JPH06317460A - Vibration measurement device for rotating bodies - Google Patents

Abstract

(57) [Summary] [Object] An object of the present invention is to provide a vibration measuring device for a rotating body that removes a pulse component from an output signal and extracts a vibration waveform capable of obtaining an amplitude. A vibration measuring device for a rotating body according to the present invention includes a rotating portion 14 having a predetermined number of recesses 15 formed on the same circumference on an outer peripheral surface thereof at regular intervals, and a vortex provided to face the recesses 15. A current displacement meter 16, a rise detection circuit 20 that detects a pulse rise portion 31 of the output signal of the eddy current displacement gauge 16, a fall detection circuit 21 that detects a pulse fall portion 32, and a predetermined value. Comparator 22 for detecting a voltage value equal to or higher than the voltage value, an adder circuit 23 for adding the output signals of the rising edge detection circuit 20, the falling edge detection circuit 21 and the comparator 22, and a hold circuit 24 for holding the output signal of the eddy current displacement gauge 16. It consists of and.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a boiling water reactor (hereinafter referred to as B
The present invention relates to an internal pump provided in WR), and particularly to a vibration measuring device that detects vibration of a rotating shaft.

[0002]

2. Description of the Related Art A conventional example of a vibration measuring device for a rotating body will be described with reference to FIGS. In FIG. 7, a shroud 2 for accommodating a reactor core (not shown) is provided in the reactor pressure vessel 1, and a steam separator 3 and a steam generator 4 are installed above the shroud 2. A control rod drive mechanism 6 and an internal pump 7 are vertically provided on an end plate 5 that constitutes the bottom of the reactor pressure vessel 1.

In the internal pump 7, as shown in FIG. 8, an upper end of a casing 10 for accommodating a motor portion 9 and the like is fitted into a nozzle 8 provided on an end plate 5, and the upper end of the casing 10 is welded to the nozzle 8. ing. A rotary shaft 11 is arranged at the axial center of the motor unit 9, and the rotary shaft 11 is connected to a pump unit 12 in the reactor pressure vessel 1. A flange 13 is provided at the lower end opening of the casing 10.

In the above structure, cooling water is injected into the casing 10 and is introduced into the reactor pressure vessel 1 through a gap around the rotary shaft 11. When a reactor water outflow accident in the reactor pressure vessel 1 is assumed, the through hole provided in the casing 10 can be a potential for reactor water outflow, so it is better not to provide the through hole in the casing 10 as much as possible.

The internal pump constructed as described above is an important device which is constantly operated during normal operation in order to circulate the reactor water in the reactor pressure vessel. Therefore, conventionally, monitoring items for maintaining the soundness have been considered. One of the items is vibration generated by eccentricity and damage of the rotary shaft 11. Therefore, conventionally, a rotation sensor 35 using an eddy current displacement gauge at the lower end of the motor is used.
Then, the accelerometer 36 was installed on the outer surface of the casing 10.

[0006]

As described above, in the prior art, the rotation sensor obtains a characteristic regarding the number of rotations of the rotary shaft based on the pulse generated by the rotation of the rotary shaft and the interval between the pulses. . Further, the accelerometer measures the acceleration associated with the vibration of the casing, but cannot measure the amplitude of the vibration or the like.

Therefore, it was difficult to measure the vibration phenomenon occurring during pump operation. The present invention has been made in view of the conventional circumstances, and an object thereof is to provide a vibration measuring device for a rotating body that removes a pulse component from an output signal and extracts a vibration waveform capable of obtaining an amplitude. Especially.

[0008]

In order to achieve the above object, in the vibration measuring device of the present invention, according to the invention of claim 1, a predetermined number of concave portions are formed on the outer circumference of the same circumference at regular intervals. An eddy current displacement meter that measures the distance between the rotating portion and the outer peripheral surface of the rotating portion, which is provided at a position facing the concave portion at a constant distance, and outputs a voltage signal according to the distance. A rising detection circuit that detects the rising portion of the pulse due to the concave portion of the output signal of the eddy current displacement meter and outputs a pulse signal, and a falling edge that detects the falling portion of the pulse due to the concave portion and outputs a pulse signal A detection circuit, a comparator for detecting and outputting a predetermined voltage value or more, an addition circuit for adding the output signals of the rising detection circuit, the falling detection circuit and the comparator, and the added signal A vibration measuring device for a rotating body, comprising: a hold circuit for holding an output signal of a current displacement meter, wherein the rising detection circuit, the falling detection circuit and a comparator are arranged in parallel. It is a thing.

According to the second aspect of the present invention, the rotating portion having a predetermined number of concave portions formed on the same circumference on the outer circumferential surface at a constant interval is provided at a position facing the concave portion with a constant distance. An eddy current displacement meter that measures the distance from the outer peripheral surface of the rotating portion and outputs a voltage signal according to the distance, and detects the trailing edge of the pulse due to the concave portion of the output signal of this eddy current displacement meter. Falling detection circuit that outputs a pulse signal, a bottom hold circuit that holds the minimum value of the output signal of the eddy current displacement meter with the pulse signal of this falling detection circuit, and the rising portion of the pulse caused by the recess Rising detection circuit that detects a pulse and outputs a pulse signal,
And a hold circuit for holding the output signal from the bottom hold circuit by the pulse signal of the rising detection circuit, wherein the rising detection circuit and the falling detection circuit are arranged in parallel. The vibration measuring device is provided.

[0010]

In the vibration measuring device having the above structure, in the invention according to claim 1, the predetermined number of concave portions provided on the outer circumference of the rotating portion on the same circumference at regular intervals are accompanied by the rotation of the rotating portion. Rotate. At this time, the eddy current displacement meter measures the distance from the outer peripheral surface of the rotating part and converts it into a voltage signal according to the distance. Therefore, the concave portion provided on the outer peripheral surface of the rotating portion is detected as a pulse signal by the eddy current displacement meter.
Further, this eddy current displacement meter detects a periodic change in the distance from the outer peripheral surface as a wavy signal when the rotating portion is rotating while vibrating. Therefore, the output signal of the eddy current displacement meter is a pulse signal superimposed on this wave-like signal. The rising detection circuit detects the rising part of the pulse signal, which is the rotational speed component of the rotating part, of the output signal of this eddy current displacement meter, and the falling detection circuit detects the falling part. is there.

Further, a comparator for detecting and outputting a certain voltage value or more is arranged in parallel with the rising detection circuit and the falling detection circuit. By setting a predetermined threshold value, the comparator compares the input signal and outputs a signal when the input signal exceeds the threshold value.

Further, an adder adds the outputs of the rising detection circuit, the falling detection circuit and the comparator arranged in parallel. Finally, the hold circuit temporarily holds the output signal from the eddy current displacement meter,
That is, it is a circuit for maintaining, and the output of the circuit is maintained at the voltage level of the output signal at the time when the hold is applied. This hold is executed by using the output signal from the adder as a control signal.

According to the second aspect of the present invention, the predetermined number of recesses provided on the outer circumferential surface of the rotating portion on the same circumference at regular intervals rotate as the rotating portion rotates. At this time, the eddy current displacement meter measures the distance from the outer peripheral surface of the rotating portion and converts it into a voltage signal according to the distance. Therefore, the concave portion provided on the outer peripheral surface of the rotating portion is detected as a pulse signal by the eddy current displacement meter. Further, this eddy current displacement meter detects a periodic change in the distance from the outer peripheral surface as a wavy signal when the rotating portion is rotating while vibrating. Therefore, the output signal of the eddy current displacement meter is a pulse signal superimposed on this wave-like signal. The trailing edge detection circuit detects the trailing edge signal of the pulse signal among the output signals of the eddy current displacement meter, and generates the pulse signal. Then, the bottom hold circuit holds and outputs the minimum value of the output signal of the eddy current displacement meter using the pulse signal generated by the fall detection circuit as a control signal. The minimum value of the held output signal is sequentially updated by detecting the next pulse signal from the falling edge detection circuit.

The rising detection circuit detects the rising portion of the pulse signal in the output signal of the eddy current displacement meter and outputs the pulse signal. This pulse signal is transmitted to the hold circuit as a control signal. Therefore, the pulse signal is input to the hold circuit every time the rising edge is detected by the rising edge detection circuit.

The signal output from the above-mentioned bottom hold circuit is input to the hold circuit, which holds and outputs the voltage level when the pulse signal from the rising detection circuit is input as the control signal. When a pulse signal is newly received from the rising edge detection circuit, the voltage level at that time is newly held and output.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a vibration measuring device according to the present invention will be described below with reference to FIG. As shown in FIG. 2, the rotating portion 14 is concentrically attached to the lower end portion of the rotating shaft 11 housed in the casing 10 of the internal pump 7. On the outer peripheral surface of the rotating portion 14, four recesses 1
5 are provided on the same circumference at regular intervals. And
An eddy current type displacement meter 16 is provided at a position facing these recesses 15.
Are attached to the flange 13 at a fixed distance. The eddy current displacement meter 16 has a sensor section 17 as shown in FIG.
That is, the distance H between the sensor unit 17 and the rotating unit 14 is electrically measured. Then, the sensor unit 17
When the distance H between the rotating unit 14 and the rotating unit 14 becomes a predetermined value or more, a predetermined voltage value, that is, a pulse signal is generated.

Further, in FIG. 1, an amplifier 18 is connected to the eddy current displacement gauge 16 and amplifies the signal output from the eddy current displacement gauge 16. The output signal of the eddy current displacement gauge 16 amplified by the amplifier 18 is a rising detection circuit 20, a falling detection circuit 21, a comparator 2
2 and the hold circuit 24 are input in parallel. The rising detection circuit 20 and the falling detection circuit 21 have a differentiating function and detect before and after a phenomenon in which the voltage of a pulse signal or the like suddenly changes, and the comparator 22 catches the voltage value itself which is equal to or higher than a predetermined value. By adding these by the adder 23, a pulse region including before and after the pulse is generated can be obtained.

FIG. 4A shows the pulse region obtained by the adder 23 and the output signal of the eddy current displacement gauge 16 amplified by the amplifier 18, which is used as the control signal of the hold circuit 24 to remove the pulse signal. The method for doing so will be described.

In FIG. 4A, the solid line indicated by the symbol A shows the output signal of the eddy current displacement gauge 16 amplified by the amplifier 18. The output signal A is a superposition of the pulse signal indicated by the symbol B and the wave-like signal indicated by the symbol C, and is parallel to the rising detection circuit 20, the falling detection circuit 21, the comparator 22 and the hold circuit 24 as described above. Is entered. Among these circuits, the rising detection circuit 20 and the falling detection circuit 21 detect the rising portion 31 and the falling portion 32 of the pulse signal B and output a pulse signal having a predetermined voltage value.

On the other hand, the comparator 22 for detecting and outputting a voltage value equal to or higher than a predetermined value is the rising detection circuit 20.
And the fall detection circuit 21.
The comparator 22 sets a predetermined threshold value and outputs a signal when the input signal exceeds the threshold value as compared with the input signal. Therefore, since the rotation speed component of the rotating shaft 11 is detected as a pulse signal, a threshold value is set which is applied to the pulse signal and does not reach the maximum value of the wavy signal. Therefore, if the signal detected and output by the rising portion 31 and the falling portion 32 and the output signal of the comparator 22 are added by the adder 23, the hold signal indicated by the broken line D in the figure is obtained. can get.

This hold signal D is used as a control signal for the hold circuit 24 in FIG.
By holding, the voltage value at the rising portion detected by the rising detection circuit 20, that is, the voltage value immediately before the peak can be output from the hold circuit 24. Therefore, the pulse signal B can be removed. As shown in FIG. 4A, the hold signal D has a width obtained by adding the rising portion 31 and the falling portion 32 to the width of the pulse signal B itself in the output signal A of the eddy current displacement meter 16. Therefore, it is possible to remove the edges of the rising portion 31 and the falling portion 32 that remain when only the pulse signal B is removed.

Then, the signal output from the hold circuit 24 is output in a form in which the pulse signal is removed as shown in FIG. 4 (b). Therefore, in this embodiment, not only the number of rotations of the rotating shaft 11 that is a rotating body but also the amplitude of vibration can be obtained.

FIG. 5 is a structural diagram showing a second embodiment of the vibration measuring device for a rotating body according to the present invention. The same parts as those in FIG. 1 are designated by the same reference numerals and the description of the structure of the parts will be omitted. In FIG. 5, the output signal of the eddy current displacement gauge 16 amplified by the amplifier 18 is the bottom hold circuit 2
5, falling detection circuit 26 and rising detection circuit 2
7 are input in parallel. A pulse signal generated by the fall detection circuit 26 detecting the fall of the pulse included in the output signal is input to the bottom hold circuit 25 as a control signal. The bottom hold circuit 25 outputs only the minimum value of the pulse signal amplified by the amplifier 18 when the pulse signal is input.

On the other hand, the rising edge detection circuit 27 detects the rising edge of the pulse signal and generates a pulse signal.
This pulse signal is input to the hold circuit 28 as a control signal. The signal output from the bottom hold circuit 25 is input to the hold circuit 28, which holds and outputs the voltage level when the pulse signal from the rising edge detection circuit is input.

A method of removing the pulse signal will be described with reference to FIG. 6 while showing the output signals of these circuits. The solid line indicated by the symbol A indicates the output signal of the eddy current displacement gauge 16 amplified by the amplifier 18. The output signal A is a superposition of the pulse signal indicated by the symbol B and the wave-like signal indicated by the symbol C, and is input in parallel to the bottom hold circuit 25, the fall detection circuit 26 and the rise detection circuit 27 as described above. It Among these circuits, the fall detection circuit 26 detects the fall portion 33 in the figure and outputs the pulse signal to the bottom hold circuit 2.
5 as a control signal. The bottom hold circuit 25 tracks the voltage value of the output signal A in time series only when the control signal from the falling detection circuit 26 is received while inputting the output signal A from the amplifier 18, and holds the minimum value. To do. For example, when the pulse signal generated by the rising detection circuit 27 in the falling portion 33a is input to the bottom hold circuit 25, the bottom hold circuit 25 traces the output signal A, and the lowest value indicated by symbol E1 in FIG. Hold. This hold state continues until the pulse signal from the trailing edge detection circuit 26 is input next, and the held minimum value is sequentially updated each time the pulse signal is input.

On the other hand, the rising detection circuit 27 detects the rising portion 34 and generates a pulse signal. The hold circuit 28 uses this pulse signal as a control signal.
The hold circuit 28 outputs the voltage value input from the bottom hold circuit 25 while the pulse signal is being input. This is indicated by the symbol F1 in FIG. The output of the hold circuit 28 is also continuously executed until the next control signal is received from the rising detection circuit 27. Therefore, F in the figure
The waveform shown by is obtained, and the pulse signal B can be removed.

Therefore, also in this embodiment, it is possible to obtain not only the number of rotations of the rotating shaft 11, which is a rotating body, but also the amplitude of vibration. The second embodiment of the present invention is a useful embodiment when the number of the concave portions 15 provided in the rotating portion 14 is large, for example, when the deceleration characteristic when the internal pump 7 is stopped is known.

[0028]

As described above, in the vibration measuring device for a rotating body of the present invention, since the pulse signal can be removed from the output signal of the eddy current displacement meter, it is possible to obtain the rotation speed and the vibration amplitude of the rotating body. Possible vibration waveforms can be measured and monitored simultaneously.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a first embodiment of a vibration measuring device for a rotating body according to the present invention.

FIG. 2 is a partially cutaway sectional view showing an enlarged main part of FIG.

FIG. 3 is a partially cutaway sectional view showing an enlarged main part of FIG.

4A is an output signal diagram of an eddy current displacement meter and an adder according to the present invention, and FIG. 4B is an output signal diagram of a hold circuit.

FIG. 5 is a configuration diagram showing a second embodiment of the vibration measuring device for a rotating body according to the present invention.

FIG. 6 is an output signal diagram of an eddy current displacement meter and a hold circuit according to the present invention.

FIG. 7 is a vertical cross-sectional view showing the configuration of a boiling water reactor.

FIG. 8 is a vertical cross-sectional view showing the structure of an internal pump.

[Explanation of symbols]

5 ... End plate 7 ... Internal pump 8 ... Nozzle 9 ... Motor part 10 ... Casing 11 ... Rotating shaft 12 ... Pump part 13 ... Flange 14 ... Rotating part 15 ... Recessed part 16 ... Eddy current displacement meter 17 ... Sensor part 18 ... Amplifier 20 ... Rise detection circuit 21 ... Fall detection circuit 22 ... Comparator 23 ... Adder 24 ... Hold circuit 25 ... Bottom hold circuit 26 ... Fall detection circuit 27 ... Rise detection circuit 28 ... Hold circuit 31 ... Rise section 32 ... Fall Part 33 ... Falling part 34 ... Rising part 35 ... Rotation sensor 36 ... Accelerometer

Claims (2)

[Claims] 1. A rotating part having a predetermined number of recesses formed on the same circumference on the outer peripheral surface at regular intervals, and an outer peripheral surface of the rotating part provided at a position facing the recess at a constant distance. An eddy current type displacement meter that measures a distance and outputs a voltage signal according to the distance, and a rising edge detection circuit that detects the rising edge portion of the pulse due to the concave portion of the output signal of this eddy current displacement meter and outputs a pulse signal A trailing edge detection circuit that detects a trailing edge of a pulse caused by the recess and outputs a pulse signal; a comparator that detects and outputs a predetermined voltage value or more; the leading edge detection circuit, a trailing edge detection circuit, and a comparator. And a hold circuit for holding the output signal of the eddy current displacement meter by the added signal, and the rising detection circuit and the falling detection circuit. A vibration measuring device for a rotating body, wherein an intelligent circuit and a comparator are arranged in parallel. 2. A rotating part having a predetermined number of recesses formed on the same circumference on the outer circumferential surface at regular intervals, and an outer peripheral surface of the rotating part provided at a position facing the recess with a constant distance. An eddy current displacement meter that measures a distance and outputs a voltage signal according to that distance, and a trailing edge that detects the trailing edge of the pulse due to the concave portion of the output signal of this eddy current displacement meter and outputs a pulse signal A detection circuit, a bottom hold circuit that holds the minimum value of the output signal of the eddy current displacement meter with the pulse signal of the falling detection circuit, and a rising portion of the pulse caused by the recess and outputs a pulse signal. It has a rising edge detection circuit and a hold circuit that holds the output signal from the bottom hold circuit with a pulse signal from the rising edge detection circuit. A vibration measuring device for a rotating body, characterized in that the intelligent circuits are arranged in parallel.