JPH01250710A - Shape measuring apparatus - Google Patents

Abstract

PURPOSE:To calibrate the error of the mount position of an ultrasonic sensor simultaneously with the measurement of the shape of an object to be measured, by mounting a calibration reflecting source on an ultrasonic sensor. CONSTITUTION:The distance L2 from the end surface of a dimension measuring device 1 to that of an ultrasonic sensor 2 can be calculated at every sensor 2 by mounting a calibration reflecting source to the sensor 2. Therefore, even when an error is generated in the mount position of the sensor 2, the distance L1+L2 from the end surface of the measuring device 1 to a channel box 3 is accurately obtained and, therefore, the shape such as the distortion degree of the box 3 can be accurately measured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an apparatus that uses a number of ultrasonic sensors to measure the shape of a measurement target placed at a remote location.

(Prior Art) For example, in a nuclear power plant, a channel box that stores fuel rods may be deformed due to the high temperature of the reactor core. This makes it difficult for the fuel rod to fit inside the channel box, and if the deformation expands, cracks occur, leading to 11i radiation leakage.

Therefore, it is necessary to constantly monitor the deformation status of the channel box.

For this reason, there has been conventionally known a shape measuring device that uses an ultrasonic sensor to monitor the state of deformation, as shown in FIG. As shown in the figure, a plurality of ultrasonic sensors 2 are attached to a dimension measuring device 1, and a distance measuring device 4 connected to these ultrasonic sensors 2 is used to measure a channel box 3 and each ultrasonic sensor 2 end face (feeding, The distance L1 to the receiving surface) is calculated.

Then, in the arithmetic control circuit 5 connected to the distance measuring device 4, the distance 11 obtained from each ultrasonic hinger 2 as described above is used to calculate the channel box 3 from the difference in size.
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However, since the above device uses a plurality of ultrasonic hinges 2, the distance L2 from the 1-method measuring device 1 to the ultrasonic sensor 2 may vary due to installation errors of the ultrasonic sensor 2, etc. It may be different for each ultrasonic sensor 2.

Therefore, the distance L1 is an unreliable value, so
It is necessary to perform calibration that takes into account the installation error of the ultrasonic sensor 2.

Therefore, a calibration channel box (not shown) whose dimensions are known is installed in place of the channel box 3, and a reference plane 6 is set between the calibration channel box and the ultrasonic sensor 2. Further, the distance 111L3 from the dimension measuring device 1 to the reference plane 6 and the distance L4 from the reference plane 6 to the calibration channel box, which are known values, are stored in the arithmetic control circuit 5.

Then, if the distance 111LI is measured with the ultrasonic sensor 2,
In the calculation 1111111 circuit 5, the distance 11L2 is determined by the following equation (1).

L2=L3+L4-Ll...(1)
Therefore, the mounting position of the ultrasonic sensor 2 is set at g! so that the distance 111L2 shown in equation (1) is equal for all ultrasonic sensors 2. By doing so, errors in the transmitting and receiving surfaces of each ultrasonic sensor 2 are calibrated, and the shape of the channel box 3 can be accurately measured.

(Problem to be Solved by the Invention) However, in the conventional example described above, the installation error of the ultrasonic sensor 2 must be calibrated every time the channel box 3 is changed, and the operator must calibrate the channel box for calibration each time. This is troublesome as it requires the work of taking things in and out.

Additionally, workers may be exposed to radiation when loading and unloading the calibration channel box.

Roughly speaking, if there is an error in the mounting position between the calibration channel box and the channel box 3 that will actually be measured, accurate measurements will not be possible even though the error in the mounting position of the ultrasonic sensor 2 has been calibrated. There was an issue.

This invention was made in order to solve such conventional problems, and its purpose is to simultaneously measure the shape of an object with an ML wave sensor, and to
It is an object of the present invention to provide a shape measuring device that can calibrate errors in the mounting position of this ultrasonic sensor without requiring a calibration channel box.

[Structure 1 of the invention (Means for solving the problem) In order to achieve the above object, the present invention transmits ultrasonic waves,
a plurality of ultrasonic sensors that receive and cover the ultrasonic waves reflected by the measurement target; and an ultrasonic sensor that is provided at a reference distance from the mounting surface position of the ultrasonic sensors and that reflects the ultrasonic waves transmitted from each of the ultrasonic sensors. Transmission/reception of the ultrasonic sensor based on the reflection source and the time required from transmitting the ultrasonic wave by the ultrasonic sensor to receiving each reflected wave by the measurement target and the ultrasonic reflection source. a distance measuring unit that calculates the respective distances from the surface to the measurement target and the ultrasonic reflection source, and subtracts the calculated distance to the ultrasonic reflection source from the reference distance to obtain a calibration distance; a calculation unit that calculates the distance from the ultrasonic sensor mounting surface to the measurement target by adding the calculated distance to the measurement target, and a shape measurement unit that calculates the shape of the measurement target based on the calculation result. It is characterized by having the following.

(Function) Since the shape measuring device according to the present invention includes a reflection source for calibration, it is possible to calibrate errors in the ultrasonic sensor mounting position at the same time as measuring the shape of the object to be measured.

Furthermore, since a calibration channel box is not required, the work of taking it in and out is eliminated.

(actual example) FIG. 1 is a block diagram showing an embodiment of the present invention.

As shown in the figure, a plurality of ultrasonic sensors 2 11 are attached to the dimension measuring instrument 1 for transmitting ultrasonic signals and receiving reflected waves from the channel box 3 to be measured.

In addition, a calibration reflection [7] is attached to the dimension measuring device 1 for each ultrasonic sensor 2, and the distance ff1L6 from the end surface of the dimension measuring device 1 (ultrasonic sensor 2 mounting surface) to each calibration reflection source 7 is
are all adjusted to a constant reference distance.

The plurality of ultrasonic sensors 2 are connected to a distance measuring device 4, and the output of this distance measuring device 4 is supplied to an arithmetic control circuit 5.

The distance measuring device 4 calculates the time required from transmitting the ultrasonic wave to receiving the reflected wave by the channel box 3 [嘗、4
By multiplying the time t2 required to receive the reflected wave from the 'liE reflection source 7 by the ultrasonic velocity, the distance 1 from the ultrasonic sensor 2@i surface to the channel box 3
111L1. And the distance L5 to the calibration reflection source 7 is calculated.

The calculation control circuit 5 calculates the distance ff obtained from each ultrasonic sensor 2.
1L5, the error in the mounting position of each ultrasonic sensor 2 is calibrated, and thereby the distance ff1L1+L2 from the dimension measuring device 1 to the channel box 3 is determined, and the shape of the channel box 3 is measured.

Next, the operation will be explained.

When an ultrasonic signal is transmitted from the ultrasonic sensor 2, a reflected wave by the channel box 32 and the calibration reflection source 7 is received.

FIG. 2 shows the relationship between the ultrasonic signal received by the ultrasonic sensor 2 and elapsed time.

In the figure, the time zero point is the time when the ultrasonic signal is transmitted from the ultrasonic sensor 2. Therefore, waveform A appearing at this time represents a transmitted wave.

Furthermore, waveform B appearing at time 12 represents a wave reflected by the calibration reflection source 7, and waveform C appearing at time 1 represents a wave reflected by the channel box 3.

The times t, , t2 thus obtained are supplied as electrical signals to the distance measuring device 4 shown in FIG.

Since the ultrasonic velocity is stored in advance in this distance measuring device 4, the time t+ * t2 is multiplied to calculate the distance L1 . and a reflection source 7 for calibration from the end face of the ultrasonic sensor 2
The distance IL5 is calculated.

And these distances! 111.12 is supplied to the arithmetic control circuit 5 as an electrical signal.

In this arithmetic control circuit 5, since the distance #tL6 is equal in each calibration reflection source 7, the distance 111L2 is determined by the following formula.
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L 2 , = 16-15 Then, by adding the distance m l-i and the distance 111L2, the distance 1 from the dimension measuring device 1 to the channel box 3 is obtained! fli L 1-1-12 is obtained.

In this way, the distance L1+1 obtained for each ultrasonic sensor 2
The strain and deformation of the channel box 3 is monitored based on the difference in size between the channels 2 and 2.

In this way, in this embodiment, the distance L2 from the dimension measuring device 1 to the ultrasonic sensor 2 is determined for each ultrasonic sensor 2 by attaching a reflection source for calibration. Even if there is an error in the position of 2, the distance 1111L1+12 from the end face of the dimension measuring device 1 to the channel box 3 can be accurately obtained. As a result, the shape of the channel box 3, such as the degree of distortion, can be accurately measured.

[Effects of the Invention] As mentioned above, according to the present invention, in order to calibrate the error in the position where the ultrasonic sensor is attached, an ultrasonic reflection source for calibration is provided. It is possible to calibrate errors in the mounting position of the ultrasonic sensor at the same time as measuring the shape of the sensor.

Therefore, there is no need to take out and take out the channel box for calibration as in the conventional case, and the work for this purpose can be omitted. Also, the risk of workers being exposed to radiation during this work is eliminated.

Furthermore, installation errors that occur when removing the object to be measured are eliminated, making it possible to perform highly accurate measurements.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing signals received by an ultrasonic sensor, and FIG. 3 is a diagram showing a conventional example. 2... Ultrasonic sensor 3... Channel box 4.
... Distance measuring device 5 ... Arithmetic control circuit 7 ... Calibration reflection source

Claims (1)

[Scope of Claims] A plurality of ultrasonic sensors that transmit ultrasonic waves and receive ultrasonic waves reflected by a measurement target; an ultrasonic reflection source that reflects the ultrasonic waves transmitted from the sensor; and the time required from the ultrasonic sensor transmitting the ultrasonic waves to the measurement target and the reception of each reflected wave by the ultrasonic reflection source. a distance measuring unit that calculates the respective distances from the transmitting/receiving surface of the ultrasonic sensor to the measurement target and the ultrasonic reflection source based on time; a calculation unit that calculates a distance from the ultrasonic sensor mounting surface to the measurement object by subtracting the distance to obtain a calibration distance and adding this to the obtained distance to the measurement object; and based on the calculation result. A shape measuring device comprising: a shape measuring section that determines the shape of the object to be measured.