Method for maintenance of heat exchange plate of plate heat exchanger and maintenance system

Abstract

To provide a method for maintenance of a heat exchange plate of a plate heat exchanger and a maintenance system capable of more efficiently inspecting presence or absence of a crack generated in the heat exchange plate.SOLUTION: The maintenance system includes: a plurality of robot arms 30 for forming, in one surface of a heat exchange plate 10 of a plate heat exchanger, a coating made of a fluorescent liquid; a conveyance device 20 for conveying the heat exchange plate 10 to the robot arms; and inspection means 60 for irradiating the other surface of the heat exchange plate 10 with ultraviolet light and determining that a through defect portion is generated at a location where fluorescence is confirmed, wherein each of the robot arms 30 forms the coating using an amount of the fluorescent liquid smaller than the total amount of the fluorescent liquid required for forming the coating on the heat exchange plate 10, or forms the coating on an area smaller than a total area on which the coating is to be formed on the heat exchange plate 10.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a maintenance method and system for heat exchanger plates of a plate heat exchanger, which can efficiently maintain the heat exchanger plates of the plate heat exchanger. [Background technology]

[0002] Plate heat exchangers are regularly maintained. One part of the maintenance involves inspecting the heat exchange plates of the plate heat exchanger to detect cracks. Specifically, a fluorescent liquid is first applied to the entire surface of one side of the heat exchange plate. Next, ultraviolet light is irradiated from the other side, and if fluorescence is confirmed, it is determined that a penetrating crack has occurred in the fluorescent area (see, for example, Patent Document 1). Recently, there has been an increasing demand for maintenance of plate heat exchangers. To meet this demand, robotic arms are being used to reduce the time required for applying the fluorescent liquid, but further efficiency improvements are required. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-121989 Summary of the Invention [Problem to be solved by the invention]

[0004] In view of the above circumstances, an object of the present invention is to provide a maintenance method and system for heat exchange plates of a plate heat exchanger that can more efficiently inspect for cracks in the heat exchange plates. [Means for solving the problem]

[0005] An embodiment for achieving the above object is a maintenance method for heat exchange plates of a plate-type heat exchanger, comprising: a coating forming step of forming a coating made of a fluorescent liquid on one surface of the heat exchange plate of the plate-type heat exchanger; and an inspection step of irradiating the other surface of the heat exchange plate with ultraviolet light and determining that a through defect has occurred at a location where fluorescence is confirmed, wherein the coating forming step is characterized in that the coating is formed on the heat exchange plate in multiple stages, and in each stage, the coating is formed with an amount of fluorescent liquid that is less than the total amount of fluorescent liquid required for the coating to be formed on the heat exchange plate, or the coating is formed on an area that is smaller than the total area of ​​the heat exchange plate on which the coating is to be formed.

[0006] Another aspect for achieving the above object is a maintenance system for heat exchange plates of a plate-type heat exchanger, comprising a plurality of robot arms that form a coating made of a fluorescent liquid on one surface of the heat exchange plates of the plate-type heat exchanger; a transport device that transports the heat exchange plates to the robot arms and transports the heat exchange plates with the coating formed thereon to the next robot arm; and inspection means that irradiates the other surface of the heat exchange plate with ultraviolet light and determines whether a through defect has occurred at a location where fluorescence is detected, wherein each of the robot arms forms the coating with an amount of fluorescent liquid that is less than the total amount of fluorescent liquid required for the coating to be formed on the heat exchange plate, or forms the coating on an area that is smaller than the total area of ​​the heat exchange plate on which the coating will be formed. [Effects of the Invention]

[0007] According to the present invention, a maintenance method and system for heat exchange plates of a plate heat exchanger are provided, which are capable of more efficiently inspecting for the presence or absence of cracks in the heat exchange plates. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic configuration diagram of a maintenance system for heat exchange plates of a plate heat exchanger. [Figure 2] FIG. 2 is a block diagram showing the functions of the maintenance system. [Figure 3] FIG. [Figure 4] FIG. 10 is a diagram showing fluorescence and a through defect portion captured in an image by a line sensor. [Figure 5] FIG. 10 is a diagram showing how fluorescent liquid is applied by two robot arms. [Figure 6] 10A and 10B are diagrams for explaining the time required for a supply operation and a coating operation. [Figure 7] FIG. 10 is a diagram showing a second robot arm having multiple brushes. DETAILED DESCRIPTION OF THE INVENTION

[0009] Fig. 1 is a schematic diagram of a maintenance system for heat exchange plates of a plate heat exchanger. Fig. 2 is a block diagram showing the functions of the maintenance system. Fig. 3 is a plan view of a heat exchange plate. The maintenance method and maintenance system of the present invention are for detecting through defects that have occurred in the heat exchange plates of a plate heat exchanger. First, the heat exchange plate will be described using Fig. 3.

[0010] 3 illustrates two types of heat exchange plates 10a and 10b, which have different shapes. The heat exchange plates 10a and 10b are collectively referred to as heat exchange plates 10. The heat exchange plates 10 are plate-shaped components used in plate heat exchangers in plants that manufacture liquid products such as beverages (hereinafter referred to as liquid products).

[0011] As shown in FIG. 3(a), the heat exchange plate 10a has liquid introduction sections 13a, 13b, 13c, and 13d at its four corners, which serve as flow paths for the liquid product and the liquid heat transfer medium, and a heat exchange section 11 formed between the liquid introduction sections 13a and 13b. The heat exchange plate 10a also has a groove 12 surrounding the liquid introduction sections 13a and 13b and the heat exchange section 11. A gasket (not shown) is fitted into the groove 12. A plurality of heat exchange plates 10 are stacked for use, and the gasket is provided to seal the gaps between adjacent heat exchange plates 10. As shown in FIG. 3(b), the heat exchange plate 10b differs from the heat exchange plate 10a in that it does not have the liquid introduction sections 13a and 13b.

[0012] In a plate heat exchanger, adjacent heat exchange plates 10a are stacked with a gasket between them, with the heat exchange plates 10a facing upside down, and a heat exchange plate 10b is attached to the outermost plate. Thus, even if the heat exchange plates 10 have the same shape, there are differences depending on whether or not they have a liquid introduction port.

[0013] The heat exchange section 11 of the heat exchange plate 10 is the region inside the grooves 12 for the gasket. The liquid product flowing on one side of the heat exchange plate 10 and the heat medium flowing on the other side are heat exchanged across the heat exchange section 11. There are no particular limitations on the shape of the heat exchange section 11, but the heat exchange section 11 of this embodiment has both ends in the vertical direction formed flat, and a plurality of irregularities that are rectangular in plan view are formed between them.

[0014] In the heat exchange plate 10, cracks penetrating in the thickness direction can occur in the heat exchange portion 11 due to various causes. These cracks are called penetrating defects. The maintenance method and maintenance system are intended to detect such penetrating defects.

[0015] As shown in FIGS. 1 and 2, the maintenance system 1 includes a transfer device 20 that transfers the heat exchange plate 10, a robot arm 30, and a control device 40.

[0016] The conveying device 20 is a device that conveys the heat exchange plate 10. There are no particular restrictions on the type of the conveying device 20 as long as it is a device that can convey the heat exchange plate 10 horizontally with one surface facing upward, and for example, a roller conveyor or a belt conveyor can be applied.

[0017] The transfer device 20 transfers the heat exchange plates 10 one by one from upstream to downstream. A first robot arm 31 and a second robot arm 32 are arranged in this order along the direction of travel of the transfer device 20. The first robot arm 31 and the second robot arm 32 are also collectively referred to as robot arm 30.

[0018] The robot arm 30 grasps the brush 34, moves the brush to a container storing the fluorescent liquid 2 to deposit the fluorescent liquid on the brush 34, and performs a coating operation (including the operation of simply bringing the brush 34 into contact) by moving the brush 34 in contact with one surface of the heat exchange plate 10. The type and specific structure of the robot arm 30 are not particularly limited as long as it is capable of performing such an operation, but it is, for example, a six-axis robot arm equipped with a function for grasping the brush 34 at its tip.

[0019] A third robot arm 33 is disposed downstream of the second robot arm 32 and upstream of a line sensor 60, which will be described later. The third robot arm 33 is capable of lifting a heat exchange plate 10 that has been transported with one surface coated with the fluorescent liquid facing upward, inverting the heat exchange plate 10 so that the other surface not coated with the fluorescent liquid faces upward, and placing it on the transport device 20. The type and specific structure of the third robot arm 33 are not particularly limited as long as it is capable of performing such operations. For example, it may be a six-axis robot arm with a gripping hand 37 attached to its tip.

[0020] The operations of the first robot arm 31 to the third robot arm 33 are controlled by a control device 40. The application of the fluorescent liquid by the first robot arm 31 and the second robot arm 32 will be described later.

[0021] A heat exchange plate sensor 50 is disposed near the transport device 20, upstream of the first robot arm 31. The heat exchange plate sensor 50 is used to identify the type of heat exchange plate 10. Specifically, the heat exchange plate sensor 50 uses a laser to identify the position of the heat exchange plate 10 that has reached a predetermined position on the transport device 20. By detecting the presence or absence of a liquid introduction section using such a laser, it is possible to determine whether the heat exchange plate is the heat exchange plate 10a or the heat exchange plate 10b shown in FIG. 3. The sensor for identifying the type of heat exchange plate 10 is not limited to a sensor that uses a laser to identify the position. For example, the heat exchange plate may be identified by capturing an image of the heat exchange plate 10 and analyzing the resulting image. Alternatively, a barcode reader may be used to read a code, such as a barcode, attached to the heat exchange plate to identify the type of heat exchange plate.

[0022] A line sensor 60 is disposed near the transport device 20, downstream of the third robot arm 33. The line sensor 60 is an imaging device that images the surface of the heat exchange plate 10. The line sensor 60 is capable of imaging an area wider than the width of the heat exchange plate 10, and forms an image of the other side of the heat exchange plate 10 (the side on which the fluorescent liquid is not applied) by capturing an image from the beginning to the end of the heat exchange plate 10 in the traveling direction as it is transported by the transport device 20.

[0023] Furthermore, although not specifically shown, a black light is provided to irradiate the imaging range of the line sensor 60 with ultraviolet light. The ultraviolet light from the black light is irradiated while the line sensor 60 is imaging. If a through defect occurs in the heat exchanger plate 10, fluorescent liquid will appear on one side (the downward-facing side) through the through defect and emit fluorescence due to the ultraviolet light. Therefore, if a through defect occurs, the line sensor 60 will form an image of the surface of the heat exchanger plate 10 containing fluorescence.

[0024] It is preferable to irradiate the imaging range of the line sensor 60 with light from multiple light sources. For example, light is irradiated from all sides of the imaging range in a plan view. By providing multiple light sources in this manner, it is possible to reduce the shadows that may appear on the uneven heat exchanger 11. By reducing the shadows on the heat exchanger 11, the shadows can be eliminated from the image formed by the line sensor, making it easier to detect through-hole defects using the image processing described below.

[0025] The control device 40 includes a CPU and a memory, and reads and executes programs stored in the memory. By executing the programs, the control device 40 selects a pattern for applying the fluorescent liquid depending on the type of heat exchange plate 10, and causes the robot arm 30 to apply the fluorescent liquid. Each function of the control device 40 is explained with reference to FIG. 2.

[0026] The control device 40 includes a transport control unit 41, a heat exchange plate determination unit 42, a coating control unit 43, and a penetration defect determination unit 44.

[0027] The transfer control unit 41 controls the transfer device 20 to transfer the heat exchange plate 10. Specifically, the transfer and stopping are performed so that the heat exchange plate 10 is at a predetermined position relative to the heat exchange plate sensor 50, the robot arm 30, and the line sensor 60.

[0028] The heat exchange plate determination unit 42 determines the type of heat exchange plate 10 based on information obtained from the heat exchange plate sensor 50. Information about the shapes of all types of heat exchange plates 10 that are handled is stored in advance in the control device 40. The heat exchange plate determination unit 42 then compares the information sent from the heat exchange plate sensor 50 with the information about the heat exchange plate 10 to determine the type of heat exchange plate 10 being transported.

[0029] The coating control unit 43 selects a coating pattern set according to the type of heat exchange plate 10, and causes the robot arm 30 to form a coating based on the selected pattern. The coating refers to the fluorescent liquid applied to the heat exchange plate 10. The coating pattern refers to the shape and arrangement of the coating applied to the heat exchange plate 10. The control device 40 stores the coating pattern in advance, and operates the robot arm 30 to form that pattern. The coating pattern will be described later. The coating control unit is an example of a coating formation control unit in the claims.

[0030] The through defect determination unit 44 determines the presence or absence of a through defect based on the image obtained by the line sensor 60. For example, as shown in FIG. 4, a fluorescent portion 6 that emits fluorescence is detected by known image processing of an image 70 obtained by the line sensor 60. If a fluorescent portion 6 is detected, it is determined that a through defect 15 has occurred in the fluorescent portion 6. This determination result may be displayed on the monitor 61 (see FIG. 1), for example, as an image 70 in which the fluorescent portion 6 is enlarged or marked. Note that the presence or absence of a through defect may also be determined by irradiating ultraviolet light in a dark room and visually observing the fluorescence.

[0031] The application of the fluorescent liquid will be described in detail using Figure 5. Two robot arms, a first robot arm 31 and a second robot arm 32, share the task of applying the fluorescent liquid to one heat exchange plate 10. Each robot arm forms a coating with an amount of fluorescent liquid that is smaller than the total amount of fluorescent liquid required for the coating to be formed on the heat exchange plate 10, or forms a coating on an area that is smaller than the total area of ​​the heat exchange plate 10 on which the coating is to be formed. Note that the coating formed on the heat exchange plate 10 refers to a coating formed over the entire area of ​​the heat exchange plate 10 where through defects may occur. In the heat exchange plate 10 shown in Figure 3, a coating is formed over the grooves 12 on one side and the entire heat exchange portion 11 located inside the grooves 12.

[0032] First, the first robot arm 31 on the upstream side forms a first coating 3 made of fluorescent liquid at multiple spaced locations on one surface of the heat exchange plate 10. In the example shown in the figure, rectangular coatings are formed at multiple spaced locations. In the case of heat exchange plate 10a, liquid introduction portions 13a-13d are present, so the pattern is such that the first coating 3 is not formed in those areas. In the case of heat exchange plate 10b, liquid introduction portions 13a-13b are not present, so the pattern is such that the first coating 3 is formed in those areas.

[0033] The second robot arm 32 on the downstream side moves the brush 34 to extend the first coating 3, thereby forming a second coating 4 that covers the entire one surface. Furthermore, the second robot arm 32 applies fluorescent liquid to the grooves 12 to form a third coating 5. In the case of the heat exchange plate 10a, the liquid introduction portions 13a to 13d are present, so the second coating 4 is not formed in those areas. In the case of the heat exchange plate 10b, the liquid introduction portions 13a to 13d are not present, so the second coating 4 is formed in those areas.

[0034] If the fluorescent liquid cannot be applied to form a coating in one operation, the application control unit 43 causes the first robot arm 31 and the second robot arm 32 to move the brush 34 to the container to apply the fluorescent liquid.

[0035] In this way, the first robot arm 31 forms a rough coating on one side of the heat exchange plate 10, and the second robot arm 32 forms a coating evenly on the entire one side of the heat exchange plate 10 and in the grooves 12.

[0036] The time-saving effect of dividing the roles is explained in Figure 6. The horizontal direction in Figure 6 indicates the time required for various operations of the robot arm.

[0037] First, as shown in Figure 6(a), when forming a coating using a single robot arm, the brush is first dipped into the fluorescent liquid in a container to adhere the fluorescent liquid to the brush. This operation is called the replenishing operation. Then, the brush is moved while in contact with one side of the heat exchange plate to form a coating on the heat exchange plate. This operation is called the coating operation. If a coating cannot be formed on the heat exchange plate in one coating operation, the replenishing operation and the coating operation are repeated as appropriate. In the example of Figure 6(a), these operations are repeated four times to form a coating on one heat exchange plate 10.

[0038] FIG. 6(b) shows the operation using two robot arms 30 as described above. The first robot arm 31 uses a smaller area and a smaller amount of fluorescent liquid than the coating formed on the entire heat exchanger plate 10, so, for example, replenishment work can be done only once. The second robot arm 32 spreads the first coating 3 already formed on the heat exchanger plate 10, so the application work can be performed without the need for replenishment work. Therefore, the second coating 4 can be formed in a considerably short time. The saved time is then used to perform the replenishment work and form the third coating 5 in the grooves 12. In this way, it is preferable to form the coating so that the work time by the first robot arm 31 and the work time by the second robot arm 32 are approximately the same.

[0039] As shown in Figure 6(b), the first robot arm 31 can reduce the time required for the coating operation because the area to be coated is small. Also, because the amount of fluorescent liquid required is small, the number of replenishment operations can be reduced, resulting in a time-saving effect. The second robot arm 32 performs a coating operation by spreading the already formed first coating 3, so replenishment operations are not necessary, and the time required for the work can be reduced accordingly.

[0040] The second robot arm 32 forms two types of coatings, the second coating 4 and the third coating 5. In such cases, it may have brushes suitable for each. Figure 7 shows an example of a second robot arm 32 equipped with multiple brushes. The second robot arm 32 is equipped with a first brush 35 and a second brush 36 at its tip. The first brush 35 is wider than the second brush 36.

[0041] Since the second coating 4 is formed by extending the scattered first coating 3 in the horizontal direction, the application control unit 43 controls the second robot arm 32 to form the second coating 4 using the wide first brush 35. On the other hand, since the third coating 5 is formed by applying fluorescent liquid to the grooves 12, the application control unit 43 controls the second robot arm 32 to form the third coating 5 using the relatively narrow and long second brush 36. Either the second coating 4 or the third coating 5 may be formed first.

[0042] By providing the second robot arm with multiple types of first brushes 35 and second brushes 36 suited to the shape of the object to be coated, a coating can be more reliably and thoroughly formed on one side of the heat exchanger plate 10. Furthermore, since there is no need for separate robot arms with the first brushes 35 and the second brushes 36, costs can be reduced. It is also possible to form the second coating 4 with the first brush 35 on a single robot arm and then replace the first brush 35 with the second brush 36 to form the third coating 5, but this method requires time for replacement. However, since the second robot arm 32 is equipped with the first brushes 35 and the second brush 36, the time required for such replacement is eliminated, thereby shortening the time required for coating formation.

[0043] The maintenance system 1 configured and controlled as described above transports the heat exchange plate 10 using the transport device 20 and forms a coating of fluorescent liquid on one surface of the heat exchange plate 10. This coating is formed by multiple robot arms 30, two in this embodiment, which share the role of forming the coating. That is, the first robot arm 31 on the upstream side forms the first coating 3 by applying the fluorescent liquid in multiple scattered locations. Next, the second robot arm 32 on the downstream side extends the first coating 3 to form a second coating 4 that covers the entire one surface and also forms a third coating 5 in the grooves 12.

[0044] The first coating 3 is smaller than the total amount of fluorescent liquid required to coat one entire surface of the heat exchanger plate 10, and is smaller than the area to be coated on that surface. Therefore, the time required to form the first coating 3 is shorter than the time required to form a coating on the entire surface. Furthermore, because the amount of fluorescent liquid to be coated is small, the number of times that the first robot arm 31 needs to carry the brush 34 to the fluorescent liquid container can be reduced, thereby shortening the time required for coating.

[0045] On the other hand, since the second coating 4 is formed by simply extending the first coating 3, the second robot arm 32 does not need to carry the fluorescent liquid to the fluorescent liquid container, thereby shortening the application time. Even if additional fluorescent liquid is required to form the second coating 4, only a small amount is required because the first coating 3 is already present, thereby shortening the application time. Furthermore, the amount of the third coating 5 is also less than the total amount of fluorescent liquid required to coat the entire one surface of the heat exchanger plate 10 and is smaller than the area to be coated on that surface. Because the amount of fluorescent liquid to be applied is small, the second robot arm 32 does not need to carry the brush 34 to the fluorescent liquid container as many times as necessary, thereby shortening the application time.

[0046] In this way, the maintenance system 1 is formed by dividing the roles among multiple robot arms 30, which can shorten the time required to apply fluorescent liquid and form a coating, thereby enabling efficient detection of penetrating defects in the heat exchange plate 10.

[0047] Although an embodiment of the present invention has been described, it goes without saying that the present invention is not limited to the above-described embodiment, and additions, omissions, substitutions, and other modifications to the configuration are possible within the scope that does not deviate from the spirit of the present invention.

[0048] Examples of coating formation patterns are given below. [Variation 1] The first robot arm 31 forms the first coating 3 and forms part of the third coating 5 made of fluorescent liquid in the grooves 12, while the second robot arm 32 extends the first coating 3 to form the second coating 4 that covers the entire one surface and forms the remaining part of the third coating 5. In other words, the first robot arm 31 and the second robot arm 32 share the work of forming the third coating 5 in the grooves 12. For example, as shown in FIG. 6(c), the work of forming the third coating 5 is shared between the robot arms 30 so that the working time of each robot arm 30 is approximately the same.

[0049] [Variation 2] The first robot arm 31 forms a coating made of fluorescent liquid on a portion of one surface, and the second robot arm 32 forms a coating made of fluorescent liquid on another portion of the one surface. That is, in the above-described embodiment, the second robot arm 32 forms the first coating 3 on the existing first coating 3, so no replenishing operation is required, but this is not limited to this, and the second robot arm 32 may perform the replenishing operation to form a coating on the heat exchange plate 10. In this case, it is preferable that the first robot arm 31 forms a coating on a portion of one surface of one heat exchange plate 10, and the second robot arm 32 forms a coating on the remaining portion of the one surface.

[0050] [Variation 3] The robot arm 30 has a brush 34, and forms a coating by dipping the brush 34 in the fluorescent liquid in the container and then moving the brush 34 over one side of the heat exchange plate 10. At this time, the brush 34 may be dipped into the fluorescent liquid in the container once per heat exchange plate 10, and the coating may be formed by the brush 34. In other words, the coating can be formed in the area of ​​one side of the heat exchange plate 10 that the robot arm 30 is responsible for by performing the refilling operation only once.

[0051] For example, in the above embodiment, the fluorescent liquid is applied with a brush to form the coating, but the method is not limited to this. For example, the coating may be formed by spraying the fluorescent liquid onto the heat exchange plate 10 from a position spaced a certain distance from the heat exchange plate 10 using a spray or injection nozzle.

[0052] Furthermore, while the fluorescent liquid is stored in a container and the brush is dipped in the fluorescent liquid to adhere to the brush, this is not a limitation. For example, a robot arm may be provided with a brush, a tank storing the fluorescent liquid, and a tube or pump for delivering the fluorescent liquid from the tank to the brush. The fluorescent liquid is then delivered from the tank to the brush, impregnating the brush with the fluorescent liquid, and the brush forms a coating on the heat exchange plate 10. This configuration eliminates the need for a refill operation, further reducing the time required.

[0053] Furthermore, although the coating formation is shared by two robot arms 30, the present invention is not limited to this method, and the coating formation may be shared by three or more robot arms.

[0054] Furthermore, the film formation by the two robot arms 30 is not limited to the above-mentioned division of labor. For example, one surface to be coated with the fluorescent liquid may be divided into areas equal to the number of robot arms, and each robot arm may form a film in each of the divided areas. [Explanation of symbols]

[0055] 1...maintenance system, 2...fluorescent liquid, 3...first coating, 4...second coating, 5...third coating, 6...fluorescent portion, 10, 10a, 10b...heat exchange plate, 11...heat exchange portion, 12...groove portion, 15...penetration defect portion, 20...transport device, 30...robot arm, 31...first robot arm, 32...second robot arm, 33...third robot arm, 34...brush, 35...first brush, 36...second brush, 37...gripping hand, 40...control device, 50...heat exchange plate sensor, 60...line sensor, 61...monitor, 70...image

Claims

1. a coating forming step of forming a coating made of a fluorescent liquid on one surface of a heat exchange plate of the plate heat exchanger; and an inspection step of irradiating the other surface of the heat exchange plate with ultraviolet light and determining that a penetration defect has occurred at a location where fluorescence is confirmed, The coating formation step includes forming the coating on the heat exchange plate in multiple stages, At each stage, forming a coating with an amount of fluorescent liquid that is less than the total amount of fluorescent liquid required for forming the coating on the heat exchange plate, or The coating is formed on an area smaller than the total area of ​​the heat exchange plate on which the coating is formed. A maintenance method for heat exchange plates of a plate heat exchanger.

2. The maintenance method for heat exchange plates of a plate heat exchanger according to claim 1, The coating formation step is performed by forming the coating on the heat exchange plate in two stages, In a first step, a first coating made of a fluorescent liquid is formed at a plurality of locations on the one surface at intervals; In the second step, the first coating is extended to form a second coating that covers the entire one surface. A maintenance method for heat exchange plates of a plate heat exchanger.

3. The maintenance method for heat exchange plates of a plate heat exchanger according to claim 1, The heat exchange plate has a groove in which a gasket is attached, The coating formation step is performed by forming the coating on the heat exchange plate in two stages, In a first step, a first coating made of a fluorescent liquid is formed at a plurality of locations on the one surface at intervals; In the second step, the first coating is extended to form a second coating that covers the entire one surface, and a third coating made of a fluorescent liquid is formed in the groove. A maintenance method for heat exchange plates of a plate heat exchanger.

4. a plurality of robot arms for forming a coating made of a fluorescent liquid on one surface of a heat exchange plate of a plate-type heat exchanger; a conveying device that conveys the heat exchange plate to the robot arm and conveys the heat exchange plate on which the coating has been formed to the next robot arm; and an inspection means for irradiating the other surface of the heat exchange plate with ultraviolet light and determining that a penetration defect has occurred at a location where fluorescence is confirmed, Each of the robotic arms forming a coating with an amount of fluorescent liquid that is less than the total amount of fluorescent liquid required for forming the coating on the heat exchange plate, or The coating is formed on an area smaller than the total area of ​​the heat exchange plate on which the coating is formed. A maintenance system for heat exchange plates of a plate heat exchanger.

5. 5. The maintenance system for heat exchange plates of a plate heat exchanger according to claim 4, The plurality of robot arms are two robot arms, a first robot arm and a second robot arm, the first robot arm forms a first coating made of a fluorescent liquid at a plurality of locations on the one surface at intervals; The second robot arm extends the first coating to form a second coating that covers the entire one surface. A maintenance system for heat exchange plates of a plate heat exchanger.

6. 5. The maintenance system for heat exchange plates of a plate heat exchanger according to claim 4, The heat exchange plate has a groove in which a gasket is attached, The plurality of robot arms are two robot arms, a first robot arm and a second robot arm, the first robot arm forms a first coating made of a fluorescent liquid at a plurality of locations on the one surface at intervals; The second robot arm extends the first coating to form a second coating that covers the entire one surface, and forms a third coating made of a fluorescent liquid in the groove. A maintenance system for heat exchange plates of a plate heat exchanger.

7. 5. The maintenance system for heat exchange plates of a plate heat exchanger according to claim 4, The heat exchange plate has a groove in which a gasket is attached, The plurality of robot arms are two robot arms, a first robot arm and a second robot arm, the first robot arm forms a first coating made of a fluorescent liquid at a plurality of intervals on the one surface and forms a part of a third coating made of a fluorescent liquid in the groove portion; a second robot arm extending the first coating to form a second coating that covers the entire one surface and forming the remainder of the third coating; A maintenance system for heat exchange plates of a plate heat exchanger.

8. 5. The maintenance system for heat exchange plates of a plate heat exchanger according to claim 4, The plurality of robot arms are two robot arms, a first robot arm and a second robot arm, the first robot arm forms a coating made of a fluorescent liquid on a part of the one surface; The second robot arm forms a coating made of a fluorescent liquid on the other part of the one surface. A maintenance system for heat exchange plates of a plate heat exchanger.

9. 7. The maintenance system for heat exchange plates of a plate heat exchanger according to claim 6, the heat exchange plate has the groove portion in which the gasket is attached, The second robot arm a brush for forming the second coating and a brush for forming the third coating, The fluorescent liquid is applied with the brush to form the second coating and the third coating. A maintenance system for heat exchange plates of a plate heat exchanger.

10. 5. The maintenance system for heat exchange plates of a plate heat exchanger according to claim 4, a heat exchange plate determination unit for determining the type of the heat exchange plate from among a plurality of types of heat exchange plates having different shapes; a coating formation control unit that selects a coating pattern set in accordance with the type of the heat exchange plate and causes the robot arm to form a coating based on the pattern. A maintenance system for heat exchange plates of a plate heat exchanger.

11. 5. The maintenance system for heat exchange plates of a plate heat exchanger according to claim 4, a container for storing a fluorescent liquid; the robot arm has a brush, and forms the coating by dipping the brush into the fluorescent liquid in the container and then moving the brush over one surface of the heat exchange plate; Furthermore, the brush is dipped into the fluorescent liquid in the container once for each heat exchange plate, and the coating is formed by the brush. A maintenance system for heat exchange plates of a plate heat exchanger.

12. 5. The maintenance system for heat exchange plates of a plate heat exchanger according to claim 4, the robot arm includes a brush, a container for storing fluorescent liquid, and a liquid delivery means for delivering the fluorescent liquid from the container to the brush; The fluorescent liquid is delivered from the container to the brush to impregnate the brush with the fluorescent liquid, and the brush is moved over one surface of the heat exchange plate to form the coating. A maintenance system for heat exchange plates of a plate heat exchanger.

13. 5. The maintenance system for heat exchange plates of a plate heat exchanger according to claim 4, The inspection means a line sensor that forms an image on the other surface of the heat exchange plate; a penetration defect determination unit that determines that the penetration defect has occurred at a location where the fluorescence reflected in the image is confirmed by image processing. A maintenance system for heat exchange plates of a plate heat exchanger.

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