JPH0245069B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field of the Invention] The present invention relates to an operating state monitoring device for a safety relief valve. [Technical Background of the Invention] Numerous relief valves and safety valves (hereinafter simply referred to as relief safety valves) are provided in plants such as nuclear power plants to ensure safety. In order to operate the plant safely, it is necessary to constantly monitor the operating status of each safety relief valve. Conventionally, this monitoring was done by opening and closing a limit switch attached to the valve stem. [Problems with Background Art] The limit switch described above may fail, and in that case, there is a risk of generating an erroneous signal. In addition, the relief safety valve is normally closed.
It opens when the pressure rises and has the role of lowering the pressure, and there are three types of abnormalities, but the conventional monitoring means described above can only determine whether the valve is open or closed. It is not possible to determine which of the following abnormalities has occurred in the safety relief valve itself. (1) Leak occurs in the valve. (2) Valve does not open when pressure increases. (3) A valve that opens when pressure rises does not close even after pressure drops. In addition, as a means for detecting the operating state of the safety relief valve, a monitoring device in which a thermometer or a differential pressure gauge is provided on the open side piping of the safety relief valve has also been put into practical use. That is, it is determined that the valve is in a closed state based on a small temperature rise in the open side piping, and it is determined that the valve is open or that a leak has occurred in the valve, depending on the temperature rise or the magnitude of the differential pressure. However, the method using temperature changes as described above is effective when handling high-temperature steam or low-temperature fluid that is significantly different from the ambient temperature in which the safety relief valve is installed.
When dealing with a fluid having a temperature close to the ambient temperature, the temperature change is small, so there is a drawback that it cannot be applied. Furthermore, detection signals from thermometers and differential pressure gauges both have low sensitivity and poor time response, so they have the drawback of low accuracy in detecting abnormalities and a tendency to cause detection delays. [Object of the Invention] The present invention has been made based on the above circumstances, and is capable of monitoring the operating state of a relief safety valve with high precision without the risk of generating a false signal, and moreover, it is capable of monitoring the operating state of a safety relief valve with high precision, and is capable of detecting any type of valve abnormality. It is an object of the present invention to provide an operating state monitoring device for a safety relief valve that can quickly determine whether a safety relief valve has occurred. [Summary of the Invention] In the present invention, the operating state and abnormality of the relief safety valve are determined from the combination of the output signal of a sensor that detects the operating state of the relief safety valve and the plant process signal that fluctuates depending on the opening and closing operations of the relief relief valve. The above objective is achieved by determining the type of. [Embodiment of the Invention] Next, an embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a block diagram showing an embodiment in which the present invention is applied to a relief safety valve provided in a pressure vessel storing high-pressure fluid. That is, in the safety relief valve operating state monitoring device according to the present embodiment, there is a device such as an AE (acoustic emission) sensor or an accelerometer in the main body of the relief safety valve 1 or in the piping in its vicinity to detect the operating state of the relief safety valve. A valve state sensor 2 is attached, and the output of the valve state sensor 2 is amplified by an amplifier 3 and input to a signal processing device 4. Furthermore, a pressure signal in the pressure vessel as a plant process signal 5 that changes depending on the opening and closing of the safety relief valve 1 is input to the signal processing device 4 . Further, the output of the signal processing device 4 is displayed on the display device 6. The signal processing device 4 determines the presence or absence of an abnormality in the relief safety valve 1 and its type in the following manner. That is, as shown in FIG. 2, the output voltage of the amplifier 3 increases as the output of the valve state sensor 2 increases in the order of valve closing, valve leak, and valve opening, so the output of the amplifier 3 is monitored. Depending on whether it is in the OA or OB range of FIG. 2, it is determined whether the valve is closed, leaking, or open. Furthermore, whether or not the valve is in a normal state is determined using plant signals as follows. If the relief safety valve is normal, the valve is closed when the pressure as a process signal is below the set value.
Opens when the set value is exceeded. Therefore, it is determined that the valve is normally closed when the output voltage V of the amplifier 3 is V<A, and that the valve is normally open when the output voltage is BV. On the other hand, if the relief safety valve is abnormal, see (1) to (3) above.
There is an abnormal condition. When the pressure is below the set value, A≦V<
In the case of B, it is determined that a leak has occurred, that is, the abnormality described in (1) above has occurred. Furthermore, even if the pressure exceeds the set value, if V<A, it is determined that the valve is inoperable, that is, the abnormality described in (2) above occurs.
Further, if the pressure is below the set value and B≦V, it is determined that the valve that was once opened remains open even after the pressure has dropped, that is, the abnormality (3) above occurs. The above criteria are summarized in Table 1 below.

〔Effect of the invention〕

As explained above, according to the safety relief valve operation state monitoring device according to the present invention, it is possible not only to accurately monitor the opening and closing operation state of the relief safety valve, but also to
When an abnormality occurs, the type of abnormality can be quickly determined. Therefore, it greatly contributes to the safe operation of the plant, and it is also possible to obtain information useful for countermeasures when an abnormality occurs.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention;
FIG. 2 is a graph for explaining its operation. 1...Relief safety valve, 2...Valve status sensor, 3...
...Amplifier, 4...Signal processing device, 5...Process signal, 6...Display device.

Claims (1)

[Claims] 1. A combination of a valve status sensor that detects whether the safety relief valve is in a closed, leaking, or open state, and the output signal of this valve status sensor and a plant process signal that fluctuates depending on the opening/closing operation of the safety relief valve. 1. An operating state monitoring device for a safety relief valve, comprising: a signal processing device that determines whether the safety relief valve is normal or abnormal, and a display device that displays the output of the signal processing device.