Opening processing equipment, method for forming opening, and method for removing foreign matter

Abstract

The present invention relates to an opening processing device, a method for forming an opening, and a method for removing foreign matter. In particular, the invention provides an opening processing device for a heat transfer tube, a method for processing an opening in the tube wall of the heat transfer tube using the same device, and a method for removing foreign matter through the same opening. The opening processing device for the heat transfer tube includes: an electrospark machining device that is inserted into the heat transfer tube and is configured to form an opening in the tube wall of the heat transfer tube by electrospark machining; an electrospark machining device transport device that is connected to the electrospark machining device and is configured to transport the electrospark machining device; an electrospark machining device drive device that is connected to the electrospark machining device and is configured to provide a force for closely contacting the electrospark machining device with the tube wall surface of the heat transfer tube; and an electrospark machining device rotating device that is configured to provide a force for rotating the electrospark machining device in a circumferential direction of a heat transfer unit in the heat transfer tube.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Korean Patent Application No. 10-2021-0042040, filed on March 31, 2021, and Korean Patent Application No. 10-2021-0083113, filed on June 25, 2021, the disclosures of which are incorporated herein by reference in their entirety. Background Art 1. Technical Field

[0004] Apparatus and methods consistent with exemplary embodiments relate to an opening processing apparatus for a heat transfer tube, a method for forming an opening in a heat transfer tube by using the same apparatus, and a method for removing foreign matter through the same opening of a heat transfer tube, and more particularly, to an opening processing apparatus for a heat transfer tube, which can remove foreign matter from the wall of a heat transfer tube by forming an opening in a heat transfer tube of a steam generator installed in a nuclear power plant.

[0005] 2. Description of Related Technology

[0006] The steam generator is one of the key devices in a nuclear power plant, which generates steam required by the turbines and generators to produce electricity.

[0007] For example, a bundle of heat transfer pipes is provided inside the steam generator, and the heat transfer pipes provide a heat exchange function between the radiated primary system water and the secondary system water that rotates the turbine, and also separate the primary system water and the secondary system water from each other.

[0008] During the steam generation process, primary system water, heated while passing through the nuclear reactor, flows through the pipes inside the steam generator's heat transfer tubes, while externally supplied secondary system water flows through pipes located outside the heat transfer tubes. The primary and secondary system water exchange heat through the walls of the heat transfer tubes. The primary system water then returns to the reactor through a closed circulation pipe, and the secondary system water is converted into steam.

[0009] Specifically, high-temperature, high-pressure radioactive water (i.e., primary system water) flows through the heat transfer pipes, while non-radioactive water (i.e., secondary system water) flows out of them. Therefore, if the heat transfer pipes become damaged, the radioactive water (i.e., primary system water) leaks outside and mixes with the non-radioactive water (i.e., secondary system water), causing contamination of the non-radioactive water (i.e., secondary system water). The contaminated water then turns into steam, which contaminates the entire facility. Therefore, ensuring the stability of the heat transfer pipes is a core task in nuclear power plant operations.

[0010] Figure 1is a partial cross-sectional view illustrating a steam generator according to the related art, Figure 2 yes Figure 1 a longitudinal cross-sectional view of a steam generator, and Figure 3 is a cross-sectional view schematically illustrating an operating principle of a steam generator according to the related art. Figures 1 to 3 The steam generator 10 includes an inlet nozzle 1 through which reactor coolant for the primary system is introduced; heat transfer tubes 3 for heat exchange; and an outlet nozzle 5 through which the reactor coolant is discharged to the outside. The heat transfer tubes 3 are placed on a tube sheet 4 and supported by tube support plates 6, which are arranged at regular height intervals in the vertical direction. A fluid distribution plate 8 is arranged between the lowermost tube support plate 6 and the tube sheet 4 to support the heat transfer tubes 3. The heat transfer tubes 3 and the tube support plates 6 are combined with a wrapper 20, which is configured to support the heat transfer tubes 3 and is spaced apart from each other in the vertical direction. The wrapper 20 has an open lower portion and a steam discharge port 21 formed on the upper portion. The wrapper 20 receives water flowing along the inner surface of the shell 2, and the introduced water is heated by the heat transfer tubes 3 to become steam, which is discharged to the outside through the upper end of the wrapper 20.

[0011] In the steam generator 10, the reactor coolant discharged from the primary system flows into the steam generator 10 through the inlet nozzle 1, flows through the heat transfer tube 3, and flows out of the steam generator 10 through the outlet nozzle 5. The reactor coolant transfers heat to the secondary system coolant and generates steam in the process.

[0012] Here, the portion through which the reactor coolant flows is referred to as the primary side, and the portion through which water and steam flow is referred to as the secondary side. The secondary system includes the main steam system, the turbine system, and the condensate and water supply system.

[0013] The steam generated on the secondary side of the steam generator 10 moves along the main steam line to rotate the turbine.

[0014] exist Figure 3In the related art steam generator 10 shown in FIG, each of the thousands of U-shaped heat transfer tubes 3 bundled together is fixed to a tube sheet 4 positioned below both ends of the heat transfer tube 3 and supported by seven stages of tube support plates 6 arranged at approximately 1 meter intervals in the vertical direction. Over time, foreign matter introduced from the outside or generated from the inside is transferred to the heat transfer tubes 3, causing scale to form on the outer surface of each heat transfer tube 3, thereby deteriorating heat exchange performance. Furthermore, the foreign matter can accumulate as sediment between each heat transfer tube 3 and each tube support plate 6. This sediment gradually solidifies, causing depressions between the tube support plates 6 and the heat transfer tube 3, leading to damage to the heat transfer tube 3. Therefore, it is important to remove scale from the surfaces of the heat transfer tubes 3, remove sediment from the tube support plates 6, and remove foreign matter accumulated between each heat transfer tube 3 to ensure the operational efficiency of the steam generator and the stability of the heat transfer tubes 3.

[0015] To remove foreign matter, in the related art, the heat transfer tube near the foreign matter needs to be cut and removed to gain access to the foreign matter. In this case, if the partially cut end portion of the heat transfer tube is not securely supported by the tube support plate 6, this end portion may come into contact with adjacent structures (e.g., adjacent heat transfer tubes or support columns), potentially causing damage due to frictional wear caused by fluid-induced vibrations. Consequently, there is a problem in that the locations where foreign matter can be removed using the related art cutting method are limited. Summary of the Invention

[0016] Aspects of one or more exemplary embodiments provide an opening processing apparatus for a heat transfer tube in a heat exchanger, which can remove foreign matter between the heat transfer tubes by forming openings in the heat transfer tubes while minimizing damage to the heat transfer tubes, and provide a method of forming openings in the heat transfer tubes using the same apparatus and a method of removing foreign matter from the heat transfer tubes through the same openings.

[0017] Additional aspects will be apparent in part from the description which follows and, in part, will be apparent from the description which follows, or may be learned by practice of the exemplary embodiments.

[0018] According to one aspect of an exemplary embodiment, an opening processing device for a heat transfer tube is provided, which includes: an EDM device, which is inserted into the heat transfer tube and is configured to form an opening in the tube wall of the heat transfer tube by EDM; an EDM device transport device, which is connected to the EDM device to transport the EDM device; an EDM device drive device, which is connected to the EDM device and is configured to provide a force for making the EDM device in close contact with the tube wall of the heat transfer tube; and an EDM device rotating device, which is configured to provide a force for rotating the EDM device along the circumferential direction of the heat transfer unit in the heat transfer tube.

[0019] The electric discharge machining device may include: a shell having a through hole extending in a radial direction, the shell being inserted into a heat transfer tube and extending in a longitudinal direction of the heat transfer tube; a discharge body arranged in the shell, the discharge body being movably arranged through the through hole and having a discharge electrode provided on a first surface of a tube wall surface facing the heat transfer tube; an operating shaft arranged in the shell, the operating shaft being moved in the longitudinal direction of the shell by an electric discharge machining device driving device and being configured to move the discharge body to the outside through the through hole; and a dielectric supply member arranged in the shell, and the dielectric supply member being configured to supply dielectric to the discharge electrode of the discharge body.

[0020] The second surface of the discharge body in close contact with the operating shaft may be inclined to have a downward inclination in the direction in which the operating shaft moves, and the first end of the operating shaft in close contact with the second surface of the discharge body may have an inclined surface corresponding to the inclined second surface of the discharge body.

[0021] The discharge electrode may be provided on the first surface of the discharge body to protrude from the first surface, and the discharge electrode may be provided over the entire surface of the first surface to contact the tube wall surface of the heat transfer tube for surface processing.

[0022] The discharge electrodes may be provided on the first surface of the discharge body to protrude therefrom, and the discharge electrodes may be provided at circumferences of upper and lower portions of the first surface to contact the tube wall surface of the heat transfer tube for linear processing.

[0023] The EDM device transport device may include: a first transport member, which is arranged at the front end of the EDM device; a first coupling member, which connects the first transport member and the EDM device in a rotatable manner; a second transport member, which is arranged at the rear end of the EDM device; a second coupling member, which connects the second transport member and the EDM device in a rotatable manner; and a connecting cable, which transmits force to move the second transport member.

[0024] The first transport member may include a first body and a plurality of first support rings, the first body being connected to the electro-spark machining device via a first coupling member, the plurality of first support rings being rotatably mounted on the first body and protruding from the surface of the first body to be in close contact with the inner circumferential surface of the heat transfer tube, and the second transport member may include a second body and a plurality of second support rings, the second body being connected to the electro-spark machining device via a second coupling member, the plurality of second support rings being rotatably mounted on the second body and protruding from the surface of the second body to be in close contact with the inner circumferential surface of the heat transfer tube.

[0025] The EDM device driving device may include a connecting rod having a first end connected to the operating shaft via the EDM device transport device and a connecting rod moving device connected to a second end of the connecting rod to provide a force for moving the connecting rod back and forth.

[0026] The electric discharge machining device rotating device may include a rotating part driving member and an operating shaft connecting member, wherein the rotating part driving member is arranged in a housing to provide a force for rotating the operating shaft, and the operating shaft connecting member connects the rotating part driving member to the operating shaft and transmits the rotational force supplied from the rotating part driving member to the operating shaft.

[0027] According to one aspect of another exemplary embodiment, a method for machining an opening in a tube wall of a heat transfer tube is provided, the method comprising: inserting an EDM device connected to an EDM device transport device to form an opening in the tube wall of the heat transfer tube; moving the EDM device inserted into the heat transfer tube to a target position where the opening is to be formed by using the EDM device transport device; rotating the EDM device moved to the target position by using an EDM device rotating device, and bringing the EDM device into close contact with the tube wall of the heat transfer tube by using an EDM device driving device; and forming an opening in the tube wall of the heat transfer tube by using the EDM device in close contact with the tube wall of the heat transfer tube.

[0028] According to one aspect of another exemplary embodiment, a method for removing foreign matter through an opening of a heat transfer tube is provided, the method comprising: inserting an electric discharge machining device connected to an electric discharge machining device transport device to form an opening in the tube wall of the heat transfer tube, and moving the electric discharge machining device to a target position where the opening is to be formed by using the electric discharge machining device transport device; after attaching the electric discharge machining device moved to the target position to the tube wall of the heat transfer tube, forming an opening by electric discharge machining; after forming the opening, removing the electric discharge machining device connected to the electric discharge machining device transport device from the interior of the heat transfer tube; and inserting a foreign matter removal tool into the heat transfer tube using the opening, sucking foreign matter arranged on the outside of the heat transfer tube into the inside of the heat transfer tube, and discharging the foreign matter to the outside of the heat transfer tube.

[0029] The foreign body removal tool may include: a clamping clamp configured to clamp a foreign body; a moving shaft connected to the clamping clamp to move the clamping clamp; a manipulation handle connected to the clamping clamp and operated by an operator to rotate the clamping clamp so that the clamping clamp grasps the foreign body; a camera provided on the clamping clamp for capturing an image of a moving path of the clamping clamp; and a monitor connected to the camera and configured to check the moving path using the image captured by the camera.

[0030] According to one or more exemplary embodiments, foreign matter between heat transfer tubes can be removed without cutting the heat transfer tubes by forming openings in the tube walls of the heat transfer tubes located near the foreign matter. This prevents the heat transfer tubes from being damaged by friction caused by fluid-induced vibrations, which occur when the ends of the heat transfer tubes are not securely supported by the tube support plates. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The above and other aspects will become more apparent from the following description of exemplary embodiments with reference to the accompanying drawings, in which:

[0032] Figure 1 is a cross-sectional view schematically illustrating a steam generator according to the related art;

[0033] Figure 2 yes Figure 1 A front view of a steam generator is shown in FIG;

[0034] Figure 3 is a cross-sectional view schematically illustrating the principle of a steam generator according to the related art;

[0035] Figure 4 is a diagram schematically illustrating an opening processing apparatus for a heat transfer pipe according to an exemplary embodiment;

[0036] Figure 5It is a schematic diagram of the use Figure 4 A diagram showing a process of forming an opening in a bent heat transfer tube using an opening processing device;

[0037] Figure 6 It is a schematic diagram of the use Figure 4 A diagram showing a process of forming an opening in a heat transfer tube using an opening processing device;

[0038] 7A to 7D It is shown in the figure Figure 6 FIG. 5 is a diagram illustrating a discharge electrode on one surface of a discharge body and a shape of an opening formed by the discharge electrode in a heat transfer tube;

[0039] Figures 8A to 8D It is shown in the figure 7A to 7D FIG. 5 is a diagram showing a modified example of a discharge electrode and the shape of an opening of a heat transfer tube formed by the modified discharge electrode;

[0040] Figure 9 is a flow chart illustrating a method for forming an opening in a heat transfer tube according to another exemplary embodiment;

[0041] Figure 10 is a flowchart illustrating a method for removing foreign matter according to another exemplary embodiment; and

[0042] Figure 11 is a diagram schematically illustrating a foreign matter removal tool used in a method for removing foreign matter through an opening of a heat transfer pipe. DETAILED DESCRIPTION

[0043] Various modifications and various embodiments will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement the present disclosure. However, it should be understood that the various embodiments are not intended to limit the scope of the present disclosure to specific embodiments, but rather they should be interpreted as including all modifications, equivalents, and alternatives of the embodiments included in the spirit and scope disclosed herein.

[0044] The terms used herein are for the purpose of describing specific embodiments only and are not intended to limit the scope of the present disclosure. The singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. In the present disclosure, terms such as "comprises", "includes", or "having / containing" should be interpreted as specifying the presence of such features, integers, steps, operations, components, parts, and / or combinations thereof, without excluding the presence of one or more other features, integers, steps, operations, components, parts, and / or combinations thereof or the possibility of adding one or more other features, integers, steps, operations, components, parts, and / or combinations thereof.

[0045] The exemplary embodiments will be described in detail below with reference to the accompanying drawings. It should be noted that throughout the various figures and exemplary embodiments, the same reference numerals represent the same parts. In certain embodiments, detailed descriptions of functions and configurations known in the art may be omitted to avoid obscuring the understanding of the present invention by those of ordinary skill in the art. For the same reason, some components may be exaggerated, omitted, or schematically illustrated in the drawings.

[0046] Figure 4 is a diagram schematically illustrating an opening processing apparatus for a heat transfer pipe according to an exemplary embodiment. Figure 5 It is a schematic diagram of the use Figure 4 A diagram showing a process of forming an opening in a bent heat transfer tube using an opening processing apparatus. Figure 6 It is a schematic diagram of the use Figure 4 A diagram showing a process of forming an opening in a heat transfer tube using an opening processing device. 7A to 7D It is shown in the figure Figure 6 FIG. 4 is a diagram illustrating a discharge electrode on one surface of a discharge body and the shape of an opening formed by the discharge electrode in a heat transfer tube. Figures 8A to 8D It is shown in the figure 7A to 7D ] A diagram illustrating a modified example of the discharge electrode and the shape of the opening of the heat transfer tube formed by the modified discharge electrode.

[0047] Reference Figure 4 8 , an opening machining apparatus 1000 for a heat transfer tube according to an exemplary embodiment includes an EDM device 1100 , an EDM device transporting device 1200 , an EDM device driving device 1300 , and an EDM device rotating device 1400 .

[0048] Reference Figure 4 and Figure 5 The electric discharge machining device 1100 is moved by being inserted into the heat transfer tube 10 of the steam generator used in the nuclear power plant. The electric discharge machining device 1100 is used to form an opening 12 in the tube wall of the heat transfer tube 10 by heat dissipation to remove foreign matter existing between the heat transfer tubes of the heat exchanger in which the heat exchange tube bundle is installed.

[0049] The electric discharge machining device 1100 includes a housing 1110, a discharge body 1120, an operating shaft 1130, and a dielectric supply member 1140. The housing 1110 has a through hole 1112 extending in the radial direction and is inserted into the heat transfer tube 10 so as to extend in the longitudinal direction of the heat transfer tube 10. A support bearing is provided on the circumferential surface of the housing 1110 so as to be in close contact with the inner wall surface of the heat transfer tube 10. The housing 1110 can be spaced apart from the inner wall surface of the heat transfer tube 10 by the support bearing.

[0050] The discharge body 1120 is accommodated in the housing 1110 and movably provided along a through hole 1112 formed in the housing 1110. A discharge electrode 1122 for forming an opening in the heat transfer tube 10 by electric discharge machining is provided on one surface of the discharge body 1120 in close contact with the inner wall surface.

[0051] Reference 7A to 7D Discharge electrodes 1122 are provided on the surface of discharge body 1120 so as to protrude from the surface of discharge body 1120. Discharge electrodes 1122 are formed over the entire area of ​​the body surface facing the inner wall surface of heat transfer tube 10. Since discharge electrodes 1122 are formed over the entire area of ​​the body surface facing the inner wall surface of heat transfer tube 10, openings 12 corresponding to the entire body surface on which discharge electrodes 1122 are formed are formed in corresponding areas of heat transfer tube 10.

[0052] Reference Figures 8A to 8D The discharge electrode 1122 is mounted so as to protrude from the surface of the discharge body 1120. The discharge electrode 1122 is linearly formed to extend along the periphery of the body surface opposite the inner wall surface of the heat transfer tube 10. The discharge electrode 1122 includes an upper frame portion and a lower frame portion. As the upper and lower frame portions of the discharge electrode 1122 contact the inner wall surface of the heat transfer tube 10, an opening 12, including an upper linear opening 12a and a lower linear opening 12b, is formed in the heat transfer tube 10. The electric discharge machining device 1100 is withdrawn from the heat transfer tube 10 through the linear openings 12a and 12b of the heat transfer tube 10, and a clamp is inserted into the heat transfer tube 10 to connect the upper linear opening 12a and the lower linear opening 12b, thereby forming the opening 12 in the heat transfer tube 10. The portion of the heat transfer tube 10 cut to form the opening 12 is removed from the heat transfer tube 10.

[0053] Reference Figures 4 to 6 The operating shaft 1130 is disposed inside the housing 1110 , and the operating shaft 1130 moves in the housing 1110 along the longitudinal direction of the housing 1110 through the EDM device transport device 1300 , thereby causing the discharge body 1120 to move outward or inward through the through hole 1112 .

[0054] The surface of the discharge body 1120 contacting the operating shaft 1130 is inclined to have a downward slope along the longitudinal direction of the housing 1110. In addition, the end of the operating shaft 1130 contacting one surface of the discharge body 1120 has an inclined surface 1130a corresponding to the inclined surface of the discharge body 1120.

[0055] When operating shaft 1130 is moved forward along the longitudinal direction of housing 1110 via EDM transport device 1300, body 1120 with discharge electrode 1122 moves outward from the interior of housing 1110 through through-hole 1112. On the other hand, when operating shaft 1130 is moved backward along the longitudinal direction of housing 1110, discharge electrode 1122 moves from the exterior into housing 1110. The interior of housing 1110 and body 1120 with discharge electrode 1122 are connected by an elastic member. When operating shaft 1130 moves backward under the elastic force of the elastic member, body 1120 with discharge electrode 1122 disposed outside housing 1110 returns to the interior of housing 1110.

[0056] The dielectric supply member 1140 provided in the housing 1110 supplies dielectric (ie, discharge fluid) so that the discharge electrode 1122 provided in the body 1120 can form an opening in the tube wall of the heat transfer tube 10 by electric discharge machining.

[0057] The EDM device 1100 is connected to an EDM device transporting device 1200 for moving the EDM device 1100. The EDM device transporting device 1200 includes a first transporting member 1210, a first engaging member 1220, a second transporting member 1230, a second engaging member 1240, and a connecting cable 1250.

[0058] The first transport member 1210 is provided at the front end portion of the electric discharge machining device 1100, and includes a first body 1211 and a plurality of first support rings 1212. The first transport member 1210 is rotatably connected to the electric discharge machining device 1100 via a first coupling member 1220.

[0059] The first body 1211 is connected to the housing 1110 of the electric discharge machining device 1100 via the first coupling member 1220, and the plurality of first support rings 1212 are rotatably mounted on the first body 1211. The first support rings 1212 mounted on the first body 1211 protrude from the surface of the first body 1211 and are in close contact with the inner circumferential surface of the heat transfer pipe 10, so that the first body 1211 can easily move in the heat transfer pipe 10.

[0060] The second transport member 1230 is provided at the rear end of the EDM device 1100 and includes a second body 1231 and a plurality of second support rings 1232. The second transport member 1230 is rotatably connected to the EDM device 1100 via a second coupling member 1240, and the operating shaft 1130 is connected to the second transport member 1230 via the EDM device rotating device 1400.

[0061] The second body 1231 is connected to the operating shaft 1130 of the EDM device 1100 via the second coupling member 1240 and the EDM device rotating device 1400 , and the plurality of second support rings 1232 are rotatably mounted on the second body 1231 .

[0062] The second supporting ring 1232 mounted on the second body 1231 protrudes from the surface of the second body 1231 and is in close contact with the inner circumferential surface of the heat transfer pipe 10 , so that the second body 1231 can easily move in the heat transfer pipe 10 .

[0063] Since the electric discharge machining device 1100 moves in a state in which the first coupling member 1220 and the second coupling member 1240 are respectively connected to the front end portion and the rear end portion of the electric discharge machining device 1100, the electric discharge machining device 1100 can easily move in the heat transfer tube 10 despite the curved shape of the heat transfer tube 10. The first body 1211 and the second body 1231 both have a cylindrical shape.

[0064] The first end of the second transport member 1240 is connected to the operating shaft 1130 via the EDM rotating device 1400, and the second end of the second transport member 1240 is connected to the connecting cable 1250. The connecting cable 1250 is used to transmit power for moving the second transport member 1240. For example, an operator grasps one end of the connecting cable 1250, which is connected to the second end of the second transport member 1240, and pushes the second connecting cable 1250 to move the EDM transport device 1200 into the heat transfer tube 10. When the connecting cable 1250 is pushed, the second transport member 1240 moves within the heat transfer tube 10, and thus the first transport member 1210 also moves within the heat transfer tube 10. Furthermore, the EDM device 1100 also moves within the heat transfer tube 10.

[0065] The EDM device 1100 is connected to an EDM device driver 1300 that supplies power, so that the EDM device 1100 is in close contact with the wall of the heat transfer tube 10. Since the EDM device driver 1300 supplies power, the discharge body 1120 having the discharge electrode 1122 of the EDM device 1100 is in close contact with the wall of the heat transfer tube 10, so that the opening 12 can be formed in the wall of the heat transfer tube 10.

[0066] The EDM driving device 1300 includes a connecting rod 1310 and a connecting rod moving member. The first end of the connecting rod 1310 is connected to the operating shaft 1130 of the EDM device 1100 via the EDM transport device 1200, and the second end of the connecting rod 1310 is connected to the connecting rod moving member. The connecting rod moving member provides the power for linearly moving the connecting rod 1310 forward and backward. As the connecting rod 1310 moves back and forth under the force of the connecting rod moving member, a discharge body 1120 equipped with a discharge electrode 1122 passes through the through-hole 1112 of the housing 1110, contacting or separating from the wall of the heat transfer tube 10. When the discharge body 1120 contacts the tube wall, an opening 12 is formed, and the discharge body 1120 separates from the tube wall and moves inward to be disposed within the housing 1110. The connecting rod 1310 is connected to the second transport member 1230 of the EDM transport device 1200 via a connecting cable 1250.

[0067] The EDM device 1100 is rotated in the circumferential direction in the heat transfer tube 10 by the EDM device rotating device 1400 , which provides a force for rotating the EDM device 1100 in the circumferential direction of the heat transfer tube 10 .

[0068] The electric discharge machining device rotating device 1400 includes a rotating part driving member 1410 and an operating shaft connecting member 1420. The rotating part driving member 1410 is disposed in the housing 1110 and is used to provide a force for rotating the operating shaft 1130. The rotating part driving member 1410 is disposed corresponding to the dielectric supply member 1140, wherein the operating shaft 1130 is interposed between the rotating part driving member and the dielectric supply member.

[0069] The operating shaft connecting member 1420 connects the rotating section driving member 1410 to the operating shaft 1130, and transmits the rotational force supplied from the rotating section driving member 1410 to the operating shaft 1130. When the operating shaft 1130 is rotated by the rotational force supplied from the rotating section driving member 1410, the electric discharge machining device 1100 rotates in the circumferential direction in the heat transfer tube 10.

[0070] The EDM device 1100 is moved by the EDM device transport device 1200 to the location where the opening 12 is to be formed in the heat transfer tube 10. The EDM device 1100 is then rotated by the EDM device rotation device 1400 so that it faces the inner surface of the heat transfer tube 10. The EDM device drive device 1300 then brings the discharge body 1120 of the EDM device 1100 into close contact with the inner surface of the heat transfer tube 10. In this state, the discharge electrode 1122 forms a linear or planar opening 12 in the heat transfer tube 10.

[0071] Figure 9 is a flow chart illustrating a method for forming an opening in a heat transfer tube according to another exemplary embodiment. Figure 9 The machining method for forming an opening in a heat transfer tube includes an EDM device inserting step S10, an EDM device moving step S20, an EDM device rotating and attaching step S30, and an opening machining step S40.

[0072] Reference Figure 4 and Figure 9 In the EDM device insertion step S10, an opening machining apparatus 1000 for a heat transfer tube is used, which includes an EDM device 1100, an EDM device transport device 1200, an EDM device driving device 1300, and an EDM device rotating device 1400. In step S10, the EDM device 1100 is inserted into the heat transfer tube 10, which is the machining target for forming the opening 12 therein. For example, the EDM device 1100 connected to the EDM device transport device 1200 is inserted into the heat transfer tube 10 to perform EDM.

[0073] The electric discharge machining device 1100 includes a housing 1110, a discharge body 1120, an operating shaft 1130, and a dielectric supply member 1140. Since the housing 1110, the discharge body 1120, the operating shaft 1130, and the dielectric supply member 1140 are the same as those described in the above embodiment, redundant descriptions thereof will be omitted.

[0074] In the EDM device moving step S20 , the EDM device 1100 is moved to a target location where the opening 12 is to be formed in the heat transfer tube 10 by using the EDM device transport device 1200 .

[0075] The EDM device transport device 1200 is used to move the EDM device 1100. The EDM device transport device 1200 includes a first transport member 1210, a first coupling member 1220, a second transport member 1230, a second coupling member 1240, and a connecting cable 1250. For example, an operator uses the connecting cable 1250 to move the first transport member 1210, the first coupling member 1220, the second transport member 1230, and the second coupling member 1240 within the heat transfer tube 10, thereby allowing the EDM device 1100, connected to the first coupling member 1220 and the second coupling member 1240, to move within the heat transfer tube 10. An endoscope device may be used in the EDM device movement step S20. After the endoscope device is delivered to the target site via the second end of the heat transfer tube 10 to form the opening 12, the EDM device 1100 is inserted into the heat transfer tube 10 via the first end and transported to the target site where the endoscope device is located. By using the endoscope device, the electric discharge machining device 1100 can be accurately moved to an accurate target portion. Since the first transport member 1210, the first coupling member 1220, the second transport member 1230, the second coupling member 1240, and the connecting cable 1250 of the electric discharge machining device transport device 1200 are the same as those of the opening machining apparatus 1000 according to the above embodiment, redundant description thereof will be omitted.

[0076] In the EDM device rotation and attachment step S30, the EDM device 1100, which is moved to the target position by the EDM device transportation device 1200, is rotated to face the inner surface of the tube wall of the heat transfer tube 10 by the EDM device rotation device 1400, and is in close contact with the inner surface of the tube wall of the heat transfer tube 10 at the target position by the EDM device driving device 1300.

[0077] The EDM rotating device 1400 for rotating the EDM 1100 includes a rotating portion driving member 1410 and an operating shaft connecting member 1420. The rotating portion driving member 1410 is provided in the housing 1110 to provide a force for rotating the operating shaft 1130.

[0078] The operating shaft connecting member 1420 connects the rotating portion driving member 1410 to the operating shaft 1130 of the electric discharge machining device 1100, and transmits the rotational force supplied from the rotating portion driving member 1410 to the operating shaft 1130. When the operating shaft 1130 is rotated by the rotational force supplied from the rotating portion driving member 1410, the operating shaft 1130 of the electric discharge machining device 1100 rotates in the circumferential direction in the heat transfer tube 10.

[0079] The EDM driving device 1300, used to attach the EDM device 1100 to the wall of the heat transfer tube 10 in which the opening 12 is to be formed, includes a connecting rod 1310 and a connecting rod moving member. The first end of the connecting rod 1310 is connected to the operating shaft 1130 via the EDM transport device 1200, and the second end of the connecting rod 1310 is connected to the connecting rod moving member. The connecting rod moving member provides the operating force for linearly moving the connecting rod 1310 forward and backward. As the connecting rod 1310 moves back and forth under the force provided by the connecting rod moving member, a discharge body 1120 equipped with a discharge electrode 1122 passes through the through-hole 1112 of the housing 1110 to contact or separate from the wall of the heat transfer tube 10. When the discharge body 1120 contacts the tube wall, the opening 12 is formed. The discharge body 1120 then separates from the tube wall and moves inward to be disposed within the housing 1110.

[0080] In the opening processing step S40, the electric discharge machining device 1100 in close contact with the tube wall of the heat transfer tube 10 is electrically driven to form the opening 12 in the tube wall of the heat transfer tube 10. According to the shape of the discharge electrode 1122, such as 7A to 8D As shown, heat transfer tube 10 is surface machined or linearly machined to form upper linear opening 12a and lower linear opening 12b. After upper opening 12a and lower opening 12b are formed, electric discharge machining device 1100 is removed from heat transfer tube 10. Next, a clamp is inserted into heat transfer tube 10 to connect upper linear opening 12a and lower linear opening 12b, thereby forming opening 12 in the tube wall of heat transfer tube 10. During the formation of opening 12, debris from heat transfer tube 10 is removed from heat transfer tube 10.

[0081] Figure 10 is a flowchart illustrating a method for removing foreign matter according to another exemplary embodiment. Figure 11 is a diagram schematically illustrating a foreign matter removal tool used in a method for removing foreign matter through an opening of a heat transfer pipe.

[0082] Reference Figure 10 The method for removing foreign matter through the opening of the heat transfer tube includes an EDM device inserting and moving step S100, a heat transfer tube opening processing step S200, an EDM device removing step S300, and a foreign matter removing step S400.

[0083] Reference Figure 10 and Figure 11In the EDM device insertion and movement step (S100), an opening machining apparatus 1000 for a heat transfer tube is used, which includes an EDM device 1100, an EDM device transport device 1200, an EDM device driving device 1300, and an EDM device rotating device 1400. In step S100, the EDM device 1100 is inserted into the heat transfer tube 10, which is the target for machining the opening 12 therein. For example, the EDM device 1100, connected to the EDM device transport device 1200, is inserted into the heat transfer tube 10 to perform EDM machining. Since the configurations of the EDM device 1100 and the EDM device transport device 1200 are the same as those in the above-described embodiment, redundant description thereof will be omitted.

[0084] In the opening machining step S200 , electric power is supplied to the electric discharge machining device 1100 in close contact with the tube wall of the heat transfer tube 10 to form the opening 12 in the tube wall of the heat transfer tube 10 .

[0085] Preferably, the EDM device rotation and attachment step is performed before starting the opening processing step S200. Here, the EDM device rotation and attachment step is the same as the step according to Figure 9 The EDM device rotating and attaching step S30 of the heat transfer tube opening machining method of the embodiments is substantially the same, and redundant description thereof will be omitted.

[0086] In the EDM device removal step S300, the EDM device 1100 and the EDM device transporting device 1200 connected to the EDM device 1100 located in the heat transfer tube 10 are pulled out of the heat transfer tube 10. In the EDM device removal step S300, the operator can unplug the connection cable 1250 connected to the EDM device 1100 to remove the EDM device 1100 connected to the connection cable 1250 from the heat transfer tube 10.

[0087] In the foreign matter removing step S400 , the foreign matter removing tool 100 collects foreign matter in the heat transfer tube 10 and discharges the collected foreign matter to the outside of the heat transfer tube 10 .

[0088] The foreign matter removal tool 100 is inserted into the heat transfer pipe 10 to pull foreign matter deposited on the outside of the heat transfer pipe 10 into the heat transfer pipe 10 on one side of the heat transfer pipe 10, and then discharge the foreign matter from the inside of the heat transfer pipe 10 to the outside on the other side of the heat transfer pipe 10. The foreign matter removal tool 100 for removing foreign matter may include a clamping jaw 110, a moving shaft 120, and a manipulation handle 130.

[0089] The clamping pliers 110 are used to clamp foreign matter deposited on the outside of the heat transfer pipe 10 through the opening 12. The clamping pliers 110 are connected to a moving shaft 120 so that the clamping pliers 110 can move in the heat transfer pipe 10. The clamping pliers 110 are connected to a manipulation handle 130. An operator manipulates the manipulation handle 130 to move the moving shaft 120 and rotate the clamping pliers 110.

[0090] The clamping forceps 110 may be provided with a camera. When the clamping forceps 110 moves and captures a foreign object to be clamped by the clamping forceps 110, the camera captures an image of the object in front of the clamping forceps 110. The image captured by the camera is transmitted to the monitor, allowing the operator to remove the foreign object through the opening 12 while monitoring the movement of the clamping forceps 110 in the image captured by the camera.

[0091] Therefore, foreign matter attached to the heat transfer tubes 10 can be removed without disassembling all of the heat transfer tubes 10. That is, according to one or more exemplary embodiments, by forming the openings 12 in the tube wall of one heat transfer tube 10, foreign matter deposited between the heat transfer tube 10 and another heat transfer tube 10 through the openings 12 can be removed. Therefore, the end portions of the heat transfer tubes 10 can be prevented from being worn due to friction between the end portions of the heat transfer tubes 10 and adjacent objects, wherein friction that may occur due to vibration caused by the fluid when the end portions of the heat transfer tubes 10 are not supported by the tube support plates can be prevented.

[0092] Although one or more exemplary embodiments have been described with reference to the accompanying drawings, it will be understood by those skilled in the art that various modifications and changes in form and details may be made in the present disclosure without departing from the spirit and scope defined by the appended claims. Therefore, the description of the exemplary embodiments should be considered in a descriptive sense only and not to limit the scope of the claims, and many alternatives, modifications and variations will be apparent to those skilled in the art.

Claims

1. An opening processing device for a heat transfer tube, the device comprising: an electric discharge machining device inserted into the heat transfer tube and configured to form the opening in the tube wall of the heat transfer tube by electric sparks; an EDM device transport device connected to the EDM device and configured to transport the EDM device; an EDM device driving device connected to the EDM device and configured to provide a force for bringing the EDM device into close contact with a tube wall surface of the heat transfer tube; as well as an EDM rotating device configured to provide a force for rotating the EDM in a circumferential direction of the heat transfer unit in the heat transfer tube, Wherein, the EDM device transportation device includes: a first transport member disposed at a front end portion of the electrical discharge machining device; a first engaging member rotatably connecting the first transport member and the EDM device; a second transport member disposed at a rear end portion of the electrical discharge machining device; a second engaging member that rotatably connects the second transport member and the electric discharge machining device; and a connecting cable that transmits force to move the second transport member, The electrospark machining device comprises: a housing having a through hole extending in a radial direction, the housing being inserted into the heat transfer tube and extending in a longitudinal direction of the heat transfer tube; a discharge body disposed in the housing, the discharge body being movably disposed through the through hole and provided with a discharge electrode on a first surface facing the tube wall surface of the heat transfer tube; an operating shaft disposed in the housing, the operating shaft being moved in the longitudinal direction of the housing by the electric discharge machining device driving device and being configured to move the discharge body to the outside through the through hole; and a dielectric supply member disposed in the housing and configured to supply dielectric to the discharge electrode of the discharge body, Wherein, the rotating device of the electric spark machining device includes: a rotating portion driving member disposed in the housing to provide a force for rotating the operating shaft; and An operating shaft connecting member connects the rotating portion driving member to the operating shaft and transmits a rotational force supplied from the rotating portion driving member to the operating shaft.

2. The device according to claim 1, wherein The second surface of the discharge body in close contact with the operating shaft is inclined to have a downward inclined portion in the direction in which the operating shaft moves, and The first end portion of the operating shaft in close contact with the second surface of the discharge body has an inclined surface corresponding to the inclined second surface of the discharge body.

3. The device according to claim 2, wherein The discharge electrode is provided on the first surface of the discharge body to protrude from the first surface, and is provided over the entire surface of the first surface to contact the tube wall surface of the heat transfer tube for surface processing.

4. The device according to claim 2, wherein The discharge electrodes are provided on the first surface of the discharge body to protrude therefrom, and are provided at peripheries of upper and lower portions of the first surface to contact the tube wall surface of the heat transfer tube for linear processing.

5. The apparatus according to claim 1, wherein The first transport member includes a first body connected to the electric discharge machining device via the first coupling member, and a plurality of first support rings rotatably mounted on the first body and protruding from a surface of the first body to closely contact the inner peripheral surface of the heat transfer tube. The second transport member includes a second body connected to the electric discharge machining device via the second coupling member, and a plurality of second support rings rotatably mounted on the second body and protruding from a surface of the second body to closely contact the inner circumferential surface of the heat transfer tube.

6. The apparatus according to claim 1, wherein The electric spark machining device driving device includes: a connecting rod having a first end connected to the operating shaft via the EDM device transport device; and A connecting rod moving device is connected to the second end portion of the connecting rod to provide a force for moving the connecting rod back and forth.

7. A method of forming an opening in a wall of a heat transfer tube, the method comprising: inserting an EDM device connected to an EDM device transport device to form the opening in the wall of the heat transfer tube; moving the electric discharge machining device inserted into the heat transfer tube to a target location where the opening is to be formed by using the electric discharge machining device transport device; Using an EDM rotating device to rotate the EDM moved to the target location, and using an EDM driving device to bring the EDM into close contact with the wall of the heat transfer tube; as well as forming an opening in the wall of the heat transfer tube by using the electric discharge machining device in close contact with the wall of the heat transfer tube, Wherein, the EDM device transportation device includes: a first transport member disposed at a front end portion of the electrical discharge machining device; a first engaging member rotatably connecting the first transport member and the EDM device; a second transport member disposed at a rear end portion of the electrical discharge machining device; a second engaging member that rotatably connects the second transport member and the electric discharge machining device; and a connecting cable that transmits force to move the second transport member, The electrospark machining device comprises: a housing having a through hole extending in a radial direction, the housing being inserted into the heat transfer tube and extending in a longitudinal direction of the heat transfer tube; a discharge body disposed in the housing, the discharge body being movably disposed through the through hole and provided with a discharge electrode on a first surface facing the tube wall surface of the heat transfer tube; an operating shaft disposed in the housing, the operating shaft being moved in the longitudinal direction of the housing by the electric discharge machining device driving device and being configured to move the discharge body to the outside through the through hole; and a dielectric supply member disposed in the housing and configured to supply dielectric to the discharge electrode of the discharge body, Wherein, the rotating device of the electric spark machining device includes: a rotating portion driving member disposed in the housing to provide a force for rotating the operating shaft; and An operating shaft connecting member connects the rotating portion driving member to the operating shaft and transmits a rotational force supplied from the rotating portion driving member to the operating shaft.

8. The method according to claim 7, wherein: The second surface of the discharge body in close contact with the operating shaft is inclined to have a downward inclined portion in the direction in which the operating shaft moves, and The first end portion of the operating shaft in close contact with the second surface of the discharge body has an inclined surface corresponding to the inclined second surface of the discharge body.

9. The method according to claim 8, wherein The discharge electrode is provided on the first surface of the discharge body to protrude from the first surface, and is provided over the entire surface of the first surface to contact the tube wall surface of the heat transfer tube for surface processing.

10. The method according to claim 8, wherein The discharge electrodes are provided on the first surface of the discharge body to protrude therefrom, and are provided at peripheries of upper and lower portions of the first surface to contact the tube wall surface of the heat transfer tube for linear processing.

11. The method according to claim 7, wherein: The first transport member includes a first body connected to the electric discharge machining device via the first coupling member, and a plurality of first support rings rotatably mounted on the first body and protruding from a surface of the first body to closely contact the inner peripheral surface of the heat transfer tube. The second transport member includes a second body and a plurality of second support rings, the second body is connected to the electrospark machining device via the second coupling member, the plurality of second support rings are rotatably mounted on the second body and protrude from the surface of the second body, and are configured to be in close contact with the inner circumferential surface of the heat transfer tube.

12. The method according to claim 7, wherein: The electric spark machining device driving device includes: a connecting rod having a first end connected to the operating shaft via the EDM device transport device; and A connecting rod moving device is connected to the second end portion of the connecting rod to provide a force for moving the connecting rod back and forth.

13. A method of removing foreign matter through an opening of a heat transfer pipe by using the apparatus according to any one of claims 1 to 6, the method comprising: inserting the EDM device connected to the EDM device transport device to form the opening in the tube wall of the heat transfer tube by EDM, and moving the EDM device to a target position where the opening is to be formed by using the EDM device transport device; After the electric discharge machining device is moved to the target portion and attached to the tube wall of the heat transfer tube, the opening is formed by electric discharge machining; After forming the opening, removing the EDM device connected to the EDM device transport device from the interior of the heat transfer tube; as well as inserting a foreign matter removal tool into the heat transfer pipe having the opening, sucking foreign matter disposed outside the heat transfer pipe into the inside of the heat transfer pipe using the opening, and discharging the foreign matter to the outside of the heat transfer pipe. The electric discharge machining device includes: a housing having a through hole extending in a radial direction, the housing being inserted into the heat transfer tube and extending in a longitudinal direction of the heat transfer tube; a discharge body disposed in the housing, the discharge body being movably disposed through the through hole and provided with a discharge electrode on a first surface facing the tube wall surface of the heat transfer tube; an operating shaft disposed in the housing, the operating shaft being moved in the longitudinal direction of the housing by the electric discharge machining device driving device and being configured to move the discharge body to the outside through the through hole; and a dielectric supply member disposed in the housing and configured to supply dielectric to the discharge electrode of the discharge body, Wherein, the foreign body removal tool comprises: a clamping forceps configured to clamp the foreign object; a moving shaft connected to the clamping jaws to move the clamping jaws; a manipulation handle connected to the clamping forceps and manipulated by an operator to rotate the clamping forceps so that the clamping forceps grasp the foreign object; a camera disposed on the clamping jaws for capturing images of a movement path of the clamping jaws; and A monitor is connected to the camera and configured to inspect the movement path using the image captured by the camera.

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