Pipe inspection system

Abstract

The piping inspection system (30) performs compressed air leak checks on the inspected section (32) of the piping (16). The piping inspection system includes a first branch pipe (34) and a second branch pipe (46). The first branch pipe branches off from the piping further upstream of the inspected section and merges with the piping further upstream of the inspected section. The second branch pipe branches off from the piping further downstream of the inspected section. The first branch pipe has a fluorescent solvent supply unit (40) for supplying fluorescent solvent (44) to the inspected section. The second branch pipe has a fluorescent solvent recovery unit (52) for recovering fluorescent solvent from the inspected section.

Description

[Technical Field]

[0001] The present invention relates to a piping inspection system for inspecting the piping through which compressed air flows. [Previous Technology]

[0002] Air compressors, such as pneumatic cylinders, operate by supplying or discharging compressed air. Therefore, if compressed air leaks from the piping connected to the air compressor, the air compressor will not operate properly. To avoid this, the compressed air supply source is connected to the air compressor via piping, and the piping is checked for leaks. For example, soapy water is sprayed onto the piping. When compressed air leaks, the soapy water forms bubbles. By observing the bubbles, the inspector can pinpoint the leak. However, this inspection requires spraying soapy water onto the entire piping system, making the inspection cumbersome.

[0003] Here, as described in Japanese Patent No. 4297862, the use of a colored inspection gas can be considered. The inspection method described in Japanese Patent No. 4297862 is to check for leaks of the inspection gas from the fuel cell. In this case, a mixture of fluorescent dye and oil (such as olive oil) is used as a coloring agent. The mixture is atomized and supplied to the fuel cell along with compressed air or hydrogen. The fuel cell is then illuminated. In this state, the fuel cell is monitored by a camera.

[0004] When a compressed air leak exists in the fuel cell, mist is ejected from the leak. At this time, fluorescent dyes in the mist are highlighted by light. Therefore, the fluorescence can be easily captured by a camera. This allows it to be determined that a leak of the inspection gas has occurred in the fuel cell. Since the inspection gas leak can be visually confirmed, this inspection is a visual inspection. [Summary of the Invention]

[0005] The inspection system described in Japanese Patent No. 4297862 does not include a structure for removing colorant from the piping. Therefore, when this inspection system is used to check for leaks in the piping of an air compressor system, colorant may flow into the interior of the air compressor. If colorant residue remains in the air compressor, there is a concern that corrosion or malfunction may occur.

[0006] The purpose of this invention is to solve the above-mentioned problems.

[0007] According to one embodiment of the present invention, a piping inspection system is provided for inspecting whether there is a compressed air leak in the inspected portion of a piping through which compressed air flows. The system is characterized by comprising: a first branch pipe that branches off from the piping upstream of the inspected portion and merges with the piping; a fluorescent solvent supply unit provided in the first branch pipe for supplying fluorescent solvent to the inspected portion; a second branch pipe that branches off from the piping downstream of the inspected portion; and a fluorescent solvent recovery unit provided in the second branch pipe for recovering the fluorescent solvent from the inspected portion.

[0008] According to the present invention, whether or not fluorescence can be observed in the inspected part can be easily determined whether there is a compressed air leak in the inspected part. Thus, the present invention can easily and quickly determine whether there is a compressed air leak. Furthermore, by identifying the starting point of the fluorescence, the compressed air leak can be quickly pinpointed. Moreover, when making this determination, the inspector does not need to have special skills or knowledge.

[0009] After the fluorescent solvent flows through the inspected section, it is recovered by the fluorescent solvent recovery unit. Therefore, in the piping, it is possible to prevent the fluorescent solvent from flowing further downstream than the inspected section. That is, it is possible to prevent the fluorescent solvent from entering the air compressor and other equipment connected to the piping. Furthermore, it is also possible to prevent the fluorescent solvent from remaining inside the piping or air compressor. Therefore, concerns about air compressor malfunction or corrosion due to fluorescent solvents can be eliminated.

[0010] The above-mentioned objectives, features and advantages should be readily understood from the following description of the embodiments illustrated with reference to the attached drawings.

Implementation Method

[0016] In the following description, the term "leakage point" refers to the location where compressed air leaks. Also, the term "upstream" indicates the upstream direction of compressed air flow. The term "downstream" indicates the downstream direction of compressed air flow.

[0017] Figure 1 is a schematic circuit diagram of an air compressor system 10. The air compressor system 10 includes a compressor 12 and a main piping 14 connected to the compressor 12. The compressor 12 generates compressed air by drawing in atmospheric air and compressing it.

[0018] A plurality of first auxiliary pipes 16 are connected to the main pipe 14. A plurality of (three in this embodiment) second auxiliary pipes 18 are connected to each first auxiliary pipe 16. A first cylinder 20, a second cylinder 22, and a third cylinder 24 are connected to each second auxiliary pipe 18. The first to third cylinders 20, 22, and 24 are a type of air compressor. Compressed air obtained from the compressor 12 flows through the main pipe 14, the first auxiliary pipes 16, and the second auxiliary pipes 18. Compressed air is individually supplied to the first to third cylinders 20, 22, and 24. The first to third cylinders 20, 22, and 24 operate individually using the compressed air as actuating air.

[0019] A piping inspection system 30 is embedded in the first auxiliary piping 16. The piping inspection system 30 is a system for checking whether there are leaks in the inspected part 32 of the first auxiliary piping 16.

[0020] The piping inspection system 30 has a first branch pipe 34. The upstream of the first branch pipe 34 branches off from a first sub-pipe 16 upstream of the inspected section 32. The downstream of the first branch pipe 34 merges with the first sub-pipe 16. The point where the first branch pipe 34 and the first sub-pipe 16 merge is located further downstream than the branch point of the first branch pipe 34 and further upstream than the inspected section 32. A first valve 36 is provided on the first sub-pipe 16, further upstream than the inspected section 32. The first valve 36 is located on the first sub-pipe 16 between the branch point of the first branch pipe 34 and the point of merging.

[0021] A second valve 38 is provided in the first branch pipe 34. Compressed air flows in the first auxiliary pipe 16 but not in the first branch pipe 34 when the first valve 36 is open and the second valve 38 is closed. Conversely, compressed air flows in the first branch pipe 34 but not in the first auxiliary pipe 16 when the first valve 36 is closed and the second valve 38 is open.

[0022] In the first branch pipe 34, a first fluorescent solvent supply unit 40 is provided downstream of the second valve 38. The first fluorescent solvent supply unit 40 has a first mist generator 42. As a specific example of the first mist generator 42, a lubricator can be taken. A lubricator is known to be a container for holding lubricating oil. Alternatively, a well-known aerator can also be used as the first mist generator 42.

[0023] A first fluorescent solvent 44 is contained within the first mist generator 42. In this embodiment, the first fluorescent solvent 44 can dilute the fluorescent agent using a solvent. The solvent for the first fluorescent solvent 44 is, for example, water. In this case, the first fluorescent solvent 44 is an aqueous solution of the fluorescent agent. Alternatively, water with added oil can be used as the solvent. In this case, the first fluorescent solvent 44 is an aqueous emulsion of the fluorescent agent. Furthermore, specific examples of fluorescent agents include coumarin or vitamin B2.

[0024] As described above, compressed air flows through the first branch pipe 34. If compressed air is discharged into the first mist generator 42 toward the first fluorescent solvent 44, the first fluorescent solvent 44 is atomized. That is, mist is generated from the first fluorescent solvent 44. The mist moves with the compressed air through the first branch pipe 34 to the inspected portion 32 of the first auxiliary pipe 16.

[0025] The piping inspection system 30 has a second branch pipe 46. The upstream of the second branch pipe 46 branches off from the first sub-pipe 16 downstream of the inspected section 32. In this embodiment, the downstream of the second branch pipe 46 merges with the first sub-pipe 16. The point where the second branch pipe 46 merges with the first sub-pipe 16 is located further downstream than the branch point of the second branch pipe 46 and further downstream than the inspected section 32. A third valve 48 is provided on the first sub-pipe 16 further downstream than the inspected section 32. The third valve 48 is located on the first sub-pipe 16 between the branch point of the second branch pipe 46 and the point of merging.

[0026] A fourth valve 50 is provided in the second branch pipe 46. Compressed air flows in the first auxiliary pipe 16 but not in the second branch pipe 46 when the third valve 48 is open and the fourth valve 50 is closed. Conversely, compressed air flows in the second branch pipe 46 but not in the first auxiliary pipe 16 when the third valve 48 is closed and the fourth valve 50 is open.

[0027] In the second branch pipe 46, a first fluorescent solvent recovery unit 52 is provided downstream of the fourth valve 50. The first fluorescent solvent recovery unit 52 has a first filter material 54. The first filter material 54 removes the first fluorescent solvent 44 (mist) contained in the compressed air. Therefore, compressed air without mist flows downstream of the first filter material 54.

[0028] In the second branch pipe 46, downstream of the first filter material 54, the first exhaust pipe 56 (exhaust section) branches off from the second branch pipe 46. A fifth valve 58 is provided at the end of the first exhaust pipe 56. The outlet of the fifth valve 58 is open to the atmosphere via the first silencer 60.

[0029] Valve 1 to 5, 36, 38, 48, 50, and 58, are, for example, automatic opening and closing valves. Valve 1 to 5, 36, 38, 48, 50, and 58, can also be manual opening and closing valves.

[0030] The piping inspection system 30 includes a first black light 62. The first black light 62 is supported, for example, by a stand (not shown). The stand is equipped with casters (not shown). Therefore, the stand and the first black light 62 can be moved by rotating the casters. The first black light 62 approaches or moves away from the part 32 being inspected.

[0031] The first black light 62 irradiates the inspected part 32 with ultraviolet light. When there is a leak in the inspected part 32 and compressed air leaks from the leak, the compressed air and the fluorescent solvent (mist) are ejected from the leak. When the ultraviolet light irradiates the fluorescent solvent, as shown in FIG4, the highlighted fluorescence F can be observed.

[0032] In the first sub-pipe 16, a regulator 64 is provided downstream of the confluence point of the second branch pipe 46. In the first sub-pipe 16, a machine inspection system 70 is embedded downstream of the regulator 64.

[0033] The machine inspection system 70 is a system for detecting leaks of compressed air from the first to third pneumatic cylinders 20, 22, 24 or connecting pipe joints 128, 130 in the plurality of first auxiliary pipes 16. Furthermore, the machine inspection system 70 is a system for detecting whether there is a leak of compressed air from any of the first to third pneumatic cylinders 20, 22, 24 or connecting pipe joints 128, 130.

[0034] The machine inspection system 70 has a first branch pipe 72. The upstream of the first branch pipe 72 branches from the first auxiliary pipe 16. The downstream of the first branch pipe 72 merges with the first auxiliary pipe 16. The point where the first branch pipe 72 and the first auxiliary pipe 16 merge is located further downstream than the branch point of the first branch pipe 72 and further upstream than the second auxiliary pipe 18. A first solenoid valve 74 is provided on the first auxiliary pipe 16, further downstream than the branch point of the first branch pipe 72.

[0035] A second solenoid valve 76 is provided in the first branch pipe 72. Compressed air flows in the first auxiliary pipe 16 but not in the first branch pipe 72 when the first solenoid valve 74 is open and the second solenoid valve 76 is closed. Conversely, compressed air flows in the first branch pipe 72 but not in the first auxiliary pipe 16 when the first solenoid valve 74 is closed and the second solenoid valve 76 is open.

[0036] A second fluorescent solvent supply unit 78 is provided downstream of the second solenoid valve 76 in the first branch pipe 72. The second fluorescent solvent supply unit 78, like the first fluorescent solvent supply unit 40, has a second mist generator 80. Specifically, the second mist generator 80 can be a lubricator or a foamer, just like the first mist generator 42.

[0037] A second fluorescent solvent 82 is contained within the second mist generator 80. In this embodiment, the second fluorescent solvent 82 can be used to dilute the fluorescent agent of the above type using a solvent. The solvent for the second fluorescent solvent 82 is, for example, a highly volatile organic solvent. In particular, organic solvents with low solubility for sealing materials or greases in the first to third pneumatic cylinders 20, 22, and 24 are ideal. Suitable examples of such organic solvents are alcohols. The organic solvent can also be a diluted alcohol. A specific example of an alcohol is ethanol. In this case, the second fluorescent solvent 82 is an ethanol solution of the fluorescent agent.

[0038] As described above, compressed air flows through the first branch pipe 72. If compressed air is discharged towards the second fluorescent solvent 82 in the second mist generator 80, the second fluorescent solvent 82 is atomized. That is, mist is generated from the second fluorescent solvent 82. The mist from the second fluorescent solvent 82 moves to the first auxiliary pipe 16 as the compressed air flows through the first branch pipe 72.

[0039] A second exhaust pipe 84 is provided in the first branch pipe 72. A second fluorescent solvent recovery unit 86 is provided in the second exhaust pipe 84. The second fluorescent solvent recovery unit 86 has a second filter material 88. The second filter material 88 removes the second fluorescent solvent 82 (mist) contained in the compressed air from the compressed air. Therefore, compressed air without mist flows downstream of the second exhaust pipe 84.

[0040] A sixth valve 90 is provided at the end of the second exhaust pipe 84. The sixth valve 90 is an automatic or manual valve. The outlet of the sixth valve 90 is open to the atmosphere via the second muffler 92.

[0041] The machine inspection system 70 has a second branch pipe 94. The upstream of the second branch pipe 94 branches from the first auxiliary pipe 16. The downstream of the second branch pipe 94 merges with the first auxiliary pipe 16. The point where the second branch pipe 94 merges with the first auxiliary pipe 16 is located further downstream than the branch point of the second branch pipe 94 and further upstream than the second auxiliary pipe 18.

[0042] A third solenoid valve 96 and a digital flow switch 98 are provided in the second branch pipe 94. The third solenoid valve 96 is located upstream of the digital flow switch 98. The digital flow switch 98 measures the flow rate of compressed air flowing in the second branch pipe 94. That is, the digital flow switch 98 is a flow meter. The digital flow switch 98 also functions as a flow regulating valve.

[0043] The first solenoid valve 74, the second solenoid valve 76, and the third solenoid valve 96 are electrically connected to the valve control device 100. The valve control device 100 controls the first solenoid valve 74, the second solenoid valve 76, and the third solenoid valve 96 to open and close. That is, the first solenoid valve 74, the second solenoid valve 76, and the third solenoid valve 96 are automatically opened and closed by the valve control device 100. Furthermore, the digital flow switch 98 is electrically connected to the personal computer (PC) 102. The digital flow switch 98 measures the flow rate of compressed air flowing through the second branch pipe 94. The PC 102 records the measured flow rate. That is, the PC 102 is a memory device.

[0044] Figure 1 illustrates a case where one first auxiliary pipe 16 branches into three second auxiliary pipes 18. Each of the three second auxiliary pipes 18 is equipped with a fourth solenoid valve 104, a fifth solenoid valve 106, and a sixth solenoid valve 108. Furthermore, the number of second auxiliary pipes 18 is not specifically limited to three. The number of solenoid valves is typically the same as the number of second auxiliary pipes 18.

[0045] As shown in Figure 2, the fourth solenoid valve 104 has: a first port 110, a second port 112, a third port 114, a fourth port 116, and a fifth port 118. A first discharge pipe 120 is connected to the first port 110. A second auxiliary pipe 18 is connected to the second port 112. A second discharge pipe 122 is connected to the third port 114. A first connecting pipe 124 is connected to the fourth port 116. A second connecting pipe 126 is connected to the fifth port 118. The first connecting pipe 124 connects the fourth solenoid valve 104 and the first pneumatic cylinder 20 via a first pipe connector 128. Similarly, the second connecting pipe 126 connects the fourth solenoid valve 104 and the first pneumatic cylinder 20 via a second pipe connector 130.

[0046] A first inner chamber 140 and a second inner chamber 142 are formed inside the first pneumatic cylinder 20. Compressed air is supplied to or exhausted from the first inner chamber 140 via a first connecting pipe 124. Compressed air is supplied to or exhausted from the second inner chamber 142 via a second connecting pipe 126.

[0047] Figure 2 illustrates the situation where compressed air is supplied to the second inner chamber 142 and discharged from the first inner chamber 140. At this time, the compressed air flowing through the second auxiliary pipe 18 moves from port 2 112 to port 5 118 within the fourth solenoid valve 104. The compressed air then flows through the second connecting pipe 126 via port 5 118 and into the second inner chamber 142. The compressed air in the second inner chamber 142 pushes the piston 144 in the direction of arrow X. As a result, the piston 144 moves in the direction of arrow X in Figure 2.

[0048] On the other hand, the piston 144 pushes the compressed air in the first inner chamber 140 toward the first connecting pipe 124. The compressed air then moves from the fourth port 116 to the first port 110 in the fourth solenoid valve 104. Furthermore, the compressed air is discharged toward the first discharge pipe 120 via the first port 110. During the above process, the third port 114 is in a closed state.

[0049] As shown in Figure 3, when the piston 144 moves in the Y direction, which is opposite to the X direction, compressed air is supplied to the first inner chamber 140, and compressed air is discharged from the second inner chamber 142. At this time, the compressed air flowing through the second auxiliary pipe 18 moves from the second port 112 to the fourth port 116 within the fourth solenoid valve 104. The compressed air then flows through the first connecting pipe 124 via the fourth port 116 and into the first inner chamber 140. The compressed air in the first inner chamber 140 pushes the piston 144 in the direction indicated by the arrow Y. The piston 144 moves in the direction indicated by the arrow Y in Figure 3.

[0050] On the other hand, the piston 144 pushes the compressed air in the second inner chamber 142 toward the second connecting pipe 126. The compressed air then moves from the fifth port 118 to the third port 114 in the fourth solenoid valve 104. Furthermore, the compressed air is discharged toward the second discharge pipe 122 via the third port 114. During the above process, the first port 110 is in a closed state.

[0051] The same structure and operation are applied to the fifth solenoid valve 106 and the second pneumatic cylinder 22 connected to the fifth solenoid valve 106. Therefore, the same reference numerals are used to denote the same components as described above, and detailed descriptions are omitted. Similarly, the same reference numerals are used to denote the sixth solenoid valve 108 and the third pneumatic cylinder 24 connected to the sixth solenoid valve 108, and detailed descriptions are omitted.

[0052] All of the first discharge pipes 120 and all of the second discharge pipes 122 are connected to a single third exhaust pipe 150 (exhaust section). A third fluorescent solvent recovery section 152 is provided in the third exhaust pipe 150. The third fluorescent solvent recovery section 152 has a third filter material 154. The third filter material 154, like the first filter material 54 and the second filter material 88, removes the second fluorescent solvent 82 (mist) contained in the compressed air from the compressed air. Therefore, compressed air free of mist flows downstream of the third filter material 154. Further downstream of the third exhaust pipe 150 than the third filter material 154, it opens to the atmosphere via a third silencer 156.

[0053] The machine inspection system 70 includes a second black light 158. The second black light 158 ​​is supported, for example, by a stand (not shown). The stand is equipped with casters (not shown). Therefore, the stand and the second black light 158 ​​can be moved by rotating the casters. The second black light 158 ​​approaches or moves away from the first to third pneumatic cylinders 20, 22, and 24.

[0054] The second black light 158 ​​irradiates ultraviolet light onto the first to third pneumatic cylinders 20, 22, and 24 and their surroundings. When any of the first to third pneumatic cylinders 20, 22, or 24 has a leak in the first pipe joint 128 or the second pipe joint 130, as shown in the schematic diagram of Figure 5, compressed air and fluorescent solvent (mist) are ejected from the leak. When the fluorescent solvent is irradiated with ultraviolet light, the highlighted fluorescence F can be observed.

[0055] In Figure 1, for ease of understanding, the first auxiliary pipe 16 and the second auxiliary pipe 18 are represented by seamless pipes in a straight shape. However, the first auxiliary pipe 16 and the second auxiliary pipe 18 are not limited to seamless pipes in a straight shape. Alternatively, the first auxiliary pipe 16 and the second auxiliary pipe 18 may also be seamless pipes bent at a predetermined angle. The first auxiliary pipe 16 and the second auxiliary pipe 18 may also be connecting pipes that connect a plurality of seamless pipes by means of pipe fittings.

[0056] In this embodiment, the air compressor system 10, including the piping inspection system 30 and the machine inspection system 70, is basically configured as described above. Next, the relationship between the effects of the piping inspection system 30 and the machine inspection system 70 and the leakage detection method will be explained. The leakage detection method has the following detailed process. Furthermore, the leakage detection method includes leakage detection methods for piping and machinery.

[0057] Leakage checks on the piping and the air compressor (in this embodiment, the first to third air cylinders 20, 22, and 24) are performed, for example, before the air compressor system 10 is started. This situation will be explained below as an example.

[0058] First, check for leaks in the inspected portion 32 of the first auxiliary piping 16 shown in Figure 1. Specifically, ultraviolet light is irradiated onto the inspected portion 32 by a first black light lamp 62. The first valve 36 and the third valve 48 located on the first auxiliary piping 16 are closed. In this state, compressed air is supplied from the compressor 12 to the main piping 14. The compressed air is distributed to each of the plurality of first auxiliary piping 16. Because the first valve 36 is closed, the flow of compressed air downstream of the first auxiliary piping 16 is prevented.

[0059] Next, valves 2 38 and 4 50 are opened. Furthermore, valves 2 38 and 4 50 may also be opened before compressed air is supplied from compressor 12 to main piping 14. If necessary, valve 58 may also be opened.

[0060] Compressed air flows through the first branch pipe 34 by opening the second valve 38. The compressed air is discharged from the first mist generator 42 toward the first fluorescent solvent 44. As a result, mist is generated in the first fluorescent solvent 44. After the compressed air flows through the first branch pipe 34, the mist flows into the inspected section 32 of the first auxiliary pipe 16.

[0061] Therefore, compressed air carrying mist flows through the inspected section 32. Since the third valve 48 is closed and the fourth valve 50 is open, the compressed air carrying mist flows into the second branch pipe 46 after passing through the inspected section 32. Here, the solvent of the first fluorescent solvent 44 is water or an aqueous emulsion. The vapor pressure of water or an aqueous emulsion is relatively low. Therefore, there is no particular need to make the first auxiliary pipe 16, the first branch pipe 34, the second branch pipe 46, the first mist generator 42, and the first filter material 54 into pressure-resistant structures that take into account the vapor pressure during mist evaporation.

[0062] A first fluorescent solvent recovery unit 52 is provided at the second branch pipe 46. The first fluorescent solvent recovery unit 52 has a first filter material 54. Mist (first fluorescent solvent 44) contained in the compressed air is captured in the first filter material 54. By capturing it, the mist is removed from the compressed air. The compressed air with the mist removed flows into the first exhaust pipe 56. When the fifth valve 58 is open, the compressed air is released from the fifth valve 58 through the first silencer 60 to the atmosphere.

[0063] In contrast, when valve 58 is closed, the compressed air from which the mist has been removed returns to sub-pipe 16 via branch pipe 46. The point where the compressed air returns to sub-pipe 16 is downstream of valve 48. Afterward, the compressed air is supplied to the machine inspection system 70. Since the mist is removed from the compressed air, concerns about water, as a solvent, flowing into solenoid valves 74 to 108 or pneumatic cylinders 20, 22, and 24 are eliminated. Therefore, corrosion of solenoid valves 74 to 108 or pneumatic cylinders 20, 22, and 24 is avoided.

[0064] During the compressed air circulation process described above, if there is no leak in the inspected part 32, fluorescence will not be observed from the inspected part 32. Furthermore, leaks may be, for example, holes, cracks, or insufficient tightening of pipe joints. Conversely, if there is a leak in the inspected part 32, compressed air and mist (first fluorescent solvent 44) are ejected from the leak. The mist contains a fluorescent agent. If the fluorescent agent is irradiated with ultraviolet light, as shown in Figure 4, highlighted fluorescence F can be observed. The inspector can identify compressed air leaks based on the observed fluorescence F.

[0065] In the example diagram of Figure 4, fluorescence F diffuses radially from a single point. The starting point of the diffusion of fluorescence F is the leak point. Thus, by investigating the starting point of the diffusion of fluorescence F, the leak point can be easily identified in a short time.

[0066] Furthermore, fluorescence F can be observed even when the amount of compressed air leakage is minute. Therefore, for example, even if the leak is a tiny hole, the inspector will not overlook the fact that the leak can be detected. Moreover, the inspector does not need to have special knowledge to determine whether a leak exists. The same applies to specific leaks; the inspector does not need to have special knowledge.

[0067] Furthermore, inspectors can quickly determine the presence of a leak based on the presence or absence of fluorescence F. That is, regardless of their skill level or knowledge, inspectors can easily determine the presence or absence of a leak. Inspectors can also easily pinpoint the leak location.

[0068] Next, the machine inspection system 70 checks for leaks in the first to third pneumatic cylinders 20, 22, and 24 (and pipe joints 128 and 130). Therefore, the fifth valve 58 is closed, and compressed air flowing through the first branch pipe 34, the inspected section 32, and the second branch pipe 46 is supplied to the first to third pneumatic cylinders 20, 22, and 24 via the regulator 64, as described above. At this time, leak checks on the piping (inspected section 32) and leak checks on the first to third pneumatic cylinders 20, 22, and 24 (and pipe joints 128 and 130) can be performed simultaneously.

[0069] Alternatively, valves 1 and 3 are switched to the open state, and valves 2 and 4 are switched to the closed state. As a result, compressed air will not flow through the first branch pipe 34 and the second branch pipe 46, but will only flow through the first auxiliary pipe 16. This compressed air is supplied to the first to third pneumatic cylinders 20, 22, and 24 via the regulator 64.

[0070] Valve control device 100 controls solenoid valves 74, 76, and 96 from the first to the third, closing solenoid valve 74 and solenoid valve 76, and opening solenoid valve 96. As a result, compressed air passing through regulator 64 flows only into the second branch pipe 94. Thus, during machine leak checks, compressed air flows through the second branch pipe 94, replacing the first auxiliary pipe 16. Digital flow switch 98 measures the flow rate of compressed air flowing through the second branch pipe 94 and converts this flow rate into an information signal. PC 102 records the information signal as flow rate. PC 102's display shows a graph with elapsed time on the horizontal axis and flow rate on the vertical axis.

[0071] Compressed air flowing through the second branch pipe 94 flows into each of the plurality of second auxiliary pipes 18. The compressed air is introduced from the second connecting pipe 126 into the second inner chamber 142 (see Figure 2) of the first to third pneumatic cylinders 20, 22, 24 via the fourth solenoid valve 104, the fifth solenoid valve 106, and the sixth solenoid valve 108. Therefore, the piston 144 moves in the X direction. The compressed air in the first inner chamber 140 passes through the first connecting pipe 124 and the fourth solenoid valve 104, the fifth solenoid valve 106, and the sixth solenoid valve 108. After passing through the first discharge pipe 120, the compressed air in the first inner chamber 140 is released towards the atmosphere from the third exhaust pipe 150 and the third silencer 156.

[0072] When there are no leaks in the first to third pneumatic cylinders 20, 22, and 24 (and pipe joints 128 and 130), when the piston 144 reaches the forward end after a predetermined time, it appears that the flow of compressed air from the second auxiliary pipe 18 toward the second inner chamber 142 of each of the first to third pneumatic cylinders 20, 22, and 24 stops. At the same time, the release of compressed air from the first inner chamber 140 of each of the first to third pneumatic cylinders 20, 22, and 24 toward the atmosphere also appears to stop. At this time, the flow rate of compressed air in the second branch pipe 94 is 0.

[0073] In contrast, for example, when a leak exists in the first cylinder 20, compressed air continues to flow from the second branch pipe 94 toward the first cylinder 20 even after the piston 144 reaches its forward end. The compressed air supplied to the first cylinder 20 is ejected into the atmosphere from the leak. Therefore, after a predetermined time has elapsed since the second branch pipe 94 began supplying compressed air to the first to third cylinders 20, 22, and 24, the flow rate of compressed air in the second branch pipe 94 is greater than 0. An inspector can recognize that the flow rate of compressed air in the second branch pipe 94 is greater than 0 by checking the display of the digital flow switch 98 or the display of the PC 102.

[0074] In other words, the inspector can determine that a leak exists in any of the first to third pneumatic cylinders 20, 22, and 24 (or pipe joints 128 and 130) based on the fact that the flow rate of compressed air in the second branch pipe 94 is greater than 0. Then, the inspector performs specific work to determine if there is a leak in any of the first to third pneumatic cylinders 20, 22, and 24 (or pipe joints 128 and 130).

[0075] Specifically, while maintaining the first solenoid valve 74 in the closed state, the inspector operates the valve control device 100 to switch the second solenoid valve 76 to the closed state. Furthermore, the inspector operates the valve control device 100 to switch the third solenoid valve 96 to the open state. Through these operations, compressed air flows only through the first branch pipe 72. Furthermore, ultraviolet light is irradiated around the first to third pneumatic cylinders 20, 22, and 24 from the second black light lamp 158.

[0076] Compressed air flowing through the first branch pipe 72 is ejected towards the second fluorescent solvent 82 within the second mist generator 80. As a result, mist is generated in the second fluorescent solvent 82. After flowing through the first branch pipe 72 with the compressed air, the mist is distributed to each of the plurality of second sub-pipes 18 via the first sub-pipe 16.

[0077] Compressed air carrying mist is then supplied to the first to third pneumatic cylinders 20, 22, and 24 respectively via the fourth solenoid valve 104 to the sixth solenoid valve 108. Ideally, compressed air is first supplied to the first inner chamber 140 (or the second inner chamber 142) and discharged from the second inner chamber 142 (or the first inner chamber 140). After a predetermined time, the purpose of supplying compressed air is switched. That is, compressed air is supplied to the second inner chamber 142 (or the first inner chamber 140) and discharged from the first inner chamber 140 (or the second inner chamber 142).

[0078] The first pneumatic cylinder 20 will be used as an example for explanation. When compressed air is supplied to the second inner chamber 142, the compressed air in the first inner chamber 140 flows in the following order: first connecting pipe 124, port 116 of the fourth solenoid valve 104, port 110 of the fourth solenoid valve 104, first discharge pipe 120, and third exhaust pipe 150 (see Figure 2). Conversely, when compressed air is supplied to the first inner chamber 140, the compressed air in the second inner chamber 142 flows in the following order: second connecting pipe 126, port 118 of the fourth solenoid valve 104, port 114 of the fourth solenoid valve 104, second discharge pipe 122, and third exhaust pipe 150 (see Figure 3). In the second pneumatic cylinder 22, compressed air passes through the fifth solenoid valve 106 instead of the fourth solenoid valve 104. In the third pneumatic cylinder 24, compressed air passes through the sixth solenoid valve 108 instead of the fourth solenoid valve 104.

[0079] A third fluorescent solvent recovery unit 152 is provided in the third exhaust pipe 150. The third fluorescent solvent recovery unit 152 has a third filter material 154. The mist (second fluorescent solvent 82) contained in the compressed air is captured in the third filter material 154. By capturing it, the mist is removed from the compressed air. The compressed air with the mist removed is released from the third exhaust pipe 150 toward the atmosphere through the third silencer 156.

[0080] For example, if there is a leak only in the first pressure cylinder 20, during the above-described flow process, as shown in FIG5, fluorescence F can be observed diffusing from the leak point in the first pressure cylinder 20. In contrast, fluorescence F is not observed in the second pressure cylinder 22 and the third pressure cylinder 24. Therefore, the inspector determines that the leak in the compressed air is in the first pressure cylinder 20 based on the observation of fluorescence F in the first pressure cylinder 20 and the absence of fluorescence F in the second pressure cylinder 22 and the third pressure cylinder 24.

[0081] A leak is observed at the second connector 130 connecting the first pneumatic cylinder 20 and the second connecting pipe 126. In this case, for example, when compressed air is supplied to the first inner chamber 140 and discharged from the second inner chamber 142, fluorescence F is observed diffusing from the second connector 130 of the first pneumatic cylinder 20. However, fluorescence F is not observed at the second connectors 130 of the second pneumatic cylinder 22 and the third pneumatic cylinder 24. Based on this observation, the inspector can determine that the compressed air leak is located at the second connector 130 of the first pneumatic cylinder 20.

[0082] Thus, according to the machine inspection system 70, firstly, from the plurality of first auxiliary pipes 16, the first to third pneumatic cylinders 20, 22, 24 (or pipe joints 128, 130) that are specifically connected to leaks of compressed air containing mist are specifically identified as having leaks. At this time, ultraviolet light is irradiated only on the first to third pneumatic cylinders 20, 22, 24 and their surroundings where leaks are determined to have occurred. Next, based on the fluorescence F emphasized by ultraviolet light, the pneumatic cylinders (or pipe joints 128, 130) from the first to third pneumatic cylinders 20, 22, 24 (or pipe joints 128, 130) that have experienced leaks are specifically identified.

[0083] According to the above procedure, it is not necessary to irradiate the first to third pneumatic cylinders 20, 22, and 24 (or pipe joints 128 and 130) of the other first auxiliary pipes 16 with ultraviolet light. Here, "other first auxiliary pipes 16" refers to the first auxiliary pipes 16 whose flow rate is measured to be 0 by the digital flow switch 98. In other words, it is determined that no leakage has occurred in the first to third pneumatic cylinders 20, 22, and 24 (or pipe joints 128 and 130) of the other first auxiliary pipes 16. That is, it is not necessary to irradiate the first to third pneumatic cylinders 20, 22, and 24 (or pipe joints 128 and 130) that have not leaked with ultraviolet light. Therefore, the miniaturization of the second black light lamp 158 can be achieved.

[0084] In the inspection of machine leaks, regardless of the inspector's skill level or knowledge, the inspector can easily determine whether there is a leak of compressed air from the first to third air cylinders 20, 22, 24 (or pipe joints 128, 130). Furthermore, the inspector can easily and quickly pinpoint the leak location.

[0085] Compressed air containing the second fluorescent solvent 82 is circulated through the fourth solenoid valve 104 to the sixth solenoid valve 108 and the first to third pneumatic cylinders 20, 22, and 24. The solvent for the second fluorescent solvent 82 is, for example, a highly volatile organic solvent. The mist evaporates rapidly. Therefore, there is almost no situation where mist remains inside the second auxiliary pipe 18, the fourth solenoid valve 104 to the sixth solenoid valve 108, and the first to third pneumatic cylinders 20, 22, and 24. Thus, it is possible to prevent malfunctions or corrosion of the fourth solenoid valve 104 to the sixth solenoid valve 108 and the first to third pneumatic cylinders 20, 22, and 24 caused by the second fluorescent solvent 82.

[0086] Furthermore, because the mist evaporates rapidly, there is almost no chance that the lubricant (grease, etc.) in the fourth to sixth solenoid valves 104 and the first to third pneumatic cylinders 20, 22, and 24 will dissolve into the mist. Therefore, it is possible to avoid affecting the sealing or operating performance of the fourth to sixth solenoid valves 104 and the first to third pneumatic cylinders 20, 22, and 24.

[0087] The main materials for the fourth solenoid valve 104 to the sixth solenoid valve 108 and the first to third pneumatic cylinders 20, 22, and 24 are metal. Metal materials have chemical stability against organic solvents. Therefore, when the solvent for the second fluorescent solvent 82 is an organic solvent, it can further prevent malfunctions or corrosion in the fourth solenoid valve 104 to the sixth solenoid valve 108 and the first to third pneumatic cylinders 20, 22, and 24.

[0088] In particular, the metal material exhibits chemical stability to alcohols such as ethanol. Moreover, alcohols are highly volatile. Therefore, it is ideal for the solvent of the second fluorescent solvent 82 to be an alcohol such as ethanol.

[0089] Furthermore, the fourth solenoid valve 104 to the sixth solenoid valve 108 and the first to third pneumatic cylinders 20, 22, and 24 are pressure-resistant structures. Therefore, even when the mist evaporates, there is no concern that the fourth solenoid valve 104 to the sixth solenoid valve 108 and the first to third pneumatic cylinders 20, 22, and 24 will deform due to vapor pressure.

[0090] After the above leak inspection is completed, replace the inspected part 32 or machine where a leak was found. Then, repeat the above leak inspection until no leak is found.

[0091] After all leak checks are completed, valve 58 is opened. Simultaneously, mist and compressed air are released from branch pipe 72 through silencer 92 towards the atmosphere. This prevents mist from accumulating in branch pipe 72.

[0092] When the air compressor system 10 is operated, valves 36, 48, and 74 are opened, while valves 38, 50, 58, 76, and 96 are closed. This allows compressed air from compressor 12 to be distributed to each of the first auxiliary pipes 16 via the main pipe 14. The compressed air is then distributed to each of the second auxiliary pipes 18, becoming the actuating air for the first to third air cylinders 20, 22, and 24. At this time, no compressed air flows through the first branch pipe 34 and the first branch pipe 72. Therefore, no mist accompanies the compressed air flow.

[0093] As described above, the inspector can quickly determine the presence of a leak based on whether fluorescence F is observed. Therefore, for example, if a compressed air leak occurs due to an unforeseen event during the operation of the air compressor system 10, stopping the operation of the air compressor system 10 allows for a quick conclusion to the leak inspection of the piping or machine. In other words, it is not necessary to shut down the air compressor system 10 for an extended period. Therefore, the air compressor system 10 can be restored earlier.

[0094] As explained above, this embodiment discloses a piping inspection system, which is a piping inspection system 30 for checking whether there is a compressed air leak in the inspected section 32 of the piping 16 through which compressed air flows. The system includes: a first branch pipe 34, which branches off from the piping upstream of the inspected section and merges with the piping; a fluorescent solvent supply unit 40, which is provided in the first branch pipe and supplies fluorescent solvent 44 to the inspected section; a second branch pipe 46, which branches off from the piping downstream of the inspected section; and a fluorescent solvent recovery unit 52, which is provided in the second branch pipe and recovers the fluorescent solvent from the inspected section.

[0095] At this time, based on whether fluorescence can be observed in the inspected part, it is easy and quick to determine whether there is a leak in the inspected part. Moreover, the inspector does not need special skills or knowledge to make this judgment.

[0096] Furthermore, after the fluorescent solvent flows through the inspected section, it is recovered by the fluorescent solvent recovery unit. Therefore, it prevents the fluorescent solvent from flowing downstream of the inspected section in the piping. That is, it prevents the fluorescent solvent from flowing into air compressors or similar equipment connected to the end of the piping. It also prevents the fluorescent solvent from remaining inside the piping or air compressor. Therefore, concerns about air compressor malfunctions or corrosion due to fluorescent solvents can be eliminated.

[0097] In this embodiment, the aforementioned fluorescent solvent supply unit has a mist generator 42 that atomizes the fluorescent solvent, and supplies the fluorescent solvent, which has been atomized, to the aforementioned piping inspection system of the inspected part.

[0098] Mist diffuses more easily than droplets. Therefore, by incorporating mist into the compressed air, the mist (fluorescent solvent) can easily reach the inspected area. Furthermore, the mist (fluorescent solvent) can easily flow out of the inspected area.

[0099] In the piping inspection system of this embodiment, the aforementioned fluorescent solvent is an aqueous solution or emulsion aqueous solution of a fluorescent agent.

[0100] Water or emulsion water has a relatively low vapor pressure. Therefore, evaporation of mist is not easy inside the piping. There is no particular need to design the piping inspection system to be pressure-resistant, taking into account the vapor pressure of the mist. This allows for lower equipment investment costs.

[0101] This embodiment discloses a piping inspection system, which includes: a first valve 36, which is provided between the branch point of the first branch pipe and the confluence point of the aforementioned piping; a second valve 38, which is provided upstream of the first branch pipe from the aforementioned fluorescent solvent supply section; a third valve 48, which is provided downstream of the aforementioned piping from the branch point of the second branch pipe; and a fourth valve 50, which is provided upstream of the second branch pipe from the aforementioned fluorescent solvent recovery section.

[0102] In this structure, the opening and closing of valves 1 to 4 can be switched individually. By switching, the fluid flowing through the section being inspected can be selectively switched to either compressed air without mist or compressed air carrying mist. That is, the fluid flowing through the section being inspected can be easily switched.

[0103] In the piping inspection system of this embodiment, the exhaust section 56 is located downstream of the aforementioned fluorescent solvent recovery section in the aforementioned second branch pipe and is open to the atmosphere.

[0104] The fluorescent solvent carried by the compressed air is separated from the compressed air by the fluorescent solvent recovery unit. Therefore, the compressed air with the fluorescent solvent removed flows downstream of the fluorescent solvent recovery unit. However, considering that due to unforeseen events, the removal of fluorescent solvent in the fluorescent solvent recovery unit may be insufficient, the compressed air can be released to the atmosphere in such cases according to the above structure. Therefore, it is possible to prevent fluorescent solvent from flowing into air compressors or the like connected to the end of the piping.

[0105] The piping inspection system disclosed in this embodiment is equipped with a black light 62 that irradiates ultraviolet light onto the part to be inspected.

[0106] When there is a leak in the piping, compressed air containing mist is sprayed out from the leak point. When irradiated with ultraviolet light, the fluorescence is highlighted by the ultraviolet light. Therefore, the leak of compressed air can be easily located.

[0107] In factories, piping is often quite long. When applying the structure described in Japanese Patent No. 4297862 to leak detection of piping, a light source and camera must be installed for the entire piping system. Therefore, dozens of light sources and cameras are required. As a result, equipment investment increases significantly.

[0108] In contrast, according to this embodiment, the amount of ultraviolet light irradiating the inspected part by the black light lamp is sufficient. Therefore, the equipment investment can be reduced.

[0109] Furthermore, the present invention is not limited to the above-described embodiments, and various structures can be adopted without departing from the spirit of the invention.

[0110] For example, when only a leak check is performed on compressed air from the piping, compressed air can be released to the atmosphere from valve 58 via silencer 60. In contrast, when only a leak check is performed on compressed air from the machine, valves 1 and 3 are opened, and valves 2, 4, and 5 are closed, supplying compressed air to branch pipe 72.

[0111] As understood therein, leak checks on the piping and leak checks on the machine can also be performed separately. Furthermore, there is no need to install both the piping inspection system 30 and the machine inspection system 70 simultaneously in the air compressor system 10. That is, it is sufficient to install only the piping inspection system 30 in the air compressor system 10.

[0112] Air compressors are not specifically limited to pneumatic cylinders. Other specific examples of air compressors include pneumatic chucks or pneumatic actuators. [Simplified Explanation of the Diagram]

[0011] [Figure 1] is a schematic circuit diagram of an air compressor system.

[0012] [Figure 2] shows a schematic circuit diagram of the state in which compressed air is supplied to the second inner chamber of the pneumatic cylinder and compressed air is discharged from the first inner chamber of the pneumatic cylinder.

[0013] [Figure 3] shows a schematic circuit diagram of the state in which compressed air is supplied to the first inner chamber of the pneumatic cylinder and compressed air is discharged from the second inner chamber of the pneumatic cylinder.

[0014] [Figure 4] is a schematic diagram showing the state of fluorescence from the inspected part of the piping.

[0015] [Figure 5] is a schematic diagram illustrating the state of fluorescence generated from a pneumatic cylinder (or a pipe joint).

Claims

1. A piping inspection system for inspecting whether there is a compressed air leak in the inspected portion (32) of a piping (16) supplying compressed air to air compressors (20, 22, 24), and wherein the piping inspection system (30) is located upstream of the air compressor in the direction of compressed air flow, characterized by comprising: a first branch pipe (34) that branches off from the piping upstream of the inspected portion and merges with the piping; a fluorescent solvent supply unit (40) provided in the first branch pipe for supplying fluorescent solvent (44) to the inspected portion; a second branch pipe (46) that branches off from the piping downstream of the inspected portion; and a fluorescent solvent recovery unit (52) provided in the second branch pipe for recovering the fluorescent solvent from the inspected portion, wherein the second branch pipe and the fluorescent solvent recovery unit are located upstream of the air compressor.

2. As in request item 1, the piping inspection system, wherein, The aforementioned fluorescent solvent supply unit has a mist generator (42) that atomizes the fluorescent solvent, and supplies the fluorescent solvent, which has been turned into mist, to the aforementioned inspected part.

3. As in request item 1, the piping inspection system, wherein, The aforementioned fluorescent solvent is an aqueous solution or emulsion aqueous solution of the fluorescent agent.

4. As in request item 1, the piping inspection system, wherein, It includes: a first valve (36) located between the branch point of the first branch pipe and the confluence point of the aforementioned piping; a second valve (38) located upstream of the first branch pipe from the aforementioned fluorescent solvent supply section; a third valve (48) located downstream of the aforementioned piping from the branch point of the second branch pipe; and a fourth valve (50) located upstream of the second branch pipe from the aforementioned fluorescent solvent recovery section.

5. The piping inspection system as requested in any one of items 1 to 4, wherein, It has an exhaust section (56) which is located downstream of the aforementioned fluorescent solvent recovery section in the aforementioned second branch pipe and is open to the atmosphere.

6. As in request item 1, the piping inspection system, wherein, It is equipped with a black light (62) that irradiates ultraviolet light toward the part being inspected.

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