Auxiliary device for deep hole machining of through type holes and machining method

Abstract

The invention discloses an auxiliary device and a machining method for deep hole machining of a through hole, and the auxiliary device comprises a plug which is detachably mounted on an axial drainage hole and a pollution discharge hole of a tube plate; the center centering mandrel is detachably mounted on the radial sewage discharge hole of the tube plate and is used for positioning the radial sewage discharge hole; the machining method is used for machining drainage holes and drainage holes in a tube plate in a steam generator of nuclear island equipment, machining of axial drainage holes or axial drainage holes is conducted firstly, and then machining of radial drainage holes is conducted. According to the auxiliary device and the machining method disclosed by the invention, the problems that the drainage hole and the drainage hole of the tube plate cannot be subjected to secondary machining and cannot be repaired are solved.

Description

Technical Field

[0001] The present invention relates to a method for deep hole machining of intersecting holes, especially for machining radial large-diameter, deep drain holes or blowdown holes that intersect with small-diameter holes on the tube sheet of a nuclear power pressurized steam generator, and a method for secondary machining of radial large-diameter, deep drain holes or blowdown holes, belonging to the technical field of mechanical equipment manufacturing. Background Art

[0002] During the operation of the steam generator, salts and corrosion products brought in by the circulating water will remain in the water. As the water evaporates, these substances will concentrate and deposit inside the steam generator. Therefore, it is necessary to regularly discharge these harmful substances through the blowdown holes to maintain the water quality and operating efficiency of the steam generator. In addition, the blowdown rate of the steam generator blowdown system is closely related to its water treatment system and operating conditions. In some nuclear power plants, in addition to normal continuous blowdown, periodic blowdown is also carried out to remove the sludge on the tube sheet. The tube sheet drain holes and blowdown holes are important and essential structures on the steam generator product of the nuclear island equipment, and are important structures for removing sediments, sludge and excess water inside the steam generator. These drain holes and blowdown holes are usually located under the tube sheet of the steam generator. Through them, the sludge on the tube sheet can be effectively removed, preventing the accumulation of dirt and corrosion products, thereby avoiding damage to the heat transfer tubes. In the event of a steam generator heat transfer tube rupture accident, it also needs to undertake a safety function, by controlling the water level and pressure of the faulty steam generator, preventing the damaged steam generator from overflowing and meeting the safety requirements.

[0003] The drain holes and blowdown holes include axial holes and radial holes. Among them, the radial holes need to be machined by a jet drilling machine. This structure requires the space inside the machining cavity to be airtight to achieve jet chip removal and the purpose of surface finish. Therefore, the existing machining methods generally adopt the method of machining the axial holes first and then the radial holes. However, this machining sequence will lead to greater production scheduling difficulties. When a machining device is repaired, the overall machining stops. In addition, it also makes it difficult to repair the machined parts. When machining errors occur in the hole diameter and hole position, it is difficult to correct them.

[0004] Therefore, it is necessary to conduct in-depth research on the existing method for deep hole machining of intersecting holes to solve the above problems. Summary of the Invention

[0005] In order to overcome the above problems, the inventor of the present invention has conducted in-depth research and designed an auxiliary device for deep hole machining of intersecting holes, including:

[0006] A plug 1, detachably installed on the tube sheet axial drain hole 91 and the blowdown hole, used to block the tube sheet axial drain hole 91 and the blowdown hole;

[0007] The central centering mandrel is detachably installed on the radial sewage discharge hole 93 of the tube sheet for positioning the radial sewage discharge hole 93.

[0008] In a preferred embodiment, the plug 1 is in a conical or frustum structure.

[0009] In a preferred embodiment, the upper end diameter of the plug 1 is larger than the lower end diameter. The lower end of the plug 1 is inserted into the axial hydrophobic hole 91 or the axial sewage discharge hole 92, and the upper end of the plug 1 protrudes from the tube sheet.

[0010] In a preferred embodiment, after the plug 1 is installed in the axial hydrophobic hole 91 or the axial sewage discharge hole 92, the depth that the lower end of the plug 1 extends into the axial hydrophobic hole 91 or the axial sewage discharge hole 92 is 20 - 40 mm, and the height that the upper end protrudes from the end face of the axial hydrophobic hole 91 or the axial sewage discharge hole 92 is 15 - 35 mm.

[0011] In a preferred embodiment, the upper end of the plug 1 has a disassembly hole.

[0012] In a preferred embodiment, the auxiliary device further includes a plug disassembly tool 2. The plug disassembly tool 2 includes a first straight rod 21 and a second straight rod 22. One end of the first straight rod 21 is connected to one end of the second straight rod 22. There is an included angle between the first straight rod 21 and the second straight rod 22. A pointed cone 23 is provided at the other end of the second straight rod 22, and the pointed cone 23 can be inserted into the disassembly hole 11.

[0013] In a preferred embodiment, the central centering mandrel is a cylindrical mandrel. One end can be fixed in the machine tool chuck, and the other end can be inserted into the radial sewage discharge hole 93.

[0014] The present invention also discloses a method for deep hole machining of intersecting type holes, which is used for machining the hydrophobic holes and sewage discharge holes on the tube sheet of the steam generator of nuclear island equipment. First, the axial hydrophobic hole 91 or the axial sewage discharge hole 92 is machined, and then the radial sewage discharge hole 93 is machined.

[0015] In a preferred embodiment, when newly machining the tube sheet hydrophobic holes and sewage discharge holes, the following steps are included:

[0016] Machine the axial hydrophobic hole 91 and the sewage discharge hole;

[0017] Install the plug 1 on the axial hydrophobic hole 91 and the sewage discharge hole;

[0018] Machine the radial sewage discharge hole 93 by using a jet - suction drill;

[0019] Remove the plug 1.

[0020] In a preferred embodiment, when performing secondary machining on the tube sheet hydrophobic holes and sewage discharge holes, the following steps are included:

[0021] Install a plug 1 on the axial hydrophobic hole 91 and the sewage drain hole;

[0022] Install a center-aligning mandrel in the radial sewage drain hole 93, fix one end of the center-aligning mandrel on the machine tool chuck, and fix the position of the fixed tube sheet and the machine tool;

[0023] Remove the center-aligning mandrel, install a gun drill on the machine tool, and perform secondary processing on the radial sewage drain hole 93;

[0024] Remove the plug 1.

[0025] The beneficial effects of the present invention include:

[0026] (1) Solve the problem that the hydrophobic holes and sewage drain holes of the tube sheet cannot be subjected to secondary processing and cannot be repaired;

[0027] (2) The auxiliary device is simple and the processing process is simple, without the need for major modification of the production line;

[0028] (3) Improve production efficiency and reduce the impact of production line abnormalities on the production schedule. Description of the Drawings

[0029] Figure 1 Show a schematic diagram of the plug installation structure in the auxiliary device for deep hole machining of intersecting type holes according to a preferred embodiment of the present invention;

[0030] Figure 2 Show a schematic diagram of the plug structure in the auxiliary device for deep hole machining of intersecting type holes according to a preferred embodiment of the present invention;

[0031] Figure 3 Show a schematic diagram of the plug structure in the auxiliary device for deep hole machining of intersecting type holes according to a preferred embodiment of the present invention;

[0032] Figure 4 Show a schematic diagram of the plug disassembly tool structure in the auxiliary device for deep hole machining of intersecting type holes according to a preferred embodiment of the present invention.

[0033] Explanation of the reference numerals in the drawings:

[0034] 1 - Plug;

[0035] 2 - Plug disassembly tool;

[0036] 11 - Disassembly hole;

[0037] 21 - First straight rod;

[0038] 22 - Second straight rod;

[0039] 23 - Taper;

[0040] 24 - cross bar;

[0041] 91 - axial drain hole;

[0042] 92 - axial sewage discharge hole;

[0043] 93 - radial sewage discharge hole. Detailed implementation mode

[0044] 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 definite.

[0045] The special term "exemplary" here means "serving as an example, embodiment or illustration". Any embodiment described as "exemplary" here does not have to be construed as superior or better than other embodiments. Although various aspects of the embodiments are shown in the drawings, the drawings do not have to be drawn to scale unless otherwise specified.

[0046] An auxiliary device for deep hole machining of intersecting type holes according to the present invention, as Figure 1 shown, includes:

[0047] Plug 1, detachably installed on the axial drain hole 91 or axial sewage discharge hole 92 of the tube sheet, for plugging the axial drain hole 91 or axial sewage discharge hole 92 of the tube sheet;

[0048] Center centering mandrel, detachably installed on the radial sewage discharge hole 93 of the tube sheet, for positioning the radial sewage discharge hole 93.

[0049] According to the present invention, there are multiple plugs 1.

[0050] Preferably, the plug 1 is of a conical or frustum - shaped structure, as Figure 2 shown, which is convenient for installation in the axial drain hole 91 or axial sewage discharge hole 92 and improves the sealing performance.

[0051] Among them, the upper end diameter of the plug 1 is larger than the lower end diameter. The lower end of the plug 1 is inserted into the axial drain hole 91 or axial sewage discharge hole 92, and the upper end of the plug 1 exposes the tube sheet, which is convenient for disassembly.

[0052] Preferably, the taper angle of the plug 1 is 0.06° - 0.08°. This angle can not only make the plug 1 easily inserted into the axial drain hole 91 or axial sewage discharge hole 92, but also ensure the contact area between the plug 1 and the axial drain hole 91 or axial sewage discharge hole 92, thereby improving the sealing performance.

[0053] According to the present invention, the plug 1 is made of an elastic material, such as nylon, etc., and uses the performance of its own material to achieve the sealing effect.

[0054] In a preferred embodiment, after the plug 1 is installed in the axial drain hole 91 or the axial sewage drain hole 92, the depth that the lower end of the plug 1 extends into the axial drain hole 91 or the axial sewage drain hole 92 is 20 - 40 mm, and the height that the upper end exposes the end face of the axial drain hole 91 or the axial sewage drain hole 92 (i.e., the end face of the tube sheet) is 15 - 35 mm. Under the condition of ensuring the sealing performance, this length facilitates the installation and removal of the plug 1.

[0055] According to the present invention, after the plug 1 is installed in the axial drain hole 91 or the axial sewage drain hole 92, the lower end does not expose the bottom ends of the axial drain hole 91 and the axial sewage drain hole 92, avoiding its entry into the radial sewage drain hole 93 and causing interference to the processing of the radial sewage drain hole 93.

[0056] According to the present invention, the plug 1 is inserted into the axial drain hole 91 or the axial sewage drain hole 92 by means of tapping to ensure the sealing performance.

[0057] In a preferred embodiment, the plug 1 is provided with scale lines to facilitate observing the depth of tapping into the axial drain hole 91 or the axial sewage drain hole 92 to ensure the sealing performance.

[0058] In an embodiment, the upper end of the plug 1 is provided with a boss to facilitate pulling out from the axial drain hole 91 and the sewage drain hole.

[0059] In another embodiment, the upper end of the plug 1 has a disassembly hole 11 to facilitate using a tool to disassemble the plug 1 installed in the axial drain hole 91 or the axial sewage drain hole 92.

[0060] In the present invention, the disassembly hole 11 can be a threaded hole and disassembled by cooperating with a screw rod. The disassembly hole 11 can also be a round hole, as Figure 3 shown, and is pried out by the plug disassembly tool 2.

[0061] In a preferred embodiment, the auxiliary device further includes a plug disassembly tool 2, as Figure 4 shown.

[0062] Preferably, the plug disassembly tool 2 includes a first straight rod 21 and a second straight rod 22. One end of the first straight rod 21 is connected to one end of the second straight rod 22. There is an included angle between the first straight rod 21 and the second straight rod 22. The other end of the second straight rod 22 is provided with a sharp cone 23, and the sharp cone 23 can be inserted into the disassembly hole 11.

[0063] Preferably, the connection end of the first straight rod 21 and the second straight rod 22 has an arc transition.

[0064] The included angle is preferably 80° - 90°, and more preferably 85° - 86°.

[0065] With the above structure, insert the tapered cone 23 into the disassembly hole 11. By lifting the first straight rod 21, the blockage 1 can be easily pulled out using the lever principle, reducing the manual bending operation and lowering the labor intensity.

[0066] More preferably, a cross bar 24 is provided at the other end of the first straight rod 21. The cross bar 24 is perpendicular to the first straight rod 21, facilitating the lifting of the first straight rod 21.

[0067] The central centering mandrel is a cylindrical mandrel. One end can be fixed in the machine tool chuck, and the other end can be inserted into the radial sewage discharge hole 93, thereby fixing the position of the tube sheet and the machine tool and achieving the positioning of the radial sewage discharge hole 93.

[0068] Further, after fixing the position of the tube sheet and the machine tool, remove the central centering mandrel and install a jet drilling machine in the machine tool to perform secondary processing on the radial sewage discharge hole 93.

[0069] In a preferred embodiment, the length of the central centering mandrel is 400 - 500 mm.

[0070] In a preferred embodiment, the outer diameter of the central centering mandrel is 0.05 - 0.1 mm smaller than the inner diameter of the radial sewage discharge hole 93, facilitating the removal of the central centering mandrel from the radial sewage discharge hole 93 while ensuring the positioning effect.

[0071] The present invention also provides a method for deep hole machining of intersecting type holes, which is used for machining the drain holes and sewage discharge holes on the tube sheet of the steam generator of nuclear island equipment. First, the axial drain hole 91 or the axial sewage discharge hole 92 is machined, and then the radial sewage discharge hole 93 is machined.

[0072] Specifically:

[0073] When newly machining the drain holes and sewage discharge holes of the tube sheet, the following steps are included:

[0074] Machine the axial drain hole 91 or the axial sewage discharge hole 92;

[0075] Install the blockage 1 on the axial drain hole 91 and the sewage discharge hole;

[0076] Machine the radial sewage discharge hole 93 using a jet drilling machine;

[0077] Remove the blockage 1.

[0078] This machining method enables the jet drilling machine to machine the axial drain hole 91 and the sewage discharge hole first during maintenance, without having to wait for the maintenance of the jet drilling machine, reducing the machining waiting time and minimizing the impact of equipment maintenance on the production schedule. At the same time, a method for secondary machining and repair of the radial drain hole after axial drain hole machining is provided.

[0079] When performing secondary processing on the tube sheet drain holes and blowdown holes, the following steps are included:

[0080] Install a plug 1 on the axial drain hole 91 and the blowdown hole;

[0081] Install a center alignment mandrel in the radial blowdown hole 93, and fix one end of the center alignment mandrel on the machine tool chuck to fix the position of the tube sheet and the machine tool;

[0082] Remove the center alignment mandrel, install a jet drilling tool on the machine tool, and perform secondary processing on the radial blowdown hole 93;

[0083] Remove the plug 1.

[0084] According to the present invention, the processing methods of the axial drain hole 91 and the blowdown hole are the same as those of the axial drain hole 91 and the blowdown hole in a conventional tube sheet, and will not be elaborated herein.

[0085] According to the present invention, during the process of installing the plug 1 on the axial drain hole 91 and the blowdown hole, preferably, after the plug 1 is placed into the axial drain hole 91 or the blowdown hole, the plug 1 is tapped, and the scale line on the plug 1 is observed until the plug 1 is tapped downward by 0.5 - 1 mm to ensure the tightness of the plug 1.

[0086] Furthermore, when there is no scale line on the plug 1, measure the aperture of the axial drain hole 91 or the blowdown hole, draw a line on the conical plug 1 according to this diameter, and draw a reference baseline above this line. Observe this reference baseline when tapping the plug 1 so that the plug 1 is tapped downward by 0.5 - 1 mm.

[0087] In a preferred embodiment, before processing the radial blowdown hole 93 using a jet drilling tool, the drill bit rotates at a low speed and penetrates into the position to be processed of the radial blowdown hole 93. First, turn on the jet drilling tool equipment and the oil pump to perform a sealing test on the radial blowdown hole 93 to verify the tightness of the plug 1.

[0088] In a preferred embodiment, during secondary processing, when it is necessary to increase the opening depth of the radial blowdown hole 93, only need to install a plug 1 on the axial drain hole 91 or the blowdown hole closest to the continuous opening end of the radial blowdown hole 93, and there is no need to install a plug 1 on other axial drain holes 91 or blowdown holes.

[0089] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "inner", "outer", "front", "rear", etc. is the orientation or positional relationship based on the working state of the present invention. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention. In addition, the terms "first", "second", "third", and "fourth" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0090] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installed", "connected", and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0091] The present invention has been described in conjunction with preferred embodiments above. However, these embodiments are merely exemplary and only serve an illustrative purpose. On this basis, various substitutions and improvements can be made to the present invention, and these all fall within the protection scope of the present invention.

Claims

1. An auxiliary device for deep hole processing of intersecting type holes, characterized in that: include: A plug (1) is detachably mounted on the axial drain hole (91) and the drain hole of the tube sheet, and is used to plug the axial drain hole (91) and the drain hole of the tube sheet; The center alignment mandrel is detachably mounted on the radial drainage hole (93) of the tube sheet and is used to position the radial drainage hole (93).

2. The auxiliary device for deep hole machining of intersecting type holes according to claim 1, characterized in that: The plug (1) is a conical or truncated cone structure.

3. The auxiliary device for deep hole machining of intersecting type holes according to claim 2, characterized in that: The diameter of the upper end of the plug (1) is larger than the diameter of the lower end. The lower end of the plug (1) is inserted into the axial drain hole (91) or the axial sewage discharge hole (92), and the upper end of the plug (1) is exposed from the tube sheet.

4. The auxiliary device for deep hole machining of intersecting type holes according to claim 1, characterized in that: After the plug (1) is installed in the axial drain hole (91) or the axial sewage discharge hole (92), the depth of the lower end of the plug (1) penetrating into the axial drain hole (91) or the axial sewage discharge hole (92) is 20 to 40 mm, and the height of the upper end exposed from the end surface of the axial drain hole (91) or the axial sewage discharge hole (92) is 15 to 35 mm.

5. The auxiliary device for deep hole machining of intersecting type holes according to claim 1, characterized in that: The upper end of the plug (1) is provided with a disassembly hole.

6. The auxiliary device for deep hole machining of intersecting type holes according to claim 1, characterized in that: The auxiliary device also includes a blockage removal tool (2), the blockage removal tool (2) includes a first straight rod (21) and a second straight rod (22), one end of the first straight rod (21) is connected to one end of the second straight rod (22), an angle is formed between the first straight rod (21) and the second straight rod (22), and the other end of the second straight rod (22) is provided with a pointed cone (23), and the pointed cone (23) can be inserted into the removal hole (11).

7. The auxiliary device for deep hole machining of intersecting type holes according to claim 1, characterized in that: The center alignment mandrel is a cylindrical mandrel, one end of which can be fixed in a machine tool chuck, and the other end of which can be inserted into a radial drainage hole (93).

8. A method for machining intersecting type deep holes, used for machining drain holes and drainage holes on tube sheets of steam generators in nuclear island equipment, using the auxiliary device as described in any one of claims 1 to 7, characterized in that: The axial drain hole or axial sewage discharge hole is processed first, and then the radial sewage discharge hole is processed.

9. The method for deep hole machining of intersecting type holes according to claim 8, characterized in that: When the drain holes and drain holes of the tube sheet are newly processed, the following steps are included: Processing of axial drain holes and drainage holes; Install plugs on the axial drain holes and drain holes; Use ejector drill to process radial drainage holes; Remove the plug.

10. The method for deep hole machining of intersecting type holes according to claim 8, characterized in that: When the drain holes and drain holes of the tube sheet are processed for secondary processing, the following steps are included: Install plugs on the axial drain holes and drain holes; Install the center alignment mandrel in the radial drain hole, and fix one end of the center alignment mandrel on the machine tool chuck to fix the position of the tube sheet and the machine tool; Remove the center alignment mandrel, install the ejector drill on the machine tool, and perform secondary processing on the radial drainage holes; Remove the plug.

Images