CN2564973Y - Sealer for rotary air preheater - Google Patents

Abstract

The utility model relates to a sealing device of a rotary air preheater, wherein one side of the radially fixed sealing plate is welded to the center beam of the preheater shell, and the other side is fixed on both sides of the fan-shaped plate by bolts; One side of the fixed sealing plate is welded to the shell of the preheater, and the other side is fixed on both sides of the axial plate with bolts; The gap between the axial sealing sheet on the casing and the sealing surface of the axial plate is determined according to the pre-calculated correction value of the thermal expansion and thermal deformation of the rotor, and is adjusted by the adjusting screw. The improvement of the design of the utility model not only overcomes the disadvantage that the adjustable sealing device is easy to wear and causes increased air leakage, but also eliminates the disadvantages that the fixed sealing device cannot be adjusted or replaced, so that the air leakage rate is reduced and stable; and it can be adjusted locally and Replacement saves maintenance cost and workload, and has obvious economic benefits.

Description

Sealing device for rotary air preheater

technical field

The utility model relates to a sealing device of a rotary air preheater, which is used in heat exchange equipment in a boiler unit of a thermal power plant.

Background technique

Rotary air preheaters are widely used in large and medium-sized power plants due to their high heat transfer surface density, compact structure, long life, and low operating costs. Its basic component is the rotor, which contains tens of thousands of square millimeters of corrugated plate heat exchange elements rolled into special shapes. When the rotor rotates, the hot flue gas discharged from the boiler after combustion enters the preheater and passes through the rotor, and the heat is recovered. At the same time, the air entering the preheater also releases the recovered heat to the air through the rotor. In this way, with the continuous rotation of the rotor, the exhausted flue gas exchanges heat with the incoming air. However, due to the gap between the rotor and the casing, and the considerable pressure difference between the air and the flue gas, the air leakage problem of the rotary air preheater becomes particularly prominent. The air leakage of the sealing device of the rotary air preheater includes two parts: direct air leakage and carry air leakage. The latter is determined by the device structure itself and is a constant. The former is proportional to the size of the sealing gap, which is the technical problem to be solved by the sealing device, and is also related to the static pressure difference and airflow density. Therefore, the air leakage rate is an important indicator to measure its technical level. The sealing method that affects the air leakage rate has gone through two development stages of "adjustable" and "fixed". The adjustable sealing device is based on the principle of adjusting the position of the fan-shaped plate or axial plate through the automatic control system, so as to keep the sealing gap unchanged. Control the air leakage rate. However, with the increase of the operating time of the preheater, the sealing device of this structure will gradually wear and tear under the action of high-pressure air flow, resulting in an increase in the amount of air leakage year by year. The fixed sealing device is to pre-calculate the thermal expansion of the rotor plus a correction value to determine the amount of sealing gap, and then adjust the distance between the fan-shaped plate and the axial plate according to this amount, and fix it by welding. In this way, once the fan-shaped plate and the axial plate are welded and fixed, they cannot be adjusted and replaced again. Otherwise, the entire sealing system needs to be dismantled and replaced completely, which obviously increases the maintenance cost of the equipment and causes unnecessary waste.

Utility model content

In order to overcome the defects of the prior art, the utility model provides a sealing device which can effectively reduce the air leakage rate of the preheater and can be adjusted and replaced locally.

The sealing device of the rotary air preheater of the utility model comprises a fan-shaped plate, an axial plate, a sealing plate, a radially fixed sealing plate and an axially fixed sealing plate, wherein one side of the radially fixed sealing plate is welded to the shell of the preheater On the center beam, the other side is fixed on both sides of the fan-shaped plate with bolts. The gap between the radial sealing sheet installed on the diaphragm and the sealing surface of the fan-shaped plate is based on the pre-calculated thermal expansion and thermal deformation of the rotor. The correction value is determined and adjusted by the adjusting screw; one side of the axially fixed sealing plate is welded to the preheater shell, and the other side is fixed on both sides of the axial plate with bolts, and the axial seal installed on the rotor shell The gap between the sheet and the sealing surface of the axial plate is determined according to the pre-calculated correction value of the thermal expansion and thermal deformation of the rotor, and is adjusted by the adjusting screw.

The improvement of the design of the sealing device of the rotary air preheater of the utility model not only overcomes the disadvantage that the adjustable sealing device is easy to wear and causes increased air leakage, but also eliminates the disadvantage that the fixed sealing device cannot be adjusted and cannot be replaced, so that the air leakage rate Reduced and stable; and can be adjusted and replaced locally, saving maintenance costs and workload, and has obvious economic benefits.

Description of drawings

Figure 1 is a schematic structural diagram of a rotary air preheater;

Fig. 2 is a schematic structural view of the utility model, that is, a schematic cross-sectional view of Fig. 1A-A;

Fig. 3 is the B-B sectional schematic diagram of Fig. 2;

FIG. 4 is a schematic cross-sectional view of C-C in FIG. 2 .

Detailed ways

Figure 1 and Figure 2 are schematic diagrams of the structure of the two-chamber rotary air preheater. Two fan-shaped plates 3 are installed on the upper and lower sides, and two axial plates 5 are installed on the shell 4. The shell 4 is fixed to the support of the preheater. The connection does not move, and the rotor equipped with corrugated plates rotates under the action of the transmission mechanism. A radial seal 7 is installed on the radial partition 8 of the rotor, and a shaft is installed on the rotor housing 9 corresponding to the radial seal 7. to the sealing sheet 6. When the rotor rotates, there is a certain sealing gap between the radial sealing sheet 7 and the axial sealing sheet 6 and the sealing surfaces of the fan-shaped plate 3 and the axial plate 5 respectively, so as to ensure the minimum air leakage. The gap between them is It is adjusted by calculating the thermal expansion and thermal deformation correction value of the rotor in advance, but it needs to be repaired and adjusted frequently with the running time to reduce the air leakage rate.

It can be seen from Fig. 3 that the fan-shaped plate 3 is fan-shaped, and one side of the radially fixed sealing plate 12 is welded and fixed to the center beam 11 from two sides, and the other side of the radially fixed sealing plate 12 is adjusted by adjusting the distance of the fan-shaped plate 3 through the screw rod 13 Finally, it is connected and fixed by a plurality of bolts 10 to the side of the fan-shaped plate 3; the axial plate 5 is arc-shaped, and is welded and fixed to the housing 4 through one side of the axially fixed sealing plate 15 from two sides, and the side of the axially fixed sealing plate 15 On the other side, after adjusting the distance of the axial plate 5 through the adjusting screw 14, it is connected and fixed with the side of the axial plate 5 by a plurality of bolts 10, as shown in FIG. 4 .

Claims (1)

1. A sealing device for a rotary air preheater, comprising a fan-shaped plate, an axial plate, a sealing sheet, a radially fixed sealing plate and an axially fixed sealing plate, characterized in that the radially fixed sealing plate (12 ) one side is welded to the center beam (11) of the preheater shell, and the other side is fixed on both sides of the fan-shaped plate (3) with bolts (10), and the radial seal (7) installed on the partition (8) ) and the sealing surface of the fan-shaped plate (3) is determined according to the correction value of the thermal expansion and thermal deformation of the rotor calculated in advance, and adjusted by the adjusting screw (13); the axially fixed sealing plate (15) One side is welded to the preheater casing (4), and the other side is fixed on both sides of the axial plate (5) with bolts (10), and the axial sealing plate (6) installed on the rotor casing (9) ) and the sealing surface of the axial plate (5) is determined according to the pre-calculated correction value of thermal expansion and thermal deformation of the rotor, and is adjusted by the adjusting screw (14).

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