JPS5834334A - Detection system for leakage position - Google Patents

Abstract

PURPOSE:To detect a leakage position from the ratio of effective values by installing acoustic emission sensors at both ends of piping, and detecting the leakage of a liquid due to the increase in sensor output effective value. CONSTITUTION:AE sensors 2 and 3 are installed at both ends of piping 1, and their outputs are passed through effective value gauges 4 and 5 to obtain effective values VA and VB, and their ratio VA/VB is found by an arithmetic device 6. The output VA/VB for a leakage point is maximized at a point A, 1 at an intermediate point, and minimized at a point B. Its curve is different in shape according to the material, diameter, thickness, etc., of the piping, and calibration is performed previously to obtain only one curve. In general, the attenuation of a 100-300kHz AE sensor band by the piping is several dBs/m and the ratio of two sensor outputs is found to decide on a leakage point precisely without reference to the amount of leakage.

Description

[Detailed description of the invention] When internal fluid leaks from piping, etc., an acoustic emission sensor (i.e.
It is well known that the effective value of an accelerometer (fl sensor) or an accelerometer increases, and is used to detect leakage.

Here, we also propose a method for detecting the leak location. The explanation will be given below according to the figures. As shown in the first figure, AH sensors 2 and 3 are installed at both ends of the pipe 1, and the effective value vA of their output is
In order to obtain VB, each is passed through an effective value meter 4.5, and the ratio 'A/V' is further determined by an arithmetic unit 6.

The "VB output for the leakage point is generally maximum at point A, as shown in the second figure, and l at the intermediate point.

It becomes minimum at point B. The shape of this curve will vary depending on the material, diameter, thickness, etc. of the pipe a, but if you compare the values in advance, you can easily determine the shape.

Generally, the Ate sensor band for purification is 100 to 300 KH.
The attenuation of 2 is several dB/m, and by finding the ratio of the sensor outputs of 21taI in this method, the leak position can be determined with high accuracy regardless of the amount of leak.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing an embodiment of the present invention, and FIG. 2 is a diagram showing the relationship between output and leakage position. 1... Piping, 2.3... AI! 2 sets/s, 4.5... Effective value meter, 6... Arithmetic unit. Agent: Patent attorney Kensuke Chika (and 1 other person)

Claims (1)

[Claims] Acoustic emission sensors are installed at both ends of the piping, and leakage of internal fluid is detected by increasing the effective value of either or both outputs, and the position of the leak is detected from the ratio of the effective values. method.