JP6100115B2 - Valve stem load measuring device, valve stem load measuring method and valve stem load measuring program - Google Patents

Description

  The present invention relates to a valve stem load measuring technique by non-disassembly of a motor-operated valve.

  For example, in various plants such as a power plant, time-planned maintenance is performed in which motor-operated valves used in the plant are inspected at a predetermined cycle. The valve body or the valve stem, which is the main object of this inspection, is stored inside the drive unit and the valve box, and needs to be disassembled for direct inspection.

However, if inspection is performed by disassembly at a nuclear power plant or the like, the inspection takes time, and the worker is exposed, which is not desirable.
Further, if the motor-operated valve that has not deteriorated is frequently disassembled, a malfunction occurs due to poor adjustment after assembly.

  For this reason, in recent years, introduction of state monitoring maintenance has been attempted in which the deterioration state of the motor-operated valve is periodically monitored by external diagnosis, and disassembled and inspected as necessary. As the diagnosis parameter, a load applied to the valve stem (hereinafter simply referred to as “valve rod load”), a motor current or voltage, and the like are used.

In particular, the valve stem load is a parameter that senses various malfunctions in the motor-operated valve with high sensitivity because the valve stem causes the valve body to reciprocate with the power from the drive unit.
In addition, the technique which diagnoses from the outside transmits the ultrasonic wave from the top part of a valve stem to the inside of a valve stem, and the technique which analyzes propagation time is known (for example, patent document 1-patent document 3).

Japanese Patent No. 2688861 JP 2012-251835 A Japanese Patent Laid-Open No. 4-93652

  However, most of the prior art is to confirm the presence or absence of specific problems such as the presence or absence of cracks in the valve stem or the vibration of the valve body from the change in propagation time (for example, Patent Document 1 or Patent Document). 2).

  In other words, these techniques do not use the valve stem load as a parameter, and cannot observe the tendency of the malfunction before the sign of the malfunction appears physically as vibration or the like. Furthermore, these techniques only detect one or two specific faults and do not provide a comprehensive diagnosis of the motorized valve.

  In addition, there is one that calculates the valve stem load from the propagation time of ultrasonic waves (for example, Patent Document 3), but a technique for comprehensive diagnosis from a series of reciprocating motions of the valve body using the valve stem load is known. Absent. In other words, there is no known technique capable of making a detailed diagnosis regarding the failure or deterioration of the motorized valve as state monitoring maintenance without modifying or disassembling the motorized valve.

  The present invention has been made in consideration of such circumstances, and the valve stem load measurement enables a detailed diagnosis regarding failure or deterioration of the motorized valve to be performed in a short time without modifying or disassembling the motorized valve. An object is to provide a device, a valve stem load measuring method, and a valve stem load measuring program.

The valve stem load measuring device according to the present embodiment includes a sensor installed on the top of the valve stem that causes the valve body of the motorized valve to reciprocate and transmits / receives ultrasonic waves, and a longitudinal direction of the valve stem during the reciprocating operation. A measuring unit that measures the propagation time of the ultrasonic wave that propagates and reflects at the bottom; a deriving unit that derives the total length of the valve stem based on the propagation time; and a plurality of components derived during operation of the valve stem A load change calculation unit that calculates a load change applied to the valve stem from the change in the total length, a deviation calculation unit that calculates a deviation of a load value at a marking point given to the load change with respect to a reference load, and the deviation is a deviation And a diagnostic unit that outputs a warning signal when the threshold value is exceeded .

  INDUSTRIAL APPLICABILITY According to the present invention, a valve stem load measuring device, a valve stem load measuring method, and a valve stem load measurement capable of performing a detailed diagnosis on a malfunction or deterioration of a motor operated valve in a short time without modifying or disassembling the motor operated valve. A program is provided.

The block diagram of the valve-rod load measuring device concerning this embodiment. The figure which shows the mode of the ultrasonic wave which propagates the valve stem of the motor operated valve to which the valve stem load measuring device concerning this embodiment is applied, and this valve stem. The figure which shows the digital signal of the ultrasonic wave sent to the measurement part of the valve-rod load measuring apparatus concerning this embodiment. The figure which shows an example of the graph of the load change computed by the load change calculation part of the valve stem load measuring apparatus concerning this embodiment. The figure which shows the determination method of propagation time (tau) of the reflected ultrasonic wave. The figure which shows an example of the graph of the historical data which showed the change by the frequency | count of measurement of the load value of the full length direction of a valve stem. The flowchart which shows the operation | movement procedure of the valve-rod load measuring method concerning this embodiment.

  Hereinafter, this embodiment is described based on an accompanying drawing.

(Embodiment)
FIG. 1 is a configuration diagram of a valve stem load measuring device 10 (hereinafter simply referred to as “measuring device 10”).
Moreover, FIG. 2 is a figure which shows the mode of the ultrasonic wave 15 (15a, 15b) which propagates the valve rod 13 of the motor operated valve 11 to which the measuring apparatus 10 concerning embodiment is applied, and this valve rod 13. As shown in FIG.

Furthermore, FIG. 3 is a diagram illustrating a digital signal of the ultrasonic wave 15 sent to the measurement unit 17 of the measurement apparatus 10 according to the embodiment.
FIG. 4 is a diagram illustrating an example of a graph of the load change Ω calculated by the load change calculation unit 19 of the measuring apparatus 10 according to the embodiment.

  As shown in FIGS. 1 to 4, the measuring apparatus 10 according to the present embodiment is installed on the top 14 of the valve stem 13 that causes the valve body 12 of the motor-operated valve 11 to reciprocate. 15b), a sensor 16 that measures the propagation time τ of the ultrasonic wave 15 that propagates in the longitudinal direction of the valve stem 13 during reciprocation and reflects at the bottom, and a valve stem based on the propagation time τ. The load change Ω applied to the valve stem 13 is calculated from the change of the total length L derived based on the ultrasonic wave 15 continuously transmitted and received during the operation of the valve stem 13 And a load change calculation unit 19 that performs the same.

Furthermore, the measuring apparatus 10 includes a deviation calculating unit 23 that calculates a deviation of the load value at the marking point M given to the load change Ω with respect to the reference load S, and the deviation exceeds the deviation threshold Y (Y ₁ , Y ₂ ). And a diagnosis unit 29 that outputs a warning signal.

  The measuring apparatus 10 includes a storage unit 22 that stores the load value as history data together with past measurement values, and a display unit 24 that displays at least one of display based on a warning signal, history data, and load change Ω. Prepare.

  As shown in FIGS. 1 and 2, the sensor 16 is installed on the top 14 of the valve stem 13 that causes the valve body 12 of the motor-operated valve 11 to reciprocate, and transmits and receives ultrasonic waves 15 (15 a and 15 b). The valve body 12 accommodated in the valve box 31 is reciprocated similarly to the normal operation, and the ultrasonic waves 15 are continuously transmitted from the sensor 16 at regular intervals.

  The sensor 16 is installed on the top 14 of the valve stem 13 protruding outside the valve box 31. The valve stem 13 may be covered with a cover together with the drive unit 26. Even when the valve stem 13 is covered, the head top portion 14 of the valve stem 13 generally protrudes from the drive portion 26, so that the cover may be removed and the sensor 16 may be installed on the head top portion 14.

  Since the sensor 16 is installed on the top of the head 14 in this way, it is not necessary to interrupt the reciprocating operation and install the sensor 16 again as in the prior art in which the sensor 16 is installed on the side surface of the valve stem 13. The sensor 16 is preferably temporarily installed on the top of the head 14 so that one sensor 16 can be reused. However, the sensor 16 may be provided permanently.

  The ultrasonic wave 15 received by the sensor 16 is sent to an ultrasonic transmission / reception unit 27 (hereinafter simply referred to as “transmission / reception unit 27”). The transmission / reception unit 27 also controls the transmission timing, wave number, intensity, and the like of the ultrasonic wave 15 of the sensor 16.

  The ultrasonic wave 15 received by the transmission / reception unit 27 is sent to the A / D conversion unit 28 and converted into a digital signal. The ultrasonic wave 15 (15c, 15d) converted into a digital signal is sent to the measurement unit 17 as a relationship between time and amplitude.

As shown in FIG. 3, the measurement unit 17 propagates in the longitudinal direction of the valve stem 13 during the reciprocating operation and propagates the propagation time τ (τ ₁ , τ ₂ ) of the ultrasonic wave 15 (15c, 15d) reflected at the bottom. τ ₃ ,...) is measured.

  FIG. 5 is a diagram showing a method for determining the propagation time τ of the reflected ultrasonic wave 15d (echo wave 15d). The echo wave 15d is smaller than the transmitted ultrasonic wave 15a (15), and may have a shape in which a plurality of waveforms are overlapped due to reflection occurring at a plurality of locations.

  Therefore, in order to prevent variation due to inconsistent position determination at the time of reception of the echo wave 15d, the time point indicating the center of gravity 32 of the echo wave 15d is measured as the time of reception of the echo wave 15d. In addition, it is desirable to extract a peak in which the absolute value of the echo wave 15d exceeds the overall average value D of the echo wave 15d and set the time at the center of gravity 32 of the extracted peak.

Thus, by filtering the waveform peak of the echo wave 15d according to whether or not it reaches the average value D, it is possible to obtain a more accurate centroid 32 of the echo wave 15d.
When it is recognized that the waveform of the echo wave 15d is close to a single sine wave, the reception time of the propagation time τ may be the time at the maximum position of the peak.

The deriving unit 18 derives the total length L of the valve rod 13 from the following equation (1) based on the propagation time τ.
L = τ · c _u / 2 (1)
Here, c _u is the speed of sound.

It is considered that the ultrasound 15 is propagated at the speed of sound, τ · c _u would represent a way that ultrasound 15 is propagated to the propagation time tau. Therefore, since the total length L of the valve stem 13 is half the length of the path through which the ultrasonic wave 15 propagates, it can be derived in (1).

The load change calculation unit 19 changes the total length L of the plurality of valve rods 13 derived based on the ultrasonic waves 15 continuously transmitted and received during the reciprocating operation, for example, to the valve rod 13 as shown in FIG. The load change Ω is calculated.
The valve stem 13 reciprocates together with the valve body 12 by power applied from the drive unit 26 via the screw thread 34 (FIG. 2). The discontinuous point of the operation of the drive unit 26, the valve body 12 and the valve stem 13 and the load change Ω resulting from this operation is referred to as an operation event Γ.

For example, if the operation event Γ is limited to that appearing in the load change Ω of the valve stem 13, in the opening operation, the gear (not shown) connected to the valve stem 13 starts to rotate “Γ ₁ ; hammer blow”. Examples include “Γ ₂ ; valve stem opening operation start” when only the rod 13 starts opening operation, “Γ ₃ ; valve body opening operation start” when the valve rod 13 starts opening operation together with the valve body 12, and the like.

In the closing operation, when the above-mentioned gear starts to reversely rotate “Γ ₄ ; hammer blow”, the valve stem 13 starts the closing operation together with the valve body 12. When “Γ ₅ ; Examples include “Γ ₆ ; valve body sheet contact” that hits the seat portion 33, and “Γ ₇ ; valve body operation stop” in which the operation of the valve body 12 is stopped by stopping the motor inside the driving unit 26.

When a valve stem load is applied to the valve stem 13 at these operation events Γ, the total length L of the valve stem 13 slightly expands and contracts, and a load change Ω applied to the valve stem 13 can be calculated from this expansion and contraction.
In order to improve the calculation accuracy of the load change Ω, the reciprocating operation of the valve body 12 may be repeated three times and four times, and the load change Ω may be calculated from the average of the measured propagation times τ.

The deviation calculator 23 calculates the deviation of the load value at the marking point M given to the load change Ω with respect to the reference load S.
Here, the marking point M refers to several to several tens of points in the load change Ω that characterizes the shape of the load change Ω derived from the operation event Γ.

The marking points M are, for example, the above-mentioned “Γ ₁ ; hammer blow”, “Γ ₂ ; valve stem opening operation start”, “Γ ₃ ; valve body opening operation start”, “Γ ₄ ; hammer blow”, and “Γ ₅ ”. A discontinuous point that is a response value of an operation event Γ such as “valve element closing operation start”, “Γ ₆ ; valve element seat contact”, “Γ ₇ ; valve element operation stop” is typical.

  However, many marking points M are generally defined more finely. The definition holding unit 25 holds definitions for each marking point M, such as which feature points of which operation event Γ or load change Ω are marked. The worker determines the position of each marking point M defined on the graph of the load change Ω from the input unit 35.

  When the wave number per unit time of the transmitted ultrasonic wave 15 increases, the interval of the discrete data constituting the graph of the load change Ω shown in FIG. it can.

  The reference load S is an optimum load value applied to the valve stem 13 at the marking point M of interest. In general, the reference load S is preferably a load value measured first at the marking point M of interest.

This is because the load value added to the valve stem 13 is considered to be constant as the load value initially measured unless a failure or deterioration occurs in the valve stem 13.
However, even if it is not the load value measured first, this load value may be used as the reference load S as long as a normal load value can be specified from the standard of the valve device, for example.

The diagnosis unit 29 outputs a warning signal when the deviation of the load value from the reference load S exceeds the deviation threshold Y (Y ₁ , Y ₂ ). The deviation threshold value Y (Y ₁ , Y ₂ ) of the deviation is held in the deviation threshold value holding unit 21.
For example, in FIG. 4, “Γ ₇ ; valve element operation stop” is a load value controlled by a torque switch that detects a torque applied to the valve stem 13 and transmits an operation stop signal.

However, if the torque switch does not detect the torque normally, the stop signal is transmitted before the fully closed state or when the pressing force A is excessively applied.
For example, if the transmission of the stop signal is delayed and the pressing force A is excessively applied, a protrusion C is formed in the load change Ω as shown in FIG.

Therefore, since the deviation of the load value from the normal state appears on the graph of the load change Ω, the failure or deterioration can be visually recognized from the load change Ω.
However, by analyzing the deviation of the load value at the marking point M of “Γ ₇ ; valve element operation stop” with the deviation threshold Y by the diagnosis unit 29, the state can be grasped more accurately.

For example, if the deviation exceeds a deviation threshold Y _1, when the warning signal "Important", exceeds a deviation threshold Y ₂ outputs a warning signal of "failed". The state of the load value may be defined in more detail by a larger number of deviation threshold values Y.

The history data does not necessarily correspond to one marking point M on a one-to-one basis.
For example, an interval between two marking points M of “Γ ₅ ; valve body closing operation start” and “Γ ₆ ; valve body seat contact” is a substantially constant valve rod during the operation of closing the valve rod 13. A load is applied.

  However, when the gland packing arranged so as to wind the valve stem 13 deteriorates, the tightening force B (FIG. 4) decreases. When the time required for such a constant valve stem load varies, the average load value of this section sandwiched between the two marking points M is diagnosed.

By taking an average of the load values, the load value applied during the closing operation of the valve stem 13 by the gland packing can be diagnosed more accurately.
In the graph of load change Ω, the straight line of the horizontal load value due to the tightening force B approaches 0 in the no-load state, so that the worker can grasp the state of the gland packing from the load change Ω.

Further, for example, a weighted average of the load values of a plurality of marking points M can be used as a new parameter.
Since the allowable range of deviation from the reference load S differs depending on each marking point M, the deviation threshold Y is defined for each marking point M.

FIG. 6 is a diagram illustrating an example of a graph of history data showing changes in the load value (absolute value) in the full length direction of the valve stem 13 depending on the number of times of measurement.
The storage unit 22 stores the load value as history data as shown in FIG.

  In addition to the history data, the storage unit 22 may store a load change Ω or a warning signal output from the diagnosis unit 29. The stored history data and the like can be freely called and used as the past data for the diagnosis unit 29 or the display unit 24 connected to the diagnosis unit 29 in the subsequent measurement.

  The display unit 24 displays at least one of display based on the warning signal, history data, and load change Ω. As a display method, various methods such as a method of changing the coloring of the marking point M from which the warning signal is generated and a method of displaying as a character can be considered, and the method is not particularly limited.

The warning signal may be displayed together with history data stored in the storage unit 22 or load change Ω.
By displaying the history data as a graph, the worker can grasp the tendency of the displayed marking point M without depending on the warning signal from the diagnosis unit 29.

  The history data is appropriately devised, such as changing the horizontal axis to the time of measurement instead of the number of measurements, or displaying the load value together with the time of measurement.

Next, the operation | movement procedure of the valve-rod load measuring method concerning embodiment is demonstrated using FIG.
FIG. 7 is a flowchart showing an operation procedure of the valve stem load measuring method according to the embodiment.

First, the sensor 16 is installed on the top 14 of the valve stem 13 (step S11).
When the top 14 of the valve stem 13 is covered with the cover of the drive unit 26, the cover is removed and installed.

  When the ultrasonic wave 15 is transmitted from the transmitter / receiver 27 via the sensor 16, the ultrasonic wave 15 propagates in the longitudinal direction of the valve rod 13 during the reciprocating operation (step S12). The ultrasonic wave 15 propagating through the valve rod 13 and reflected at the bottom is received by the sensor 16 (step S13).

The ultrasonic wave 15 (15a, 15b) received by the sensor 16 is received by the transmission / reception unit 27 and converted into a digital signal by the A / D conversion unit 28.
The propagation time τ of the ultrasonic wave 15 is measured from the transmission time point of the incident wave 15c (15) of the ultrasonic wave 15 that has become a digital signal to the reception time point of the echo wave 15d (15) (step S14).

Based on this propagation time τ, the total length L of the valve stem 13 is derived (step S15).
A load change Ω applied to the valve stem 13 is calculated from a change in the total length L of the valve stem 13 continuously measured and derived (step S16).

The series of steps until the calculation of the load change Ω is repeated until the valve body 12 finishes the reciprocating operation (step S17; NO; to step S12).
When the reciprocating operation of the valve body 12 is completed (step S17; YES), the worker determines the position of the marking point M on the graph of the load change Ω from the input unit 35 (step S18).

  The marking point M at which the worker determines the position is defined and held in the definition holding unit 25. And the deviation calculation part 23 calculates the deviation of the load value and the reference load S at the input marking point M (step S19).

  Here, the load value at each marking point M is added to the history data of the storage unit 22 and stored (step S20).

  And it is diagnosed in the diagnostic part 29 whether the calculated deviation exceeded the deviation threshold value Y (step S21). When this deviation exceeds the deviation threshold Y (step S21; NO), the diagnosis unit 29 outputs a warning signal (step S22).

The method of outputting the warning signal is not limited, for example, a method of changing the coloring of characters or graphs displayed on the display unit 24 and a method of notifying by sound or vibration.
At the same time, the load change Ω or history data is displayed on the display unit 24 (step S21).

If the deviation of the load value does not exceed the deviation threshold Y (step S21; YES), only the load change Ω or history data is displayed (step S23), and the operation is terminated.
If a warning signal is output during measurement, the warning signal is also stored in the storage unit 22.

  As described above, according to the measuring apparatus 10, the valve stem load measuring method, and the valve stem load measuring program according to the present embodiment, a series of valve stem loads with high sensitivity to the malfunction of the motor operated valve 11 are applied. By performing the measurement over the reciprocating operation, a detailed diagnosis regarding the failure or deterioration of the motor-operated valve 11 can be performed without modifying or disassembling the motor-operated valve 11.

  Furthermore, by installing the sensor 16 on the top 14 of the valve stem 13, it is possible to perform measurement in a short time without requiring re-installation of the position of the sensor 16.

Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention.
These embodiments can be implemented in various other forms, and various omissions, replacements, changes, and combinations can be made without departing from the scope of the invention.
These embodiments and modifications thereof are included in the scope of the invention and the scope of the gist thereof, and are also included in the scope of the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 10 ... Valve rod load measuring device (measuring device), 11 ... Motorized valve, 12 ... Valve body, 13 ... Valve rod, 14 ... Head part, 15 (15a, 15b, 15c, 15d) ... Ultrasonic, 15d (15) DESCRIPTION OF SYMBOLS ... Echo wave, 16 ... Sensor, 17 ... Measurement part, 18 ... Derivation part, 19 ... Load change calculation part, 21 ... Deviation threshold value holding part, 22 ... Storage part, 23 ... Deviation calculation part, 24 ... Display part, 25 ... Definition holding unit, 26 ... drive unit, 27 ... ultrasonic transmission / reception unit (transmission / reception unit), 28 ... A / D conversion unit, 29 ... diagnostic unit, 31 ... valve box, 32 ... center of gravity, 33 ... seat part, 34 ... screw mountain, 35 ... input section, A ... pressing force, B ... clamping force, C ... projection, D ... average value (intensity threshold), L ... full _{length, M (M 1, M 2} , ...) ... marking point, S ... reference _{load, Y (Y 1, Y 2} ) ... deviation _{threshold, Γ (Γ 1 ~Γ 7)} ... operation event, Omega ... load Reduction, τ ... propagation time.

Claims (7)

A sensor installed on the top of the valve stem that causes the valve body of the motorized valve to reciprocate, and transmits and receives ultrasonic waves;
A measuring unit that measures the propagation time of the ultrasonic wave that propagates in the longitudinal direction of the valve stem during reciprocating operation and reflects at the bottom; and
A derivation unit for deriving the total length of the valve stem based on the propagation time;
A load change calculation unit for calculating a load change applied to the valve stem from a plurality of changes in the total length derived during operation of the valve stem;
A deviation calculator for calculating a deviation of a load value at a marking point given to the load change with respect to a reference load;
And a diagnostic unit that outputs a warning signal when the deviation exceeds a deviation threshold . A storage unit for storing the load value at the marking point as history data together with past measurement values;
Wherein based on the warning signal display, valve stem load measuring device according to claim 1, characterized in that it comprises a display unit for displaying at least one of the history data and the load change. The propagation time, the bottom portion is reflected the ultrasonic wave is a valve stem load measuring device according to any one of claims 1 or claim 2, characterized in that it is measured on the basis of the time it shows the tallest peak . The said propagation time is measured based on the time point which shows the gravity center of the said ultrasonic wave reflected on the said bottom part, The valve-rod load measuring apparatus of any one of Claim 1 to 3 characterized by the above-mentioned. 5. The valve stem load measuring device according to claim 4 , wherein the time point indicating the center of gravity is derived by extracting the ultrasonic wave having an amplitude exceeding an intensity threshold. Transmitting and receiving ultrasonic waves propagating in the longitudinal direction inside the valve stem that causes the valve body of the motorized valve to reciprocate and reflected at the bottom;
Measuring the propagation time of the received ultrasound;
Deriving the overall length of the valve stem based on the propagation time;
Calculating a load change applied to the valve stem from a plurality of changes in the overall length derived during operation of the valve stem;
Calculating a deviation of a load value at a marking point given to the load change with respect to a reference load;
And outputting a warning signal when the deviation exceeds a deviation threshold value . On the computer,
Transmitting and receiving ultrasonic waves propagating in the longitudinal direction inside the valve stem that causes the valve body of the motorized valve to reciprocate and reflected at the bottom;
Measuring the propagation time of the received ultrasound;
Deriving the total length of the valve stem based on the propagation time;
Calculating a load change applied to the valve stem from a plurality of changes in the overall length derived during operation of the valve stem;
Calculating a deviation of a load value at a marking point given to the load change with respect to a reference load;
A valve stem load measuring program that executes a step of outputting a warning signal when the deviation exceeds a deviation threshold value .

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