JPH07119825B2 - Internal pump rotation status detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention is an apparatus for detecting the rotational state of an internal pump provided in a boiling water reactor (hereinafter abbreviated as BWR). It is about.

(Prior Art) A BWR equipped with an internal pump is generally configured as shown in FIG. In the figure, reference numeral 1 is a reactor pressure vessel, a shroud 2 for accommodating a reactor core (not shown) is provided in the reactor pressure vessel 1, and a steam separator 3 and steam are provided above the shroud 2. A dryer 4 is installed. Further, a control rod drive mechanism 6 and an internal pump 7 are vertically provided on an end plate 5 forming the bottom of the reactor pressure vessel 1. Then, as shown in FIG. 5, the internal pump 7 fits the upper end of the casing 10 accommodating the motor portion 9 and the like to the nozzle 8 provided on the end plate 5, and welds the upper end of the casing 10 to the nozzle 8. ing. In FIG. 5, reference numeral 11 denotes a rotary shaft of the motor unit 9, and the rotary shaft 11 is connected to the pump unit 12 in the reactor pressure vessel 1. Further, 13 is a flange that closes the lower end opening of the casing 10.

By the way, in such an internal pump 7, when the bearing supporting the rotary shaft 11 is damaged by rust or dust generated in the casing 10, the rotary shaft 11 rotates while vibrating, and the internal pressure of the reactor pressure vessel 1 increases. This will give an undesirable vibration. However, conventionally, the rotation speed of the rotary shaft 11 of the internal pump 7 was measured by a tachometer, but the vibration of the rotary shaft 11 was not detected.

(Problems to be Solved by the Invention) As described above, the internal pump 7 is conventionally used.
I was measuring the number of revolutions of the rotating shaft 11 of
Since the vibration of the rotating shaft 11 was not detected,
It was not possible to detect damage to the bearing that supports the rotating shaft 11.

The present invention has been made in view of the above-mentioned problems, and an object thereof is to provide an internal pop rotation state detection device capable of simultaneously detecting the rotational speed and vibration of a rotary shaft of an internal pump. To do.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above problems, the present invention provides a rotating body concentrically attached to a rotating shaft of an internal pump, and an outer peripheral surface of the rotating body. A plurality of recesses provided on the same circumference at regular intervals, an eddy current type displacement meter installed at a position facing these recesses with a certain distance, and a pulse from the output signal of this eddy current type displacement meter. A pulse signal extracting means for extracting only the signal, and a vibration waveform extracting means for extracting and outputting only the vibration waveform from the pulse signal extracted by the pulse signal extracting means and the output signal of the eddy current displacement meter are provided. It is characterized by having done.

(Operation) In the present invention, since the signal output from the eddy current displacement meter includes the rotational speed component and the vibration component of the rotary shaft, these are extracted by the pulse signal extraction means and the vibration waveform extraction means, respectively. By doing so, it is possible to simultaneously detect the rotational speed and the rotational vibration of the rotary shaft of the internal pump.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a rotational state detecting device for an internal pump according to the present invention. In FIG. 1, 14 is concentrically attached to a lower end portion of a rotary shaft 11 of an internal pump 7 as shown in FIG. It is a rotating body. On the outer peripheral surface of the rotating body 14, a plurality of recesses 15 are provided on the same circumference at regular intervals. An eddy current displacement gauge 16 is provided at a position facing the recesses 15 at a predetermined distance from the flange.
Installed on 13. As shown in FIG. 3, the eddy current displacement meter 16 has a sensor section 17 at the tip, and the sensor section 17
Thus, the displacement of the rotating body 14, that is, the distance H between the sensor unit 17 and the rotating body 14 is electrically measured. When the distance H between the sensor unit 17 and the rotating body 14 exceeds a certain value, an overvoltage, that is, a pulse signal is generated.

Further, in FIG. 1, reference numeral 18 is an amplifier for amplifying the signal output from the eddy current displacement meter 16, and the output signal of the eddy current displacement meter 16 amplified by this amplifier 18 is a pulse amplifier 19 and a waveform shaper 20. Entered in. The pulse amplifier 19 is for extracting only the pulse signal from the output signal of the eddy current displacement meter 16, and the threshold value for extracting the pulse signal is set in advance. Further, the waveform shaper 20 is for extracting only the vibration waveform from the output signal of the eddy current displacement meter 16, and inputs the output signal of the eddy current displacement meter 16 and the output signal of the pulse amplifier 19 in synchronization. However, the pulse signal included in the output signal of the eddy current displacement meter 16 is removed.

With such a configuration, when the rotary shaft 11 of the internal pump 7 rotates at a constant speed, the rotary body 14 attached to the lower end of the rotary shaft 11 rotates integrally. At this time, the eddy current type displacement meter 16 has a plurality of concave portions 15 provided on the outer circumferential surface of the rotating body 14 on the same circumference at regular intervals on the same circumference.
An overvoltage, that is, a pulse signal is generated each time the signal passes in front of.

When the rotating shaft 11 of the internal pump 7 is eccentrically rotated due to damage to the bearings, etc., the rotating body 14 concentrically attached to the lower end of the rotating shaft 11 is also eccentrically rotated, so that the vortex is generated. The current type displacement meter 16 outputs a signal A having a waveform as shown in FIG. Therefore, by inputting the signal A output from the eddy current displacement meter 16 to the pulse amplifier 19 and the waveform shaper 20 via the amplifier 18, the pulse amplifier 19 outputs a pulse indicating the rotation speed of the rotary shaft 11. Since the signal B is output and the signal C representing the vibration of the rotary shaft 11 is output from the waveform shaper 20, the rotation speed and vibration of the rotary shaft 11 of the internal pump 7 can be detected at the same time.

[Effects of the Invention] As described above, according to the present invention, the rotational speed and vibration of the rotary shaft of the internal pump can be detected at the same time, and therefore damage to the bearings supporting the rotary shaft can be detected. Therefore, the operation of the internal pump can be stopped before the vibration of the rotating shaft becomes large, and the safety of the nuclear reactor can be improved. Further, in the present invention, since the vibration waveform of the rotating shaft is extracted from the output signal of the eddy current displacement meter and the pulse signal extracted by the pulse signal extraction means, the vibration waveform other than the pulse can be extracted as it is with high accuracy. Therefore, the vibration waveform in the high frequency range can be accurately extracted.

[Brief description of drawings]

1 to 3 are views showing an embodiment of the present invention, FIG. 1 is a configuration diagram showing a rotational state detecting device for an internal pump according to the present invention, and FIG. 2 is a casing lower part of the internal pump. FIG. 3 is a sectional view showing the positional relationship between the rotating body and the eddy current displacement gauge, FIG. 4 is a sectional view showing the structure of the BWR, and FIG. 5 is a sectional view showing the structure of the internal pump. . DESCRIPTION OF SYMBOLS 1 ... Reactor pressure vessel, 2 ... Shroud, 3 ... Steam separator, 4 ... Steam dryer, 6 ... Control rod drive mechanism, 7 ... Internal pump, 11 ... Rotating shaft, 14 ... Rotating body, 15 ... Recessed portion , 16 ... Eddy current type displacement meter, 18 ... Amplifier, 19 ... Pulse amplifier, 20 ... Waveform shaper.

Claims (1)

[Claims] 1. A rotary body concentrically attached to a rotary shaft of an internal pump, a plurality of concave portions provided on an outer peripheral surface of the rotary body at regular intervals on the same circumference, and these concave portions. An eddy current type displacement meter provided at a position facing each other with a certain distance, a pulse signal extracting means for extracting only a pulse signal from an output signal of the eddy current type displacement meter, and the pulse signal extracting means. A rotational state detecting device for an internal pump, comprising: a vibration waveform extracting means for extracting and outputting only a vibration waveform from a pulse signal and an output signal of the eddy current displacement meter.