Auto Centering Device ACD
Application
The Auto Centering Device ACD is used to measure the horizontal displacement along an inverted plumb line bore hole.
Description
The centering torpedo which is connected to a measuring tape will be lowered with a winch into the inverted plumb line bore hole to measure the displacement.
The centering torpedo can be stopped at any position to center there the wire exactly. At this position a measurement will be taken, manually with a coordiscope KK84 or automatically with a Telependulum VDD2.
Additionally the Z-displacement (vertical) can be measured between the lower anchor point and the upper one (tension device). Therefore a second wire (invar) is needed. The measurement can manually be done with a setdeflectometer at the tension device.
Technical Data
| Type | ACD |
|---|---|
| Bore hole | Special drilling procedure Vertical deviation at ø 80 mm max. 5 mm Vertical deviation at ø 100 mm max. 10 mm |
| Tubing | Fully grouted between tube and rock ø 80 mm or ø 100 mm INOX tube with smooth surface Smooth tube connections |
| Centering torpedo | Length of upper part 280 mm Length of lower part 303 mm Total length 583 mm Weight 6.5 kg |
| Measuring tape | INOX 50 m or 100 m with 1 cm graduation |
| Measurement | contactless, manual with Coordiscope KK84 contactless, automatic with Telependulum VDD2 |
| Stabilizing time | 2–5 min (depending of wire length between centering torpedo and floater) |
| Measuring precision * | < 0.5 mm |
* As per the manufacturer HQ a precision of ±0.5 mm can be reached.
With a good tube quality (surface) even a better precision can be reached.
