Grinding air pre-heater sealing device capable of increasing flow damping coefficient

Abstract

The invention discloses a grindable air pre-heater sealing device capable of increasing a flow damping coefficient. The grindable air pre-heater sealing device at least comprises a first cellular board, a second cellular board, a rigid sealing piece, a distance sleeve, an M-shaped spring, a bolt and a nut. First and second mounting holes distributed along the length direction are respectively formed in the upper ends of the first and second cellular boards; kidney-shaped holes distributed in the length direction are formed in the upper end of the rigid sealing piece, and the longitudinal length of the kidney-shaped holes is larger than the diameter of the first mounting hole and the diameter of the second mounting hole. The M-shaped spring is arranged at the inner bottom of the waist-shaped hole; the first cellular board, the rigid sealing piece and the second cellular board are sequentially stacked in the thickness direction, and the upper edge of the first cellular board and the upper edge of the second cellular board both exceed the upper edge of the rigid sealing piece by at least 1 mm; the distance sleeves simultaneously penetrate through the corresponding first mounting holes, the second mounting holes and the waist-shaped holes, and the length of the distance sleeves is greater than the sum of the thicknesses of the first honeycomb plate, the rigid sealing sheet and the second honeycomb plate; and a bolt penetrates through the distance sleeve and is fixed by a nut. The device is good in sealing performance, simple and stable.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of sealing of Ljungstrom air preheater, and relates to a sealable air preheater sealing device with increased flow damping coefficient. BACKGROUND

[0002] Ljungstrom air preheater (hereinafter referred to as "air preheater") is a heat exchange equipment for large-scale power plant boiler, which uses the heat of boiler flue gas to heat the air required for combustion. The air preheater rotor is composed of a large number of heat storage elements, when the rotor rotates slowly, the flue gas and air flow reversely and alternately through the rotor, the heat storage elements absorb heat on the flue gas side and release heat on the air side, thereby achieving the preheating effect of reducing the flue gas temperature of the boiler and increasing the hot air temperature, and improving the economy of the power plant.

[0003] The air preheater rotor is actually a huge cylinder, and the rotor changes from cold state to hot state. Due to the temperature difference between the upper and lower end faces and the weakening of the rigidity of the steel material after being heated, the "mushroom-shaped" deformation is generated. Therefore, when installed in cold state, a gap is required to be reserved between the air preheater rotor and the stator, and the size of the reserved gap depends on the deformation amount of each part of the air preheater, especially the deformation amount of the air preheater rotor; in principle, it is necessary to ensure that the rotor and the stator do not collide under any working condition, so as to prevent the rotor from being stuck and causing safety accidents.

[0004] Since the air side pressure of the air preheater is higher than the flue gas side pressure, a sealing device is required to reduce the leakage of air to the flue gas side, so as to reduce the energy loss. The conventional method in engineering is to install sealing sheets on the rotor partition plate, and the sealing sheets and the rotor partition plate are connected by bolts. The rotor partition plate is generally long, and the shorter sealing sheets are connected end to end to form a complete seal. The traditional sealing sheet is a straight sheet type, and a larger sealing gap and a smaller sealing sheet thickness need to be reserved during installation to ensure the safe and stable operation of the air preheater.

[0005] In engineering application, the traditional sealing sheet has some problems, such as that the too small reserved gap of the traditional sealing sheet may cause the air preheater rotor to be stuck, and the too large reserved gap may increase the leakage. In engineering, it is often necessary to make a compromise between the two. Therefore, the sealing gap always exists, and the air leaks from the sealing gap to the flue gas side, causing additional heat loss and power consumption loss. The main ways to reduce the leakage amount include two aspects: ① reducing the sealing gap as much as possible under the premise of ensuring that the air preheater rotor is not stuck; and ② increasing the flow damping coefficient at the sealing gap. However, the traditional sealing sheet is generally a single sheet or a laminated sheet structure of 2-3 sheets, and the flow damping coefficient is small. SUMMARY

[0006] The purpose of the present application is to provide a sealable air preheater sealing device with increased flow damping coefficient, which can ensure the safe and stable operation of the air preheater under the premise of minimizing the air leakage rate of the air preheater.

[0007] To solve the above technical problems, the technical scheme of the present application is: The application discloses a sealing device of an abradable pre-filter for increasing a flow damping coefficient, which comprises at least a first honeycomb plate, a second honeycomb plate, a rigid sealing sheet, a distance sleeve, an M-shaped spring, a bolt and a nut. The upper end of the first honeycomb plate is provided with first mounting holes distributed along the length direction, and the upper end of the second honeycomb plate is provided with second mounting holes distributed along the length direction, wherein the first mounting holes and the second mounting holes are circular and equal in size; the upper end of the rigid sealing sheet is provided with a waist-shaped hole (a slot-shaped hole) distributed along the length direction, wherein the transverse width of the waist-shaped hole is not less than the diameter of the first mounting holes and the second mounting holes, and the longitudinal length of the waist-shaped hole is greater than the diameter of the first mounting holes and the second mounting holes; the first mounting holes, the second mounting holes and the waist-shaped hole are in one-to-one correspondence. The M-shaped spring is arranged at the bottom of the waist-shaped hole. The first honeycomb plate, the rigid sealing sheet and the second honeycomb plate are sequentially stacked along the thickness direction, and the upper edges of the first honeycomb plate and the second honeycomb plate both exceed the upper edge of the rigid sealing sheet by at least 1 mm; the distance sleeve is located in the corresponding first mounting hole, the waist-shaped hole and the second mounting hole at the same time, and the length of the distance sleeve is greater than the sum of the thicknesses of the first honeycomb plate, the rigid sealing sheet and the second honeycomb plate (so as to facilitate the flexible yielding of the rigid sealing sheet); the tail end of the bolt is fixed by the nut after penetrating through the distance sleeve (the outer diameters of the head end of the bolt and the nut are both greater than the inner diameter of the sleeve, and the bolt rod part can penetrate through the distance sleeve); the distance sleeve is located above the M-shaped spring and is in contact with the recessed part in the center of the top of the M-shaped spring.

[0008] The application is abradable, that is, allows wear, on the one hand due to good wear resistance, slow wear rate, on the other hand this wear will not cause equipment failure.

[0009] The above-mentioned upper edges of the first honeycomb plate and the second honeycomb plate both exceed the upper edge of the rigid sealing sheet by at least 1 mm refers to the initial state. However, even if the first honeycomb plate and the second honeycomb plate are worn in long-term continuous operation, the rigid sealing sheet will effectively yield flexibly, while ensuring the sealing, and can effectively avoid failure such as jamming.

[0010] The above-mentioned "upper edge" refers to the edge located at the top.

[0011] The above-mentioned M-shaped spring has protrusions at both ends of the top and a recess in the center, of course, the recess is also obviously higher than both ends of the bottom of the M-shaped spring, so that the rigid sealing sheet has a flexible yielding space. Once there is a collision and wear, the rigid sealing sheet extrudes the M-shaped spring to yield flexibly.

[0012] The above-mentioned device can significantly increase the flow damping coefficient through the wall surface of the honeycomb hole and the viscous shear of the fluid.

[0013] In order to further improve the flow damping effect, the axial direction of the honeycomb holes on the first and second honeycomb plates is consistent with the thickness direction of the honeycomb plate.

[0014] The honeycomb holes on the first and second honeycomb plates are square or hexagonal, and the number of cross-sectional honeycombs per square decimeter is not less than 120.

[0015] In order to improve the stability of the sealing device structure and facilitate maintenance, the abovementioned sealing device with an increased flow damping coefficient also includes a first clamp plate and a second clamp plate, which are sequentially arranged along the thickness direction. The first clamp plate is provided with third mounting holes distributed along the length direction, and the fourth clamp plate is provided with fourth mounting holes distributed along the length direction. The third mounting holes and the fourth mounting holes are circular and equal in size, and the hole diameter of the third mounting holes and the fourth mounting holes is equal to the inner diameter of the distance sleeve. The tail end of the bolt passes through the third mounting hole, the distance sleeve and the fourth mounting hole in turn and is fixed with a nut. The two ends of the distance sleeve are attached to the first clamp plate and the second clamp plate respectively.

[0016] The first mounting hole, the second mounting hole, the third mounting hole, the fourth mounting hole and the waist-shaped hole are one-to-one corresponding.

[0017] A gasket is arranged between the head of the bolt and the first clamp plate, and between the nut and the second clamp plate.

[0018] In order to ensure the structural strength and operational stability of the device, the thickness of the first clamp plate and the second clamp plate is 1-3mm.

[0019] The thickness direction refers to the thickness direction of each plate, and each plate is stacked together along the thickness direction.

[0020] In order to improve safety and operational stability, the upper edge of the first clamp plate and the second clamp plate is lower than the upper edge of the rigid sealing piece.

[0021] In order to balance the operational stability and sealing effect, the upper edge of the first honeycomb plate and the upper edge of the second honeycomb plate are at least 2-5mm higher than the upper edge of the rigid sealing piece.

[0022] In order to better ensure the structural strength, the thickness of the rigid sealing piece is 2-4mm.

[0023] In order to further ensure the flow damping effect, the thickness of the first honeycomb plate and the second honeycomb plate is 10-30mm.

[0024] In order to reduce the friction force of the sealing device after impact and abrasion, the first honeycomb plate and the second honeycomb plate are made of self-lubricating composite material, such as Cu-2Ni-5Sn-(graphite+PbO).

[0025] The technologies not mentioned in the present application are prior art.

[0026] The present application increases the flow damping coefficient of the abradable air preheater sealing device, significantly improves the flow damping coefficient at the sealing gap, and ensures the safe and stable operation of the air preheater under the premise of minimizing the air preheater air leakage rate. Even if the first honeycomb plate and the second honeycomb plate are worn in long-term continuous operation, the rigid sealing piece will effectively give way to flexibility, ensuring the sealing while effectively avoiding jamming and other failures. The structure is simple, ingenious and reasonable, low in cost, long in service life and easy to transform. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 The structure diagram of the abradable air preheater sealing device of the present application; Figure 2 The setting diagram of the M-shaped spring of the present application; In the figure, 1 is a first honeycomb plate, 2 is a second honeycomb plate, 3 is a rigid sealing piece, 4 is a fixed distance sleeve, 5 is an M-shaped spring, 6 is a first clamping plate, 7 is a second clamping plate, 8 is a bolt, and 9 is a nut. DETAILED DESCRIPTION

[0028] In order to better understand the present application, the content of the present application will be further illustrated below in combination with examples, but the content of the present application is not limited to the following examples only.

[0029] The orientation words of the present application, such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. are based on the relative orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0030] Example 1

[0031] As shown in Figure 1 An abradable air preheater sealing device for increasing the flow damping coefficient, at least comprising a first honeycomb plate, a second honeycomb plate, a rigid sealing piece, a fixed distance sleeve, an M-shaped spring, a bolt and a nut; The upper end of the first honeycomb plate is provided with first mounting holes distributed along the length direction, the upper end of the second honeycomb plate is provided with second mounting holes distributed along the length direction, the first mounting holes and the second mounting holes are circular and equal in size; the upper end of the rigid sealing sheet is provided with waist-shaped holes (slot-shaped holes) distributed along the length direction, the transverse width of the waist-shaped holes is not less than the diameter of the first mounting holes and the second mounting holes, and the longitudinal length of the waist-shaped holes is greater than the diameter of the first mounting holes and the second mounting holes; the first mounting holes, the second mounting holes and the waist-shaped holes correspond one by one; The M-shaped spring is arranged at the bottom of the waist-shaped hole; The first honeycomb plate, the rigid sealing sheet and the second honeycomb plate are sequentially stacked along the thickness direction, the upper edges of the first honeycomb plate and the second honeycomb plate both exceed the upper edge of the rigid sealing sheet by at least 1 mm; the distance sleeve is located in the corresponding first mounting hole, waist-shaped hole and second mounting hole at the same time, and the length of the distance sleeve is 1.5 mm greater than the sum of the thicknesses of the first honeycomb plate, the rigid sealing sheet and the second honeycomb plate; the tail end of the bolt is fixed with a nut after passing through the distance sleeve (the outer diameters of the head end of the bolt and the nut are both greater than the inner diameter of the sleeve, and the bolt rod part can pass through the distance sleeve); the distance sleeve is located above the M-shaped spring and contacts the recessed part in the center of the top of the M-shaped spring.

[0032] The device can significantly increase the flow damping coefficient by the viscous shear between the wall surface of the honeycomb hole and the fluid. Even if the first honeycomb plate and the second honeycomb plate are worn in long-term continuous operation, the rigid sealing sheet can effectively yield flexibly, which can effectively avoid the failure of jamming while ensuring the sealing.

[0033] Embodiment 2

[0034] On the basis of embodiment 1, the following improvements are further made: in order to further improve the flow damping effect, the axial direction of the honeycomb hole on the first honeycomb plate and the second honeycomb plate is consistent with the thickness direction of the honeycomb plate. The honeycomb hole on the first honeycomb plate and the second honeycomb plate is hexagonal, and the number of honeycomb sections per square decimeter is not less than 120.

[0035] Embodiment 3

[0036] On the basis of embodiment 2, the following improvements are further made: in order to improve the stability of the structure of the sealing device and facilitate maintenance, the flow damping coefficient abrasion-preventing air preheater sealing device further comprises a first clamping plate and a second clamping plate, the first clamping plate, the first honeycomb plate, the rigid sealing sheet, the second honeycomb plate and the second clamping plate are sequentially arranged along the thickness direction, the first clamping plate is provided with third mounting holes distributed along the length direction, the fourth clamping plate is provided with fourth mounting holes distributed along the length direction, the third mounting holes and the fourth mounting holes are circular and equal in size, the diameters of the third mounting holes and the fourth mounting holes are equal to the inner diameter of the distance sleeve, the tail end of the bolt passes through the third mounting hole, the distance sleeve and the fourth mounting hole in sequence and is fixed by a nut, and the two ends of the distance sleeve are attached to the first clamping plate and the second clamping plate respectively. In order to improve safety and operation stability, the upper edges of the first clamping plate and the second clamping plate are both 10mm lower than the upper edge of the rigid sealing sheet. In this example, a gasket is arranged between the head of the bolt and the first clamping plate and between the nut and the second clamping plate.

[0037] Embodiment 4

[0038] On the basis of embodiment 3, the following improvements are further made: in order to balance operation stability and sealing effect, in this example, the upper edges of the first honeycomb plate and the second honeycomb plate are both 5mm beyond the upper edge of the rigid sealing sheet. The thickness of the rigid sealing sheet is 3mm. The thicknesses of the first honeycomb plate and the second honeycomb plate are both 20mm. The thicknesses of the first clamping plate and the second clamping plate are both 2mm. The first honeycomb plate and the second honeycomb plate are both made of self-lubricating composite material, such as Cu-2Ni-5Sn-(graphite+PbO).

[0039] In a certain 600MW class coal-fired unit, two Houghton 32VNT1830 type air preheaters are configured, and the air preheater sealing device of the application is adopted, so that the air leakage rate is stably controlled below 5% (under full load working condition) for a long time.

[0040] The flow damping coefficient abrasion-preventing air preheater sealing device of each of the above examples significantly improves the flow damping coefficient at the sealing gap, ensures the safe and stable operation of the air preheater under the premise of minimizing the air leakage rate of the air preheater, and effectively avoids the failure of being stuck even if the first honeycomb plate and the second honeycomb plate are abraded in long-term continuous operation. The rigid sealing sheet can effectively give way flexibly while ensuring sealing. The structure is simple, ingenious and reasonable, the cost is low, the service life is long, and the transformation is easy.

[0041] The above embodiments do not limit the application in any form, and any technical solutions obtained by equivalent substitution or equivalent transformation fall within the protection scope of the application.

Claims

1. A sealing device for a wearable air preheater that increases the flow damping coefficient, characterized in that: It includes at least a first honeycomb plate, a second honeycomb plate, a rigid sealing sheet, a spacer sleeve, an M-type spring, bolts, and nuts; The upper end of the first honeycomb panel is provided with a first mounting hole distributed along the length direction, and the upper end of the second honeycomb panel is provided with a second mounting hole distributed along the length direction. Both the first and second mounting holes are circular and of equal size. The upper end of the rigid sealing sheet is provided with an oblong hole distributed along the length direction. The transverse width of the oblong hole is not less than the diameter of the first and second mounting holes, and the longitudinal length of the oblong hole is greater than the diameter of the first and second mounting holes. The first mounting hole, the second mounting hole, and the oblong hole correspond one-to-one. The M-type spring is installed at the bottom of the waist-shaped hole; The first honeycomb panel, the rigid sealing sheet, and the second honeycomb panel are stacked sequentially along the thickness direction. The upper edge of the first honeycomb panel and the upper edge of the second honeycomb panel both extend at least 1 mm beyond the upper edge of the rigid sealing sheet. The spacer sleeve is simultaneously located in the corresponding first mounting hole, the waist-shaped hole, and the second mounting hole, and the length of the spacer sleeve is greater than the sum of the thicknesses of the first honeycomb panel, the rigid sealing sheet, and the second honeycomb panel. The tail end of the bolt passes through the spacer sleeve and is fixed with a nut. The spacer sleeve is located above the M-shaped spring and contacts the recess in the center of the top of the M-shaped spring.

2. The wearable air preheater sealing device with increased flow damping coefficient according to claim 1, characterized in that: The axial direction of the honeycomb holes on the first and second honeycomb plates is consistent with the thickness direction of the honeycomb plates.

3. The wearable air preheater sealing device with increased flow damping coefficient according to claim 1 or 2, characterized in that: On the first and second honeycomb panels, the honeycomb holes are square or hexagonal, and the number of honeycomb holes per square decimeter is not less than 120.

4. The wearable air preheater sealing device with increased flow damping coefficient according to claim 1 or 2, characterized in that: It also includes a first clamping plate and a second clamping plate. The first clamping plate, the first honeycomb plate, the rigid sealing sheet, the second honeycomb plate, and the second clamping plate are arranged sequentially along the thickness direction. The first clamping plate is provided with a third mounting hole distributed along the length direction, and the fourth clamping plate is provided with a fourth mounting hole distributed along the length direction. The third mounting hole and the fourth mounting hole are both circular and equal in size. The diameter of the third mounting hole and the fourth mounting hole is equal to the inner diameter of the spacer sleeve. The tail end of the bolt passes through the third mounting hole, the spacer sleeve, and the fourth mounting hole in sequence and is then fixed with a nut. The two ends of the spacer sleeve are respectively attached to the first clamping plate and the second clamping plate.

5. The wearable air preheater sealing device with increased flow damping coefficient according to claim 4, characterized in that: The upper edges of both the first and second clamping plates are lower than the upper edge of the rigid sealing sheet.

6. The wearable air preheater sealing device with increased flow damping coefficient according to claim 4, characterized in that: The thickness of both the first and second clamping plates is 1-3mm.

7. The wearable air preheater sealing device with increased flow damping coefficient according to claim 1 or 2, characterized in that: The upper edge of the first honeycomb panel and the upper edge of the second honeycomb panel both extend at least 2-5 mm beyond the upper edge of the rigid seal.

8. The wearable air preheater sealing device with increased flow damping coefficient according to claim 1 or 2, characterized in that: The thickness of the rigid sealing sheet is 2-4mm.

9. The wearable air preheater sealing device with increased flow damping coefficient according to claim 1 or 2, characterized in that: The thickness of both the first and second honeycomb panels is 10-30mm.

10. The wearable air preheater sealing device with increased flow damping coefficient according to claim 1 or 2, characterized in that: Both the first and second honeycomb panels are made of self-lubricating composite materials.

Images