| 摘要 |
PURPOSE:To permit continuous measurement of the slime interface in a drilled hole or the like by providing the first and second electrodes, sandwiching an insulating material, on both sides of an intermediate electrode, and detecting the change of the resistance between the intermediate and the second electrodes with respect to the resistance between the intermediate and the first electrodes. CONSTITUTION:Sandwiching an insulating material, the first and second electrodes 3 and 4 are provided on both sides of an intermediate electrode 1, and conductors 6 are secured to the respective electrodes to constitute an interface detector 5. A bridge circuit is constituted to measure the resistances between the intermediate and the first electrodes 1 and 3 and between the intermediate and the second electrodes 1 and 4 respectively. The resistances are converted 10 into voltages and inputted to a differential amplifier 11, which is connected through a Schmitt circuit 12 to a speaker 13. A tape scale is secured to the interface detector 5, and this is inserted into a drilled hole 8. When the intermediate electrode 3 of the detector 5 reaches the slime interface, the balance of the bridge circuit is destroyed. Consequently, an output is generated in the differential amplifier 11, and the speaker 13 is operated. Reading the scale of the tape scale at that time permits the interface in the drilled hole to be known. |
