JPS60179586A - Monitor for valve gear - Google Patents

Abstract

PURPOSE:To prevent wrong operation in a valve monitor from occurring, by taking 'AND' between a threshold value of a signal level and a time variation of the signal level of an output signal out of a vibro-detector installed in a valve gear. CONSTITUTION:The detection signal obtained out of a vibro-detector 11 installed in a valve gear 1 is made to find a square mean value at a signal extractor 12, and at the next comparator circuit 14, is compared with a preset threshold value alpha in time of valve opening and that whether the valve is in a state of being opened or not is judged. At a gradient calculation circuit 15, either positive or negative in a variation of the said detection signal per unit time is discriminated whereby whether the valve is in a state of being opened or not is judged. A comparator circuit 16 calculates 'AND' of each output of a comparator circuit 14 and the gradient calculation circuit 15, and if the result is one that shows the valve opened state, the effect is displayed on a warning displayer 18.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a monitoring device for a valve device, particularly a leak detection and monitoring device for a valve device that detects fluid leakage from a sliding portion of a two-valve device. Two matters.

[Technical background of the invention and its problems]

Nuclear power plant, thermal power plant, chemical plant, etc. (In order to smoothly control the operation of nuclear power plant, thermal power plant, chemical plant, etc. The heating steam generated from the turbine is supplied through the main steam pipe to the turbine ζ2.
On the other hand, if the nuclear reaction in the reactor core does not follow suit, the steam pressure inside the reactor vessel will exceed the predetermined pressure and the plant itself will be in a dangerous state ζ;
Become. In order to avoid such a situation, the main steam pipe (two safety valves are installed), and when the steam pressure in this main steam pipe exceeds a predetermined pressure (= the deterrent force of the female valve (two safety valves), the main steam It is configured to discharge from the tube to the outside.

By the way, in general (2, valve device) 2, the tip of the valve stem (
-The provided valve body slides and comes into close contact with the valve seat (;yoυ
The structure is such that the fluid flow is controlled by 1tIIJ#, but at this time, if a foreign object is caught between the valve body and the valve seat, or if either one (= foreign object is attached), the valve closes (No. Even if the valve body is slid and folded into the valve seat, a gap may occur, fluid may leak from this gap, and the valve device itself may not operate properly.

For this reason, the opening and closing of the valve device is confirmed by checking the limit switch (2) attached to the valve stem, but in the unlikely event that the limit switch becomes defective (2), an erroneous signal will be generated.
Or, the valve device is normal (even if the valve device operates twice, there is a risk that the first open signal will be missed.Therefore, a thermocouple is installed downstream of the valve device to serve as a backup for the limit switch, but
NI= had the disadvantage that detection sensitivity was low and it was therefore difficult to determine the amount of leakage.

The purpose is to provide a valve device monitoring device that can quickly detect even minute leaks in a valve device and accurately measure the amount of leakage.

[Summary of the invention]

In order to achieve the above object, the present invention includes: a vibration detector installed in the valve device or its downstream side, and a signal extractor that calculates the envelope or root mean square value of the detection signal detected by the vibration detector. a comparison circuit that compares the calculated value with one value in a valve open state or a valve leak state; a slope calculation circuit that calculates a slope of the calculated value in a certain time width; and the comparison circuit and the slope. A monitoring device for a valve device comprising a logical product output with a calculation circuit (2) and a device for monitoring valve opening or valve leakage of the valve device.

It is also equipped with a valve leak monitoring circuit (second is leak! calculation circuit).

[Embodiments of the invention]

Embodiments of the present invention will be described with reference to the drawings.

Figure s1 is a side view of a safety valve to which the valve device monitoring device of the present invention is applied. That is, the opening 3 of the main steam pipe 2 (two safety valves 10 and a valve seat 4 are arranged).The valve seat 4 (two faces of which a valve element 5 is arranged). The valve gljh device t7 is driven twice through the valve 6. Normally, the valve seat 4 and the valve body 5 are configured to be in close contact with the bullet 8, and fluid flows from this contact surface. Steam does not leak. However, even if the valve body 5 is closed due to foreign matter adhering to the space between the valve seat 4 and the valve body 5, or due to some other reason, the valve body 5 and the valve seat 4 may be closed. If it does not come in close contact, steam will leak (Second).

However, when the steam pressure in the main steam #2 exceeds the predetermined pressure (=, the safety valve 10 bullets 1 = deterrent force (2 strokes won and the valve body 5
is separated from the valve seat 4, creating a gap through which steam flows out and is stored in the steam storage chamber 10 via the exhaust pipe 9.

On the other hand, when a valve opens or a valve leak occurs as described above, an abnormal signal is detected from the vibration detector 110 such as an Ag detector or an acceleration detector installed in the valve device 1 or its downstream side (= installed), and the signal extractor 12 detects an abnormal signal. is input.

The signal extractor 12 converts the envelope or root mean square value of the detection signal into a digital value (2) in the next stage A/D converter B. Compare it with the threshold value of the state.Furthermore, the slope of the detection signal level is calculated at a constant time width at the sixth secondary stage slope calculation circuit 15).The comparison circuit 16 compares the comparison result of the comparison circuit 14 with the slope calculation circuit. After confirming that the slope of No. 15 is changing continuously (two changes), it is determined that the valve is in an open state or a leak state, and the alarm indicator 181 = OK alarm is issued (the leakage amount calculation circuit 17 The comparator circuit 14 performs integral calculations for the time period in which the threshold value is exceeded, and calculates the difference, which is displayed on the report display 18 (2).

Next, a flowchart of the valve device monitoring device of the present invention explained above will be explained with reference to FIG.

The detection signal obtained from the vibration detector 11 is sent to the signal extractor 12
The envelope or root mean square value of this detection signal is calculated by two people, and the output is converted into a digital value by the A/D converter 13 (2). It is compared with the set threshold value α for opening the valve, and if it is larger than this (-value α, it is determined that the valve is open (==), and if it is smaller than 1-value α, it is determined that the valve is not open. do.

Furthermore, it is compared with a preset threshold value β at the time of valve leakage, and if the +al value β is larger than this, it is determined that the valve is in a leakage state, and if it is smaller than the threshold value β, it is determined that the valve is not in a leakage state. .

Next, the slope calculation circuit 15 calculates the slope of the digital value of the detection signal in a certain fixed time width. In the comparison circuit 16, the previous IC
As a result of the judgment by the comparison circuit 14, that is, if the valve is in the open state and the gradient is continuously increased by JQ, it is judged that the valve is open, and the percentage information display 18 displays this. In addition, if the valve leak condition ia + second 9, KARI 11 is determined to be ``9 valve leak if the rhyme gradient is continuously increasing'', the alarm indicator 18 (displays 2). When the valve leaks, the amount of steam leakage that exceeds the +d value β is calculated by the leak i μ output circuit 17, and this calculation is converted into −
The information is displayed on the information display 18.

〔Effect of the invention〕

According to the valve device monitoring device of the present invention, since the 1 m value of the signal level of the detection signal and the gradient of the signal level are used together, noise from the atmosphere or magnetic noise, etc.
There is no A excitation, and it is also possible to estimate the leakage filter from the detection signal.
It has an excellent advantage of being able to detect ζ: with high sensitivity compared to the conventional device t+.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a safety valve to which an embodiment of the present invention is applied, and FIG. 2 is a 70-chart of the embodiment of the present invention. 1...Safety valve 2...Main steam pipe 10...Steam storage chamber 11...Retreat detector'12.
...Signal extractor 13...A/D converter 14, 16.
... Comparison circuit 15 ... Gradient calculation circuit 17 ... Leak amount calculation circuit 18 ... Alarm indicator (8733) Agent Patent attorney Yoshiaki Inomata (and one other person) Figure 2

Claims (2)

[Claims] (1) A vibration detector installed in the valve device or the downstream side of the valve device, a No. 1d extractor that calculates the envelope or root mean square value of the detection No. 11 detected by the vibration detector, and the above-mentioned calculation. a comparator circuit that compares the calculated value with the 1st shift in the valve open state or valve leak state, a gradient output circuit that calculates the gradient in one foot time width of the shift calculated by the previous day; A monitoring device for a valve device which is equipped with a device for monitoring valve opening or valve leakage of the valve device. (2) A monitoring device for a valve device according to claim 1, wherein valve leakage is monitored by a leak amount calculation circuit.