Sealing tool for welding seam pressure test of heat exchanger tube and tube plate

Abstract

The utility model discloses a sealing tool for a heat exchanger tube and tube plate welding seam pressure test, which comprises a sealing plate, a cylinder body, a sealing structure and a sealing ring, a plurality of heat exchange tubes are positioned in the cylinder body, two ends of each heat exchange tube are respectively connected with a first tube plate and a second tube plate in a welding manner, and a gap between the inner wall of the cylinder body and the first tube plate forms an annular opening. The sealing plate seals the opening; the sealing structure is annular and sleeves the outer side of the second tube plate, the inner diameter of the sealing structure is smaller than that of the barrel, the sealing ring is located between the inner side of the sealing structure and the outer side of the second tube plate, the inner side and the outer side of the sealing ring abut against and are tightly connected with the second tube plate and the sealing structure respectively, and the bottom end of the sealing structure is tightly connected with the top end of the barrel. The sealing tool has a good sealing effect, the second tube plate and the sealing structure can move relatively under certain thrust formed by internal pressure, and the situation that the connecting structure of the second tube plate and the sealing tool generates plastic deformation, further cracks are generated, and finally sealing failure is caused can be avoided.

Description

Technical Field

[0001] The utility model belongs to the field of pressure test sealing devices, in particular to a sealing tool for pressure testing of welds between heat exchanger tubes and tube plates. Background Art

[0002] Currently, shell-and-tube heat exchangers consist of two tube sheets and multiple heat exchange tubes. The shell side is non-sealed, with the tubes and tube sheet connected by welding. The reliability of the welds between the tubes and tube sheet is a crucial factor in ensuring the heat exchanger's reliability and performance. To verify the strength and airtightness of the welds, pressure tests and helium leak tests are required. Typically, a fixed connection method, such as welding, is used to seal the shell side, creating a sealed chamber. After the test medium is filled to the test pressure, the welds between the tubes and tube sheet are inspected for leaks to complete the pressure and helium leak tests. Sealing fixtures using fixed connections, such as welding, primarily consist of a sealing plate and a cylinder. These seals enclose the tubes and tube sheet to form a sealed chamber. When the test medium is filled to the test pressure, the tubes and tube sheet experience an outward thrust, causing them to stretch outward. Generally, the higher the test pressure, the greater the thrust, and the greater the elongation. Since the sealing position of the sealing fixture with a fixed connection method is absolutely fixed, when the heat exchange tube and the tube sheet have a certain amount of elongation under the pressure test, it is impossible to continue to contain the heat exchange tube and the tube sheet. When the elongation reaches a certain level, the stress at the connection between the sealing fixture and the heat exchange tube-tube sheet will be very large, which will cause plastic deformation, further cracks, and eventually lead to seal failure.

[0003] Therefore, a new technology is needed to solve the problem in the prior art that cracks are easily generated at the connection between the sealing tooling and the heat exchange tube-tube sheet during the weld pressure test, resulting in sealing failure. Utility Model Content

[0004] In order to solve the above-mentioned problems in the prior art, the utility model provides a sealing tool for the pressure test of the weld between the heat exchanger tube and the tube sheet. The joint between the heat exchanger tube and the tube sheet is less likely to produce cracks and cause sealing failure during the weld pressure test.

[0005] The utility model adopts the following technical solutions:

[0006] A sealing tool for pressure testing welds between heat exchanger tubes and tube sheets, comprising a sealing plate, a barrel, a sealing structure, and a sealing ring. Several heat exchange tubes are located within the barrel, with both ends of each heat exchange tube welded to a first tube sheet and a second tube sheet, respectively. An annular opening is formed between the inner wall of the barrel and the first tube sheet, and the sealing plate seals the opening.

[0007] The sealing structure is annular and is sleeved on the outer side of the second tube sheet. The inner diameter of the sealing structure is smaller than the inner diameter of the cylinder. The sealing ring is located between the inner side of the sealing structure and the outer side of the second tube sheet. The inner and outer sides of the sealing ring are respectively in contact with and tightly connected to the second tube sheet and the sealing structure. The bottom end of the sealing structure is tightly connected to the top end of the cylinder.

[0008] As a further improvement of the technical solution of the present utility model, the sealing structure includes a sealing portion and a cover plate, the sealing portion is annular, the bottom end of the sealing portion is fixedly connected to the top end of the cylinder, the inner side of the upper end is provided with an annular notch, the outer part of the sealing ring is accommodated in the annular notch, the cover plate is located above the sealing portion and the sealing ring and is detachably fixedly connected to the sealing portion, and the inner diameter of the cover plate is smaller than the outer diameter of the sealing ring;

[0009] The inner diameter of the sealing ring is smaller than the inner diameter of the sealing portion, and the outer diameter of the sealing ring is larger than the maximum outer diameter of the annular gap.

[0010] As a further improvement of the technical solution of the present invention, the outer diameter of the cover plate, the outer diameter of the sealing portion and the outer diameter of the cylinder are equal.

[0011] As a further improvement of the technical solution of the present utility model, an annular connecting surface is provided at the bottom end of the sealing portion, and the connecting surface is adapted to the upper end surface of the cylinder.

[0012] As a further improvement of the technical solution of the present invention, a transition surface is provided between the inner side of the connecting surface and the inner side surface of the sealing portion, and the diameter of the transition surface gradually increases from top to bottom.

[0013] As a further improvement of the technical solution of the present invention, the sealing plate is annularly sleeved on the outside of the first tube plate and is welded to the first tube plate, and the sealing plate is welded to the bottom end of the cylinder.

[0014] As a further improvement of the technical solution of the present invention, the sealing plate is located between the cylinder and the first tube sheet, and the outer side of the sealing plate is welded to the inner wall of the cylinder.

[0015] Compared with the prior art, the beneficial effects of the present invention are:

[0016] The sealing plate and the first tube sheet together seal the opening at one end of the cylinder, while the sealing structure and the second tube sheet together seal the opening at the other end of the cylinder. When the test medium is filled into the closed chamber to the test pressure, the heat exchange tube-tube sheet is subjected to an outward thrust and tends to stretch outward. The higher the test pressure, the greater the thrust, and the greater the elongation. When the tube-tube sheet stretches a certain amount under the pressure test, the cylinder can no longer accommodate the tube-tube sheet in its original connection state. When the elongation reaches a certain level, the stress at the connection between the sealing fixture and the tube-tube sheet will be very high, resulting in plastic deformation, further cracking, and ultimately seal failure. The sealing plate is fixed to the first tube sheet and the cylinder by welding, that is, one end of the sealing tooling cannot move relative to the second tube sheet, while a sealing ring is provided between the other end of the sealing tooling and the first tube sheet, which has a good sealing effect and can move a certain distance relative to each other under a certain thrust formed by the internal pressure, thereby avoiding plastic deformation of the connection structure between the second tube sheet and the sealing tooling, further cracking, and ultimately leading to sealing failure. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The technology of the utility model is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0018] Figure 1 It is a schematic diagram of the overall structure of the utility model;

[0019] Figure 2 yes Figure 1 A magnified view of the structure of part A.

[0020] Reference numerals:

[0021] 1- Sealing plate;

[0022] 2-cylinder;

[0023] 3-sealing structure; 31-sealing portion; 311-annular gap; 312-transition surface; 313-connecting surface; 32-cover plate;

[0024] 4-sealing ring;

[0025] 5- retaining ring;

[0026] 6-first tube sheet;

[0027] 7-heat exchange tube;

[0028] 8- Second tube sheet. DETAILED DESCRIPTION

[0029] The following will be combined with the embodiments and drawings to clearly and completely describe the concept, specific structure and technical effects of the present invention so as to fully understand the purpose, scheme and effect of the present invention. It should be noted that the embodiments and features in the embodiments of this application can be combined with each other unless there is a conflict. The same reference numerals used throughout the drawings indicate the same or similar parts.

[0030] It should be noted that, unless otherwise specified, when a feature is referred to as being "fixed" or "connected" to another feature, it may be directly fixed or connected to the other feature or indirectly fixed or connected to the other feature. In addition, the terms "upper," "lower," "left," and "right" used in this utility model are only used with respect to the relative positions of the components of the utility model in the accompanying drawings.

[0031] Reference Figure 1 and Figure 2 A sealing fixture for pressure testing the weld seams between tubes and tubesheets of a heat exchanger comprises a sealing plate 1, a barrel 2, a sealing structure 3, and a sealing ring 4. Several heat exchange tubes 7 are positioned within the barrel 2, each of which is welded to a first tubesheet 6 and a second tubesheet 8 at both ends. The gap between the inner wall of the barrel 2 and the first tubesheet 6 forms an annular opening, which the sealing plate 1 seals. The sealing structure 3 is annular and fits over the outside of the second tubesheet 8. The inner diameter of the sealing structure 3 is smaller than that of the barrel 2. The sealing ring 4 is positioned between the inner side of the sealing structure 3 and the outer side of the second tubesheet 8. The inner and outer sides of the sealing ring 4 abut and are tightly connected to the second tubesheet 8 and the sealing structure 3, respectively. The bottom end of the sealing structure 3 is tightly connected to the top end of the barrel 2. The sealing plate 1 and the first tubesheet 6 together seal one end of the barrel 2, while the sealing structure 3 and the second tubesheet 8 together seal the other end of the barrel 2, forming a sealed chamber within the barrel 2, sealing the shell side of the heat exchanger.

[0032] When the test medium is filled into the sealed chamber to the test pressure, the heat exchange tube 7-tube sheet is subjected to an outward thrust, tending to stretch outward. The higher the test pressure, the greater the thrust, and the greater the elongation. When the tube-tube sheet stretches to a certain extent under the pressure test, the cylinder 2 cannot continue to contain the tube-tube sheet in its original connection state. When the elongation reaches a certain level, the stress at the connection between the sealing fixture and the tube-tube sheet will be very high, causing plastic deformation, further cracking, and ultimately leading to seal failure. The sealing plate 1 is fixed to the first tube sheet 6 and the cylinder 2 by welding. That is, one end of the sealing fixture cannot move relative to the second tube sheet 8, while the other end of the sealing fixture is provided with a sealing ring 4 between the first tube sheet 6, which has a good sealing effect and can move relative to each other a certain distance under a certain thrust. This can prevent the connection between the second tube sheet 8 and the sealing fixture from plastic deformation, further cracking, and ultimately leading to seal failure.

[0033] Specifically, the sealing structure 3 includes a sealing portion 31 and a cover plate 32. The sealing portion 31 is annular. The bottom end of the sealing portion 31 is fixedly connected to the top end of the cylinder 2. The inner side of the upper end is provided with an annular notch 311. The outer portion of the sealing ring 4 is accommodated in the annular notch 311. The cover plate 32 is located above the sealing portion 31 and the sealing ring 4 and is detachably fixed to the sealing portion 31. The cover plate 32 and the sealing portion 31 can be connected by bolts, which facilitates installation and disassembly. By tightening the bolts used to fix the cover plate 32 and the sealing portion 31, the flange cover can be pressed against the sealing ring 4 to achieve radial compression. The inner diameter of the cover plate 32 is smaller than the outer diameter of the sealing ring 4, which is smaller than the inner diameter of the sealing portion 31. The outer diameter of the sealing ring 4 is larger than the maximum outer diameter of the annular notch 311, resulting in good sealing performance. During the pressure test, the test medium in the cylinder 2 passes through the gap between the sealing portion 31 and the first tube sheet 6 and enters the sealed space within the annular notch 311 where the sealing ring 4 is located. This force pushes the tube-tube sheet outward. Thanks to the placement of the sealing ring 4, a complete sealed space remains. The sealing ring 4 elastically deforms under pressure, filling the annular notch 311 and achieving a seal.

[0034] Specifically, the sealing tooling for the pressure test of the weld between the heat exchanger tube and the tube sheet of this scheme also includes an annular retaining ring 5. The upper part of the annular gap 311 is used to accommodate the sealing ring, and the cross-sectional area of the lower part decreases from top to bottom. The retaining ring 5 is adapted to the lower structure of the annular gap 311. The retaining ring 5 is accommodated in the lower part of the annular gap 311. The upper end face of the retaining ring 5 is horizontally arranged to provide a relatively flat support surface for the sealing ring 4, thereby ensuring that the sealing ring 4 has a better sealing effect.

[0035] Specifically, the outer diameter of the cover plate 32 , the outer diameter of the sealing portion 31 and the outer diameter of the cylinder 2 are equal.

[0036] Specifically, an annular connecting surface 313 is provided at the bottom end of the sealing portion 31 , and the connecting surface 313 is adapted to the upper end surface of the cylinder 2 so as to facilitate welding and fixing of the connecting surface 313 and the upper end surface of the cylinder 2 .

[0037] Specifically, a transition surface 312 is provided between the inner side of the connecting surface 313 and the inner side surface of the sealing portion 31 . The bottom of the inner side of the sealing portion 31 is tapered to form the transition surface 312 at the taper. The diameter of the transition surface 312 gradually increases from top to bottom.

[0038] Specifically, the sealing plate 1 is annularly sleeved on the outside of the first tube plate 6 and is welded to the first tube plate 6 , and the sealing plate 1 is welded to the bottom end of the cylinder 2 .

[0039] Specifically, the sealing plate 1 is located between the cylinder 2 and the first tube plate 6 , and the outer side of the sealing plate 1 is welded to the inner wall of the cylinder 2 .

[0040] Other contents of the sealing tool for pressure testing of weld seams between heat exchanger tubes and tube sheets described in the present invention can be found in the prior art and will not be described in detail here.

[0041] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Therefore, any modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A sealing tool for pressure testing of welds between heat exchanger tubes and tube sheets, characterized by: It includes a sealing plate, a cylinder, a sealing structure and a sealing ring. Several heat exchange tubes are located in the cylinder. Both ends of each heat exchange tube are welded to the first tube sheet and the second tube sheet respectively. The gap between the inner wall of the cylinder and the first tube sheet forms an annular opening, and the sealing plate seals the opening. The sealing structure is annular and is sleeved on the outer side of the second tube sheet. The inner diameter of the sealing structure is smaller than the inner diameter of the cylinder. The sealing ring is located between the inner side of the sealing structure and the outer side of the second tube sheet. The inner and outer sides of the sealing ring are respectively in contact with and tightly connected to the second tube sheet and the sealing structure. The bottom end of the sealing structure is tightly connected to the top end of the cylinder.

2. The sealing tool for the pressure test of the heat exchanger tube and tube sheet weld according to claim 1, characterized in that: The sealing structure includes a sealing portion and a cover plate. The sealing portion is annular, the bottom end of the sealing portion is fixedly connected to the top end of the cylinder, and the inner side of the upper end is provided with an annular notch, and the outer part of the sealing ring is accommodated in the annular notch. The cover plate is located above the sealing portion and the sealing ring and is detachably fixed to the sealing portion. The inner diameter of the cover plate is smaller than the outer diameter of the sealing ring. The inner diameter of the sealing ring is smaller than the inner diameter of the sealing portion, and the outer diameter of the sealing ring is larger than the maximum outer diameter of the annular gap.

3. The sealing tool for the pressure test of the weld between the heat exchanger tube and the tube sheet according to claim 2, characterized in that: The outer diameter of the cover plate, the outer diameter of the sealing portion and the outer diameter of the cylinder are equal.

4. The sealing tool for the pressure test of the heat exchanger tube and tube sheet weld according to claim 3, characterized in that: The bottom end of the sealing portion is provided with an annular connecting surface, and the connecting surface is adapted to the upper end surface of the cylinder.

5. The sealing tool for the pressure test of the weld between the heat exchanger tube and the tube sheet according to claim 4, characterized in that: A transition surface is provided between the inner side of the connecting surface and the inner side surface of the sealing portion, and the diameter of the transition surface gradually increases from top to bottom.

6. The sealing tool for the pressure test of the heat exchanger tube and tube sheet weld according to claim 1, characterized in that: The sealing plate is annularly sleeved on the outer side of the first tube plate and is welded to the first tube plate. The sealing plate is welded to the bottom end of the cylinder.

7. The sealing tool for the pressure test of the weld between the heat exchanger tube and the tube sheet according to claim 6, characterized in that: The sealing plate is located between the cylinder and the first tube plate, and the outer side of the sealing plate is welded to the inner wall of the cylinder.

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