A leak detection device at the weld joint between tubes and tube sheet in a screen-type heat exchanger

Abstract

A leak detection device for the weld seam between tubes and tubesheet in a screen-type heat exchanger relates to the field of screen-type heat exchanger manufacturing technology. It addresses the problem that existing technologies cannot detect the welding quality between tubes and tubesheets in heat exchangers, thus preventing the detection of heat exchanger manufacturing quality and leading to frequent heat exchanger malfunctions. The device involves aligning a sealing gasket with the groove of a test plug plate, and then placing the test plug plate onto the plane of the half-tubesheet. The edge of the test plug plate is aligned with the edge of the half-tubesheet, and the four fixing holes on the edge are aligned with the support fixture. It is then secured with fixing bolts. A baffle plate is inserted, and a pressure plate is placed. The bottom hook of the locking screw is used to hook the baffle plate, and the threaded end passes through the through hole on the pressure plate and is locked in place with the locking nut. This creates a sealed cavity using the test plug plate, sealing gasket, and the upper surface of the half-tubesheet. The cavity is then filled with helium, and an operator uses a handheld helium leak detector to conduct a helium leak detection test. This invention is applicable to the field of heat exchangers.

Description

Technical Field

[0001] This utility model relates to the field of screen heat exchanger manufacturing technology, specifically to a leakage detection device at the weld seam between the tube and tube sheet of a screen heat exchanger. Background Technology

[0002] The heat exchanger is a screen-type heat exchanger with an unclad tube system. The tubes and tubesheet are welded together, and the header shell must be attached before a tube-side hydrostatic test can be performed. If defects are found at the tube-to-tubesheet weld during the hydrostatic test, only two solutions are available for repair: either completely cut the weld between the header shell and the tubesheet half-sheet, or disconnect the heat exchange tubes and plug them, limiting the leak to only two heat exchange tubes. Therefore, ensuring the quality of the tube-end welds is crucial, and internal weld quality inspection is very important. Researching a tube-end weld inspection device for screen-type heat exchangers, enabling airtightness and helium leak detection tests, is essential to guarantee the quality of the tube-to-tubesheet welds.

[0003] In summary, the existing technology cannot detect the welding quality between the tubes and tube sheets in the heat exchanger, which in turn makes it impossible to detect the processing quality of the heat exchanger, leading to frequent failures of the heat exchanger. Utility Model Content

[0004] This invention addresses the problem in existing technologies where the welding quality between tubes and tube sheets in heat exchangers cannot be inspected, leading to an inability to assess the processing quality of the heat exchanger and consequently, frequent malfunctions. It proposes a leakage detection device for the weld seam between tubes and tube sheets in a screen-type heat exchanger.

[0005] This utility model discloses a leakage detection device at the weld seam between tubes and tube sheet of a screen heat exchanger, which comprises a pressure plate 1, a test plug plate 2, a locking screw 3, a sealing gasket 5, a baffle 7, an air inlet pipe 8, and a helium leak detector 9.

[0006] The upper surface of the half-tube sheet 6 in the screen heat exchanger is provided with a test plug plate 2, and a sealing gasket 5 is provided at both ends of the test plug plate 2 and the upper surface of the half-tube sheet 6 along the length direction. The upper surface of the test plug plate 2 is provided with a pressure plate 1, and n through holes are uniformly machined at both ends of the pressure plate 1 along the length direction, where n is a positive integer. A baffle 7 is provided between every two sets of container heat exchange tubes 4 in the screen heat exchanger, and a locking screw 3 is provided inside each through hole on the pressure plate 1. A hook is provided at the bottom of the locking screw 3, and the inner wall of the hook at the bottom of the locking screw 3 contacts the bottom surface of the baffle 7. A through hole is provided at the center of the pressure plate 1 and the test plug plate 2, and the bottom end of the air inlet pipe 8 passes through the through hole on the pressure plate 1 and is fixedly connected to the top end of the through hole on the test plug plate 2. A helium leak detector 9 is provided on the outside of the half-tube sheet 6 in the screen heat exchanger.

[0007] Furthermore, the axis of the test blocking plate 2 forms a 45° angle with the axis of the pressure plate 1;

[0008] Furthermore, a locking nut is provided on the upper part of the locking screw 3;

[0009] Furthermore, the number of through holes n at the end of the upper surface of the pressure plate 1 is equal to half the number of the 4 sets of heat exchange tubes in the container of the screen heat exchanger.

[0010] Furthermore, the number of through holes n at the end of the upper surface of the pressure plate 1 is 6≤n≤20;

[0011] Furthermore, the upper part of the outer surface of the air intake pipe 8 is machined with a threaded section;

[0012] Furthermore, the top end of the air intake pipe 8 is connected to the air source via a flange and an air pipe;

[0013] Furthermore, the lower surface of the test block plate 2 is provided with strip grooves along its length at both ends, and the top surface of the strip grooves on the lower surface of the test block plate 2 is in contact with the upper surface of the sealing gasket 5.

[0014] Furthermore, in use, first, align the sealing gasket 5 with the strip groove of the test plug plate 2, and then fasten the test plug plate 2 onto the plane of the half-tube plate 6. The edge of the test plug plate 2 is aligned with the edge of the half-tube plate 6, and the four fixing holes on the edge are aligned with the support fixture. Then, fix it with fixing bolts.

[0015] Next, insert the baffle 7, place the pressure plate 1, hook the baffle 7 with the hook at the bottom of the locking screw 3, and pass the threaded end through the through hole on the pressure plate 1 to lock and fix it with the locking nut; in this way, use multiple locking screws 3 to clamp the half tube plate 6 and the test plug plate 2, and tighten the locking nut. Tighten it evenly multiple times to ensure uniform force, and observe the force on the sealing gasket at any time to ensure the sealing effect;

[0016] Next, connect the top of the air inlet pipe 8 to the air source through a flange and an air pipe, and perform an airtightness test on the joint to ensure there is no leakage.

[0017] Finally, the device is filled with helium. The operator uses a helium leak detector 9 to perform a helium leak detection test on the weld between the half-tube sheet 6 and the container heat exchange tube 4. If the helium leak detector 9 does not detect helium, it indicates that the weld between the half-tube sheet 6 and the container heat exchange tube 4 is of high quality. Conversely, if helium is detected, it indicates that there is a quality defect in the weld between the half-tube sheet 6 and the container heat exchange tube 4, and the device should be returned to the factory for processing. After the test, the gas is released and the device is removed.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] This invention overcomes the shortcomings of existing technologies. The sealing gasket is aligned with the groove of the test plug plate, and the test plug plate is then fastened onto the plane of the semi-tube plate. The edge of the test plug plate is aligned with the edge of the semi-tube plate, and the four fixing holes on the edge are aligned with the support fixture. It is then secured with fixing bolts. A baffle is inserted, and a pressure plate is placed. The hook at the bottom of the locking screw is used to hook the baffle plate, and the threaded end passes through the through hole on the pressure plate and is locked in place with the locking nut. Thus, a sealed cavity is formed using the test plug plate, the sealing gasket, and the upper surface of the semi-tube plate. Pressure is then applied to the upper surface of the test plug plate using the pressure plate, locking screw, and baffle plate, improving... To ensure the sealing of the cavity, the top of the inlet pipe is connected to the gas source via a flange and a gas pipe for inflation. The operator then uses a handheld helium leak detector to perform a helium leak test at the weld between the tube sheet and the heat exchange tubes in the container. If the detector does not detect helium, the weld is of high quality; conversely, if it detects helium, the weld has a quality defect and the tube sheet needs to be returned to the factory. This type of detection device can quickly inspect the welding quality between the tubes and the tube sheet in the heat exchanger, thus preventing heat exchanger malfunctions. Attached Figure Description

[0020] Figure 1 This is a main sectional view of a leakage detection device at the weld seam between tubes and tube sheet in a screen-type heat exchanger, as described in this utility model.

[0021] Figure 2 This is a schematic diagram showing the distribution of pressure plates and test plugs in a leak detection device for the weld seam between tubes and tube sheet in a screen-type heat exchanger, as described in this utility model.

[0022] Figure 3 This is a schematic diagram of the welding process between the half-tube sheet and the heat exchange tubes in a screen-type heat exchanger.

[0023] Figure 4 This is a main sectional view of the connection between the half-tube sheet and the heat exchange tubes of the container in a screen-type heat exchanger. Detailed Implementation

[0024] Specific implementation method one: Combining Figures 1 to 4 This embodiment describes a leakage detection device at the weld seam between tubes and tube sheet in a screen-type heat exchanger. The device comprises a pressure plate 1, a test plug 2, a locking screw 3, a sealing gasket 5, a baffle 7, an air inlet pipe 8, and a helium leak detector 9.

[0025] The upper surface of the half-tube sheet 6 in the screen heat exchanger is provided with a test plug plate 2, and a sealing gasket 5 is provided at both ends of the test plug plate 2 and the upper surface of the half-tube sheet 6 along the length direction. The upper surface of the test plug plate 2 is provided with a pressure plate 1, and n through holes are uniformly machined at both ends of the pressure plate 1 along the length direction, where n is a positive integer. A baffle 7 is provided between every two sets of container heat exchange tubes 4 in the screen heat exchanger, and a locking screw 3 is provided inside each through hole on the pressure plate 1. A hook is provided at the bottom of the locking screw 3, and the inner wall of the hook at the bottom of the locking screw 3 contacts the bottom surface of the baffle 7. A through hole is provided at the center of the pressure plate 1 and the test plug plate 2, and the bottom end of the air inlet pipe 8 passes through the through hole on the pressure plate 1 and is fixedly connected to the top end of the through hole on the test plug plate 2. A helium leak detector 9 is provided on the outside of the half-tube sheet 6 in the screen heat exchanger.

[0026] In this specific embodiment, when in use, first, align the sealing gasket 5 with the strip groove of the test plug plate 2, and then fasten the test plug plate 2 onto the plane of the half tube plate 6. The edge of the test plug plate 2 is aligned with the edge of the half tube plate 6, and the four fixing holes on the edge are aligned with the support fixture. Fix it with fixing bolts.

[0027] Next, insert the baffle 7, place the pressure plate 1, hook the baffle 7 with the hook at the bottom of the locking screw 3, and pass the threaded end through the through hole on the pressure plate 1 to lock and fix it with the locking nut; in this way, use multiple locking screws 3 to clamp the half tube plate 6 and the test plug plate 2, and tighten the locking nut. Tighten it evenly multiple times to ensure uniform force, and observe the force on the sealing gasket at any time to ensure the sealing effect;

[0028] Next, connect the top of the air inlet pipe 8 to the air source through a flange and an air pipe, and perform an airtightness test on the joint to ensure there is no leakage.

[0029] Finally, the device is filled with helium. The operator uses a helium leak detector 9 to perform a helium leak detection test on the weld between the half-tube sheet 6 and the container heat exchange tube 4. If the helium leak detector 9 does not detect helium, it indicates that the weld between the half-tube sheet 6 and the container heat exchange tube 4 is of high quality. Conversely, if helium is detected, it indicates that there is a quality defect in the weld between the half-tube sheet 6 and the container heat exchange tube 4, and the device should be returned to the factory for processing. After the test, the gas is released and the device is removed.

[0030] Specific Implementation Method Two: Combining Figures 1 to 4 This embodiment further defines the detection device described in Specific Embodiment 1. In this embodiment, the test plug plate 2 forms a 45° angle with the axis of the pressure plate 1 at the weld seam of the tube and tube sheet of a screen heat exchanger.

[0031] Specific implementation method three: Combining Figures 1 to 4This embodiment further defines the detection device described in Specific Embodiment 1. The leakage detection device at the weld seam between the tube and tube sheet of the screen heat exchanger described in this embodiment has a locking nut on the upper part of the locking screw 3.

[0032] Specific implementation method four: Combination Figures 1 to 4 This embodiment further defines the detection device described in Specific Embodiment 1. In this embodiment, the number of through holes n at the end of the upper surface of the pressure plate 1 is equal to half the number of the 4 sets of heat exchange tubes in the upper container of the screen heat exchanger.

[0033] Specific Implementation Method Five: Combining Figures 1 to 4 This embodiment further defines the detection device described in Specific Embodiment 4. In this embodiment, the number of through holes n at the end of the upper surface of the pressure plate 1 in a leak detection device at the weld between the tube and the tube sheet of a screen heat exchanger is 6 ≤ n ≤ 20.

[0034] Specific Implementation Method Six: Combination Figures 1 to 4 This embodiment further defines the detection device described in Specific Embodiment 1. The leak detection device at the weld between the tube and tube sheet of the screen heat exchanger described in this embodiment has a threaded section machined on the upper part of the outer surface of the air inlet pipe 8.

[0035] In this specific embodiment, the upper part of the outer surface of the air intake pipe 8 is machined with a threaded section so that the top end of the air intake pipe 8 can be connected to the air source through a flange and an air pipe.

[0036] Specific implementation method seven: Combining Figures 1 to 4 This embodiment further defines the detection device described in Specific Embodiment Six. In this embodiment, the top end of the air inlet pipe 8 is connected to the air source via a flange and an air pipe in a screen-type heat exchanger tube and tube sheet leakage detection device.

[0037] Specific implementation method eight: Combination Figures 1 to 4 This embodiment further defines the detection device described in Specific Embodiment 1. In this embodiment, a leakage detection device for the weld seam between the tube and tube sheet of a screen heat exchanger is provided. The test plug plate 2 has strip-shaped grooves machined along its length at both ends of its lower surface, and the top surface of the inner top surface of the strip-shaped grooves on the lower surface of the test plug plate 2 is in contact with the upper surface of the sealing gasket 5.

[0038] Working principle

[0039] When using it, first, align the sealing gasket 5 with the strip groove of the test plug plate 2, and then fasten the test plug plate 2 onto the plane of the half tube plate 6. The edge of the test plug plate 2 is aligned with the edge of the half tube plate 6, and the four fixing holes on the edge are aligned with the support fixture. Then, fix it with fixing bolts.

[0040] Next, insert the baffle 7, place the pressure plate 1, hook the baffle 7 with the hook at the bottom of the locking screw 3, and pass the threaded end through the through hole on the pressure plate 1 to lock and fix it with the locking nut; in this way, use multiple locking screws 3 to clamp the half tube plate 6 and the test plug plate 2, and tighten the locking nut. Tighten it evenly multiple times to ensure uniform force, and observe the force on the sealing gasket at any time to ensure the sealing effect;

[0041] Next, connect the top of the air inlet pipe 8 to the air source through a flange and an air pipe, and perform an airtightness test on the joint to ensure there is no leakage.

[0042] Finally, the device is filled with helium. The operator uses a helium leak detector 9 to perform a helium leak detection test on the weld between the half-tube sheet 6 and the container heat exchange tube 4. If the helium leak detector 9 does not detect helium, it indicates that the weld between the half-tube sheet 6 and the container heat exchange tube 4 is of high quality. Conversely, if helium is detected, it indicates that there is a quality defect in the weld between the half-tube sheet 6 and the container heat exchange tube 4, and the device should be returned to the factory for processing. After the test, the gas is released and the device is removed.

Claims

1. A device for detecting leaks at tube-to-tubesheet welds of a plate heat exchanger tube, characterized in that: It includes a pressure plate (1), a test plug plate (2), a locking screw (3), a sealing gasket (5), a baffle (7), an inlet pipe (8), and a helium leak detector (9). A test plug plate (2) is provided on the upper surface of the half tube plate (6) in the screen heat exchanger, and a sealing gasket (5) is provided at both ends of the test plug plate (2) and the upper surface of the half tube plate (6) along the length direction. A pressure plate (1) is provided on the upper surface of the test plug plate (2), and n through holes are uniformly machined at both ends of the pressure plate (1) along the length direction, where n is a positive integer. A baffle (7) is provided between every two sets of container heat exchange tubes (4) in the screen heat exchanger, and the pressure plate (7) is provided with a baffle (7) along the length direction. Each through hole on the plate (1) is provided with a locking screw (3), the bottom of the locking screw (3) is provided with a hook, and the inner wall of the hook at the bottom of the locking screw (3) is in contact with the bottom surface of the baffle (7). The pressure plate (1) and the test block plate (2) are respectively provided with a through hole, and the bottom end of the air inlet pipe (8) passes through the through hole on the pressure plate (1) and is fixedly connected to the top end of the through hole on the test block plate (2). The half tube plate (6) in the screen heat exchanger is provided with a helium leak detector (9).

2. A screen heat exchanger tube to tube sheet weld leak detection apparatus as claimed in claim 1, wherein: The axis of the test blocking plate (2) forms a 45° angle with the axis of the pressure plate (1).

3. The leakage detection device at the weld seam between tubes and tube sheet in a screen-type heat exchanger according to claim 1, characterized in that: The upper part of the locking screw (3) is provided with a locking nut.

4. The leakage detection device at the weld seam between tubes and tube sheet in a screen-type heat exchanger according to claim 1, characterized in that: The number of through holes n at the end of the upper surface of the pressure plate (1) is equal to half the number of heat exchange tubes (4) in the container of the screen heat exchanger.

5. The leakage detection device at the weld seam between tubes and tube sheet in a screen-type heat exchanger according to claim 4, characterized in that: The number of through holes n at the end of the upper surface of the pressure plate (1) is 6≤n≤20.

6. The leakage detection device at the weld seam between tubes and tube sheet in a screen-type heat exchanger according to claim 1, characterized in that: The upper part of the outer surface of the air intake pipe (8) is machined with a threaded section.

7. The leakage detection device at the weld seam between tubes and tube sheet in a screen-type heat exchanger according to claim 6, characterized in that: The top end of the air inlet pipe (8) is connected to the air source via a flange and an air pipe.

8. The leakage detection device at the weld seam between tubes and tube sheet in a screen-type heat exchanger according to claim 1, characterized in that: The test block (2) has strip grooves machined at both ends of its lower surface along the length direction, and the top surface of the strip grooves on the lower surface of the test block (2) is in contact with the upper surface of the sealing gasket (5).

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