Piping inspection method

Abstract

To provide a piping inspection method that can perform piping inspection while reducing inspection incidental work such as attachment and detachment of a heat insulator.SOLUTION: A piping inspection method includes: a first procedure for arranging an outer coil 13 and a camera 14 on an outer side of a heat insulator 1 by using an access tool 15; a second procedure for measuring a thickness of piping 2 at a position of an ultrasonic sensor 11 by using the ultrasonic sensor 11, an inner coil 12, the outer coil 13 and a control device 16 which are pre-fixed to an inner side of the heat insulator 1 and the outer surface of the piping 2; a third procedure for imaging the heat insulator 1 by using the camera 14; a fourth procedure for removing the heat insulator 1 from the piping 2 when it is determined that a thickness of the piping 2 at the position of the ultrasonic sensor 11 is abnormal, or it is determined that an appearance of the heat insulator 1 is abnormal; a fifth procedure for placing the ultrasonic sensor 23 on the outer surface of the piping 2; and the sixth procedure for measuring the thickness of the piping 2 at the position of the ultrasonic sensor 23 by using the ultrasonic sensor 23 and the control device 16.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a piping inspection method. [Background technology]

[0002] Because high-temperature fluids flow through plant piping, the exterior surfaces are covered with insulation. Furthermore, the interior surfaces of the piping can be corroded by the high-temperature fluid, causing thinning. Therefore, inspections are conducted to measure the thickness of the piping.

[0003] This section explains a pipe inspection method assuming that the pipe is located at a high altitude. In a typical pipe inspection method, workers assemble scaffolding to work close to the pipe. Then, the workers on the scaffolding remove the insulation from the pipe, place an ultrasonic sensor on the outer surface of the pipe, and use this ultrasonic sensor to measure the thickness of the pipe.

[0004] On the other hand, in the pipe inspection method of Patent Document 1, a worker on the floor uses an access tool to remove a detachable portion of the thermal insulation material attached to a specific position on the outer surface of the pipe (in other words, a portion that is detachable from other portions of the thermal insulation material) and place an ultrasonic sensor at the specific position. The access tool has a rod whose tip can hold the ultrasonic sensor and whose base end is held by the worker, a hook attached to the tip of the rod and capable of engaging with the detachable portion of the thermal insulation material, and an operating lever attached to the base end of the rod and capable of operating the hook. Using the access tool eliminates the need to assemble scaffolding and can reduce incidental inspection work. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-156806 Summary of the Invention [Problem to be solved by the invention]

[0006] Although the pipe inspection method of Patent Document 1 does not require the assembly of scaffolding, it does require the attachment and detachment of thermal insulation, leaving room for improvement in terms of reducing the work incidental to the inspection. One possible method for avoiding the attachment and detachment of thermal insulation is to fix ultrasonic sensors to the inside of the thermal insulation and to the outer surface of the pipe in advance, and measure the thickness of the pipe using these ultrasonic sensors. However, for various reasons, this method has a limit to the number of ultrasonic sensors that can be fixed to the outer surface of the pipe, making it difficult to measure the thickness of the pipe at positions other than the positions where the ultrasonic sensors are fixed.

[0007] The present invention has been made in consideration of the above circumstances, and its object is to provide a piping inspection method that can perform piping inspection while reducing incidental inspection work such as attaching and detaching thermal insulation materials. [Means for solving the problem]

[0008] In order to achieve the above object, a pipe inspection method of the present invention includes a first step of using an access tool that holds an outer coil and a camera to place the outer coil and the camera outside a thermal insulation material that covers an outer surface of a pipe; a first ultrasonic sensor that is fixed in advance inside the thermal insulation material and on the outer surface of the pipe; an inner coil that is placed in advance inside the thermal insulation material and connected to the first ultrasonic sensor; the outer coil that is placed outside the thermal insulation material in the first step so as to face the inner coil; and a control device that inputs and outputs signals to and from the first ultrasonic sensor by utilizing electromagnetic induction between the inner coil and the outer coil, to measure the thickness of the pipe at the position of the first ultrasonic sensor and determine whether or not there is an abnormality in the thickness of the pipe. a third step of photographing the insulation material using the camera arranged outside the insulation material in the first step and determining whether there is an abnormality in the appearance of the insulation material; a fourth step of removing the insulation material from the pipe if it is determined in the second step that there is an abnormality in the thickness of the pipe or if it is determined in the third step that there is an abnormality in the appearance of the insulation material; a fifth step of arranging a second ultrasonic sensor on the outer surface of the pipe from which the insulation material has been removed in the fourth step; and a sixth step of measuring the thickness of the pipe at the position of the second ultrasonic sensor using the second ultrasonic sensor arranged on the outer surface of the pipe and a control device that inputs and outputs signals between the second ultrasonic sensor and the second ultrasonic sensor in the fifth step. [Effects of the Invention]

[0009] According to the present invention, piping inspection can be performed while reducing incidental inspection work such as attaching and detaching thermal insulation materials. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a block diagram showing the configuration of a piping inspection device according to an embodiment of the present invention. [Figure 2] 1 is a schematic diagram illustrating an access tool and its method of use in accordance with one embodiment of the present invention. [Figure 3]2 is a schematic diagram showing the arrangement of a first ultrasonic sensor, an inner coil, and an outer coil in one embodiment of the present invention. FIG. [Figure 4] FIG. 2 is a diagram illustrating a monitor screen according to an embodiment of the present invention. [Figure 5] FIG. 10 is a diagram showing a waveform signal when no thinning of the pipe occurs in one embodiment of the present invention. [Figure 6] FIG. 4 is a diagram showing a waveform signal when thinning of a pipe occurs in an embodiment of the present invention. [Figure 7] FIG. 4 is a schematic diagram illustrating the arrangement of a second ultrasonic sensor in one embodiment of the present invention. [Figure 8] 1 is a flowchart showing the procedure of a piping inspection method according to an embodiment of the present invention. [Figure 9] 10 is a schematic diagram illustrating an access tool and its method of use according to one variation of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] An embodiment of the present invention will be described with reference to the drawings.

[0012] Fig. 1 is a block diagram showing the configuration of a piping inspection device in this embodiment. Fig. 2 is a schematic diagram showing an access tool and a method of using the same in this embodiment. Fig. 3 is a schematic diagram showing the arrangement of a first ultrasonic sensor, an inner coil, and an outer coil in this embodiment. Fig. 4 is a diagram showing a monitor screen in this embodiment. Note that Figs. 1 to 3 show only one set of ultrasonic sensor and inner coil out of multiple sets of ultrasonic sensors and inner coils.

[0013] The piping inspection device of this embodiment includes a plurality of ultrasonic sensors 11 (first ultrasonic sensors) that are pre-fixed inside the thermal insulation material 1 and on the outer surface of the piping 2 via adhesive 3 (see Figure 5(a) or Figure 6(a) described below), a plurality of inner coils 12 that are pre-arranged inside the thermal insulation material 1 and connected to the plurality of ultrasonic sensors 11 via wiring, an outer coil 13, a camera 14, an access tool 15 that holds the outer coil 13 and the camera 14, a control device 16 that is connected to the outer coil 13 and the camera 14 via wiring and a connector, and a monitor 17 that is connected to the control device 16 via wiring.

[0014] 2, the access tool 15 is configured as a rod, for example, with the tip side holding the outer coil 13 and the camera 14, and the base side being held by the worker. When the piping 2 is at a high altitude, the worker 4 on the floor can use the access tool 15 to position the outer coil 13 and the camera 14 outside the thermal insulation material 1 covering the outer surface of the piping 2.

[0015] The thermal insulation material 1 has, for example, a plurality of marks that respectively indicate the positions of the plurality of inner coils 12. An operator sequentially selects one inner coil 12 from the plurality of inner coils 12 and positions the outer coil 13 so as to face the selected inner coil 12. The control device 16 inputs and outputs signals to and from the corresponding ultrasonic sensor 11 by utilizing electromagnetic induction between the selected inner coil 12 and outer coil 13 (more specifically, the conversion of an electric signal to magnetic flux by one coil and the reconversion of the magnetic flux to an electric signal by the other coil).

[0016] The control device 16 has a switching unit 18, a pulser 19, a receiver 20, a signal processing unit 21, and a storage unit 22. The switching unit 18 is composed of a multiplexer or the like, the signal processing unit 21 is composed of a processor or the like that executes processing according to a program, and the storage unit 22 is composed of a hard disk, memory, or the like.

[0017] The switching unit 18 of the control device 16 switches between the pulser 19 and the receiver 20 to connect them to the outer coil 13. The pulser 19 of the control device 16 outputs a pulse signal (electrical signal) to the ultrasonic sensor 11 via the outer coil 13 and the inner coil 12. The piezoelectric element of the ultrasonic sensor 11 vibrates in response to the pulse signal and transmits ultrasonic waves to the piping 2. The piezoelectric element of the ultrasonic sensor 11 receives ultrasonic waves reflected by the outer and inner surfaces of the piping 2, converts the received ultrasonic waves into a waveform signal (electrical signal), and outputs the waveform signal to the control device 16 via the inner coil 12 and the outer coil 13. The ultrasonic sensor 11 stores identification information and outputs the identification information to the control device 16 via the inner coil 12 and the outer coil 13.

[0018] The receiver 20 of the control device 16 digitizes the waveform signal and identification information of the ultrasonic sensor 11 and outputs them to the signal processing unit 21. The memory unit 22 of the control device 16 stores in advance the relationship between the identification information of the ultrasonic sensor 11 and the fixed position. The signal processing unit 21 of the control device 16 uses the relationship stored in the memory unit 22 to obtain the fixed position of the ultrasonic sensor 11 based on the identification information input from the ultrasonic sensor 11. The input waveform signal S of the ultrasonic sensor 11 is then stored in the memory unit 22 in association with the position of the ultrasonic sensor 11, and is also displayed on the monitor 17 (see FIG. 4).

[0019] The signal processing unit 21 of the control device 16 uses gates A1 and A2 (more specifically, the expected ranges of time and amplitude) to extract the propagation time of the ultrasonic wave (external echo) B reflected on the outer surface of the pipe 2 and the propagation time of the ultrasonic wave (internal echo) C0 reflected on the inner surface of the pipe 2 from the waveform signal S0 (see FIG. 5(b)) of the ultrasonic sensor 11 acquired initially, that is, when no thinning of the pipe 2 has occurred as shown in FIG. 5(a), and calculates the initial value t0 of the thickness of the pipe 2 based on the difference between them. Then, a thickness threshold t L is set based on the initial value t0 of the thickness and stored in the storage unit 22.

[0020] The signal processing unit 21 of the control device 16 extracts the propagation time of the ultrasonic wave B reflected on the outer surface of the pipe 2 and the propagation time of the ultrasonic wave C reflected on the inner surface of the pipe 2 from the waveform signal S (see FIG. 6(b)) of the ultrasonic sensor 11 acquired after a predetermined time has elapsed, for example, when thinning of the pipe 2 occurs as shown in FIG. 6(a) using gates A1 and A2, and calculates the thickness t of the pipe 2 based on the difference between them. Then, the signal processing unit 21 calculates the thickness t of the pipe 2 based on the difference between the propagation time of the ultrasonic wave B reflected on the outer surface of the pipe 2 and the propagation time of the ultrasonic wave C reflected on the inner surface of the pipe 2 using gates A1 and A2. L At the same time, the thickness t is displayed on the monitor 17 (see FIG. 4).

[0021] The signal processing unit 21 of the control device 16 processes the video P from the camera 14 and displays it on the monitor 17 (see FIG. 4).

[0022] The piping inspection device of this embodiment further includes an ultrasonic sensor 23 (second ultrasonic sensor) connectable to the control device 16 via wiring and a connector, instead of the outer coil 13. The ultrasonic sensor 23 can be repositioned on the outer surface of the piping 2 when the heat insulating material 1 is removed from the piping 2, as shown in FIG.

[0023] When the ultrasonic sensor 23 is connected, the control device 16 inputs and outputs signals to and from the ultrasonic sensor 23. More specifically, the pulser 19 of the control device 16 outputs a pulse signal to the ultrasonic sensor 23. The piezoelectric element of the ultrasonic sensor 23 vibrates in response to the pulse signal and transmits ultrasonic waves to the piping 2. The piezoelectric element of the ultrasonic sensor 23 receives ultrasonic waves reflected by the outer and inner surfaces of the piping 2, converts the received ultrasonic waves into waveform signals, and outputs the waveform signals to the control device 16.

[0024] The signal processing unit 21 of the control device 16 extracts the propagation time of the ultrasonic wave reflected on the outer surface of the pipe 2 and the propagation time of the ultrasonic wave reflected on the inner surface of the pipe 2 from the waveform signal of the ultrasonic sensor 23 using gates A1 and A2, and calculates the thickness t of the pipe 2 based on the difference between them. L At the same time, the thickness t is displayed on the monitor 17.

[0025] Next, a pipe inspection method using the above-described pipe inspection device will be described. Fig. 7 is a flowchart showing the procedure of the pipe inspection method in this embodiment.

[0026] First, in step S1, a worker 4 on the floor uses an access tool 15 to place the outer coil 13 and the camera 14 outside the thermal insulation material 1 (see FIG. 2 above). At this time, the worker 4 selects one inner coil 12 from the multiple inner coils 12, and places the outer coil 13 so that it faces the selected inner coil 12. In addition, the worker 4 confirms the proximity of the outer coil 13 and the inner coil 12 by the image P or waveform signal S displayed on the monitor 17.

[0027] Then, the process proceeds to step S2, and the worker 4 on the floor uses the ultrasonic sensor 11, the inner coil 12, the outer coil 13, and the control device 16 to measure the thickness t at the position of the ultrasonic sensor 11, that is, at a representative position of the pipe 2 (for example, a position set at 50 mm intervals). Then, the process proceeds to step S3, and the worker 4 checks whether the thickness t of the pipe 2 displayed on the monitor 17 is equal to or greater than the threshold value t. L Depending on whether the thickness is equal to or less than the above, it is determined whether there is an abnormality in the thickness of the pipe 2 at the representative position.

[0028] If there is no abnormality in the thickness of the pipe 2 at the representative position, the process proceeds to step S4. In step S4, the worker 4 on the floor uses the camera 14 to photograph the thermal insulation material 1. Thereafter, the process proceeds to step S5, and it is determined from the image P displayed on the monitor 17 whether there is any abnormality in the appearance of the thermal insulation material 1 (for example, deformation, discoloration, or cracks).

[0029] The above-described steps S1 to S5 are repeatedly performed by changing the position of the outer coil 13, i.e., the representative position of the pipe 2. If there is an abnormality in the thickness of the pipe 2 at any of the representative positions or if there is an abnormality in the appearance of the heat insulating material 1, the process proceeds to step S6.

[0030] In step S6, worker 4 connects ultrasonic sensor 23 to control device 16 via wiring and a connector. Worker 4 also assembles scaffolding (not shown) to work close to pipe 2. Then, worker 4 on the scaffolding removes thermal insulation material 1 from pipe 2. Thereafter, proceeding to step S7, worker 4 on the scaffolding places ultrasonic sensor 23 at a position other than the representative position on the outer surface of pipe 2 (for example, a position set at 20 mm intervals). Thereafter, proceeding to step S8, ultrasonic sensor 23 and control device 16 are used to measure the thickness t at the position of ultrasonic sensor 23, i.e., at another position of pipe 2.

[0031] As described above, in this embodiment, a screening inspection is performed through steps S1 to S5. In this screening inspection, the outer coil 13 and the camera 14 are placed outside the thermal insulation material 1 using the access tool 15. Then, the thickness of the pipe 2 at a representative position is measured using the ultrasonic sensor 11, the inner coil 12, the outer coil 13, and the control device 16, and the thermal insulation material 1 is photographed using the camera 14. This eliminates the need to assemble scaffolding. Furthermore, if no abnormalities are found in the screening inspection, the thermal insulation material 1 is not removed from the pipe 2. This allows the piping inspection to be performed while reducing incidental inspection work, such as assembling scaffolding and attaching and detaching the thermal insulation material. As a result, the workload and work time of periodic inspections can be reduced, for example.

[0032] Furthermore, in this embodiment, if an abnormality is found in the screening inspection, scaffolding is erected and the thermal insulation material 1 is removed from the pipe 2. Then, the ultrasonic sensor 23 and the control device 16 are used to measure the thickness t of the pipe 2 at positions other than the representative position. Therefore, the extent of thinning of the pipe 2 can be ascertained, and measures such as replacing the pipe 2 can be considered.

[0033] In the above embodiment, the piping inspection device has been described as having a common control device 16 for the ultrasonic sensor 11 and the ultrasonic sensor 23, but this is not limiting. The piping inspection device may also have a first control device that inputs and outputs signals to and from the ultrasonic sensor 11 via the outer coil 13 and the inner coil 12, and a second control device that inputs and outputs signals to and from the ultrasonic sensor 23.

[0034] In the above embodiment, the access tool 15 is described as a rod held by an operator, but the present invention is not limited to this. As shown in a modified example in Fig. 8, the access tool 15A may be an aircraft remotely controlled by an operator (more specifically, an aircraft that moves in response to commands from an operating device 24 operated by the operator).

[0035] In the above embodiment, the control device 16 displays the waveform signal S of the ultrasonic sensor 11 acquired when the outer coil 13 and the inner coil 12 approach each other on the monitor 17, but this is not limiting. The control device 16 may detect whether the outer coil 13 and the inner coil 12 are approaching each other based on the amplitude of the waveform signal S of the ultrasonic sensor 11. When the control device 16 detects that the outer coil 13 and the inner coil 12 are approaching each other, it may notify this fact using an alarm (in detail, for example, a message may be displayed on the monitor 17 or a buzzer may sound). [Explanation of symbols]

[0036] 1 Heat insulation material 2 Piping 11 Ultrasonic sensor (first ultrasonic sensor) 12 inner coil 13 Outer coil 14 Camera 15,15A Access Tool 16 Control device 23 Ultrasonic sensor (second ultrasonic sensor)

Claims

1. a first step of using an access tool that holds the outer coil and the camera to position the outer coil and the camera outside the thermal insulation covering the outer surface of the piping; a second step of measuring the thickness of the pipe at the position of the first ultrasonic sensor and determining whether there is an abnormality in the thickness of the pipe using a first ultrasonic sensor fixed in advance inside the heat insulating material and on the outer surface of the pipe, an inner coil placed in advance inside the heat insulating material and connected to the first ultrasonic sensor, the outer coil placed outside the heat insulating material in the first step so as to face the inner coil, and a control device that inputs and outputs signals to and from the first ultrasonic sensor using electromagnetic induction between the inner coil and the outer coil; a third step of photographing the heat insulating material using the camera disposed outside the heat insulating material in the first step and determining whether there is an abnormality in the appearance of the heat insulating material; a fourth step of removing the heat insulating material from the piping when it is determined in the second step that there is an abnormality in the thickness of the piping or when it is determined in the third step that there is an abnormality in the appearance of the heat insulating material; a fifth step of disposing a second ultrasonic sensor on the outer surface of the pipe from which the heat insulating material has been removed in the fourth step; a sixth step of measuring the thickness of the pipe at the position of the second ultrasonic sensor using the second ultrasonic sensor arranged on the outer surface of the pipe in the fifth step and a control device that inputs and outputs signals between the second ultrasonic sensor and the control device; A piping inspection method comprising:

2. The piping inspection method according to claim 1, The second step is to measure the thickness of the pipe at a representative position; The sixth step is a pipe inspection method, wherein the thickness of the pipe is measured at a position other than the representative position.

3. The piping inspection method according to claim 1, A piping inspection method, characterized in that the access tool is composed of a rod that is held by a worker.

4. The piping inspection method according to claim 1, A piping inspection method, characterized in that the access tool is composed of an aircraft remotely controlled by an operator.

5. The piping inspection method according to claim 1, the first ultrasonic sensor stores and outputs identification information; The control device pre-stores the relationship between the identification information of the first ultrasonic sensor and its fixed position, and acquires the fixed position of the first ultrasonic sensor based on the identification information input from the first ultrasonic sensor.

6. The piping inspection method according to claim 1, A piping inspection method characterized in that the control device displays on a monitor the waveform signal of the first ultrasonic sensor acquired by the approach of the outer coil and the inner coil, or notifies the approach of the outer coil and the inner coil with an alarm.

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