accordingly, more complete combustion at a short distance is ensured.

The location of the holes on the conical shells provides a sufficient supply of atmospheric air to the combustion chamber, necessary for complete combustion of the fuel, on the one hand (slight formation of CO and unburned hydrocarbons), and on the other hand, provides combustion at not very high temperatures (up to 1000 ° C), which does not lead to the formation of a significant amount of nitrogen oxides (NO _x ).

Ignition of the gas generator is carried out using the ignition electrode (16). Flame monitoring is carried out by flame monitoring sensors (17).

The air heater operates as follows.

The fan starts, the gas line is blown, gas is supplied to the burner and the burner is ignited. By adjusting the opening angle of the gate, the size of the torch and the degree of excess oxygen are regulated. When the gate starts to hide behind itself, the pressure in the chamber (7) behind the gate drops, the pressure behind the entire burner drops and, accordingly, the pressure differential between the inlet and outlet of the heat and gas generator increases, at a constant fan speed. As a result, the air flow rate in the chambers (6) and (8) increases. The increased air velocity in the chamber (8) leads to the flow of more air into the chamber (14) through the holes (15), which naturally leads to a change in the gas-air ratio in the combustion chamber (14). By adjusting this ratio, you can achieve the most optimal conditions for combustion.

By turning the shutter damper, it is easy to adjust the mode of maximum complete combustion at various outdoor temperatures, thereby increasing the thermal regulation coefficient of the entire heater, with a minimum amount of harmful substances formed: carbon oxides (CO) and nitrogen oxides (NO _x ). The gate valve can be controlled either manually or with the help of an electric drive in an autonomous (unmanned) version.

The efficiency of gas combustion and the interval of "clean" combustion increases and does not depend on inter-seasonal fluctuations in street temperature

Claims (2)

1. The heater is a mixing type, a gas heat generator containing a housing, air chambers, a combustion chamber, characterized in that the combustion chamber is made of two conical shells with an opening angle within 4 ÷ 12 °, and the combustion modes can be adjusted using the rotary damper - gate integrated in the burner itself. 2. The heater according to claim 1, characterized in that the gas chamber is made of a seamless pipe, and the combustion chamber is welded to it by spot welding.

Images