RU1815512C - Air preheater - Google Patents

Abstract

Use: for heating air in boilers. SUMMARY OF THE INVENTION: an air heater of finned heat pipes 3 arranged in transverse rows in the chambers is installed in front of the main heating surfaces in the air heaters, while pipes 3 of one or two rows are connected to one lower and one upper additionally installed collectors 5 and 6 to form Autonomous removable sections. 3 ill.

Description

The invention relates to the field of power engineering, and more particularly, to air preheaters for eliminating the possibility of a dew point occurring with a corrosive breakdown of boiler air heaters.

The aim of the invention is to provide the possibility of removing air when sealing the pipes of the pre-heater, adjusting, if necessary, the level of the intermediate coolant in the pipes, constantly or periodically monitoring its presence in them, performing the defect of failed pipes, repairing or replacing them.

Figure 1 shows a pre-heater, section; in FIG. 2 is a cross section of a pre-heater; Fig. 3 shows an assembly on an enlarged scale.

The pre-heater contains the upper (air) 1 and lower

(gas) 2 parts with vertical pipes 3, common for both parts, from the inside, which are smooth and inside, which are fins 4 to intensify heat transfer and are filled with an intermediate coolant - water. Vertical pipes 3 are combined above and below into autonomous sections by connecting each transverse direction of gas and air movement of a series of pipes to the upper 5 and lower 6 collectors. An air vent with valve 7 is installed on each upper collector to fill the air when each autonomous section is filled with an intermediate coolant and at the beginning of vaporization it starts. To connect a water indicating device to each autonomous section, fittings with valves 8 and -9 connected to the upper and lower headers are used sections. A horizontal partition separating the air 1 from the gas 2 part of the pre-heater is formed by the support flanges 10,

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fixed to the walls of this heater and supported on these flanges of plates 11, mounted on the pipes 3 of each section. The air part 1 is connected at the air inlet to the duct 12 from the blower fan (not shown in the drawing), and at the outlet with the main air heater 13. The gas part 2 at the inlet is connected to the gas duct 14 from the convection shaft of the boiler, and at the inlet to the outlet gas duct fifteen.

Preheater works as follows.

Before the preheater is turned on, its autonomous sections located simultaneously in the air 1 and gas 2 parts are filled with an intermediate heat carrier - water, for which purpose the valves 7 of the air vents located on the upper manifolds 5 are opened to the fittings with valves 8 and 9 installed at the ends of the manifolds 5 and 6, fixed or removable water-reducing devices (not shown in the drawing) are connected and a water supply is connected to the nozzle with valve 8. At the same time, water fills the lower collectors 6 of the autonomous sections and the vertical pipes 3 connected to them. The latter are filled by at least half the height (the specific filling height of the pipes is verified by tests) so that the filled part of the pipes is located in the gas part 2 for increase in heat transfer from gas to the intermediate heat transfer medium. After filling the autonomous sections, the air vent valves 7 remain open to remove air when the intermediate coolant is vaporized (the presence of air impairs heat exchange and leads to corrosion). With the start of operation, the source air from the blower fan (not shown) enters through the air duct 12 into the air part

1 pre-heater. At the same time, the gas moves to the gas part

2 through the duct 14 from the convection shaft of the boiler. Gas passing through the gas part 2 heats the lower part of the pipes 3 and through their walls with fins 4, heats the intermediate heat carrier, which boils with the formation of steam inside the upper half of the pipes 3. With the appearance of steam from the air vents, the valves 7 are closed, because from this

it follows that the air is removed from the pipes. The steam of the intermediate heat carrier in the air part 1 transfers its heat to the air moving to the main heater 13 through the walls of the upper half of the pipes 3 with fins 4. After cooling, the intermediate heat carrier constantly condenses and flows into the lower halves of the pipes 3 for reheating and vaporization.

The advantages of the claimed invention are as follows: it is possible to remove air when sealing the pipes in which the intermediate coolant is enclosed; the level of the intermediate coolant in the pipes is regulated depending on the mode of operation of the boiler; the ability to constantly or periodically monitor the level of coolant in

pipes for maintaining an appropriate mode and detecting defective pipes in autonomous sections; sectional repair of the upstream heater is provided, which reduces the complexity of the repair and improves maintainability (accessibility to defective parts).

Claims (1)

SUMMARY OF THE INVENTION A preheater comprising an upper air chamber connected by an inlet and outlet through air ducts to a blower fan and a main heater, respectively, and a lower gas chamber connected at the inlet through a gas duct to the convection part of the boiler, and at the outlet, a gas duct for removing gases from boiler, and tubes finned outside and filled with an intermediate heat carrier, mounted vertically in said chambers, characterized in that, in order to increase the efficiency reliability and reliability, it additionally contains upper and lower horizontal collectors, equipped with air vents and fittings, respectively, for connecting the level indicator of the intermediate coolant, these pipes are placed in chambers in transverse rows and every 1-2 rows are connected to one upper and one lower collectors with the formation of autonomous removable sections.