| 摘要 |
1481850 Determining leak location electrically B BRANDES 25 July 1974 [26 July 1973] 32875/74 Heading G1N To determine the position of a leak 10 from an electrically conductive pipe-line carrying fluid, a ninevolt battery is connected to the pipe-line by a line 20 whereby if a leak occurs to short the pipe-line to a signal conductor 6, fastened to the pipe-line but insulated from it in the absence of a leak, current flows via line 20, the pipe-line, conductor 6, and resistor 26 to cause changeover of switch 27. Thereby the positive pole of a twenty volt battery is connected to one end 13 of the conductor 6 of which the other end 11 returns to the battery via diode 24 and line 23, the potential across the conductor being stabilized by a Zener diode 25. The voltmeter 12 thus lies in a measuring loop constituted by diode 31 line 32, the pipe-line, that length of the conductor 6 lying between the leak and the end 11, diode 24 and line 23. Thus the voltage indication on the voltmeter represents the distance of the leak from a datum point on the pipe-line, usually the end of a line segment disposed in a manhole. An amplifier 33 is disposed across a resistor 29 disposed in the line 28 from the twenty volt battery to the conductor 6 and acting in response to current flow in the line 28 to cause the voltmeter to retain its reading. The voltmeter may be a digital voltmeter. |
