JPH0473477A - Error detection method for slidable contact section and device therefor - Google Patents

Abstract

PURPOSE:To properly and quantitatively evaluate error status in a short time by detecting the displacement and vibration of a slide element to move according to a travel signal, and graphically displaying the displacement and vibration at the same timing. CONSTITUTION:A displacement gauge 21 is provided as a displacement detection means for detecting the displacement of a plug 14 as a slide element and outputting an electrical displacement signal corresponding thereto. Also, a vibration sensor 23 is fitted to a stem 17 as a vibration detection means for detecting the vibration of the plug 14 and outputting an electrical vibration signal corresponding thereto. In addition, a signal generator 24 is so constituted as to automatically generate a changing lift signal (shift signal) C. This signal is applied to a positioner 18 via an interface 15. In this case, the displacement signal A, vibration signal B and lift signal C are inputted to a recorder 25 as a display means, and each of the signals is recorded and displayed at the same timing. According to the aforesaid construction, a relationship among the aforesaid three signals can be easily judged and an error, if any, can be immediately judged.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] This invention is directed to the prevention of contamination of foreign matter and galling phenomena in sliding parts such as control valves and pistons, and sliding parts of structures having meshing parts. The present invention relates to a method and device for detecting an abnormality in a sliding part, which detects abnormalities such as jamming and scratches.

``Conventional Technology J'' In the past, abnormalities in sliding parts were mainly detected using tentacles or visually inspected by disassembly.

For example, in detecting an abnormality in the sliding part of a control valve, the inspector sets a lift signal (movement signal) one time at a time, gives the lift signal to the positioner to make the slider slide, and at that time,
The movement of the index attached to the slider was checked visually or by touch to check whether the sliding position was correct, that is, whether there were any abnormalities.

In this way, in the past, the movement signal (lift signal) was manually changed in sequence, and the displacement state of the slider was confirmed each time by visual inspection or by touch, so inspections took a relatively long time, and abnormalities were detected. It is difficult to accurately quantitatively evaluate the condition, and therefore the degree of abnormality cannot be properly known.

[Means for Solving the Problems J According to this invention, the slider is moved by a movement signal, the amount of displacement of the slider is detected as a displacement signal by a displacement detection means, and the vibration of the slider is detected as a displacement signal. A vibration signal is detected by the detection means, and the movement signal, displacement signal, and vibration signal are graphically displayed at the same timing.

``Example'' Next, an example in which the present invention is applied to a sliding part of a control valve will be described with reference to the drawings. A valve seat 12 is provided in the middle of the passage 11, and a valve part 13 that can open and close the opening of the valve seat 12 is arranged.The valve part 13 is attached to the lower end of a plug 14, and the plug 14 slides on a cylindrical guide part 15. The upper end of the plug 14 is freely inserted, and the upper end of the plug 14 is connected to the lower end of a stem 17. The stem 17 is moved up and down in response to a lift signal manually inputted to a positioner 18, and the opening of the valve seat 12 is opened and closed by the valve portion 13. Here, the plug 14 and the guide section 15 constitute a sliding section, the plug 14 is a slider, and the lift signal is a movement signal that displaces the slider (plug 14).

In this invention, a displacement meter 21 is provided as a displacement detection means for detecting the amount of displacement of the plug 14, which is a slider, and outputting an electrical displacement signal according to the amount of displacement.
The input section 1 is connected to the upper end side of the stem 17 by a lever 22, and for example, the input section 1 is connected to the upper end side of the stem 17 by a lever 22.
0%), and the state where the valve part 13 fully opens the passage 11 is 10%.
A signal indicating the amount of displacement of the plug 14, which is 0%, is output as a displacement signal.

Further, a vibration sensor 23 is connected to the stem 1 as a vibration detection means for detecting the vibration of the plug 14 and outputting it as an electrical vibration signal.
Attached to 7. The vibration sensor 23 is, for example, an acceleration sensor, and a sensor whose detection direction has a large degree of vibration mainly in a direction perpendicular to the stem 17 can be used.

The output lead wire of this acceleration sensor is made longer than the maximum vertical movement amount of the stem 17.

As shown in FIG. 2, a lift signal (movement signal) is generated from the signal generator 24, and the lift signal is applied so that the displacement of the plug 14 changes linearly from 0% to 100%.
The change is made for a predetermined period of time, for example, 50 seconds. The signal generator 24 is configured to automatically generate a lift signal (movement signal) that changes in this way. This lift signal is given to the positioner 18 via the interface 15. At this time, the displacement signal obtained from the displacement meter 21 and the vibration signal obtained from the vibration sensor 23 are respectively input to the recorder 25 as a display means via the interface 15, and the lift signal is also input to the recorder 25. , a lift signal (movement signal) record 26, a displacement signal record 27, and a vibration signal record 2 days are obtained for the same time axis. In other words, the lift signal, displacement signal, and vibration signal are recorded at the same timing. Note that the output vibration signal of the vibration sensor 23 is recorded on the recorder 25 as an amount representing the locus of the peak value of vibration. So that the lift signal for changing the plug 14 (slider) from 0% to 100% and the displacement signal when the plug 14 is displaced from 0% to 100% correspond to 0% to 100% of the recorded value, respectively. For example, each signal is converted at the interface 15.

FIG. 3 shows an example of recording when the sliding part is normal.

The lift signal record 26 and the displacement signal record 27 match, and the vibration signal record 28 shows vibrations at startup and vibrations at stop, and no vibration occurs between them. Note that this is a case in which records 29 and 31 each indicating the allowable upper limit value and allowable lower limit value for the displacement signal are also displayed at the same time.

FIG. 4 shows an example of recording when a foreign object enters the sliding part.

As a result, vibrations occur discretely in the vibration signal record 28 during the displacement, and the displacement signal record 27 is not a smooth straight line but has jagged edges.

FIG. 5 shows records when the lift signal was changed from 0% to 100% all at once, and from 100% to 0% all at once. Response characteristics such as the delay of the displacement signal with respect to the lift signal, that is, the immobility time T0, the rise time T1, and the fall time T2 can be known.

FIG. 6 shows records when the lift signal was gradually changed from 0% to 100% and from 100% to 0%. In this case, the horizontal axis is a lift signal, and the vertical axis is a displacement signal, which allows the input/output characteristics to be known.

In the above, a personal computer is used in place of the signal generator 24, a lift signal is generated from the personal computer, a displacement signal and a vibration signal are inputted to the personal computer, and the lift signal, displacement signal, and vibration signal are displayed on the display of the personal computer. Similar to recording, it may be displayed at the same timing. In the above description, the present invention has been applied to detecting an abnormality in a sliding part of a control valve, but it can generally be similarly applied to detecting an abnormality in other sliding parts.

"Effects of the Invention" As described above, according to the present invention, a movement signal for displacing the slider is automatically generated, and the displacement and vibration of the slider at that time are detected. abnormalities can be detected automatically and in a short time.

Moreover, since these movement signals, displacement signals, and vibration signals are displayed at the same timing, it is easy to determine the relationship between these kings, and to immediately determine an abnormality. By determining patterns in advance for various abnormalities, for example, vibration signals occur sporadically and randomly between 0% and 100% of the movement signal, or occur continuously. - It is also possible to know the type of abnormality (intrusion of foreign matter, scratches, etc.) and the location of the abnormality, depending on whether the displacement signal occurs concentratedly in one place or whether the displacement signal also has jagged edges. Further, the degree of abnormality can be determined based on the magnitude of the jaggedness of the displacement signal and the magnitude of the amplitude of the vibration signal.

Furthermore, abnormality detection can be performed with the control valve attached to the pipe, for example, and the number of disassembly and inspections can be reduced accordingly. It is also possible to measure the input/output characteristics, rise and fall characteristics of control valves, etc., if necessary.

If there is an abnormality in the sliding part, a peak will appear in the vibration waveform,
The signal from the displacement sensor becomes jagged, and its position can be determined by the position of the displacement signal.

In addition, conventionally, control valve input/output characteristic tests were performed manually, but by using this device, internal abnormalities are inspected and at the same time, input/output characteristic data is automatically read, ensuring that the characteristics are within tolerance values. It can be determined whether the That is, the displacement signals at each point of 0.2550% to 75.100% of the movement signal are read and processed on a computer, etc., and the determination of the allowable value and the creation of a graph are automatically performed.
The presence or absence of an abnormality in the signal transmission mechanism of the control valve can be detected by the degree of displacement of the movement signal and the displacement signal.

Conventionally, abnormalities in sliding parts were detected by focusing on the relationship between the air pressure of the operating part and the valve opening during operation, but this method covers the entire stroke of the sliding part, and detects movement signals and displacement signals. By ascertaining the relationship and comparing it with data measured during normal operation, abnormalities in the signal transmission mechanism and abnormalities such as friction and galling of sliding parts can be detected. Additionally, step response testing can be performed automatically.

Previously, the movement signal was changed manually and the response time was read and calculated on a recorder, but with a single key operation, a programmed step-like movement signal is automatically generated and the displacement signal at that time is calculated. Read, automatically calculate and display immobility time, rise time, fall time.

The above can be determined visually by giving recording instructions as shown in Figures 3 to 6, but it is also possible to automatically determine if the criteria for determination is included in the computer program. Furthermore, measurement reports can be created automatically.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a structural example of a control valve to which the present invention is applied, FIG. 2 is a block diagram showing a structural example of the present invention, and FIG.
Figure 4 shows an example of normal recording, Figure 4 shows an example of abnormal recording, Figure 5 shows an example of measurement of rise and fall characteristics,
FIG. 6 is a diagram showing an example of measurement of input/output characteristics.

Claims (2)

[Claims] (1) Apply a movement signal to the sliding part to move the slider, detect the displacement of the slider, and also detect the vibration of the slider, and combine the movement signal and the detected displacement. , a method for detecting an abnormality in a sliding part in which the detected vibrations are graphically displayed at the same timing. (2) An abnormality detection device for a sliding part configured to move a slider by applying a movement signal, comprising: displacement detection means for detecting the amount of displacement of the slider as a displacement signal; A vibration detecting means for detecting vibration as a vibration signal; and a display means to which the movement signal, the displacement signal, and the vibration signal are supplied and display them graphically at the same timing. Abnormality detection device for sliding parts.