JP2004149263A - Abnormality detection method for material moving system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for detecting abnormality in a material moving system generated while a material is moved continuously in the system in which a plurality of motor-driven devices are installed. <P>SOLUTION: Two A and B are selected out of the motor-driven devices installed in this system, whereto the power is fed from the same power supply, a one A in which the current consumption changes large relatively in compliance with the load and another B in which the current consumption changes small relatively, and when the material is moving normally with the specified load amount inside the system, the current consumption of each device is measured, and the correlational formula between the two current consumptions is determined. When detecting abnormality, the current consumptions of the devices A and B are measured, and the difference of the obtained measurement from the current consumption calculated by applying the measurement to the correlational formula described above, and existence of abnormality is judged if the difference lies within the predetermined allowable range or not. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for promptly detecting, when a substance is continuously moved, an abnormality such as blockage in a moving system, when the abnormality occurs.
[0002]
[Prior art]
In factories, substances are continuously moved between processes and the like. For example, in the case of producing a composition by mixing several types of powders at a predetermined ratio, the powders are continuously extracted at a predetermined ratio from the storage tank in which each powder is stored, It is transported to a mixing device by a belt conveyor or other transport means and mixed. Also, in the case of continuously preparing a solution by dissolving powders and granules in a solvent, the powders and granules are continuously extracted from the storage tank so as to have a predetermined ratio to the solvent, and transported by a belt conveyor or the like. Supply to the melting device. In any case, it is necessary that the extraction of the granular material from the storage tank and the transport of the extracted granular material be performed in a predetermined amount per unit time.
[0003]
As a storage tank for the granular material, a container having a conical lower portion and a discharge port provided with a rotary valve at a lower end portion thereof is preferably used in order to smoothly discharge the granular material. . The control of the discharge speed is performed by controlling the rotation speed of the rotary valve. However, depending on the type of the granular material, the granular material is solidified in the storage tank or cross-linking occurs between the granular materials. Excretion of the body may slow down. Therefore, when the discharge speed is reduced, it is necessary to detect it promptly and take a countermeasure, but an appropriate method has not yet been known.
[0004]
[Problems to be solved by the invention]
A potential index for detecting a decrease in the discharge speed is the current consumption of the electric motor driving the rotary valve or the belt conveyor. In other words, when the load decreases due to a decrease in the amount of emission, the amount of current consumed by the electric motor that drives these devices decreases. Therefore, monitoring the amount of current consumption may make it possible to detect the occurrence of an abnormality. However, in practice, changes in the current consumption of these motors due to changes in emissions are small, and there is also a voltage fluctuation in the power supply of the electric power supplied to these motors at the factory. Is difficult to detect. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a method for detecting occurrence of an abnormality that is difficult to detect from such a change in the current consumption of each electric device.
[0005]
[Means for Solving the Problems]
According to the present invention, the occurrence of an abnormality in continuously moving a substance in a substance transfer system incorporating a plurality of electric devices is determined by a method including the following steps (1) and (2). Can be detected.
Step (1): Among the electric devices incorporated in the mass transfer system, power is supplied from the same power source, and the current consumption is relatively large depending on the amount of the mass moving in the system. The electric motor (A) that changes and the electric motor (B) that changes relatively small are selected, and the current consumption of each of the electric motors when the substance is moving normally in the system at a predetermined load amount is selected. Measure and determine the correlation between both current consumptions.
[0006]
Step (2): At the time when an abnormality is to be detected, the current consumption of the electric motor (A) and the electric motor (B) is measured, and the measured value and the correlation equation obtained in step (1) , A difference from the calculated current consumption is obtained, and the presence or absence of an abnormality is detected based on the difference.
That is, according to the present invention, for two motors in a mass transfer system, the load is varied during normal operation and the current consumption of one motor is displayed as a function of the current consumption of the other motor. A relational expression is determined, and thereafter, the current consumption of the two electric devices is measured, and the current consumption of one of the two electric devices is applied to the above relational expression to calculate the current consumption of the other device in a normal state. Then, the difference between the calculated current consumption and the actually measured current consumption is obtained, and if the difference is out of a predetermined range, it can be determined that an abnormality has occurred. By using the combination of the current consumptions of the two electric devices incorporated in the mass transfer system as an index as described above, it is possible to eliminate the influence due to the fluctuation of the power supply voltage and the like. An abnormality that is difficult to detect from the measured value of the current consumption itself can be easily detected.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
In the present invention, two electric devices whose current consumption changes in accordance with the amount of material moving in the system, that is, the load, are selected from a number of electric devices incorporated in the mass transfer system, and the current consumption is selected. The electric motor (A) needs to have a large change in current consumption with respect to a change in the load amount, and the other electric motor needs to have a small change in current consumption. Preferably, the electric device (A) is selected so that the change in current consumption with respect to the change in load is as large as possible. Also, the two electric devices for measuring the current consumption need to be connected to the same power supply so that the influence of the fluctuation of the power supply appears at the same time. Preferably, power is supplied to each motor from a power source in close proximity to the two motors.
[0008]
INDUSTRIAL APPLICABILITY The present invention can be applied to various mass transfer systems that move a mass continuously. One example of a preferable application is a powder / particle transfer system in which powder is extracted from a storage tank or the like via a rotary valve and transferred by a bucket conveyor or the like. The current consumption of the motor driving the rotary valve has a relatively small load dependency, and the current consumption of the motor driving the bucket conveyor and the like has a relatively large load dependency. What is necessary is just to measure the current consumption of the drive motor of the rotary valve and the drive motor such as the bucket conveyor.
[0009]
In the present invention, when the mass transfer system is operating normally, the load of the system is changed, and a correlation equation between the two is created from the measured values of the current consumption of the two electric devices. A preferable example of the correlation formula is that when the consumed current amount of the electric device having a large load dependency of the current consumption is Y and the consumed current amount of the electric device having a small load dependency is X,
Y = aX + b
Is a linear expression. Of course, other correlation equations can be used if desired. If a correlation equation between the two is created during normal operation, an abnormality in the system is detected using the equation. That is, the current consumption (X ₁ , Y ₁ ) of the two electric devices is measured, Y is obtained by substituting X ₁ into the above equation, and the difference from the measured value Y ₁ is calculated. Can be determined to have occurred. The allowable amount of the difference may be appropriately determined in consideration of the dispersion of the measured values when the above formula is created. In one preferred embodiment, the process computer in advance incorporate the above equation, and input to a measurement of the current consumption online to calculate the difference between Y and Y _1, if this exceeds the allowable value abnormality To alert you.
[0010]
【Example】
The present invention was applied to the bisphenol A granulator shown in FIG. In FIG. 1, 1 is a granulation tower, 2 is a molten bisphenol supply pipe, 3 is a cooling gas supply pipe, 4 is a blower, 5 is a gas discharge pipe, 6 is a discharge pipe for bisphenol A particles, 7 is a rotary valve, 8 Is a bucket conveyor.
[0011]
In the granulation tower 1, the molten bisphenol A supplied via the pipe 2 is dropped in a droplet form from the top of the tower, and the cooling gas supplied to the lower part of the tower via the pipe 3 rises countercurrent thereto. It is flowing out of the pipe 5. The bisphenol A particles generated by solidification of the droplets accumulate in the lower part of the tower, are discharged to a bucket conveyor 8 via a rotary valve 7 provided in a discharge pipe 6, and are sent to a shipping device. The amount of bisphenol A discharged is controlled by the rotation speed of the rotary valve. Electric power is supplied to the drive motors of the rotary valve and the bucket conveyor from a common power supply installed in the vicinity. The current consumption is input to the process computer online.
[0012]
As a result of measuring the current consumption (X) of the drive motor of the rotary valve and the current consumption (Y) of the drive motor of the bucket conveyor at the time of normal operation, both were Y = 2.3X + 2.6.
It has been found that the approximation can be approximated by the following linear equation.
Therefore, the allowable amount of the difference between the calculated value and the measured value of the current consumption of the driving motor of the bucket conveyor by the above equation is set to 2.0, and an alarm is issued if the difference between the two exceeds 2.0. did.
[0013]
When the operation was performed in this manner, an alarm was issued, and the equipment was immediately inspected. The bucket conveyor was running empty, the outlet of the granulation tower was blocked, and bisphenol A particles were accumulated inside. I was doing it. Therefore, the granulation equipment was immediately stopped, and when the internal bisphenol A was manually discharged, the operation could be resumed in 2 hours.
[0014]
On the other hand, a method of monitoring an increase in the discharge pressure of the blower 4 (such that the discharge of bisphenol A particles from the granulation tower does not work well and the bisphenol A particles accumulate in the tower to cover the outlet of the cooling gas). Then, the blowout of the cooling gas was hindered, and the discharge pressure of the blower increased.) When the operation was performed, the discharge pressure increased, and the equipment was inspected. The outlet of the granulation tower was closed, and a large amount of bisphenol A particles had accumulated inside. The granulation equipment was immediately stopped, and the internal bisphenol A was discharged, but it took 10 hours to resume operation.
[Brief description of the drawings]
FIG. 1 is a flow sheet of one example of an apparatus for granulating molten bisphenol.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Granulation tower 2 Molten bisphenol supply pipe 3 Cooling gas supply pipe 4 Blower 5 Gas discharge pipe 6 Bisphenol A particle discharge pipe 7 Rotary valve 8 Bucket conveyor

Claims (3)

A method for detecting an abnormality when a substance is continuously moved in a substance transfer system in which a plurality of electric devices are incorporated, comprising the following steps (1) and (2). how to.
Step (1): Among the electric devices incorporated in the mass transfer system, power is supplied from the same power source, and the current consumption changes relatively largely depending on the amount of the mass moving in the system. And the electric device (B), which changes relatively small, and measures the current consumption of each of the electric devices when the substance is moving normally in the system at a predetermined load. Then, a correlation equation between the two current consumptions is obtained.
Step (2): At the time when an abnormality is to be detected, the current consumption of the electric motor (A) and the electric motor (B) is measured, and the measured value and the correlation equation obtained in step (1) Then, a difference from the calculated current consumption is obtained, and the presence or absence of an abnormality is determined based on the difference. 2. The method according to claim 1, wherein the correlation is expressed by a linear expression, and when the difference between the measured value and the value calculated from the linear expression exceeds a predetermined value, it is determined that the correlation is abnormal. . A mass transfer system is provided with a storage tank for the granular material having a discharge port at a lower portion, an electric rotary valve installed at the discharge port to control a discharge speed of the granular material by a rotation speed, and a rotary valve from the discharge port. An electric conveyer for receiving and transporting the granular material discharged through the valve, wherein the electric device (A) is an electric conveyor and the electric device (B) is an electric rotary valve The method according to claim 1, wherein:

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