Indirect air cooling system and sealing method thereof

Abstract

The present application discloses an indirect air cooling system and a sealing method thereof, wherein the indirect air cooling system comprises: an indirect air cooling tube bundle, comprising a plurality of base tubes arranged in parallel; a tube sheet with a plurality of tube holes, wherein the base tubes pass through the tube holes one by one; a manifold connected to the tube sheet; a sealing ring sleeved on the base tube and located between the tube sheet and the manifold to achieve a sealed connection between the base tube, the tube sheet and the manifold, wherein the axial dimension of the sealing ring located in the middle area of ​​the tube sheet is greater than the axial dimension of the sealing ring located in the remaining areas of the tube sheet. The above-mentioned indirect air cooling system can improve the sealing effect of the base tube, the tube sheet and the manifold without increasing the manufacturing cost, reduce the risk of liquid seepage or even leakage, and ensure the normal operation of the generator set.

Description

Technical Field

[0001] The present invention relates to the technical field of power generation equipment, and in particular to an indirect air cooling system. The present invention also relates to a sealing method suitable for the indirect air cooling system. Background Art

[0002] In the indirect air cooling system of the power plant, the core component is the indirect air cooling tube bundle, which is formed by allowing multiple base tubes to pass through the tube sheet in parallel, wherein the tube sheet is arranged on the lower header and connected to the opening of the lower header with bolts on both sides to seal the opening of the lower header. Since the lower header is filled with high-pressure liquid, in the actual working process, the tube sheet will deform under the action of hydraulic pressure and bolt preload, and the deformation of the tube sheet will gradually increase from both sides to the middle, so that the tube sheet forms a shape similar to an arch bridge (i.e., an arch), and the deformation of the tube sheet will cause a large gap between the base tube and the tube sheet, and between the tube sheet and the lower header. The high-pressure liquid filled in the lower header has a great risk of leakage or even leakage, which seriously affects the normal operation of the generator set.

[0003] In order to avoid leakage of high-pressure liquid in the prior art, the method generally adopted is to increase the thickness of the tube sheet to reduce the deformation of the tube sheet. However, increasing the thickness of the tube sheet will greatly increase the manufacturing cost of the indirect air cooling system. Summary of the invention

[0004] In view of this, the present invention provides an indirect air cooling system, which can improve the sealing effect of the base tube, tube sheet and header without increasing the manufacturing cost, reduce the risk of liquid leakage or even leakage, and ensure the normal operation of the generator set. The present invention also provides a sealing method for the indirect air cooling system.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] An indirect air cooling system, comprising:

[0007] An indirect air-cooling tube bundle includes a plurality of base tubes arranged in parallel;

[0008] A tube sheet having a plurality of tube holes, wherein the base tubes pass through the tube holes one by one;

[0009] A header connected to the tube sheet;

[0010] A sealing ring is sleeved on the base tube and located between the tube sheet and the header to achieve a sealed connection between the base tube, the tube sheet and the header, and the axial dimension of the sealing ring located in the middle area of ​​the tube sheet is greater than the axial dimension of the sealing ring located in the remaining area of ​​the tube sheet.

[0011] Preferably, in the above-mentioned indirect air cooling system, in the width direction of the tube sheet, the tube sheet comprises a middle area, a side area and an edge area, the deformation amounts of which decrease in sequence, and the side areas are located on both sides of the middle area, and the edge area is located on a side of the side area away from the middle area;

[0012] The axial dimension of the sealing ring located in the middle area is greater than that of the sealing ring located in the side area, and the axial dimension of the sealing ring located in the side area is greater than that of the sealing ring located in the edge area.

[0013] Preferably, in the above-mentioned indirect air cooling system, in the width direction of the tube sheet, the base tubes passing through the tube sheet are arranged in six rows. Among the six rows of base tubes, the two middle rows of base tubes are arranged in the middle area, the row of base tubes located on one side of the two middle rows of base tubes and the row of base tubes located on the other side of the two middle rows of base tubes are respectively located in the two side areas, and the remaining two rows of base tubes are respectively located in the two edge areas.

[0014] Preferably, in the above-mentioned indirect air cooling system, the header is a lower header arranged at the bottom of the tube sheet, and two sides of the lower header are respectively connected to two long side edges of the tube sheet by bolts and nuts.

[0015] A sealing method for an indirect air cooling system, which is applicable to the above-mentioned indirect air cooling system, comprises the following steps:

[0016] Allowing the plurality of base tubes to pass through the plurality of tube holes one by one, and achieving fixed connection between the base tubes and the tube sheet by tube expansion operation, so as to form an indirect air-cooling tube bundle having six rows of base tubes;

[0017] Sealing rings with a first axial dimension are sleeved on the middle two rows of the six rows of base tubes, and the sealing rings are close to the connection parts between the base tubes and the tube sheet;

[0018] Among the six rows of base tubes, sealing rings having a second axial dimension are sleeved on two rows of base tubes adjacent to and located on both sides of the two rows of base tubes in the middle, and the sealing rings are close to the connection between the base tubes and the tube sheet, wherein the second axial dimension is smaller than the first axial dimension;

[0019] Sealing rings having a third axial dimension are sleeved on the outermost two rows of the six rows of base tubes, and the sealing rings are close to the connection between the base tubes and the tube sheet, wherein the third axial dimension is smaller than the second axial dimension;

[0020] The tube sheet and the header are connected by bolts and nuts so that the tube sheet and the header squeeze all the sealing rings on both sides, so that the sealing rings sleeved on each base tube respectively realize the sealing connection between different base tubes and the tube sheet and the header.

[0021] The indirect air cooling system provided by the present invention sleeves sealing rings with different axial sizes on base tubes located at different parts of the tube sheet, and makes the axial size of the sealing ring on the base tube set in the middle area of ​​the tube sheet larger than the axial size of the sealing ring on the base tube in other areas of the tube sheet, so that the sealing ring with a larger axial size can more fully fill and seal the middle area of ​​the tube sheet with a larger deformation. The above-mentioned indirect air cooling system, by using sealing rings with different axial sizes, can carry out targeted sealing of parts of the tube sheet that have undergone different degrees of deformation. Compared with the setting method of increasing the thickness of the tube sheet in the prior art, there is no need to increase the thickness of the tube sheet, that is, without increasing the manufacturing cost of the indirect air cooling system, it can significantly improve the sealing effect of the base tube, tube sheet and manifold, reduce the risk of liquid seepage or even leakage, and provide a more reliable guarantee for the normal operation of the generator set. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0023] Figure 1 A schematic diagram of the structure of the base tube and the tube sheet in the indirect air cooling system provided by an embodiment of the present invention;

[0024] Figure 2 It is a schematic diagram of the structure of the base tube, tube sheet, header and sealing ring;

[0025] Figure 3 for Figure 2 A partial enlarged view of

[0026] Figure 4 It is a schematic diagram of the structure of the sealing ring.

[0027] In the above Figure 1-Figure 4 middle:

[0028] 1-base tube, 2-tube sheet, 3-header, 4-sealing ring, 5-bolt, 6-nut;

[0029] 101 - first row of base tubes, 102 - second row of base tubes, 103 - third row of base tubes, 104 - fourth row of base tubes, 105 - fifth row of base tubes, 106 - sixth row of base tubes, 201 - middle area, 202 - side area, 203 - edge area, 401 - first type of sealing ring, 402 - second type of sealing ring, 403 - third type of sealing ring. DETAILED DESCRIPTION

[0030] The present invention provides an indirect air cooling system, which can improve the sealing effect of base tubes, tube sheets and headers without increasing manufacturing costs, reduce the risk of liquid seepage or even leakage, and ensure the normal operation of the generator set.

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] like Figure 1-Figure 4 As shown, an embodiment of the present invention provides an indirect air cooling system, which mainly includes an indirect air cooling tube bundle, a tube sheet 2, a header 3 and a sealing ring 4 (other necessary components of the indirect air cooling system are not particularly described in this application because they are not improved in this application), wherein the indirect air cooling tube bundle includes a plurality of base tubes 1 arranged in parallel, and a plurality of tube holes are opened on the tube sheet 2, and the base tube 1 can pass through the plurality of tube holes one by one. After the base tube 1 passes through the tube hole, the base tube 1 can be expanded (i.e., the diameter of the base tube 1 is increased) to make the original clearance fit or over-fit. The base tube 1 and the tube hole of the transition fit are transformed into an interference fit, so as to realize the fixed connection between the base tube 1 and the tube sheet 2 to form an indirect air-cooling tube bundle. The base tubes 1 of the indirect air-cooling tube bundle can be distributed on the tube sheet 2 in four rows, six rows, eight rows, etc. The tube sheet 2 is arranged on the header 3, and the header 3 includes a lower header and an upper header; when the sealing ring 4 is arranged, it is sleeved on the base tube 1, and each base tube 1 is sleeved with a sealing ring 4. When the sealing ring 4 is sleeved on the base tube 1, the sealing ring 4 is also arranged close to the connection between the base tube 1 and the tube sheet 2, that is, the sealing ring 4 is arranged close to the surface of the tube sheet 2, such as Figure 2 and Figure 3As shown, when the tube sheet 2 and the header 3 are connected, the sealing ring 4 can be squeezed on both sides of the sealing ring 4 (the squeezing process is to squeeze all the sealing rings 4 at the same time), so that the compressed sealing ring 4 is closely abutted against the base tube 1, the tube sheet 2 and the header 3 to achieve the sealing connection of the three (or any two of the three). At the same time, all the sealing rings 4 arranged on the base tube 1 are not the sealing rings of exactly the same size, that is, the sealing rings 4 used in the indirect air cooling system of the present application include at least two types of sealing rings, and the difference between the different types of sealing rings is that the axial size of the sealing ring 4 is different (or the sealing ring 4 has different widths or heights), and further, the axial dimension of the sealing ring 4 located in the middle area 201 of the tube sheet 2 (i.e., the sealing ring 4 sleeved on the base tube 1 arranged in the middle area 201 of the tube sheet 2) is greater than the axial dimension of the sealing ring 4 located in the remaining areas of the tube sheet 2. In other words, a sealing ring 4 with a larger thickness is arranged in the middle area 201 of the tube sheet 2 where the deformation is the largest (i.e., the part where the curvature of the arch is the largest), so that the base tube 1, the tube sheet 2 and the header 3 can be sealed and connected in a larger size and space, and even if the tube sheet 2 has a large degree of bending deformation, the sealing effect can be well guaranteed.

[0033] The above-mentioned indirect air cooling system, by using sealing rings 4 with different axial sizes, can specifically seal the parts of the tube sheet 2 that are deformed to different degrees, that is, the sealing rings 4 with different axial sizes are coordinated with the different deformation degrees of different parts of the tube sheet 2 (the axial sizes of the sealing rings 4 at different parts are determined based on the actual deformation conditions, theoretical calculations, test data, etc.). Compared with the setting method of increasing the thickness of the tube sheet 2 in the prior art, there is no need to increase the thickness of the tube sheet 2, that is, without increasing the manufacturing cost of the indirect air cooling system, the sealing effect of the base tube 1, the tube sheet 2 and the header 3 can be significantly improved, the risk of liquid leakage or even leakage is reduced, and a more reliable guarantee is provided for the normal operation of the generator set.

[0034] like Figure 1 As shown, in this embodiment, for the convenience of description, the tube sheet 2 is divided into multiple areas, specifically: in the width direction of the tube sheet 2 (i.e. Figure 1 In the left and right directions, the tube sheet 2 includes a middle area 201, a side area 202 and an edge area 203, the deformation amounts of which decrease in sequence, wherein the side areas 202 are located on both sides of the middle area 201, and the edge area 203 is located on the side of the side area 202 away from the middle area 201. That is, the tube sheet 2 includes a middle area 201, two side areas 202 and two edge areas 203, which are all symmetrically arranged about the center line of the tube sheet 2 (the center line refers to Figure 1The vertical dotted line perpendicular to the width direction of the tube sheet 2 is shown in FIG. 1 , that is, from the center line to the left, there are half of the middle area 201, a side area 202 and an edge area 203. Similarly, from the center line to the right, there are half of the middle area 201, a side area 202 and an edge area 203. The reason for this division is that the tube sheet 2 is arched when deformed ( Figure 1-Figure 3 It reflects the structure when the tube sheet 2 is not deformed), which is a symmetrical structure, so symmetrically dividing different areas of the tube sheet 2 and arranging sealing rings 4 with different axial sizes in different areas can better coordinate and match with the deformation of the tube sheet 2.

[0035] Furthermore, in this embodiment, it is also preferred that the axial size of the sealing ring 4 located in the middle area 201 is larger than the axial size of the sealing ring 4 located in the side area 202, and the axial size of the sealing ring 4 located in the side area 202 is larger than the axial size of the sealing ring 4 located in the edge area 203. That is, in this embodiment, it is preferred that the sealing ring 4 includes not only two sizes, but three sizes. Among the sealing rings 4 of these three sizes, since the deformation (or curvature) of the middle area 201 of the tube sheet 2 is the largest, the first type of sealing ring 401 with the largest axial size (the axial size of the first type of sealing ring 401 is Figure 4 The first type of sealing ring 401 with the largest axial dimension seals the middle area 201 of the tube sheet 2, such as Figure 2 As shown; the side regions 202 located on both sides of the middle region 201 have a smaller deformation (or curvature) than the middle region 201, so the second type of sealing ring 402 with a smaller axial dimension (the axial dimension of the second type of sealing ring 402 is Figure 4 The second type of sealing ring 402 with a reduced axial dimension is sleeved on the base tube 1 at the side region 202, so that the second type of sealing ring 402 with a reduced axial dimension seals the side region 202 of the tube sheet 2, such as Figure 2 As shown; the outermost edge area 203 at both ends of the entire tube sheet 2 is close to the connection point between the tube sheet 2 and the header 3, so its deformation (or bending) is the smallest, so the third type sealing ring 403 with the smallest axial size (the axial size of the third type sealing ring 403 is Figure 4 The third type of sealing ring 403 (denoted as L3 in the figure) is sleeved on the base tube 1 located in the edge area 203 so that the third type of sealing ring 403 with the smallest axial dimension can seal the side area 202 of the tube sheet 2, such as Figure 2As shown. L1>L2>L3, by setting in this way, different parts of the tube sheet 2 can be more targeted and reliably sealed by using more types and sizes of sealing rings 4, and the selection and setting of the sealing ring 4 are more coordinated and matched with the deformation degree of different parts of the tube sheet 2, so it is used as the preferred setting mode of this embodiment. In addition, on the basis of making the sealing ring 4 have more sizes, the sealing effect of the sealing ring 4 can be further improved through other improvements, for example, the material and composition of the sealing ring 4 can be improved, so that the sealing effect of the sealing ring 4 corresponding to different areas of the tube sheet 2 is different.

[0036] like Figure 1 and Figure 2 As shown, in the width direction of the tube sheet 2, the base tubes 1 passing through the tube sheet 2 are preferably arranged in six rows. Among the six rows of base tubes 1, the two rows of base tubes 1 located in the middle are arranged in the middle area 201, the row of base tubes 1 located on one side of the two rows of base tubes 1 in the middle and the row of base tubes 1 located on the other side of the two rows of base tubes 1 in the middle are respectively located in the two side areas 202, and the remaining two rows of base tubes 1 are respectively located in the two edge areas 203. For the convenience of description, this embodiment will be Figure 1 and Figure 2 The six rows of base tubes 1 are defined as the first row of base tubes 101, the second row of base tubes 102, the third row of base tubes 103, the fourth row of base tubes 104, the fifth row of base tubes 105 and the sixth row of base tubes 106 from left to right, wherein the third row of base tubes 103 and the fourth row of base tubes 104 are two rows of base tubes 1 located in the middle area 201, the second row of base tubes 102 and the fifth row of base tubes 105 are two rows of base tubes 1 located in the two side areas 202, respectively, and the first row of base tubes 101 and the sixth row of base tubes 106 are two rows of base tubes 1 located in the two edge areas 203, respectively, and preferably the first type of sealing rings 401 are sleeved on the third row of base tubes 103 and the fourth row of base tubes 104, the second type of sealing rings 402 are sleeved on the second row of base tubes 102 and the fifth row of base tubes 105, and the third type of sealing rings 403 are sleeved on the first row of base tubes 101 and the sixth row of base tubes 106. The reason why the indirect air-cooling pipeline of this embodiment is preferably provided with six rows of base tubes 1 is that the deformation of the tube sheet 2 of the indirect air-cooling tube bundle with six rows of base tubes 1 is much greater than that of the conventional indirect air-cooling tube bundle with four rows of base tubes 1. On this basis, after adopting a plurality of sealing rings 4 with different axial sizes, the sealing effect of the indirect air-cooling tube bundle with six rows of base tubes 1 can be significantly improved, so that the sealing effect of the sealing rings 4 is fully exerted, the risk of liquid leakage is greatly reduced, and the indirect air-cooling system is more economical. In addition, the indirect air-cooling tube bundle provided with a plurality of sealing rings 4 with different axial sizes can also have four rows of base tubes 1, eight rows of base tubes 1, etc.

[0037] Specifically, Figure 2As shown, in this embodiment, the header 3 is preferably a lower header arranged at the bottom of the tube sheet 2, and the two sides of the lower header are respectively connected to the two long edges of the tube sheet 2 by bolts 5 and nuts 6. That is, in this embodiment, it is preferred to use a plurality of sealing rings 4 with different axial sizes to seal and connect the tube sheet 2 and the lower header. Of course, the above-mentioned header 3 can also be an upper header, that is, a plurality of sealing rings 4 with different axial sizes can also be used to seal and connect the tube sheet 2 and the upper header. The use of bolts 5 and nuts 6 to connect the two long edges of the tube sheet 2 (the tube sheet 2 is a long strip) to the lower header can facilitate disassembly on the one hand, and can also be consistent with the existing connection method on the other hand, so that the sealing connection effect of the two can be effectively guaranteed.

[0038] In addition, this embodiment also provides a sealing method for an indirect air cooling system, which is applicable to the above-mentioned indirect air cooling system, and the method comprises the following steps:

[0039] Allow multiple base tubes 1 to pass through multiple tube holes one by one, and realize fixed connection between the base tubes 1 and the tube sheet 2 through tube expansion operation to form an indirect air-cooling tube bundle with six rows of base tubes 1, that is, the tube sheet 2 forms an indirect air-cooling tube bundle with a fixed shape by connecting, fixing and constraining the base tubes 1;

[0040] Sealing rings 4 (i.e., first-type sealing rings 401) with a first axial dimension are sleeved on the middle two rows of base tubes 1 (i.e., the third row of base tubes 103 and the fourth row of base tubes 104) among the six rows of base tubes 1, and the sealing rings 4 are placed close to the connection between the base tubes 1 and the tube sheet 2, so as to squeeze the sealing rings 4 when the subsequent tube holes and the header 3 are connected;

[0041] Among the six rows of base tubes 1, sealing rings 4 having a second axial dimension (i.e., second type sealing rings 402) are sleeved on two rows of base tubes 1 (i.e., the second row of base tubes 102 and the fifth row of base tubes 105) which are adjacent to the middle two rows of base tubes 1 and located on both sides of the middle two rows of base tubes 1, and the sealing rings 4 are close to the connection between the base tubes 1 and the tube sheet 2, wherein the second axial dimension is smaller than the first axial dimension;

[0042] Sealing rings 4 having a third axial dimension (i.e., a third type of sealing ring 403) are sleeved on the outermost two rows of base tubes 1 (i.e., the first row of base tubes 101 and the sixth row of base tubes 106) among the six rows of base tubes 1, and the sealing rings 4 are placed close to the connection between the base tubes 1 and the tube sheet 2, wherein the third axial dimension is smaller than the second axial dimension, i.e., in the direction from the middle portion of the tube sheet 2 to the edge portion, the axial dimension of the provided sealing rings 4 becomes smaller and smaller, so as to correspond to the deformation mode in which the deformation amount of the tube sheet 2 becomes smaller and smaller from the middle portion to the edge portion;

[0043] The tube sheet 2 and the header 3 are connected by bolts 5 and nuts 6, so that the tube sheet 2 and the header 3 squeeze all the sealing rings 4 on both sides, so that the sealing rings 4 sleeved on each base tube 1 respectively realize the sealing connection between different base tubes 1 and the tube sheet 2 and the header 3. Since the sealing rings 4 matching the deformation amounts are arranged at the parts with different deformation amounts, the tube sheet 2 and the lower header 3 can be fully and reliably sealed.

[0044] Taking a typical 660MW unit as an example, sealing rings 4 with a variety of different axial sizes are used to seal the base pipe 1, tube sheet 2 and header 3. Compared with the method of thickening the tube sheet 2 in the prior art, it can directly save costs of nearly 400,000 yuan.

[0045] In this specification, each part of the structure is described in a progressive manner, and the structure of each part focuses on the differences from the existing structure. The overall and partial structures of the indirect air cooling system can be obtained by combining the structures of the above multiple parts.

[0046] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An indirect air cooling system, characterized in that: include: An indirect air-cooling tube bundle includes a plurality of base tubes arranged in parallel; A tube sheet having a plurality of tube holes, wherein the base tubes pass through the tube holes one by one; A header connected to the tube sheet; A sealing ring is sleeved on the base tube and located between the tube sheet and the header to achieve a sealed connection between the base tube, the tube sheet and the header, and the axial dimension of the sealing ring located in the middle area of ​​the tube sheet is greater than the axial dimension of the sealing ring located in the remaining area of ​​the tube sheet; In the width direction of the tube sheet, the tube sheet comprises a middle area, a side area and an edge area, the deformation amounts of which decrease in sequence, and the side areas are located at both sides of the middle area, and the edge area is located at a side of the side area away from the middle area; The axial dimension of the sealing ring located in the middle area is greater than that of the sealing ring located in the side area, and the axial dimension of the sealing ring located in the side area is greater than that of the sealing ring located in the edge area.

2. The indirect air cooling system according to claim 1, characterized in that: In the width direction of the tube sheet, the base tubes passing through the tube sheet are arranged in six rows. Among the six rows of base tubes, the two middle rows of base tubes are arranged in the middle area, the row of base tubes located on one side of the two middle rows of base tubes and the row of base tubes located on the other side of the two middle rows of base tubes are respectively located in the two side areas, and the remaining two rows of base tubes are respectively located in the two edge areas.

3. The indirect air cooling system according to claim 1, characterized in that: The header is a lower header arranged at the bottom of the tube sheet, and two sides of the lower header are respectively connected to two long side edges of the tube sheet through bolts and nuts.

4. A sealing method for an indirect air cooling system, characterized in that: The method is applicable to the indirect air cooling system according to claim 2, and the method comprises the following steps: Allowing the plurality of base tubes to pass through the plurality of tube holes one by one, and achieving fixed connection between the base tubes and the tube sheet by tube expansion operation, so as to form an indirect air-cooling tube bundle having six rows of base tubes; Sealing rings with a first axial dimension are sleeved on the middle two rows of the six rows of base tubes, and the sealing rings are close to the connection parts between the base tubes and the tube sheet; Among the six rows of base tubes, sealing rings having a second axial dimension are sleeved on two rows of base tubes adjacent to and located on both sides of the two rows of base tubes in the middle, and the sealing rings are close to the connection between the base tubes and the tube sheet, wherein the second axial dimension is smaller than the first axial dimension; Sealing rings having a third axial dimension are sleeved on the outermost two rows of the six rows of base tubes, and the sealing rings are close to the connection between the base tubes and the tube sheet, wherein the third axial dimension is smaller than the second axial dimension; The tube sheet and the header are connected by bolts and nuts so that the tube sheet and the header squeeze all the sealing rings on both sides, so that the sealing rings sleeved on each base tube respectively realize the sealing connection between different base tubes and the tube sheet and the header.

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