Heat transfer tube eddy current detection double-probe tube aligning device for heat exchanger and tube aligning method

Abstract

The invention discloses a heat transfer tube eddy current detection double-probe tube aligning device for a heat exchanger and a tube aligning method. The tube aligning device is provided with two supporting legs and two eddy current probe channels for guiding eddy current probes to enter a heat transfer tube; when in use, the pipe aligning device is only required to be placed near a to-be-detected pipe hole, complete alignment is not required, the two supporting legs can keep elastic extension and go deep into the pipe hole under the action of the springs, the pipe aligning device is accurately fixed on the plane of a pipe plate, automatic fine adjustment is performed at the same time, and alignment of two eddy current probe channels and a heat transfer pipe hole is completed. And the eddy current probe is inserted through the eddy current probe channel.

Description

Technical Field

[0001] This invention relates to a dual-probe tube alignment device and method for eddy current detection of heat transfer tubes in heat exchangers, which is mainly used to quickly and accurately complete the tube alignment operation for eddy current detection of heat transfer tubes in steam generators. Background Technology

[0002] Shell-and-tube heat exchangers exchange heat through heat transfer tubes. To ensure heat exchange efficiency, the tube walls are typically very thin, commonly 1.01mm, 1.04mm, or 1.27mm. During assembly, pushing and pulling the tubes, as well as vibrations during operation, can cause the tubes to scrape and rub against baffles and other components, potentially damaging the tube walls. Therefore, eddy current testing is necessary to assess the severity of any damage to the tube walls.

[0003] Eddy current testing requires inserting the eddy current probe into the heat transfer tubes. Currently, manual alignment is commonly used, where the testing personnel manually align the eddy current probe with the heat transfer tube opening, and then a transmission device moves the probe inside the tube to complete the eddy current test. A steam generator is a shell-and-tube heat exchanger used in pressurized water reactor nuclear power plants to exchange heat between the primary and secondary loops. It has a large number of closely spaced heat transfer tubes, requiring eddy current testing on over 12,000 tube openings, averaging over 1,650 openings per square meter on the testing area. Relying entirely on manual alignment is slow, inefficient, labor-intensive, and prone to errors.

[0004] During eddy current testing, the eddy current probe moves at a very high speed, typically exceeding 300 mm / s, and sometimes reaching 1200 mm / s. Due to the limitation of heat exchanger length, the length of heat transfer tubes generally does not exceed 10 meters, and U-shaped heat transfer tubes do not exceed 20 meters. The time required for an eddy current probe to complete one heat transfer tube scan is generally only a few seconds, but the testing personnel usually need at least one minute to operate on the tube. Furthermore, the shape and appearance of the heat transfer tube openings are visually almost identical, which inevitably leads to visual fatigue for testing personnel after prolonged operation. In practice, a 10-minute break is required every hour of work.

[0005] The tube-to-tube operation has become a bottleneck in improving the overall efficiency of eddy current testing.

[0006] There is an urgent need for a device and method that can free up testing personnel from tube alignment operations, allowing them to ensure alignment without manual aiming, thereby reducing labor intensity, shortening tube alignment time, and improving overall eddy current testing efficiency. Summary of the Invention

[0007] To overcome the above problems, the inventors conducted intensive research and designed a dual-probe tube aligner and method for eddy current detection of heat transfer tubes in heat exchangers. This aligner has two legs and provides two eddy current probe channels to guide the eddy current probes into the heat transfer tubes. In use, the aligner is simply placed near the tube hole to be tested; complete alignment is not required. The two legs will elastically extend under spring action, penetrating deep into the tube hole, accurately fixing the aligner to the tube sheet plane while automatically fine-tuning to align the two eddy current probe channels with the heat transfer tube hole. The eddy current probes are then inserted through these channels. Thus, the invention is complete.

[0008] Specifically, the purpose of this invention is to provide a dual-probe tube pairer for eddy current detection of heat transfer tubes in heat exchangers. The tube pairer includes a base 1, on which four through holes are provided, and the axes of the four through holes are parallel to each other. Among the four through holes, the two with larger inner diameters are tube mounting holes 11, and the two with smaller inner diameters are support mounting holes 12.

[0009] The arrangement of the four through holes is consistent with the arrangement of the heat transfer tubes to be tested by eddy current. When the two support mounting holes 12 are aligned with the two heat transfer tubes, the two conduit mounting holes 11 are aligned with the other two heat transfer tubes.

[0010] A conduit is installed in the conduit mounting hole 11, and an eddy current probe channel 6 is provided in the conduit. The eddy current probe is guided into the heat transfer tube through the eddy current probe channel 6.

[0011] The conduit includes a short conduit 4 and a long conduit 5. The short conduit 4 is embedded in one conduit mounting hole 11, and the long conduit 5 is embedded in another conduit mounting hole 11. Both the short conduit 4 and the long conduit 5 are provided with eddy current probe channels 6.

[0012] The support leg 2 is provided in the support leg mounting hole 12. The upper end of the support leg 2 is provided with an outward protruding boss 21, and the lower end of the support leg 2 is provided with a downward pointing cone 22, and the cone 22 extends out from the support leg mounting hole 12.

[0013] The support leg 2 is cylindrical, and its outer diameter is basically equal to or slightly smaller than the inner diameter of the heat transfer tube. When the support leg 2 is inserted into the heat transfer tube under the guidance of the cone 22, the support leg 2 and the heat transfer tube are basically coaxial.

[0014] Wherein, the outer diameter of the support leg 2 is smaller than the inner diameter of the lower edge 121 of the support leg mounting hole, and the outer diameter of the boss 21 is smaller than the inner diameter of the support leg mounting hole 12, but larger than the inner diameter of the lower edge 121 of the support leg mounting hole. Under the restriction of the boss 21 and the lower edge 121 of the support leg mounting hole, the support leg 2 can only enter and exit the support leg mounting hole in one direction and cannot pass through the support leg mounting hole 12.

[0015] An end cap 3 is provided at the top of the support leg mounting hole 12, and a compression spring 7 is provided between the end cap 3 and the boss 21. The compression spring 7 presses the support leg 2 outward so that the support leg 2 can be inserted into the heat transfer tube under the guidance of the cone 22.

[0016] The present invention also provides a tube alignment method for eddy current detection of heat transfer tubes for heat exchangers, which is implemented by the dual-probe tube alignment device for eddy current detection of heat transfer tubes for heat exchangers described above.

[0017] The method includes the following steps:

[0018] Step 1: Assemble the heat exchanger tube eddy current detection dual probe tube assemblies, that is, install the support leg 2, compression spring 7 and end cap 3 into the support leg mounting hole 12; install the short tube 4 and long tube 5 into the tube mounting hole 11;

[0019] Step 2: Hold the heat exchanger and use the heat transfer tube eddy current detection dual probe tube aligner to bring the pointed cone 22 on the support leg 2 close to the heat transfer tube. When both pointed cones 22 are inserted into the heat transfer tube, quickly press down the tube aligner to fix it on the tube sheet plane. At the same time, allow the tube aligner to make fine adjustments on its own to complete the alignment of the two eddy current probe channels 6 with the heat transfer tube holes.

[0020] Step 3: Input the eddy current probe into the heat transfer tube through the eddy current probe channel 6 to complete the eddy current detection of the heat transfer tube.

[0021] The beneficial effects of this invention include:

[0022] (1) According to the heat exchanger heat transfer tube eddy current detection dual probe tube aligner and tube alignment method provided by the present invention, when using the tube aligner, it is only necessary to place the tube aligner near the tube hole to be detected. It does not need to be fully aligned. The two legs will penetrate into the tube hole under the action of the spring, accurately fix the tube aligner on the tube sheet plane and automatically make fine adjustments to complete the alignment of the two eddy current probe channels with the heat transfer tube hole.

[0023] (2) According to the heat exchanger heat transfer tube eddy current detection dual probe tube pairer and tube pairing method provided by the present invention, the tube pairer is provided with two tubes of different lengths so that the two eddy current probe channels can be quickly distinguished; in addition, the tube pairer also has the characteristics of beautiful appearance, small size, light weight, and convenient carrying and use.

[0024] (3) According to the heat exchanger heat transfer tube eddy current detection dual probe tube pairer and tube pairing method provided by the present invention, the eddy current probe channel of the tube pairer is matched with the end of the eddy current probe guide tube. The end of the eddy current probe guide tube can be connected to the guide tube of the tube pairer with a simple operation, and then the eddy current probe is introduced into the heat transfer tube. This can improve the efficiency of eddy current detection, improve the accuracy of tube pairing, avoid human error, and improve the quality of eddy current detection. Attached Figure Description

[0025] Figure 1 This application provides a schematic diagram of the overall structure of the dual-probe tube pair for eddy current detection of heat transfer tubes in heat exchangers.

[0026] Figure 2 This diagram shows the structure of the base in the dual-probe tube pair for eddy current detection of heat transfer tubes in a heat exchanger.

[0027] Figure 3 This paper shows a cross-sectional view of the dual-probe tube pair for eddy current detection of heat transfer tubes in heat exchangers provided in this application.

[0028] Explanation of reference numerals in the attached figures

[0029] 1-Base

[0030] 11-Conduit mounting hole

[0031] 12-Outrigger mounting holes

[0032] 121-Lower edge of base support leg hole

[0033] 2-leg

[0034] 21-Protrusion

[0035] 22-pointed cone

[0036] 3-End Cap

[0037] 4-Short catheter

[0038] 5-Long catheter

[0039] 6-Eddy current probe channel

[0040] 7-Compression Spring Detailed Implementation

[0041] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Through these descriptions, the features and advantages of the present invention will become clearer and more apparent.

[0042] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments. Although various aspects of embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless specifically indicated otherwise.

[0043] This invention provides a dual-probe tube pair for eddy current detection of heat transfer tubes in heat exchangers, such as... Figure 1 , Figure 2 and Figure 3As shown, the tube assembly includes a base 1 with four through holes, the axes of which are parallel to each other. The two through holes with larger inner diameters are tube mounting holes 11, and the two with smaller inner diameters are support leg mounting holes 12. The bottom of the base is smooth, which allows it to fit snugly against the tube sheet without scratching it.

[0044] The arrangement of the four through holes is consistent with the arrangement of the heat transfer tubes to be tested by eddy current, or the hole spacing on the base 1 is a multiple of the heat transfer tube spacing, ensuring that when the two leg mounting holes 12 are aligned with the two heat transfer tubes, the two conduit mounting holes 11 are aligned with the other two heat transfer tubes. Preferably, the relative positions of the four through holes correspond exactly to the positions of the four adjacent heat transfer tubes, with the two with larger relative spacing being the conduit mounting holes 11 and the two with smaller relative spacing being the leg mounting holes 12. This arrangement minimizes the base volume, makes the entire tube aligner compact, and is most convenient to use.

[0045] A conduit is installed in the conduit mounting hole 11, and an eddy current probe channel 6 is provided in the conduit. The eddy current probe is guided into the heat transfer tube through the eddy current probe channel 6.

[0046] In this application, one end of the conduit is provided with threads or snaps to match the internal structure of the conduit mounting hole 11, so as to facilitate the quick and stable installation of the conduit into the conduit mounting hole 11; the other end of the conduit matches the end of the eddy current probe conduit, and the eddy current probe can be inserted into the conduit with a simple operation, shortening the alignment time. For example, it can be set with a chamfered thread structure, and quick alignment can be achieved by chamfering and screwing in the bolt.

[0047] In a preferred embodiment, the conduit includes a short conduit 4 and a long conduit 5. The short conduit 4 is embedded in one conduit mounting hole 11, and the long conduit 5 is embedded in another conduit mounting hole 11. Both the short conduit 4 and the long conduit 5 have eddy current probe channels 6. The short conduit 4 and the long conduit 5 have different lengths so that the operator can quickly distinguish between the two eddy current probe channels 6.

[0048] In a preferred embodiment, a support leg 2 is provided in the support leg mounting hole 12. The upper end of the support leg 2 is provided with an outwardly protruding boss 21, and the lower end of the support leg 2 is provided with a downward-pointing pointed cone 22, which extends out of the support leg mounting hole 12.

[0049] Preferably, the support leg 2 and its pointed cone 22 are made of a material compatible with the heat transfer tube, which will not scratch the heat transfer tube or cause contamination to the heat transfer tube (such as fluorine, chlorine, sulfur and ferrite contamination). The preferred material is chromium-nickel austenitic stainless steel, such as S304 and S316.

[0050] Preferably, the support leg 2 is cylindrical, and its outer diameter is slightly smaller than the inner diameter of the heat transfer tube. When the support leg 2 is inserted into the heat transfer tube under the guidance of the cone 22, the gap between the support leg 2 and the heat transfer tube is less than 0.5 mm to ensure that the two are basically coaxial, thereby ensuring that the two conduit mounting holes 11 are aligned with the two heat transfer tubes.

[0051] In a preferred embodiment, the outer diameter of the support leg 2 is smaller than the inner diameter of the lower edge 121 of the support leg mounting hole, and the outer diameter of the boss 21 is smaller than the inner diameter of the support leg mounting hole 12 but larger than the inner diameter of the lower edge 121 of the support leg mounting hole. Under the restriction of the boss 21 and the lower edge 121 of the support leg mounting hole, the support leg 2 can only enter and exit the support leg mounting hole 12 in one direction, and the maximum stroke is when the support leg boss 21 contacts the lower edge 121 of the support leg mounting hole, but cannot pass through the support leg mounting hole 12.

[0052] Preferably, an end cap 3 is provided at the top of the leg mounting hole 12, and a compression spring 7 is provided between the end cap 3 and the boss 21. The compression spring 7 presses the leg 2 outward so that the leg 2 can be inserted into the heat transfer tube under the guidance of the cone 22. The end cap 3 is used to compress the compression spring to provide sufficient elastic force, and also to close the leg mounting hole 12 on the base.

[0053] Preferably, the outrigger mounting hole 12 is also provided with an internal thread that mates with the end cap 3, so as to quickly and easily screw the end cap 3 into the outrigger mounting hole 12.

[0054] The present invention also provides a tube alignment method for eddy current detection of heat transfer tubes for heat exchangers, which is implemented by the dual-probe tube alignment device for eddy current detection of heat transfer tubes for heat exchangers described above.

[0055] In a preferred embodiment, the method includes the following steps:

[0056] Step 1: Assemble the heat exchanger tube eddy current detection dual probe tube assemblies, that is, install the support leg 2, compression spring 7 and end cap 3 into the support leg mounting hole 12; install the short tube 4 and long tube 5 into the tube mounting hole 11;

[0057] Step 2: Hold the heat exchanger and use the heat transfer tube eddy current detection dual probe tube aligner to bring the pointed cone 22 on the support leg 2 close to the heat transfer tube. When both pointed cones 22 are inserted into the heat transfer tube, quickly press down the tube aligner to fix it on the tube sheet plane. At the same time, allow the tube aligner to make fine adjustments on its own to complete the alignment of the two eddy current probe channels 6 with the heat transfer tube holes.

[0058] Step 3: Input the eddy current probe into the heat transfer tube through the eddy current probe channel 6 to complete the eddy current detection of the heat transfer tube.

[0059] Example

[0060] use Figure 1 , Figure 2 and Figure 3 The heat exchanger shown uses a dual-probe tube-to-tube eddy current testing device to perform eddy current testing on the heat transfer tubes on the tube sheet of the AP1000 steam generator. The specific operation process is as follows:

[0061] Step 1: Assemble the heat exchanger tube eddy current detection dual probe tube assemblies, that is, install the support leg 2, compression spring 7 and end cap 3 into the support leg mounting hole 12; install the short tube 4 and long tube 5 into the tube mounting hole 11;

[0062] Step 2: Hold the heat exchanger and use the heat transfer tube eddy current detection dual probe tube aligner to bring the cone 22 on the support leg 2 close to the heat transfer tube. When both cones 22 are inserted into the heat transfer tube, quickly press down the tube aligner to fix it on the tube sheet plane. At the same time, allow the tube aligner to make fine adjustments on its own to complete the alignment of the two eddy current probe channels 6 with the heat transfer tube holes.

[0063] Step 3: Input the eddy current probe into the heat transfer tube through the eddy current probe channel 6 to complete the eddy current detection of the two heat transfer tubes that have been aligned with the eddy current probe channel 6.

[0064] Step 4: Remove the dual probe for eddy current testing of heat transfer tubes on the heat exchanger, and align it with the other heat transfer tubes to be tested. Repeat steps 2 and 3 until all heat transfer tubes have been tested for eddy current.

[0065] Statistics show that a worker, holding a heat exchanger and using a dual-probe tube-to-tube eddy current testing device, completed eddy current testing of 530 heat exchange tubes in 3 hours of continuous work, and the test results were accurate and reliable, with no errors occurring during the process.

[0066] Without using the dual-probe tube pairer for eddy current testing of heat transfer tubes provided in this application, the worker could only complete the eddy current testing of 140 heat transfer tubes in 3 hours.

[0067] This demonstrates that the dual-probe tube aligner and tube alignment method for eddy current detection of heat transfer tubes in heat exchangers provided in this application greatly reduce labor intensity and improve eddy current detection efficiency.

[0068] The present invention has been described above with reference to preferred embodiments; however, these embodiments are merely exemplary and illustrative. Various substitutions and modifications can be made to the present invention based on these embodiments, all of which fall within the scope of protection of the present invention.

Claims

1. A dual-probe tube pair for eddy current detection of heat transfer tubes in heat exchangers, characterized in that, The tube assembly includes a base (1) with four through holes provided on the base (1), and the axes of the four through holes are parallel to each other. The two through holes with larger inner diameters are tube mounting holes (11), and the two with smaller inner diameters are leg mounting holes (12). The arrangement of the four through holes is consistent with the arrangement of the heat transfer tubes to be tested by eddy current. When the two support mounting holes (12) are aligned with the two heat transfer tubes, the two conduit mounting holes (11) are aligned with the other two heat transfer tubes. A conduit is installed in the conduit mounting hole (11), and an eddy current probe channel (6) is opened in the conduit. The eddy current probe is guided into the heat transfer tube through the eddy current probe channel (6).

2. The dual-probe tube pairer for eddy current detection of heat transfer tubes in heat exchangers according to claim 1, characterized in that, The conduit includes a short conduit (4) and a long conduit (5). The short conduit (4) is embedded in one conduit mounting hole (11), and the long conduit (5) is embedded in another conduit mounting hole (11). Both the short conduit (4) and the long conduit (5) are provided with eddy current probe channels (6).

3. The dual-probe tube pairer for eddy current detection of heat transfer tubes in heat exchangers according to claim 1, characterized in that, A support leg (2) is provided in the support leg mounting hole (12). The upper end of the support leg (2) is provided with an outward protruding boss (21), and the lower end of the support leg (2) is provided with a downward pointing cone (22), and the cone (22) extends out from the support leg mounting hole (12).

4. The dual-probe tube pairer for eddy current detection of heat transfer tubes in heat exchangers according to claim 3, characterized in that, The support leg (2) is cylindrical, and its outer diameter is slightly smaller than the inner diameter of the heat transfer tube. When the support leg (2) is inserted into the heat transfer tube under the guidance of the cone (22), the support leg (2) and the heat transfer tube are basically coaxial.

5. The dual-probe tube pairer for eddy current detection of heat transfer tubes in heat exchangers according to claim 3, characterized in that, The outer diameter of the support leg (2) is smaller than the inner diameter of the lower edge (121) of the support leg mounting hole. The outer diameter of the boss (21) is smaller than the inner diameter of the support leg mounting hole (12) but larger than the inner diameter of the lower edge (121) of the support leg mounting hole. Under the restriction of the boss (21) and the lower edge (121) of the support leg mounting hole, the support leg (2) can only enter and exit the support leg mounting hole in one direction and cannot pass through the support leg mounting hole (12).

6. The dual-probe tube pairer for eddy current detection of heat transfer tubes in heat exchangers according to claim 3, characterized in that, An end cap (3) is provided at the top of the support leg mounting hole (12), and a compression spring (7) is provided between the end cap (3) and the boss (21). The compression spring (7) presses the support leg (2) outward so that the support leg (2) can be inserted into the heat transfer tube under the guidance of the cone (22).

7. A tube alignment method for eddy current detection of heat transfer tubes in a heat exchanger, characterized in that, This method is achieved using a dual-probe tube pairer for eddy current detection of heat transfer tubes in heat exchangers, as described in any one of claims 1 to 6.

8. The tube alignment method for eddy current detection of heat transfer tubes for heat exchangers according to claim 7, characterized in that, The method includes the following steps: Step 1: Assemble the heat exchanger tube eddy current detection dual probe tube assembly, that is, install the support leg (2), compression spring (7) and end cap (3) into the support leg mounting hole (12); install the short tube (4) and long tube (5) into the tube mounting hole (11); Step 2: Hold the heat exchanger and use the heat transfer tube eddy current detection dual probe tube aligner to bring the cone (22) on the support leg (2) close to the heat transfer tube. When both cones (22) are inserted into the heat transfer tube, quickly press down the tube aligner to fix it on the tube sheet plane. At the same time, allow the tube aligner to make fine adjustments on its own to complete the alignment of the two eddy current probe channels (6) with the heat transfer tube holes. Step 3: Input the eddy current probe into the heat transfer tube through the eddy current probe channel (6) to complete the eddy current detection of the heat transfer tube.

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