JPS6230955A - Detector for rotor contact position - Google Patents

Abstract

PURPOSE:To locate the contact position accurately, by arranging AE sensors which measure light frequency vibration signals generated from the contact between the rotating part of a rotor and a non-rotating part at three points and a correlator for computing functions of correlation between signals at three points. CONSTITUTION:AE signals generated at contact points 9 are measured with AE sensors 10 to 12 mounted at three points of a casing 5 of a turbine. The AE signals pass through a preamplifier 13 and a BPE14 to extract the high frequency vibration component only caused by contacting and further introduced to a correlator 16 through an amplifier 15. The correlator 16 calculates functions of correlation between three signals of the sensors 10-12. An effective value meter 17 measures the intensity of the AE signals measured with the sensors 10-12. Thus, the intensity of the AE signals and functions of correlation between the AE signals can be jointly used thereby enabling accurate locating of the contact position.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a rotating body contact position detection device that can be applied to rotating bodies such as turbine generators and axial flow compressors.

[Conventional technology]

For example, in order to detect the contact position between the rotating and non-rotating parts of a turbine generator, conventionally the measurer mainly used a listening rod to listen to the vibration sounds of each part of the turbine generator to detect the presence and location of contact. However, it required a high level of skill and was extremely inaccurate and unreliable.

[Problem that the invention seeks to solve]

In recent years, turbine-powered 1W machines have become larger and more efficient, so the gap between rotating parts and non-rotating parts, including labyrinth seals, has become very narrow.

For this reason, the rotating part and the non-rotating part may come into contact with each other during a trial run, and abnormal vibrations may occur. Therefore, when abnormal vibration occurs, it is necessary to quickly determine whether the cause of the abnormal vibration is contact, and if contact is the cause, locate the contact position and take countermeasures.

The present invention provides a rotating body contact position detection device that can automatically and reliably detect the presence or absence of contact and its location by measuring high frequency vibrations during operation of a rotating body such as a turbine generator. purpose.

[Failure to solve the problem]

The rotating body contact position detection device according to the present invention uses an Ag sensor (Acoustic E
The present invention is characterized in that it is equipped with a correlation meter that calculates the number of correlations between signals at three locations.

That is, in the present invention, high-frequency fIL frequency vibrations (Acoust
ic Emission) signal at three locations,
By calculating the correlation between these three signals, the relative difference in signal transmission time from the contact position to each measurement point is determined and the contact location is detected.

[Effect]

According to the present invention, by measuring high-frequency vibrations caused by contact between a rotating part and a non-rotating part, it is easy to separate them from low-frequency vibrations basically generated by a rotating part, and a correlator is used to measure high-frequency vibrations caused by contact between a rotating part and a non-rotating part. The signal transmission time difference from the location to the measurement point is calculated, and the contact location is detected from this.

〔Example〕

An example in which the present invention is applied to a turbine will be described. FIG. 1 shows a cross-sectional view of the turbine, and in this example, the locations I to 4 are labyrinth seals that may come into contact.

5 is a casing and a rotating part, 6 is a center shaft and a rotating part, and 7 is a blade installed on the axle.

An example where the portion 9 in FIG. 1 makes contact will be described below. Each of the AE sensors 10, 11 and 12 attached to the turbine casing 5 at three locations measures the AE a and -f generated at the 9 contact locations. This Ag signal is first amplified by a preamplifier 13, and a bandpass filter 14 (usually with a center frequency of 100 KHz) removes low frequency components such as unbalanced vibration signals caused by rotation, and extracts only high frequency vibration components caused by contact. be done. Further, the signal is amplified by an amplifier 15 and guided to a correlator 16 . Correlation meter 16
Then, the correlation between the three signals of each AE sensor 10, 11, 12 is calculated.

FIGS. 2 to 4 show examples of the calculated correlation ratios, and FIG. 5 shows an example of the Ag signal. FIG. 2 shows the correlation number of the AE sensor 11 with respect to the AE sensor 10, and the time T1 at which the correlation number becomes maximum indicates the time difference until the Ag signal reaches each AE sensor 10 and II. In this example, AE sensor 1
This shows that the time it takes to reach 0 is longer than that of the AE sensor 11 by T. Similarly, FIGS. 3 and 4 respectively mean that the time for the ox to reach the AE sensor 11 is longer than that of the AE sensor 12 by T. Since the propagation speed of AE is known to be about 3.000 m/s (in steel material), the above three relative time differences T1 + T2
From r T3, the relative distance relationship between the contact stand 9 and each measurement position can be determined.

In addition, each AE sensor 10°11.1 is measured by the effective value meter 17.
By measuring the intensity of the Ag signal measured in step 2, it becomes possible to compare the respective signal intensities, and by using this together with the above-mentioned correlation number, the accuracy of positioning can be further improved. I can do it.

〔Effect of the invention〕

As described above, according to the present invention, the following excellent effects can be achieved.

(1) The presence or absence of contact can be detected with high accuracy by detecting the low-frequency vibrations that are basically emitted by rotating machinery and the AE multiplication, which has a significantly different frequency range.

(2) The contact position can be determined by simultaneously measuring the Ag signal at three different locations and measuring the (l function) between the AE beams measured at each location.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the schematic structure of a turbine and the configuration of an embodiment of the present invention, FIGS. 2 to 4 are examples of the number of correlations in the present invention, and FIG. A diagram showing an example of the Ag signal, Figure 6 shows the relative 1 of each of the 81 measurement points and the contact position.
Place it! It is a figure showing a relationship. 10.11.12... AE sensor, 16... Correlation meter.

Claims (1)

[Claims] an AE sensor that measures high-frequency vibration signals generated by contact between a rotating part and a non-rotating part of a rotating body at three locations;
1. A rotating body contact position detection device comprising: a correlation meter that calculates a correlation between signals at two locations.