JPS5892835A - Leakage detector - Google Patents

Abstract

PURPOSE:To detect a leakage accurately independently of charge and discharge flow rates to and from a liquid preservation tank and display the quantity of the leakage, by detecting the difference between charge and discharge flow rates to and from the tank and the variation of the liquid level in a unit time in respect to detection for leakage of the liquid preservation tank. CONSTITUTION:The flow-in rate to a tank 1 and the flow-out rate from the tank 1 are detected in unit time flow rate integrating devices 10 and 11, and their difference is operated in a flow rate difference operator 14. A liquid level is detected in a level transmitter 17, and the variation of the net capacity is operated in a unit time variation measuring device 19 and a variation operation 21. The difference between outputs of two operators 14 and 21 is operated in a leakage quantity operator 16. The quantity of leakage is displayed on an indicator 26, and a preliminarily set value and the output of the leakage quantity operator 16 are compared with each other to operate an alarm device 28 as required. Though only the lowering of the liquid level is monitored in the conventional method, an abnormality is detected quickly and accurately in this method.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to a leak detection device that can accurately and quickly detect leaks in a liquid tank, regardless of whether liquid is flowing in or out.

(Technical Background of the Invention) A large number of various liquid storage tanks are used in nuclear power plants and other various plants.If a leakage accident occurs in one of these liquid tanks, it must be quickly detected and the tank replaced. It is necessary to take measures such as maintenance and recovery of leakage amount.

For this reason, a liquid level needle is usually installed in a liquid tank to issue an alarm when the liquid level drops below a specified value.

(Problems with the background technology) However, since the conventional technology only monitors the drop in the liquid level, it is not possible to detect abnormalities until the liquid level reaches a specified value. If liquid spills occur frequently, depending on the amount of inflow and outflow, the liquid level may not go down and may even rise, so even if a leakage accident occurs, it will not last for a long time. Even after crossing the line, it remained undetected and there was a risk of serious secondary disasters occurring.

(Objective of the Invention) The present invention solves the problems of the prior art described above, detects abnormalities in liquid level changes regardless of the presence or absence of liquid inflow and outflow, and issues leakage alarms to detect leakage as necessary. The object of the present invention is to provide a leakage detection device that can indicate the scale of leakage.

(Summary of the Invention) In order to achieve the above-mentioned object, the present invention calculates the following based on the flow rate of liquid flowing into the liquid tank through the pipe within a unit time and the flow rate of liquid flowing out from the liquid tank through the pipe within the same time. Calculates the difference in the amount of liquid flowing in and out within a unit time, calculates the net liquid change amount based on the amount of liquid level change before and after the unit time, and compares the results of these calculations to detect the presence or absence of leakage. The present invention relates to a leakage detection device that is configured as described above, and can also display the scale of leakage if necessary.

(Embodiment of the Invention) Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

Liquid flows into the liquid tank 1 through a pipe 6 provided with a pump 2, and flows out through a pipe 5 with a pump 4.

Flow rate valves 6 and 7 are installed in the pipes 3 and 5, respectively, and their outputs are led to a unit time flow rate integration device 10.11 via a signal line 8.9.

The output of the unit time flow rate integrating device 10.11 is connected to the signal line 12.
．． 13 to the flow rate difference calculator 14, and the pipes 3 and 5
The difference between the amount flowing into tank 1 and the amount flowing out from it is calculated by 1:□'.

The output of this calculator 14 is led to a leakage amount calculator 16 via a signal line 15.

On the other hand, a level transmitter 17 is connected to the tank 1, and its output is sent to the unit time change measurement device 1 via a signal line 18.
Guided by 9.

The output of this unit time change amount measuring device 19 is led to a change amount calculation unit 21 via a signal line 20, where a net volume change amount is calculated based on the amount of liquid level change and the cross-sectional area of the tank.

The output of this change amount calculator 21 is led to the leakage amount calculator 16 via a signal line 22.

The leak amount calculator 16 calculates the difference between the output of the flow rate difference calculator 14 and the output of the change amount calculator 21, and sends the result to the signal line 2.
3 to the comparator circuit 24, and also to the indicator 26 via the signal line 25 and displayed on the indicator.

The comparison circuit 24 compares a preset value with the output of the leak amount calculator 16, and outputs an alarm output if the latter exceeds the former value.

This alarm output is led to the alarm device 28 via the signal line 27 and is activated.

The operation of the apparatus of the present invention having such a configuration will be explained using a specific example.

In advance, the unit time of the unit time integrating device 1110.11 and the unit time variation measuring device 19 is set to seven hours to provide simultaneity.

The indications of the flow rate transmitters 6 and 7 are F In Cm7h ) and F ont (m/h ), and the level transmitter 1
The output value of 7 changes from Ll('') to Lt(-
), the above flow rates Fin and F out
The unit time integration device 10.11 calculates the flow rate F for seven hours.
/rn (m”) and F'out (m”)
are integrated t6゜ These integrated values F'in and F'out are led to the flow rate difference calculator 14 to calculate the L゛ time flow rate difference (F'in -
F'out) is calculated.

On the other hand, the unit time change measurement device 19 measures ΔL” (LI
IQ).

This ΔL is input to the change amount calculator 21 and multiplied by the cross-sectional area A of the liquid tank 1 to obtain the unit time change amount (ΔLXA).

The above (F'in - F'out) and (ΔLXA) are input to the leakage amount calculator 16, and B = ((F'in
-F'out) -(ΔLXA)) and inputs this output B to the comparison circuit 24.

The comparison circuit 24 compares B with a set value O±α that takes into account instrument errors, evaporation, etc., and issues an alarm output when the value of B exceeds the set value.

When this alarm output is transmitted, the alarm device 28 operates and issues a leak warning by blinking a lamp or sounding a buzzer.

Further, since the leakage amount calculated by the leakage amount calculator 16 is indicated to the indicator 26 connected to the calculator 16, the scale of the leakage can be known.

In the above explanation, we have explained an example in which the liquid flows into the liquid tank and the liquid flows out from the tank through one pipe each. However, when there are multiple pipes, the flow rate of each pipe is By summing the total amount and inputting it to the unit time flow integrating device, leakage from the liquid tank can be detected in exactly the same manner as described above.

(Effects of the Invention) As described above, the present invention provides a unit time flow rate integrating device (2) that calculates the flow rate of people flowing into a tank during a unit time, calculates the difference, and calculates the difference between this and the change in the liquid level in the tank. Since the system detects the presence or absence of leakage from the tank based on the amount of level change, leakage accidents can be detected accurately and quickly regardless of whether liquid is flowing into or out of the tank. It can also detect and display the scale of a leak.

[Brief explanation of the drawing]

The figure is a configuration diagram showing an embodiment of the leakage detection device of the present invention. 1 ・・・・・・・・・・・・Liquid tank 2.4 ・・・
...Pop 3.5 ...Piping 6.7 ...Flow rate transmitter 17 ...Liquid level transmitter 8.9, 12
,13i5i8,20,22,23゜25.27...
・・・・・・・・・Signal Line Agent Patent Attorney Sasa Suyama
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Claims (1)

[Claims] 1. A flow rate transmitter that detects the flow rate of liquid flowing into and out of a liquid tank through piping, and a flow rate transmitter that calculates the difference in the amount of liquid flowing in and out within a unit time based on the outputs of these flow rate transmitters. a difference calculator, a liquid level transmitter that detects the liquid level in the liquid tank, and a change amount calculator that calculates the amount of change in the liquid before and after the unit time based on the output from the liquid level transmitter. A leakage detection device comprising: a leakage amount calculator that inputs the outputs of the change amount calculator and the flow rate difference calculator, calculates a leakage amount from the difference therebetween, and outputs the calculated leakage amount. 2. The output of the leakage calculator is led to the comparison circuit and compared with a preset value, and if the output of the leakage calculator is larger (= an alarm signal is sent and the alarm device is activated) Claim 1 characterized in that it is configured to
Leak detection device as described in section. 6. Claim 1 or 2, characterized in that the output of the leak amount calculator is displayed on an indicator.
Leak detection device as described in section.