A method for detecting and preventing leakage of a cable transition box in a ballast tank

Abstract

The application discloses a kind of for the cable transition box leakproofness detection and leakage prevention method in ballast tank, the method is sealed to the cable transition box by first carrying out leakproofness detection, after being sealed to door hole by sealing plate, leakproofness detection is carried out again, negative pressure leakproofness detection is carried out to small steel plate on sealing plate, finally, door cover is installed on fixed plate, and cable transition box leakproofness detection and leakage prevention operation are completed.The application carries out leakproofness detection to door cover first, and re-welds to the leak welding seam, and the sealing plate is welded and sealed using to door hole, and leakproofness detection is carried out again to sealing plate, and the double sealing of cable transition box is realized by installing door cover, improve the sealing effect of cable transition box, prolong the service life of cable transition box, avoid the cable break problem.

Description

Technical Field

[0001] This invention belongs to the field of shipbuilding technology, and in particular relates to a method for testing the tightness and preventing leakage of cable transition boxes in ballast tanks. Background Technology

[0002] In modern shipbuilding design, there are numerous cable devices. Arranging cable ducts and cable transition boxes in a limited space can be very crowded and sometimes even affect the arrangement of equipment. Therefore, some cable transition boxes are placed in ballast tanks.

[0003] When a ship is sailing normally, ballast water is present in the ballast tanks, and the cable transfer box will be submerged in ballast water. If the box's airtightness does not meet the requirements, ballast water will seep into the box, corroding the cables or causing short circuits, resulting in serious consequences. Currently, a door cover is installed on the cable transfer box's access door for sealing and waterproofing. However, during the use of the cable transfer box, the airtightness of the door cover is difficult to guarantee, allowing ballast water to seep into the box, corroding the cables or causing short circuits, resulting in serious consequences. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for leak detection and prevention of leakage in cable transition boxes inside ballast tanks. This method involves first installing a door cover on the cable transition box, then performing leak detection on both the door cover and the cable transition box, re-welding any leaking welds, sealing the door opening with a sealing plate, and then performing a leak detection on the sealing plate again before finally installing the door cover. This achieves a double seal for the cable transition box, improving its sealing effect, extending its service life, and preventing cable breakage.

[0005] To achieve the above-mentioned objectives, the technical solution provided by this invention patent is as follows:

[0006] A method for leak detection and prevention of leakage in a cable transition box inside a ballast tank, wherein the cable transition box has cable holes on both sides, which are welded and fixed to cable pipes respectively, and a door hole is opened in the middle of the upper end face of the cable transition box. The method specifically includes the following steps:

[0007] The first step is to lay the cable in the cable hole. The cable enters from the cable hole at one end of the cable transition box and exits from the cable hole at the other end of the cable transition box. After the cable is installed, seal the cable pipe ports on both sides of the cable transition box.

[0008] The second step is to weld a fixing plate into the door hole and install the door cover on the fixing plate. The door cover has an air inlet in the middle. The air inlet on the door cover is used to test the tightness of the cable transition box.

[0009] The third step is to remove the door cover from the fixing plate after the airtightness test is completed, and install the sealing plate in the door hole to seal the door hole. The sealing plate has a sealing air inlet in the middle. The sealing weld between the sealing plate and the door hole is tested for sealing through the sealing air inlet.

[0010] The fourth step is to weld a small steel plate at the air inlet to seal the air inlet. After the sealing test of the weld between the sealing plate and the door hole is completed, a vacuum hood is used to test the seal of the weld between the small steel plate and the sealing plate.

[0011] Fifth, after the sealing test of the weld between the small steel plate and the sealing plate is completed, the door cover is installed on the fixed plate to complete the airtightness test and leak prevention operation of the cable transfer box in the ballast tank.

[0012] The fixing plate in the second step above is generally ring-shaped, and multiple fixing bolts are provided on the end face of the fixing plate. The fixing bolts are evenly distributed on the end face of the fixing plate, and the upper end of the fixing bolts does not exceed the upper end face of the cable transition box. When the fixing plate is installed on the door hole, the bolts on the fixing plate face outward of the cable transition box.

[0013] The aforementioned door cover is circular in shape, and multiple door holes are provided on the outer side of the end face of the door cover. A rubber gasket is provided at the lower end of each door hole.

[0014] When the aforementioned door cover is installed on the fixed plate, the door holes on the door cover correspond one-to-one with the fixing bolts on the fixed plate. The fixing bolts pass through the door holes and are connected and fixed to the fixed plate by fixing nuts.

[0015] The specific steps for conducting a tightness test on the cable transition box after the installation of the middle door cover in the second step mentioned above are as follows:

[0016] S1, connect the air intake pipe of the air intake device to the air inlet of the door cover, and apply soapy water to the weld seam on the cable transition box;

[0017] S2, the air intake device inflates the cable transition box through the air intake pipe. After the air pressure in the cable transition box reaches the set pressure, observe whether there is bubbling when soapy water is applied to the weld seam on the cable transition box. Mark the weld seam that shows bubbling and re-weld the marked weld seam.

[0018] S3. After the marked weld seam is re-welded, the cable transition box is re-tested for tightness. Step S2 is repeated. When the soapy water applied to the weld seam on the cable transition box does not bubble and the air pressure inside the cable transition box remains unchanged, the tightness test of the cable transition box is completed.

[0019] The cable transition box welds that need to be coated with soapy water in S1 above include the cable transition box body welds and the welds between the cable conduit and the cable hole.

[0020] The set air pressure in the cable transition box in S2 above is 0.02 MPa.

[0021] When performing a tightness test on the cable transition box after re-welding in S3 above, if the pressure change of the set air pressure in the cable transition box within 30 minutes does not exceed 10% of the set air pressure, then the set air pressure in the cable transition box remains unchanged.

[0022] The sealing plate in the third step above is circular in shape, and its diameter is the same as the inner diameter of the fixing plate. The inner diameter of the sealing air inlet in the middle of the sealing plate is 10mm. The sealing plate is welded and fixed to the fixing plate to seal the cable transition box. The sealing test of the weld between the sealing plate and the door hole is the same as the sealing test of the cable transition box after the door cover is installed in the second step.

[0023] The aforementioned small steel plate is a 50*50mm square steel plate. The specific steps for using a vacuum hood to perform a sealing test on the weld between the small steel plate and the sealing plate are as follows:

[0024] S11, apply soapy water to the weld between the small steel plate and the sealing plate, and cover the small steel plate with a vacuum cover, the vacuum cover and the end face of the sealing plate are sealed.

[0025] S12, the air intake device fills the vacuum hood with air from the vacuum hood inlet and then exits the vacuum hood outlet to carry away the air inside the vacuum hood, so that the vacuum hood is in a negative pressure state, and the negative pressure inside the vacuum hood is 0.015Mpa.

[0026] S13, observe whether there is any bubbling in the soapy water at the weld between the small steel plate and the sealing plate inside the vacuum chamber. If there is bubbling, re-weld the bubbling weld between the small steel plate and the sealing plate, and repeat steps S11 and S12 to perform a sealing test on the weld between the small steel plate and the sealing plate. This completes the sealing test on the weld between the small steel plate and the sealing plate.

[0027] Based on the above technical solution, the present invention patent's method for detecting the tightness and preventing leakage of cable transition boxes in ballast tanks has achieved the following technical advantages through practical application:

[0028] 1. The present invention provides a method for leak detection and prevention of leakage in cable transition boxes inside ballast tanks. This method involves first performing a leak detection test on the access door cover and re-welding any leaking welds. Then, a sealing plate is welded and sealed to the access door opening. The sealing plate is then tested for leak detection again before the access door cover is installed. This achieves a double seal for the cable transition box, improving its sealing effect, extending its service life, and preventing cable breakage.

[0029] 2. The present invention provides a method for leak detection and prevention of leakage in cable transition boxes in ballast tanks. By conducting leak detection on the door cover, sealing plate and small steel plate respectively, and by conducting positive and negative pressure tests, the problem of weld leakage on the cable transition box is avoided. Through multi-level leak detection, the service life of the cable transition box is extended. Attached Figure Description

[0030] Figure 1 This is a structural diagram of a cable transition box used in the present invention for a method of detecting the tightness and preventing leakage of a cable transition box in a ballast tank.

[0031] Figure 2 This is a schematic diagram of the leak detection of the cable transition box after the installation of the access cover in a method for leak detection and prevention of leakage of cable transition boxes in ballast tanks according to the present invention.

[0032] Figure 3 This is a schematic diagram illustrating the sealing test of the weld between the sealing plate and the door hole in a method for leak detection and prevention of leakage of cable transition boxes in ballast tanks according to the present invention.

[0033] Figure 4 This is a diagram of the small steel plate installation structure in a method for leak detection and prevention of leakage of cable transition boxes in ballast tanks according to the present invention.

[0034] Figure 5 This is a schematic diagram of the weld sealing test between the small steel plate and the sealing plate in a method for leak detection and prevention of leakage of cable transition boxes in ballast tanks according to the present invention. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is described below with reference to specific examples shown in the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0036] This invention relates to a method for leak detection and prevention of leakage of cable transition boxes in ballast tanks. The cable transition box 1 has cable holes on both sides, which are welded and fixed to cable pipes 11 respectively. A door hole 12 is opened in the middle of the upper end face of the cable transition box 1.

[0037] like Figure 1-5 The method described above, for testing the tightness and preventing leakage of cable transition boxes inside ballast tanks, specifically includes the following steps:

[0038] The first step is to lay the cable in the cable hole. The cable enters from the cable hole at one end of the cable transition box 1 and exits from the cable hole at the other end of the cable transition box 1. After the cable is installed, seal the cable pipe 11 ports on both sides of the cable transition box 1.

[0039] The second step is to weld the fixing plate 2 into the door hole 12 and install the door cover 3 on the fixing plate 2. The door cover 3 has an air inlet 31 in the middle. The air inlet 31 on the door cover 3 is used to test the tightness of the cable transition box 1.

[0040] The third step is to remove the door cover 3 from the fixing plate 2 after the airtightness test is completed, and install the sealing plate 4 in the door hole 12 to seal the door hole 12. The sealing plate 4 has a sealing air inlet 41 in the middle. The sealing weld between the sealing plate 4 and the door hole 12 is tested through the sealing air inlet 41.

[0041] The fourth step is to weld a small steel plate 42 at the air inlet to seal the air inlet. The small steel plate 42 seals the air inlet, and a vacuum hood 5 is used to test the seal between the small steel plate 42 and the sealing plate 4.

[0042] Fifth, after the sealing test of the weld between the small steel plate 42 and the sealing plate 4 is completed, the door cover 3 is installed on the fixed plate 2 to complete the tightness test and leak prevention operation of the cable transition box 1 in the ballast tank. By first testing the tightness of the door cover 3 and re-welding the leaking weld, then welding and sealing the door hole 12 with the sealing plate 4, and then testing the tightness of the sealing plate 4 again, and then installing the door cover 3, the double sealing of the cable transition box 1 is achieved, which improves the sealing effect of the cable transition box 1, extends the service life of the cable transition box 1, and avoids the problem of cable breakage.

[0043] In the second step above, the fixing plate 2 is generally ring-shaped. Multiple fixing bolts 21 are provided on the end face of the fixing plate 2. The fixing bolts 21 are evenly distributed on the end face of the fixing plate 2. The upper end of the fixing bolts 21 does not exceed the upper end face of the cable transition box 1. When the fixing plate 2 is installed on the door hole 12, the bolts on the fixing plate 2 face the outside of the cable transition box 1.

[0044] The aforementioned door cover 3 is generally circular. Multiple door holes 12 are provided on the outer side of the end face of the door cover 3. A rubber gasket is provided at the lower end of each door hole 12. The rubber gasket at the lower end of the door hole 12 improves the sealing effect of the door cover 3 on the door hole 12 and prolongs the sealing effect of the door cover 3.

[0045] When the aforementioned door cover 3 is installed on the fixing plate 2, the door hole 12 on the door cover 3 corresponds one-to-one with the fixing bolt 21 on the fixing plate 2. The fixing bolt 21 passes through the door hole 12 respectively, and the door cover 3 is connected and fixed to the fixing plate 2 by fixing nuts.

[0046] The specific steps for performing a tightness test on the cable transition box 1 after the installation of the middle door cover 3 in the second step mentioned above are as follows:

[0047] S1, connect the air intake pipe of the air intake device to the air intake port 31 of the door cover 3, and apply soapy water to the weld seam on the cable transition box 1;

[0048] S2, the air intake device inflates the cable transition box 1 through the air intake pipe. After the air pressure in the cable transition box 1 reaches the set pressure, observe whether there is bubbling when soapy water is applied to the weld seam on the cable transition box 1. Mark the weld seam that shows bubbling and re-weld the marked weld seam.

[0049] S3. After the marked weld is re-welded, the cable transition box 1 is re-tested for tightness. Step S2 is repeated. When the soapy water applied to the weld on the cable transition box 1 does not bubble and the air pressure inside the cable transition box 1 remains unchanged, the tightness test of the cable transition box 1 is completed.

[0050] The welds of the cable transition box 1 that require the application of soapy water in S1 above include the cable transition box body weld 13 and the weld 14 between the cable conduit and the cable hole.

[0051] The set air pressure in the cable transition box 1 in S2 above is 0.02 MPa.

[0052] When the cable transition box 1 is re-welded and tested for tightness in S3 above, if the pressure change of the set air pressure in the cable transition box 1 within 30 minutes does not exceed 10% of the set air pressure, then the set air pressure in the cable transition box 1 remains unchanged.

[0053] In the third step above, the sealing plate 4 is generally circular, and the diameter of the sealing plate 4 is the same as the inner diameter of the fixing plate 2. The inner diameter of the sealing air inlet 41 in the middle of the sealing plate 4 is 10mm. The sealing plate 4 is welded and fixed to the fixing plate 2 to seal the cable transition box 1. The sealing test step of the weld between the sealing plate 4 and the door hole 12 is the same as the sealing test step of the cable transition box 1 after the door cover 3 is installed in the second step.

[0054] The aforementioned small steel plate 42 is a 50*50mm square steel plate. The specific steps for using the vacuum chamber 5 to perform a sealing test on the weld between the small steel plate 42 and the sealing plate 4 are as follows:

[0055] S11, apply soapy water to the weld between the small steel plate 42 and the sealing plate 4, and cover the small steel plate 42 with the vacuum cover 5, and the vacuum cover 5 is sealed to the end face of the sealing plate 4.

[0056] S12, the air intake device fills the vacuum hood 5 with air from the inlet of the vacuum hood 5, and then exhausts the air from the outlet of the vacuum hood 5 to carry away the air inside the vacuum hood 5, so that the vacuum hood 5 is in a negative pressure state, and the negative pressure inside the vacuum hood 5 is 0.015Mpa.

[0057] S13, observe whether there is bubbling in the soapy water at the weld between the small steel plate 42 and the sealing plate 4 inside the vacuum chamber 5. If there is bubbling, re-weld the bubbling weld between the small steel plate 42 and the sealing plate 4, and repeat steps S11 and S12 to perform a sealing test on the weld between the small steel plate 42 and the sealing plate 4. The sealing test on the weld between the small steel plate 42 and the sealing plate 4 is completed. By performing sealing tests on the door cover 3, the sealing plate 4, and the small steel plate 42 respectively, and by using positive and negative pressure to test, the problem of weld leakage on the cable transition box 1 is avoided. Through multi-level sealing tests, the service life of the cable transition box 1 is extended.

[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of the invention or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the technical solutions claimed in the present invention.

Claims

1. A method for detecting and preventing leakage of a cable transition box in a ballast tank, the cable transition box (1) having cable holes on both sides, the cable holes being respectively welded and fixed with cable pipes (11), and a door hole (12) being formed in the middle of the upper end face of the cable transition box (1), characterized in that, The method specifically comprises the following steps: First, the cable is laid in the cable hole, the cable is inserted from the cable hole at one end of the cable transition box (1) and then is taken out from the cable hole at the other end of the cable transition box (1), and after the cable is installed, the cable pipe (11) ports on both sides of the cable transition box (1) are sealed; Second, the fixed plate (2) is welded in the door hole (12), the door cover (3) is installed on the fixed plate (2), the middle part of the door cover (3) is provided with an air inlet (31), and the cable transition box (1) is detected in airtightness through the air inlet (31) on the door cover (3); Third, after the airtightness detection is completed, the door cover (3) is removed from the fixed plate (2), the sealing plate (4) is installed in the door hole (12) to seal the door hole (12), the middle part of the sealing plate (4) is provided with a sealing air inlet hole (41), and the welding seam between the sealing plate (4) and the door hole (12) is detected in airtightness through the sealing air inlet hole (41); Fourth, after the sealing detection of the welding seam between the sealing plate (4) and the door hole (12) is completed, a small steel plate (42) is welded at the sealing air inlet, the small steel plate (42) seals the sealing air inlet, and the welding seam between the small steel plate (42) and the sealing plate (4) is detected in airtightness by using a vacuum cover (5); The specific steps of detecting the welding seam between the small steel plate (42) and the sealing plate (4) in airtightness by using the vacuum cover (5) are as follows: S11, soap water is applied to the welding seam between the small steel plate (42) and the sealing plate (4), and the vacuum cover (5) is covered above the small steel plate (42), and the vacuum cover (5) is in close contact with the end face of the sealing plate (4); S12, the air inlet device charges air into the vacuum cover (5) from the inlet of the vacuum cover (5), and then discharges air from the outlet of the vacuum cover (5) to take away the air in the vacuum cover (5) to make the vacuum cover (5) in a negative pressure state, and the negative pressure in the vacuum cover (5) is 0.015Mpa; S13, whether the soap water of the welding seam between the small steel plate (42) and the sealing plate (4) in the vacuum cover (5) bubbles is observed, if the soap water bubbles, the welding seam between the small steel plate (42) and the sealing plate (4) is welded again, and the welding seam between the small steel plate (42) and the sealing plate (4) is detected in airtightness by repeating steps S11 and S12, and the sealing detection of the welding seam between the small steel plate (42) and the sealing plate (4) is completed; Fifth, after the sealing detection of the welding seam between the small steel plate (42) and the sealing plate (4) is completed, the door cover (3) is installed on the fixed plate (2), and the cable transition box (1) in the ballast tank is detected in airtightness and the leakage prevention operation is completed.

2. The method for leak detection and prevention of a cable transition box in a ballast tank according to claim 1, wherein, In the second step, the fixed plate (2) is annular as a whole, a plurality of fixed bolts (21) are arranged on the end face of the fixed plate (2), the fixed bolts (21) are uniformly distributed on the end face of the fixed plate (2), and the upper ends of the fixed bolts (21) are not higher than the upper end face of the cable transition box (1); when the fixed plate (2) is installed on the door hole (12), the bolts on the fixed plate (2) face the outside of the cable transition box (1).

3. The method for leak detection and prevention of a cable transition box in a ballast tank according to claim 1, wherein, The door cover (3) is circular as a whole, and a plurality of door holes (12) are arranged on the outer side of the end face of the door cover (3), and a rubber gasket is arranged at the lower end of each door hole (12).

4. The method for detecting and preventing leakage of a cable transition box in a ballast tank according to claim 3, wherein, When the door cover (3) is installed on the fixed plate (2), the door holes (12) on the door cover (3) correspond to the fixed bolts (21) on the fixed plate (2) one by one, the fixed bolts (21) pass through the door holes (12) respectively, and the door cover (3) is connected and fixed with the fixed plate (2) through the fixed nuts.

5. The method for leak detection and prevention of a cable transition box in a ballast tank according to claim 1, wherein, The specific steps for the tightness detection of the cable transition box (1) after the installation of the door cover (3) in the second step are as follows: S1, connect the air inlet pipeline of the air inlet device with the air inlet (31) of the door cover (3), and apply soapy water to the welds on the cable transition box (1); S2, the air inlet device inflates the cable transition box (1) through the air inlet pipeline, and when the air pressure in the cable transition box (1) reaches the set pressure, observe whether the soapy water applied to the welds on the cable transition box (1) bubbles, mark the welds that appear bubbles, and re-weld the marked welds; S3, after the re-welding of the marked welds is completed, the tightness of the cable transition box (1) is detected again, and the step S2 is repeated, when the soapy water applied to the welds on the cable transition box (1) does not bubble, and the air pressure in the cable transition box (1) does not change, the tightness detection of the cable transition box (1) is completed.

6. A method for leak detection and prevention of a cable transition box (1) in a ballast tank according to claim 5, characterized in that, The welds of the cable transition box (1) that need to be applied with soapy water in S1 include the cable transition box body weld (13) and the weld (14) between the cable pipe and the cable hole.

7. The method for leak detection and prevention of a cable transition box in a ballast tank according to claim 5, wherein, The set air pressure in the cable transition box (1) in S2 is 0.02 Mpa.

8. The method for leak detection and prevention of a cable transition box in a ballast tank according to claim 5, wherein, In the tightness detection of the cable transition box (1) after the re-welding in S3, when the set air pressure in the cable transition box (1) changes by not more than 10% of the set air pressure within 30 minutes, the set air pressure in the cable transition box (1) does not change.

9. The method for leak detection and prevention of a cable transition box in a ballast tank according to claim 1, wherein, The sealing plate (4) in the third step is circular as a whole, the diameter of the sealing plate (4) is the same as the inner diameter of the fixed plate (2), the inner diameter of the sealing air inlet hole (41) in the middle of the sealing plate (4) is 10 mm, the sealing plate (4) is welded and fixed with the fixed plate (2) to seal the cable transition box (1), and the sealing detection steps of the welds between the sealing plate (4) and the door holes (12) are the same as the tightness detection steps of the cable transition box (1) after the installation of the door cover (3) in the second step.

10. The method for leak detection and prevention of a cable transition box in a ballast tank according to claim 1, wherein, The small steel plate (42) is a square steel plate with a size of 50*50 mm.

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