JP2511181B2 - Wall thickness measuring device - Google Patents

Description

TECHNICAL FIELD The present invention relates to an ultrasonic wall thickness measuring device for measuring the thickness of pipes of various plants and inspecting a thinned state.

[Conventional technology]

Conventionally, there has been the following method as one of the methods for inspecting the thinning state of piping and the like. That is, a marking line is written on the inspection surface, an ultrasonic wave is vertically incident on the surface of the pipe by an ultrasonic thickness gauge, and the wave reflected on the inner surface of the pipe is detected. Then, as shown in FIG. 6, the wall thickness is measured by measuring the time from the transmission to the reception, and the thickness reduction amount is obtained from the difference from the wall thickness when the wall thickness is not reduced. Further, the position of the ultrasonic sensor is measured with a finger or the like on the basis of the marking line, and the thinning position and the thinning state are recorded. By performing such a process on the entire surface of the pipe, it is possible to know the thinning distribution of the entire pipe.

In addition, in order to automatically do such a thing,
As shown in the figure, an automatic inspection device capable of scanning the ultrasonic sensor 11 in the circumferential direction and the axial direction has been developed. The structure will be described. A scanner 130 is constituted by a track 131 provided in the pipe 9 and a carriage 132 that moves in a circumferential direction on the track 9 and a scanning shaft 133 that moves in an axial direction on the carriage. 134 this scanner 1
30 controllers. The ultrasonic sensor 11 is attached to the tip of the scanning shaft 133. The pulsar receiver 4 sends an electric pulse to the ultrasonic sensor 11 to generate an ultrasonic wave, and amplifies the signal detected by the ultrasonic sensor 11. The distance measuring circuit 5 (thickness measuring circuit) measures the time from transmission to reception based on the signal thus detected. Based on the output of the distance measuring circuit 5 and the ultrasonic sensor position information from the scanner controller 134, the arithmetic circuit 7 calculates the amount of thinning at each position. Then, the result is displayed on the display 8.

In this apparatus, the controller 134 automatically scans the ultrasonic sensor 11 in the circumferential direction and the axial direction, measures the thinning at every constant pitch movement, and displays the color tone according to the thinning amount on the display unit 8.
At, the image is displayed on the two-dimensional display surface corresponding to the inspection surface. With this, it is possible to know the thinning distribution.

[Problems to be Solved by the Invention]

Although the conventional inspection device shown in FIG. 7 can perform automatic inspection, in the actual plant piping, there are many pedestals that support the piping, branch pipes branching from the pipe, elbows, and adjacent pipes. There may be no space to install the device. Even if it can be installed again, the part that can be automatically inspected is small, and the applicable range is considerably limited. Moreover, it is necessary to instruct the device in advance which part to inspect. Also, it takes time to install and the inspection efficiency is poor. Furthermore, if the pipe diameter changes, a device matching it will be required, and there is no flexibility.

On the other hand, in the case of manual operation, it takes a lot of time and labor to find the inspection position, and the inspection efficiency is extremely poor.

[Means for solving the problem]

In order to solve the above-mentioned conventional problems, the present invention provides an ultrasonic probe having a plurality of ultrasonic sensors arranged in a row, rollers arranged at both ends, and an encoder for detecting the rotation of the rollers; A position detection sensor that can be attached to the surface of the subject in the shape of a strip; a pulsar receiver that excites the ultrasonic sensor to transmit and receive ultrasonic waves; a thickness measurement that calculates the thickness of the subject based on the ultrasonic signal A circuit; a position detection circuit capable of detecting the pressed position when a part of the position detection sensor is pressed; and an encoder detection circuit for calculating the position of the ultrasonic probe based on the signal of the encoder. Thickness measuring device
In addition, the position detection sensor has a plurality of sets of positive electrodes and negative electrodes, and a conductive rubber that is inserted between the positive electrodes and the negative electrodes and whose electric resistance is reduced by compression, and a wall thickness measuring device. It is a proposal.

[Action]

In the present invention, since the flexible band-shaped position detection sensor is used, it is possible to easily cope with a change in the diameter of the pipe and the mounting is easy. At the time of inspection, the initial position on the circumference can be automatically detected by pressing the position detection sensor with the ultrasonic probe. The absolute position of the ultrasonic probe can be easily detected by moving the ultrasonic probe in the axial direction by hand from there and detecting the moving distance by the encoder in the ultrasonic probe.

According to the present invention, an inspector having an ultrasonic probe can freely avoid an inspection even if there is a stand, a branch pipe, a proximity pipe or the like that supports the pipe. Moreover, even a curved surface such as an elbow can be traced and scanned by the human hand with the ultrasonic probe, so that the inspection is easy. At this time, the position of the ultrasonic probe is detected by the above method, and the thickness distribution can be easily known by automatically processing and displaying by using this information and the thickness information by the ultrasonic probe.

〔Example〕

FIG. 1 is an overall view showing an embodiment in which the present invention is applied to a pipe thinning inspection device, FIG. 2 is a view showing a structure of an ultrasonic probe of this device, and FIG. 3 is a structure of a position detection sensor. And FIG. 4 is a connection diagram of the position detection sensor.

First, in FIG. 1, reference numeral 1 is an ultrasonic probe for measuring the wall thickness of the pipe 9. Reference numeral 4 denotes a pulser / receiver which sends an electric pulse to the ultrasonic probe 1 to generate an ultrasonic wave and amplifies and outputs an ultrasonic wave reflected by the inner surface of the pipe and detected by the ultrasonic probe 1. Reference numeral 5 denotes a distance measuring circuit (thickness measuring circuit) which measures the time from the transmission signal to the reflection signal based on the signal of the pulser / receiver 4 to measure the thickness. An encoder detection circuit 6 detects the moving distance of the ultrasonic probe 1 from the output of an encoder (13 in FIG. 2) built in the ultrasonic probe. Reference numeral 2 is a band-shaped position detection sensor wound around the pipe 9. Reference numeral 3 denotes a position detection circuit, which detects a position when a certain portion of the position detection sensor 2 is pressed. Reference numeral 7 is an arithmetic circuit for inputting information from the above device to calculate the position of the ultrasonic probe 1 and the thinning state, and 8 is a display for displaying the thinning distribution.

Next, the ultrasonic probe 1 is, as shown in FIG.
A large number of small ultrasonic sensors 11 are arranged in a straight line inside, and a spring 15 or the like presses the ultrasonic sensors 11 against the inspection surface. Furthermore, rollers 14 and encoders 13 are attached to both ends, and when they are moved in the direction perpendicular to the paper surface, the rollers 14 rotate,
The rotation is detected by the encoder 13, and the movement amount 1 can be known. Further, the ultrasonic sensors 11 arranged in a large number are excited by the pulsar receiver 4, and the wall thicknesses of a large number of points can be measured at one time.

As shown in FIG. 3, the position detection sensor 2 includes positive and negative electrodes 24 and 25 in a belt-shaped rubber sheet 22 and 23 at regular intervals.
Are arranged in a straight line.
It is a flexible sensor with 21 attached. This sensor is attached to the pipe 9 with a rubber magnet 21, and a rubber sheet
If the top of 22 is pressed, the electrodes 24 and 25 will contact. Then, by detecting which point is touched by the position detection circuit 3,
The pressed position can be obtained.

Next, the connection of each electrode of the position detection sensor 2 will be described with reference to FIG. This is an example in the case of 9 pairs of electrodes (= 3 × 3). With respect to the positive electrode 24, three lines in which three adjacent contact points are connected are sequentially taken out as one signal line to form a cable 26. As for the negative electrode 25, a cable 27 is formed by sequentially taking out three lines connected to every three contacts as one signal line.
By detecting which wire of the cable 26 and the cable 27 is short-circuited, it is possible to know the contact position of the contact. By connecting in this way, it is possible to obtain m × n contact information with m positive electrode cables and n negative electrode cables, and reduce the number of signal line cables (m + n) from the position detection sensor 2. can do.

In addition, a structure in which a conductive rubber whose electric resistance decreases by compression is inserted between the positive and negative electrodes 24 and 25, and the electrodes are short-circuited by pressing the conductive rubber may be considered. In the connection between the electrodes, the contact surface is likely to be small or the surface is likely to be deteriorated due to electric discharge. However, if the conductive rubber is used, this is eliminated and the durability is improved.

The operation and the like when using such an apparatus will be described below. The inspector holds the ultrasonic probe 1 in his / her hand, presses a part of the position detection sensor 2 around which the pipe 9 is wound, and moves from that position along the pipe 9 in the axial direction. At this time, the position of the contact point that is short-circuited by the ultrasonic probe 1 first is detected by the position detection sensor 2, and the moving position is determined by the encoder 13
Required by. At each ultrasonic probe position, the wall thickness at each point is measured by measuring the generation time of the internal reflection signal of the ultrasonic signals of the ultrasonic sensor 11 in the ultrasonic probe 1. The position information and the wall thickness information of each of these positions are guided to the arithmetic circuit 7, and the wall thinning condition is calculated from these and the wall thickness data when the wall thickness is not thinned, which is given in advance. Is displayed. For display, the surface scanned by the ultrasonic probe 1 is developed and displayed on a plane. The point on this plane corresponds to the inspection position calculated from the information on the position of the ultrasonic probe 1 and the arrangement of the harmonic sensor 11 in the ultrasonic probe 1, and the point corresponds to the color corresponding to the above-mentioned thickness reduction. Is displayed. This display shows the distribution of thinning of the pipe.

〔The invention's effect〕

 According to the present invention, the following effects can be obtained.

(1) The position of the ultrasonic probe can be detected with a simple mechanism, and the mechanism of the device is simple and easy to handle.

(2) Since the ultrasonic probe is scanned by human hands, even if there is a pipe support, branch pipe, etc., it can be easily avoided and inspected.
Flexible.

(3) By using an ultrasonic probe with a plurality of ultrasonic sensors built-in, a wide range of inspections can be performed in one scan, and the inspection time can be shortened.

[Brief description of drawings]

FIG. 1 is an overall view showing an embodiment of the present invention, FIG. 2 is a sectional view showing an ultrasonic probe structure in the embodiment, FIG. 3 is a sectional view showing a structure of a position detecting sensor, and FIG. [Fig. 3] is a connection diagram of the same position detection sensor. FIG. 5 is a diagram for explaining a method for measuring the wall thickness by ultrasonic waves, and FIG. 6 is a diagram for explaining a method for obtaining the wall thickness from an ultrasonic signal. FIG. 7 is an overall configuration diagram showing an example of a conventional automatic wall thickness measuring device. 1 ... Ultrasonic probe, 2 ... Position detection sensor, 3 ... Position detection circuit, 4 ... Pulser receiver, 5 ... Distance measurement circuit (thickness measurement circuit), 6 ... Encoder detection circuit, 7 ... Arithmetic circuit, 8 …… Display, 9 …… Piping, 11 …… Ultrasonic sensor, 12 …… Casing, 13 …… Encoder, 14 …… Roller, 15 …… Spring, 21 …… Rubber magnet, 23 …… Rubber sheet, 24 …… Electrode (positive), 25 …… Electrode (negative), 26 …… Positive cable, 27 …… Negative cable, 101 …… Ultrasonic propagation path, 102 …… Transmission signal, 103 …… Internal reflection signal, 130 …… scanner, 131 …… trajectory, 132 …… carriage, 133 …… axial scanning axis, 134 …… scanner controller.

Claims (2)

(57) [Claims] 1. An ultrasonic probe having a plurality of ultrasonic sensors arranged in a line, rollers arranged at both ends, and encoders for detecting the rotation of the rollers; a flexible belt-shaped ultrasonic probe attached to the surface of a subject. Position detection sensor; pulser receiver that excites the ultrasonic sensor to transmit and receive ultrasonic waves; thickness measurement circuit that calculates the thickness of the subject based on the ultrasonic signal; part of the position detection sensor A wall thickness measuring device, comprising: a position detection circuit capable of detecting the pressed position when is pressed; and an encoder detection circuit for calculating the position of the ultrasonic probe based on the signal of the encoder. 2. The position detecting sensor has a plurality of sets of positive electrodes and negative electrodes, and conductive rubber that is inserted between the positive electrodes and the negative electrodes and whose electrical resistance is reduced by compression. The wall thickness measuring device according to item (1).