KR101178698B1 - Ultrasonic Cleaning Equipment and Method for Heat Exchanger - Google Patents

Abstract

The present invention relates to an apparatus and a cleaning method for cleaning a heat exchanger by an ultrasonic element mounted on a mobile robot. The present invention includes a mobile robot having a rail surrounding a surface of a heat exchanger and a holder movably mounted on the rail, and having a holder on which an ultrasonic element is mounted. It includes an ultrasonic element for cleaning.

Therefore, the ultrasonic cleaning efficiency is increased by the arrangement of the efficient ultrasonic elements, and a thinner detergent can be used, thereby reducing the waste liquid treatment cost.

Description

Ultrasonic Cleaning Equipment and Method for Heat Exchanger

The present invention relates to a heat exchanger ultrasonic cleaning device and a cleaning method for removing foreign substances such as sludge deposited on the heat exchanger tube or tube in the heat exchanger, and more particularly, an apparatus and method for removing foreign substances by placing ultrasonic elements on the surface of the heat exchanger. It is about.

In the case of a general heat exchanger, various particles agglomerate on the surface of the heat exchange tube to form scale or sludge, which reduces heat exchange efficiency, which leads to waste of energy and corrosion of the heat exchanger, which shortens the life cycle. Inflicted. Particularly in the case of nuclear power plants, metallic particles coming out of the nuclear power plant components are collected in a heat exchanger of a special environment called a steam generator, and sludge is formed. This leads to erosion and also leads to corrosion of the steam generator, which is the boundary between radiation and non-radioactive fluids, shortening the steam generator life cycle, resulting in huge budget losses.

Therefore, in general, in the case of a large heat exchanger, sludge or scale deposited in the heat exchanger is periodically removed. There are two cleaning methods. In this way, high-pressure water is sprayed to remove the deposited sludge and foreign substances or to clean it with a high concentration of chemical cleaner. Among them, the sludge removal method using the high pressure water injection method is a device for removing the sludge deposited on the top of the pipe plate (pipe support plate) inside the steam generator, which is a heat exchanger of a nuclear power plant. The robot moves and a large number of tubes are sprayed with high pressure water to clean the heat pipes arranged in a high density. This prevents the flow of water injected at high pressure by the heat pipes, which prevents the high pressure water from moving far between the heat pipes. The further away from the location, the lower the efficiency, and the sludge removed from the heat pipes or tube supports accumulate again.

In addition, cleaning with a high concentration of chemical cleaners uses a high concentration of chemicals, so that the inside of the heat exchanger can be cleaned. However, the cost of the cleaning agent is high and the concentration of the waste liquid generated after cleaning is high. In addition, in the case of steam generators, which are heat exchangers for nuclear power plants, high concentrations of chemical cleaners do not frequently perform chemical cleaning because they also affect the material integrity of the heat exchanger. Recently, in order to solve these problems, chemical cleaning is performed using a low concentration of chemical regulators, which does not yield satisfactory results in cleaning once as high concentration chemical cleaning.

Ultrasonic cleaning is widely used in the general industry, and it is common to see that ultrasonics are used to clean glasses at an optician. This is due to the cavitation by ultrasonic waves. When the positive and negative pressure sections pass through the device vibrating by the ultrasonic wave, small bubbles called cavities are generated through vaporization due to pressure drop. Is generated, and the bubbles repeatedly grow through the positive pressure section and the negative pressure section, and when exceeded a certain radius, the bubbles are exploded and dissipated into the bubbles. The sludge or foreign substances are removed from the object to be cleaned by the shock wave. The debris is removed and the debris is crushed to perform the cleaning.

This phenomenon is sometimes applied to the steam generator of nuclear power plant, which is a heat exchanger of large structure. By induction, the inside of the steam generator is cleaned. However, since the device welds the circular metal rod to the steam generator tube, it is impossible to move the ultrasonic element, which makes it difficult to diversify the ultrasonic wave propagation start point. In addition, in the case of the nuclear power plant steam generator, if a circular metal rod is installed by welding the steam generator tube plate, this has a problem that the design change of the steam generator should be examined in advance.

SUMMARY OF THE INVENTION An object of the present invention is to provide an apparatus and method for cleaning a heat exchanger by an ultrasonic element mounted on a movable mobile robot.

In order to achieve the above object, the present invention includes a mobile robot having a holder surrounding the surface of the heat exchanger and movable on the rail, the holder having an ultrasonic element.

The ultrasonic element includes a technique of cleaning the inside of the heat exchanger by emitting an ultrasonic wave inside the heat exchanger. The rail includes a band surrounding the surface of the heat exchanger, a gear tooth bolted to the belt and the gear tooth has a fastening hole and the gear teeth are connected by a band inserted through the fastening hole and fixed by the fastening means. The mobile robot includes a bracket for coupling the mobile robot to the rail, an integrated cable line including a cable required for operation of the mobile robot, and a holder for coupling the mobile robot to the heat exchanger.

According to the ultrasonic element mounted on the mobile robot for cleaning the heat exchanger according to the present invention, the ultrasonic wave propagation starting point due to the welding of the circular metal rod is fixed, so that a plurality of ultrasonic elements can be efficiently removed in order to remove a section in which the cleaning is not performed well. It can be arranged to change the specific pattern caused by the superposition and attenuation by the ultrasonic wave to increase the efficiency of cleaning. In addition, the ultrasonic cleaning efficiency is increased due to the efficient arrangement of the ultrasonic elements, so that a thinner ultrasonic cleaner can be used, thereby lowering the concentration of the waste liquid generated after the ultrasonic cleaning, thereby reducing the waste liquid treatment cost, and in particular, the nuclear power plant steam generator. In the case of rinsing wastes, the volume of low- and low-level radioactive waste, which is left over from the effluent treatment, can be reduced.

Hereinafter, the same reference numerals will be described in detail with reference to the accompanying drawings with reference to the same components preferred embodiments of the present invention. The terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary meanings and should be construed in accordance with the technical meanings and concepts of the present invention.

1 is a perspective view illustrating a state in which a heat exchanger ultrasonic cleaning device is uniformly cleaned for a steam generator of a nuclear power plant according to an embodiment of the present invention. Referring to Figure 1, the ultrasonic cleaning apparatus of the present invention includes a rail 200, a mobile robot 300 equipped with ultrasonic generating means.

The steam generator 100 includes a heat transfer tube (not shown) by the steam generator shell 101, a tube plate 102 for fixing a plurality of heat transfer tubes. The ultrasonic heat exchanger cleaning device is mounted on the surface of the steam generator 100 to remove foreign substances present in the heat transfer tube inside the steam generator 100.

The rail 200 is fixed to surround the surface of the steam generator 100, and a plurality of mobile robots 300 are included in each of the rails 200 in pairs of two rows. It can be installed and used to clean the heat exchanger 100.

The mobile robot 300 may be mounted on an ultrasonic wave generating means to move on the rail 200 attached to the surface of the steam generator to clean the steam generator 100.

FIG. 2 is a perspective view showing the rail of FIG. 1. FIG. Referring to FIG. 2, the rail is composed of a metal strip 220 and a gear tooth 210. The rail 200 has a flexible property to surround the steam generator surface to provide a moving path of the mobile robot, it may be made of a metal material to correspond to the external environment. The gear tooth 210 has a screw hole 240, the metal strip 220 is inserted through the fastening hole 230 to connect the gear teeth 210. The gear teeth 210 connected by the metal band 220 are fastened to the metal band 220 by fastening the screw hole 240 of the gear tooth 210 with a bolt or the like, so that the rail 200 is formed. . As an embodiment of the present invention, the fastening hole 230 preferably has a rectangular shape.

As a preferred embodiment of the present invention by adding a fastening means to the metal strip 220 can be fixed to the gear tooth 210 firmly to the metal strip 220, the rail 200 is flexible wheel In order to surround the steam generator surface and firmly tighten the metal strip 220, the rail 200 may be installed in one set so that the rail 200 does not move, and several sets may be installed as necessary.

3 is a perspective view showing the mobile robot of FIG. Referring to FIG. 3, the mobile robot includes a bracket 310, an integrated cable line 320, and a holder 330.

The bracket 310 stabilizes the mobile robot 300 so as not to rotate and serves as a leg in which the mobile robot 300 can freely move on the rail. As a preferred embodiment of the present invention, the coupling portion with the rail may have a symmetrical shape having left and right ends having a c-shape.

The integrated cable line 320 may prevent the interference of the path of the mobile robot 300 by integrating various cables and supply lines necessary for the operation of the mobile robot 300.

The holder 330 may use an electromagnet to bond the mobile robot 300 to a steam generator, and includes ultrasonic generating means. As the ultrasonic wave generating means, an ultrasonic element 340 made of a single module may be used. As an embodiment of the present invention, the ultrasonic element 340 not only needs a power source for operation, but also includes cooling means because a considerable amount of heat is generated.

4A is a perspective view illustrating the bracket of FIG. 3 in detail. Referring to FIG. 4A, the bracket 310 includes a servo motor 311, a sprocket 312, a rolling bearing 313, and a ball bearing 314.

The servo motor 311 is a driving unit for providing a power to move the mobile robot on the rail. As a preferred embodiment of the present invention, the servo motor 311 may include an encoder 315, and when the position of the mobile robot is notified to the operation unit, the operation unit may remotely adjust the mobile robot and automatically position the robot at a desired position. have. Therefore, there is a feature that can be cleaned even where the working time of the operator, such as a radiation zone is limited or impossible.

The sprocket 312 is an energy transmission device for transmitting the power of the servo motor 311 to the rail gear teeth to move the mobile robot.

The rolling bearing 313 minimizes friction with the rail and prevents the mobile robot from being separated from the rail.

The ball bearing 314 minimizes the friction between the mobile robot and the steam generator surface, and serves to balance the round surface of the steam generator.

FIG. 4B shows the rolling bearing 313 at the distal end of the bracket of FIG. 3 attached to the rail 200. The rolling bearings 313 at both ends of the c-shaped ends of the bracket 310 are in contact with the rails 200, and the rolling bearings 313 extend over the grooves of the gear teeth (250 in FIG. 2) to separate from the rails. Can be prevented.

Figure 5 is a perspective view showing an integrated cable line required for the operation of the mobile robot as an embodiment of the present invention. Referring to FIG. 5, the integrated cable line 320 is a power and signal supply line 510 of an ultrasonic element, a servo motor cable 520 for driving a servomotor, a coolant line 530 of an ultrasonic element, and an electromagnet holder. Coils (not shown), compressed air supply lines 540, and tight liquid supply lines (not shown).

The cooling water line 530 uses a high power ultrasonic element because a large structure of the steam generator requires a lot of ultrasonic energy, the high power ultrasonic element generates a large amount of heat, so the ultrasonic element is wound around the cooling element Play a role.

Figure 6a is a perspective view showing a holder that is a portion including a ultrasonic element bonded to the steam generator. Referring to FIG. 6A, the holder 330 includes an ultrasonic element 340, a compressed air supply line 640, and a close liquid supply line 550. The holder 330 is an apparatus for coupling the mobile robot to the steam generator including the ultrasonic element 340, may use an electromagnet including a coil 610 for coupling to the steam generator. When bolting the ultrasonic element 340 to the holder 330, it is preferable that the relatively large and heavy ultrasonic element 340 is strongly adhered to the steam generator, so that the electromagnet holder 330 is wound around a relatively thick coil 610 It can be configured to have magnetic force.

The compressed air supply line 540 penetrates a part of the electromagnet holder 330 and extends to the distal end of the ultrasonic element 340 to remove foreign substances that may exist on the surface of the steam generator with compressed air.

The tight liquid supply line 550 penetrates a part of the electromagnet holder 330 and extends to the distal end of the ultrasonic element 340 and is cleaned by the compressed air fired through the compressed air supply line 540. It serves to supply the contact liquid composed of special components so that the ultrasonic waves can be propagated well.

6b is a plan view from above of the holder; Referring to FIG. 6B, the contact portion between the holder 330 and the steam generator is recessed to match the radius of the steam generator to increase the adhesion between the holder 330 and the steam generator. In addition, the end of the ultrasonic element 340 may be designed using a negative tolerance such that the end of the ultrasonic element 340 protrudes from the contact portion of the electromagnet holder 330 so that the ultrasonic element 340 is very strongly in contact with the steam generator.

7 is a perspective view showing a mobile robot case which is an embodiment of the present invention. Referring to FIG. 4, the mobile robot case includes various cables and supply lines such as an ultrasonic element, a power supply and a signal supply line of an ultrasonic element, a coolant line of an ultrasonic element, a coil of an electromagnet holder, a compressed air supply line, a contact liquid supply line, and the like. Serves to protect the

Figure 8a is a perspective view showing the structure of a steam generator according to an embodiment of the present invention. Referring to FIG. 8A, the steam generator 100 includes a steam generator shell 101, a heat transfer tube 103, a tube plate 102, a fixing rod 105, and a hand tool 104.

Figure 8b is a flow chart showing a steam generator cleaning method using a steam generator ultrasonic cleaning apparatus of an embodiment of the present invention. Referring to FIG. 8, a method of cleaning a steam generator using an ultrasonic cleaning device includes a first step of installing a rail on an outer surface of the steam generator, a second step of placing a mobile robot having an ultrasonic element on the rail, and the ultrasonic wave. And generating a ultrasonic wave by an element to clean the inside of the steam generator.

Agglomerated hard sludge is deposited on the upper end of the tube plate 102 which is a steam generator, so that ultrasonic sludge is directly transmitted to the tube plate 102 in order to remove the sludge, and it is applicable to remove the sludge on the upper part of the tube plate 102. 103) In the case of sludge deposited on the surface of the steam generator can be cleaned by installing the ultrasonic cleaning equipment to surround the heat transfer tube 103, not the tube plate 102 portion.

In the first step (s10) to assemble the rail by fastening the gear teeth and the metal band bolts, the assembled rail is installed around the circumference of the steam generator to tighten tightly so as not to flow down.

In the second step (s20), the mobile robot is mounted on the installed rail, and the rolling bearing is inserted into the groove of the gear cog so that the mobile robot is not separated from the rail and the gear of the servo cog and the gear of the sprocket are aligned. Install to receive. In this way, an appropriate number of mobile robots equipped with sound wave elements may be installed according to the size of the steam generator. In the case of the steam generator of the Korean standard nuclear power plant, it is preferable to install several ultrasonic cleaning equipments over the steam generator in the six-stage heat pipe support layer having the highest amount of sludge deposited on the heat pipe 103.

In the arrangement of the ultrasonic cleaning equipment, the ultrasonic cleaning equipment heat installed in the steam generator shell 101 and the ultrasonic cleaning equipment heat installed in the steam generator tube plate 102 can be divided. The ultrasonic cleaning equipment installed in the steam generator shell 101 aims to remove relatively soft ductile sludge deposited on the surface of the steam generator heat pipe 103, and the ultrasonic cleaning equipment installed in the steam generator tube plate 102 is mainly a tube plate 102. The main purpose is to remove the relatively hard hard sludge deposited on the top and the heat transfer tube 103 is forcibly fitted on the tube plate 102 so that the ultrasonic energy propagated to the tube plate 102 is transferred to the heat transfer tube 103 and is incidentally transferred to the heat transfer tube 103. The soft sludge on the (103) surface can also be removed.

Prior to installing the rails in the first step, it is possible to maximize the cleaning effect by putting the tax information into the steam generator. When the nuclear power plant and general industrial steam generator ultrasonic cleaning equipment is installed through the rail, when only the upper part of the tube plate 102 under the steam generator is cleaned, the steam generator is hand-operated 104 or blow down line. The fine information preparation is added and the hand tool 104 and the blow down line are sealed. In case of cleaning the steam generator electric field, it takes more time but inputs tax information using only blow down line.

After the input of the tax preparation, the second step of intensively arranging the ultrasonic elements by using the mobile robot in the high deposition rate, referring to the rough sludge deposition profile through ECT (Eddy current test) in advance. Go through (s20).

In general, the upper part of the tube plate 102, which is the lower part of the steam generator, is concentrated in the human bean-shaped zone around the middle stay cylinder 105, and in the case of the upper part of the steam generator, When the steam generator is divided on both sides of the divider plate, it is ductile to the surface of the heat pipe 103 existing in the 5 to 7 stage tube plate 102 region of the hot leg hemisphere where relatively hot coolant exists. Sludge is distributed a lot. Therefore, a rail is installed in the six-stage tube plate 102 area of the hot leg hemisphere and the ultrasonic elements are concentrated using a mobile robot. In addition, it is possible to maximize the cavitation by the ultrasonic wave if the level of the tax information preparation to match the arrangement of the ultrasonic elements.

After the arrangement of the ultrasonic elements by the mobile robot, the foreign substances existing on the surface of the steam generator shell 101 or the tube plate 102 are blown out through the compressed air supply line, and the specific liquid is evenly applied to the contact area by using the contact liquid supply line. After that, the ultrasonic elements mounted to protrude slightly with a negative tolerance using the electromagnet holder are brought into very strong contact with the steam generator shell 101 and the tube plate 102.

Ultrasonic energy is transferred to the steam generator for several hours to several tens of hours depending on the amount of sludge deposit, causing cavitation in the liquid detergent preparation injected into the steam generator, and maximizing the chemical action of the detergent. Remove sludge at the same time. The sludge removed in this way is passed through a filter through a suction line to remove particulate sludge and agglomerated sludge, and the fine preparation is sent back to the steam generator to be used again for ultrasonic cleaning. It may be repeated several times depending on the sludge deposition of the steam generator. Particularly, in the case of the model F type steam generator, there is a gap in which a flow path called quarter foil is formed in the tube plate 102 holding the heat transfer tube 103. When the sludge is deposited in this portion to block the flow path, the steam generator In some cases, it may lead to unstable water levels, reducing the output of nuclear power plants. If the flow blockage is serious, it may be repeated several times to remove the flow blockage.

As described above, the steam generator, which is a kind of heat exchanger of a nuclear power plant, has been described in detail. However, the present invention may also be applied to a general industrial heat exchanger installed horizontally. In addition, although the rail and the sprocket were used as a means for transporting the steam generator surface by mounting the mobile robot, a roller made of permanent magnets may be used as the mobile robot transporting means.

Although the preferred embodiments of the present invention have been illustrated and described above, the present invention is not limited to the specific embodiments described above, and the present invention is not limited to the specific embodiments of the present invention, without departing from the spirit of the invention as claimed in the claims. Many modifications are possible to those skilled in the art. In addition, matters that can be easily inferred from the accompanying drawings are to be regarded as included in the contents of the present invention even if they are not described in the detailed description, and various modifications may be separately understood from the technical spirit or the prospect of the present invention. Will not be.

1 is a perspective view showing a state of uniformly cleaning the heat exchanger ultrasonic cleaning device for the steam generator of the nuclear power plant according to an embodiment of the present invention,

Figure 2 is a perspective view showing a rail for providing a moving path of the mobile robot as an embodiment of the present invention,

3 is a perspective view showing a state in which the cover is removed from the mobile robot according to an embodiment of the present invention;

Figure 4A is a perspective view specifically showing a bracket as an embodiment of the present invention,

Figure 4B is a perspective view showing the rolling bearing is attached to the rail at the end of the bracket as an embodiment of the present invention,

Figure 5 is a perspective view showing an integrated cable line required for the operation of the mobile robot as an embodiment of the present invention,

6A is a perspective view illustrating a holder which is a part that is joined to a heat exchanger including an ultrasonic element as an embodiment of the present invention;

6B is a plan view from above of the holder,

7 is a perspective view showing a mobile robot case which is an embodiment of the present invention, and

8 is a flow chart illustrating a heat exchanger cleaning method using an ultrasonic heat exchanger cleaning device according to an embodiment of the present invention.

Claims (13)

A rail surrounding the surface of the heat exchanger; And A mobile robot installed on the rail to be movable and having an ultrasonic element thereon; The ultrasonic element emits ultrasonic waves into the heat exchanger to clean the inside of the heat exchanger, The rail is A band surrounding the surface of the heat exchanger; Includes; a plurality of gear teeth bolted to the belt and The plurality of gear teeth have a fastening hole and the belt is inserted through the fastening hole is coupled to the plurality of gear teeth, characterized in that further fixed by the belt and the fastening means, The mobile robot A bracket for coupling the mobile robot to the rail; An integrated cable line including a cable required for operation of the mobile robot; And And a holder for coupling the mobile robot to the heat exchanger. The holder is A compressed air supply line for injecting compressed air to a contact surface of the ultrasonic element and the heat exchanger; And And a close liquid supply line for injecting a close liquid to a contact surface of the ultrasonic element and the heat exchanger. The integrated cable line further comprises the compressed air supply line and the tight liquid supply line heat exchanger ultrasonic cleaning device. The method of claim 1, wherein the bracket Servo motor; A sprocket coupled to the gear teeth of the rail and driven by the power of the servo motor to move the mobile robot on the rail; Rolling bearings which are inserted at both ends of the c-shaped end of the bracket and attached to the rail and rotatably coupled to the valley between the gear tooth and the belt of the rail to attach the mobile robot to the rail; And C-shaped end of the bracket is included in the contact with the heat exchanger ball bearing for reducing the surface friction; heat exchanger ultrasonic cleaning device comprising a. The method of claim 2, wherein the servo motor Including an encoder for detecting the position of the mobile robot, And an operation unit for moving the mobile robot to a desired position by using the position information of the mobile robot by the encoder. A rail surrounding the surface of the heat exchanger; And A mobile robot installed on the rail to be movable and having an ultrasonic element thereon; The ultrasonic element emits ultrasonic waves into the heat exchanger to clean the inside of the heat exchanger, The rail is A band surrounding the surface of the heat exchanger; It comprises a; a plurality of gear teeth fastened to the belt and bolts, The plurality of gear teeth have a fastening hole and the belt is inserted through the fastening hole is coupled to the plurality of gear teeth, characterized in that further fixed by the belt and the fastening means, The mobile robot A bracket for coupling the mobile robot to the rail; An integrated cable line including a cable required for operation of the mobile robot; And And a holder for coupling the mobile robot to the heat exchanger. The bracket Servo motor; A sprocket coupled to the gear teeth of the rail and driven by the power of the servo motor to move the mobile robot on the rail; Rolling bearings which are inserted at both ends of the c-shaped end of the bracket and attached to the rail and rotatably coupled to the valley between the gear tooth and the belt of the rail to attach the mobile robot to the rail; And A c-shaped end of the bracket is included in contact with the heat exchanger to reduce surface friction; and The holder is heat exchanger ultrasonic cleaning device, characterized in that the contact portion with the heat exchanger is concave in accordance with the radius of the heat exchanger, the end of the ultrasonic element protrudes than the contact surface of the holder in contact with the heat exchanger. The method of claim 4, wherein the servo motor Including an encoder for detecting the position of the mobile robot, And an operating unit for moving the mobile robot to a desired position by using the position information of the mobile robot by the encoder. A heat exchanger cleaning method using the heat exchanger ultrasonic cleaning device according to any one of claims 1 to 5, A first step of installing a rail in the heat exchanger shell; Disposing a mobile robot on which the ultrasonic element is mounted on the rail; And And a third step of cleaning the inside of the heat exchanger by generating an ultrasonic wave by the ultrasonic element. The method of claim 6, wherein the first step The cleaning method of the heat exchanger, characterized in that the washing agent is added to the inside of the heat exchanger before installing the rail. The method of claim 6, wherein the second step Heat exchanger cleaning method characterized in that the mobile robot is arranged uniformly or concentrated in a specific area. The method of claim 6, wherein the second step And arranging the mobile robot in an area adjacent to the tube plate of the heat exchanger. 8. The method of claim 7, wherein the third step transmits ultrasonic energy to the heat exchanger for several hours to several tens of hours to cause cavitation in the tax preparation prepared in the heat exchanger, and maximizes the chemical reaction of the tax preparation to heat exchange Heat exchanger cleaning method characterized in that to remove the sludge at the top of the top and the tube plate at the same time. 11. The method of claim 10, wherein particulate sludge and agglomerated sludge are removed from the removed sludge and the cleaning aid is sent to the heat exchanger again for ultrasonic cleaning. delete delete

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