JPS58213227A - Method for diagnosing abnormality of hdraulic equipment - Google Patents

Abstract

PURPOSE:To detect automatically states of internal wastage, deterioration and wear of a hydraulic instrument by detecting a pressure, a flow amount and a wear particle concn. of a hydraulic fluid and a displacement of a functioning part material and by comparing a mutual relation of these detected values with a criterion value and a permissible deviation. CONSTITUTION:An oil pressure of a hydraulic cylinder 8d is measured by a pressure gauge P, the flow amount of a drain circuit U is measured by a flow meter 9, the wear particle concn. in the functioning oil is measured by a wear particle concn. meter 10. In the meter 10, the functioning oil returns to a tank 3 from a bypass type line 19 through a pipe line 17 in the detector, and the magnetic wear particles in oil particles are captured by gradient magnetic field of a permanent magnet 18 in an order of the particle size. The wear particle concn. is displayed on a display device 11 by an electrostatic capacity unit 20 and a detector 21 of large and small particles. These detected values and the deviation of a steam valve V are compared with the criterion value and the predetermined value of the permissible deviation, and the states of the internal wastage, deterioration and wear of the hydraulic instrument are detected automatically.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for diagnosing the presence or absence of an abnormality in hydraulic control equipment for a steam turbine, and is particularly improved to be suitable for diagnosing the presence or absence of wear and tear or deterioration of hydraulic control equipment. The present invention relates to an abnormality diagnosis method.

A hydraulic control device for a steam valve for a steam turbine is comprised of a hydraulically driven device that opens and closes the steam valve, and a sequence valve, servo valve, etc. that controls the hydraulically driven device.

Conventionally, in general, there has been no method for automatically predicting a failure by detecting the operating state of each device constituting the above hydraulic control device, making a comprehensive judgment, and automatically estimating the fA wear state.

Therefore, even if the drive characteristics change due to, for example, wear and tear of seals or sliding members inside the hydraulic drive equipment, abnormal changes cannot be detected early, and the hydraulic drive equipment becomes unable to operate. In many cases, abnormalities could not be detected until Further, even if a malfunction occurs, it is not easy to find the cause of the malfunction, and the hydraulic control device must be disassembled and inspected, which often results in large losses such as the steam turbine being shut down for a long period of time.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a method that can automatically detect the state of internal wear, deterioration, and abrasion of hydraulic equipment, diagnose the presence or absence of abnormality, and predict the occurrence of failure. With the goal.

In order to achieve the above object, the present invention detects the pressure, flow rate, wear particle concentration, and displacement of the operating member of the hydraulic fluid of a hydraulic control device, and sets the relationship between these detected values to a preset reference value. It is characterized by diagnosing the presence or absence of an abnormality by comparing it with the allowable deviation.

Next, one embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is an example of a hydraulic control device for a steam turbine configured to apply the method for diagnosing hydraulic equipment according to the present invention. First, the general structure will be explained.

J is a hydraulic drive device, which mainly includes a hydraulic cylinder 8 and includes a piston 8a, a biasing spring 8b for the piston, and a piston rod 8C, and the piston rod 8C is a steam valve V.
It is connected to. ■ is a displacement gauge attached to the piston rod 8C, and 8d is a chamber in the hydraulic cylinder.

A dump mechanism 9 is provided at the bottom of the hydraulic cylinder 8, and the cylinder bottom chamber 8d is kept oil-tight by a dump valve 9a. Reference numeral 9b is a bolt that urges the dump valve 9a in the valve closing direction.

The structure is such that when the piston rod 8C of the above-mentioned hydraulic drive system [J is pushed up, the steam valve V is opened, and when the first piston rod 8C is lowered, the steam valve V is closed.

K is the above hydraulic drive system [! (controls the operation of the IJ) (is a lubricating mechanism, and is composed of a shutoff valve 5, a servo valve 6, and an electromagnetic quick-closing valve 7).

L is a hydraulic power source for operating the above-mentioned hydraulic drive device J, 1 is an electric motor, 2 is an oil pump, and 3 is a hydraulic oil tank.

The oil discharged from the oil pump 2 is supplied to the cylinder bottom chamber 8d of the hydraulic cylinder 8 via the shutoff valve 5 and the servo valve 6, and moves the piston 8a up and down to open and close the steam valve VT. At the same time, the oil discharged from the oil pump 2 is supplied to the dump mechanism 9 via the emergency shutoff valve 4 and the electromagnetic quick-closing valve 7, pushing up the dump valve 9a and keeping the cylinder bottom chamber 8d oil-tight.

During operation of the steam turbine, when the turbine must be suddenly stopped due to some sudden accident, the electromagnetic quick-closing valve 7 is operated to cut off the pressure oil supply tm to the dump mechanism 9, and the hydraulic oil in the dump mechanism 9 is drained from the drain circuit. Drop it to U. This opens the damp valve 9a, and the cylinder bottom gBd
The oil pressure inside the steam valve decreases, the piston 8a descends, and the steam valve ■ closes.

During normal operation, the dump valve 9a is closed, and the vertical movement of the piston 8a is controlled by the servo valve 6.

In order to apply the method of the present invention to the hydraulic control device for the steam valve (■) of a steam turbine configured as described above, a pressure gauge (■) that detects the oil pressure in the bottom chamber 8d of the hydraulic cylinder and a flow rate in the drain circuit U are detected. 'A flow meter ◎ and a wear particle concentration detector 10 in the hydraulic oil are installed. In this embodiment, a bypass pipe 19 branched from the drain circuit U is connected to a bypass pipe 19 to allow the abrasion particle concentration detector' 10 to flow therethrough.

FIG. 2 shows the structure of the wear particle concentration detector 10 described above.

The sample oil flows from the drain pipe 19 through the pipe 17 inside the detector and returns to the tank 3.

A permanent magnet 18 having a magnetic field is installed adjacent to the pipe line 17 described above. Due to the magnetic field of the permanent magnet 18, magnetic wear particles in the oil flow are attracted and captured in the order of particle size. That is, large-diameter particles are adsorbed at the inflow part,
Particles with smaller diameters are successively adsorbed. In order to measure the amount of these adsorbed particles, a capacitor 20 and a large particle detection receiver 2 are installed.
1 and a small particle detection receiver 22 are provided, and the wear particle concentration is displayed on the display 11.

The abnormal wear coefficient Is is defined as shown in the following equation.

Is = (Db-)'Ds) (DL-Da
)=D1. -D% However, DL is the concentration of large wear particles, and Ds+ is the concentration of small wear particles.

In the above equation, (D'L + Ds) represents the total wear particle concentration, and (Dt, Ds) represents the difference in concentration between large and small particles.

It is known as a rule of thumb that in the case of normal wear, DL≧I)+, and in the case of abnormal wear, Dt, >>Ds. Therefore, if 18 is large, it means that the wear condition is abnormal.

In general, the progress of wear on machinery shows a tendency as shown in Figure 3. During initial operation, the wear particle concentration rises slightly due to the initial wear phenomenon, and during normal operation, wear progresses little, so the wear particle concentration reaches a low value. keep it.

The concentration of wear particles increases when some kind of abnormal condition occurs, such as increased play due to natural wear and tear, or noise caused by foreign matter getting stuck or oil deterioration.

Therefore, if a reference value is determined by actually measuring the abnormal wear coefficient Is in the normal operating state shown in FIG. 3, when abnormal wear occurs, the abnormality can be detected by the increase in the Is value.

Generally, during steam turbine operation, a test signal is sent to the servo valve 6 for each steam valve to confirm the operation function of the steam valve V.
Opening/closing operation tests are periodically conducted by gradually closing and gradually opening the steam valve V.

Normally, there is a proportional relationship between valve displacement (value detected by displacement gauge ■) and cylinder drive oil pressure (value detected by oil pressure gauge O) as shown in the solid line in diagram m4 when the valve is closed, and as shown in Figure 5 when the valve is open. There is a proportional relationship as shown by the solid line. Therefore, if the relationship between the actual measured position of displacement and the actual measured value of oil pressure is out of proportion and a hydraulic pressure difference ΔP occurs as shown by the broken line in both figures above, it is assumed that some abnormality has occurred. However, it is not possible to determine the cause from this amount of data.

If an abnormality occurs in the relationship between displacement and oil pressure as described above,
Broadly speaking, there are two types of phenomena: (1) the pressure reaches the specified value but the displacement does not reach the specified value, and (11) the case where neither the pressure nor the displacement reaches the specified value.

In the case of (1) above, the valve is difficult to move even though a predetermined hydraulic pressure is being generated, so it is presumed that a mechanical restraint force such as foreign matter is caught or seized. Ru.

In case (II), the valve movement is insufficient because the predetermined hydraulic pressure is not generated, so it is presumed that a hydraulic malfunction such as an increase in internal leakage has occurred.

Taking the above assumption further, it is possible to determine whether the cause of the malfunction is due to mechanical damage and requires urgent overhaul, or whether it is necessary to carry out routine inspections such as checking the adjustment status of the pressure regulating valve while continuing operation. The concentration of wear particles in the oil is an important factor in determining whether the problem can be repaired by maintenance measures.

FIG. 6 is a chart showing an example of changes in wear particle concentration, where the horizontal solid line shows the reference value of the abnormal wear coefficient Is described above, and the dashed lines above and below it show the allowable deviation ΔIam. If the abnormal wear coefficient 1 detected by the aforementioned wear particle concentration detector 10 (Fig. 2) increases as shown by the broken line and the deviation ΔIs of the abnormal wear coefficient exceeds the range of the allowable deviation ΔIs+s, the machine It is determined that some serious damage has occurred, so the turbine must be brought to an emergency stop for inspection and maintenance.

An example of abnormality diagnosis using the method of the present invention will be described below based on the above-mentioned study results. An allowable deviation ΔP1 of the hydraulic pressure deviation ΔP with respect to the reference hydraulic pressure curve shown in FIGS. 4 and 5 is set in advance, and an abnormality diagnosis is performed as shown in the block diagram shown in FIG. 7. This block diagram is an example of diagnosis when an abnormal phenomenon as illustrated in FIG. 6 occurs.

As shown in block 21, the relationship between pressure ■ and displacement ■ under normal conditions of the hydraulic equipment is actually measured, reference characteristics are set, and stored in a computer (not shown), and the hydraulic pressure tolerance ΔPl is also stored. Then, in block 22, manually input the measured pressure ■ and the measured displacement ■, and as shown in equation (a), ΔP becomes Δ
It is determined whether or not it is larger than Pg. In this example, Δ
It is determined that P>ΔPg. On the other hand, in block 23, the abnormal wear coefficient ΔIs is compared with the allowable deviation ΔIss, and formula (b)
It is determined whether or not it holds true. In this example, the ton Δ
It is determined to be Ism. Based on the fact that both formulas (a) and (b) above are satisfied, a diagnosis is made in block 24, and it is diagnosed that abnormal wear has occurred because both formulas (a) and (b) are satisfied. (Block 25).

As in this example, if a diagnosis is made based on the relationship between the drive oil pressure and displacement in the operating state of the hydraulic drive device, and the reference value and tolerance regarding wear particle concentration, mechanical damage will occur inside the cylinder 8 and the hydraulic pressure This has the effect of automatically detecting a slight abnormality in the dynamic characteristics of the device at an early stage.

FIG. 8 shows changes in characteristics when signs of abnormality appear in a form different from that described above. In this abnormal example, the abnormal wear coefficient Is increases as in the example shown in FIG. 6, and the drain circuit U
The internal leak value measured by the flowmeter ◎ installed in (Figure 1) has increased beyond the allowable deviation ΔQ.

A block diagram of an example of diagnosis in such a case is shown in FIG.

In block 31, ΔIss and ΔIs are compared to determine whether equation (b) ΔIs)ΔIsi+ holds true, and the actual measured value ΔQ of the increase in leakage flow rate and the leakage flow rate when the hydraulic cylinder 8 (Fig. 1) is stationary. Increase l [volume deviation Δ
Q, is compared in block 32, and formula (C) ΔQ>ΔQ
Determine whether - holds true. and (b) and (C) above.
If both formulas hold true, it is diagnosed that abnormal wear has occurred (
Block 33).

If the diagnosis is made based on the reference value and tolerance of the internal leakage flow rate and wear particle concentration when the hydraulic drive unit is stationary as in this example, mechanical damage will occur inside the cylinder 8 and the hydraulic equipment will be damaged. Automatically detects slight abnormalities in static characteristics at an early stage.

It has the effect of

FIG. 10 shows a change in characteristics when a sign of abnormality appears in a manner different from that described above. In this abnormal example, the pressure when the hydraulic drive device is stationary decreases, causing a deviation of ΔP compared to the reference value, and the abnormal wear coefficient Is increases to exceed the allowable deviation ΔI sm.

A block diagram of an example of diagnosis in such a case is shown in Fig. 11.

In block 41, ΔI■ is compared with ΔIss and (b) formula Δ
It is determined whether Is>ΔIss holds true, and in block 42, the pressure deviation ΔP is compared with the allowable deviation ΔPm, and formula (d) ΔP>ΔP is obtained.
It is determined whether m holds true, and if both equations (b) and (d) above hold, it is diagnosed that abnormal wear has occurred (block 43).

Diagnosis based on the pressure and wear particle concentration of the hydraulic drive unit when it is stationary, as in this example, allows automatic and early diagnosis when mechanical damage to the hydraulic cylinder affects the stationary pressure. can be discovered.

As explained above, the present invention detects the pressure, flow rate, wear particle concentration, and displacement of operating members of hydraulic fluid in a hydraulic control device, and determines the relationship between these detected values with preset reference values and allowable deviations. By diagnosing the presence or absence of abnormalities by comparing the It is possible to predict the occurrence of a failure before it stops.

[Brief explanation of the drawing]

Figure m1 is a hydraulic system diagram of a steam valve control device for a steam turbine configured to apply the abnormality diagnosis method for hydraulic equipment according to the present invention, and Figure 9 is an explanation of the structure of a wear particle concentration detector used in the above device. Figure 3 is a chart showing changes in wear particle concentration over time, Figures 4 and 5 are charts showing the relationship between oil pressure and displacement, and Figure 6 is a chart showing an example of signs of failure. , FIG. 7 is a block diagram showing an example of diagnosing the above-mentioned symptoms by the method of the present invention, FIG. 8 is a diagram showing an example of failure symptoms different from the above, and FIG. 9 is a diagram illustrating the diagnosis of the above-mentioned symptoms by the method of the present invention. FIG. 3 is a block diagram of an example; FIG. 1...Electric motor, 2...Pump, 3...Tank, 4
...Emergency shutoff device, 5...Shutoff valve, 6...
・Servo valve, 7... Solenoid quick-close valve, 8... Hydraulic cylinder, 8a... Piston, 8b... Spring, 8C...
Piston rod, 8d... Cylinder bottom chamber, 9... Dump mechanism, 9a... Dump valve, 9b... Spring, 10.
... Wear particle concentration detector, 11... Wear particle concentration indicator, 18... Permanent magnet, 19... Bypass pipe line, 2
0... Capacitor, 21... Receiver for large particle detection,
21... Small particle detection receiver, ■... Steam valve, J.
... Hydraulic drive system [, K... Pulp mechanism, L... Hydraulic source, U... Drain circuit, ■... Displacement gauge, ■... Pressure gauge, ◎... Flow meter. Agent Patent Attorney Masami Akimoto 'VJ 1 Fig. 2 Fig. 3 Fig. South - Fig. 4'

Claims (1)

[Claims] 1. Detecting the pressure, flow rate, wear particle concentration, and displacement of the operating member of the hydraulic fluid of the hydraulic control device, and comparing the relationship between these detected values with preset reference values and tolerance deviations. A method for diagnosing an abnormality in hydraulic equipment, characterized by diagnosing the presence or absence of an abnormality. 2. The scope of the claim characterized in that the preset reference value and allowable deviation include a reference value and allowable deviation regarding the relationship between the hydraulic pressure and displacement and the concentration of wear particles during the operation of the hydraulic drive device. The abnormality diagnosis method for hydraulic equipment according to item 1. 3. Claims characterized in that the preset reference value and tolerance include the reference value and tolerance of internal leakage flow rate and wear particle concentration of the hydraulic drive device while the hydraulic drive device is stationary. A method for diagnosing an abnormality in hydraulic equipment according to item 1 or 2. 4. The preset reference value and tolerance include the reference value and tolerance of the pressure and wear particle concentration while the hydraulic drive device is at rest. The method for diagnosing an abnormality in hydraulic equipment according to item 2.