JPS6383478A - Diagnosis method for electrically operated valve - Google Patents

Abstract

PURPOSE:To judge beforehand the necessity of disassembling and inspecting a valve by selecting a valve, the driving mechanism of which is deteriorated among a lot of electrically operated valves. CONSTITUTION:An input voltage and an input current of a valve driving electric motor 1 are input to a converter 14 through an instrument transformer 2 and a current transformer 3, and the voltage, current and power factor are converted to digital values by the converter 4 to be input to a central processing unit 5. In the processing unit 5, the input electric energy of the valve driving electric motor is calculated from the input and transmitted and stored as a series of data together with inputs from a keyboard 6 in an auxiliary memory device 7. The initial data is obtained by conducting the above operation when a valve is sound, and after the lapse of a fixed period, a series of operations are performed to the compared with the initial data. Thus, the deterioration of an electrically driven valve is judged.

Description

DETAILED DESCRIPTION OF THE INVENTION [Objective of the Invention 1 (Industrial Application Field) The present invention relates to a motor-operated valve used when a nuclear power plant has a large number of motor-operated valves and performs periodic maintenance and inspection, for example. Concerning diagnostic methods.

(Prior Art) In a nuclear power plant, there are several thousand electrically operated valves per plant, and these are periodically overhauled and inspected to confirm their soundness. The frequency of overhaul is determined to be once every 1 to 5 years, depending on the importance of the purpose of use of the electric valve.

(Problems to be Solved by the Invention) In a nuclear power plant, operation is stopped for approximately 10 () days once a year to replace fuel. Various equipment is inspected using this stoppage period, and as mentioned above, the soundness of motor-operated valves is confirmed by disassembly and inspection at a certain frequency.

Therefore, even electric valves that have not deteriorated have been uniformly overhauled and inspected, which may not be effective, and conversely, there have been cases where foreign matter has entered the valve due to disassembly, impairing its integrity.

Generally, electric valves are installed in piping systems on-site, creating a poor working environment and requiring a great deal of effort to disassemble and inspect them. Particularly in nuclear power plants, there are electrically operated valves installed in areas with high radioactivity levels, and overhauling these valves poses a problem in terms of radiation exposure for workers.

An object of the present invention is to select a motorized valve whose drive side has deteriorated from among a large number of motorized valves, and to determine in advance whether the motorized valve needs to be overhauled or inspected. Our goal is to provide the following.

(Means for Solving the Problems) The electric valve diagnosis method according to the present invention includes the unique device number of the electric valve, the voltage and current when opening and closing operations are performed under normal conditions,
A constant power factor is input into a computer during sampling, the input electric tank is ejected, and when the electric valve is opened and closed again after a certain period of time, the voltage, current, and power factor are calculated by the same sum Ei [
[This feature is characterized in that the state of deterioration of the drive groove of the motor-operated valve is determined by inputting it to I and comparing it with the previous input electric tank.

(Function) In d3 of the present invention, the state of deterioration of the motor-operated valve is determined by comparing the input power consumption when the motor-operated valve is healthy with the input power amount at the time of diagnosis. This makes it possible to perform a primary diagnosis without any trouble, and it is possible to minimize disassembly and inspection of the electric valve.

(Example) An example of the present invention shown in the drawings will be described below. In the drawing, the input voltage and input current of a valve drive motor 1 are connected to an instrument transformer 2. input to the converter 4 via the current transformer 3;
This converter 4 converts the voltage, current, and power factor into digital values and inputs them to the central processing unit 5.

At the same time, the date of measurement, the electric valve number, and the operation state of dark or open are input to the central processing unit 5 from the keyboard 6.

Chuo 2E Ritsudokoro J! ! In the Soken 5, the input electric power of the valve drive motor is calculated from the input, and combined with the input from the keyboard 6, a series of data is stored in the auxiliary storage device 7.
It is transmitted to and stored.

Perform the above operations when the soundness of the electric valve has been confirmed, and check the initial data with Determine the state of deterioration of the electric valve.

Next, the operation of the electric valve diagnostic device of the present invention will be explained.

First, electric valves open and close by moving the valve stem up and down using an electric motor, but if this drive mechanism deteriorates, mechanical frictional resistance increases, causing the valve to change from fully open to fully open. This will increase the amount of power required for the electric motor.

Therefore, by comparing the input power of the valve drive motor when the spreadability is confirmed immediately after an overhaul and the input power m of the valve drive motor at the time of diagnosis after a certain period of time, it is possible to The state of deterioration can be determined.

In other words, in the drawings, the date of measurement, the valve number, the open or closed operation state, the date of measurement, the valve number, the open or closed operation status, etc.
The input power amount of the valve drive motor 1 is input to the auxiliary storage device 7 and recorded/recorded.

Note that here, the input power ff1Pi is given by the following equation.

” = l'tgov, ・li -CO3θdtVi: Motor input voltage Ii Motor input current CO3θ: Power factor to: Start time of opening or closing operation of motorized valve tQ+t: Time of end of opening or closing operation of motorized valve Conventional analysis After a certain period of time during which the inspection was carried out, perform the series of operations again and measure the input voltage level of the valve drive motor 1. If this input power amount has increased significantly compared to when it is healthy, It is determined that the mechanical frictional resistance of the valve drive mechanism is increasing and the electric valve is deteriorating, and that it is necessary to disassemble and inspect the electric valve.

If the input power amount is about the same as when it is healthy, it is determined that the electrically operated valve continues to be healthy, and it is determined that disassembly and inspection of the electrically operated valve is unnecessary.

Conventionally, electric valves have been overhauled at regular intervals to maintain their health, but in this example, the input power of the valve drive motor is checked before overhauling. By measuring, it is possible to determine the state of deterioration of the electric valve, and whether or not an overhaul is necessary. Furthermore, even if there are a large number of electrically operated valves, the soundness can be easily checked by using a chisel.

In addition, in the example, the driving type! [The input power amount was calculated using the input voltage, current, and power factor, but if it is confirmed that the input voltage is approximately constant, it may be possible to make a determination using only the input current value. This is possible, and the same effect can be obtained more easily than the implementation described above.

U Effects of the Invention As described above, by periodically diagnosing a motorized valve using the motorized valve diagnostic device of the present invention, the necessity of disassembly and inspection of the motorized valve can be determined under normal operating conditions. , the regular disassembly and inspection work of electric valves that was conventionally carried out can be greatly reduced. For example, in the nuclear power generation plan 1~, the labor required for periodic inspections will be greatly reduced, and the electric valves will be more efficient. If it is in a high range, it is possible to reduce the amount of damage to the worker.

[Brief explanation of the drawing]

The drawing is a configuration diagram showing one embodiment of the electric valve diagnostic device of the present invention. 1... Valve drive electric motor, 2... Instrument transformer 3
...Current transformer, 4...Converter 5...Central processing unit 6...Keyboard, 7...Auxiliary storage device (
8733) Agent: Yoshiaki Inomata, patent attorney (and 1 others)
given name)

Claims (3)

[Claims] (1) Calculate the amount of input electricity by inputting the electric valve's unique equipment number and the voltage, current, and power factor during normal opening/closing operations into a computer at a certain sampling period, and then An electric valve diagnosis characterized by determining the state of deterioration of the electric valve drive mechanism by inputting the voltage, current, and power factor when the valve is opened and closed again into a computer and comparing it with the input electricity quantity. Method. (2) The electrically operated valve diagnostic method according to claim 1, wherein the input amount of electricity is an input amount of electricity calculated from the voltage, current, and power factor input into a computer. (3) Enter the unique device number of the motor-operated valve and the current when opening and closing the motor-operated valve under normal conditions into the computer at a certain sampling period, and calculate the current when the motor-operated valve is opened and closed again after a certain period of time. 2. The electric valve diagnostic method according to claim 1, wherein the electric current is also input into a computer and compared with the input current.