Auto Warning Tell Tale Extensometer are used to provide a highly visible immediate warning of excessive movement occurring in Rock bolted tunnel or mine roadways with the help of colour bands.
The Auto Warning Tell Tale Extensometer of PMT has two LED lights that are provided in the body of housing. The deformation gap can be adjusted from 5mm to 25mm. The adjusting arrangement is provided in the bottom of the scale pipe assembly. When the deformation of roof reaches its preset value, the LED will start flashing continuously which can be adjusted upto 30 days on demand. The tri clolour scale is also visible to actual deformation, hence the actual roof convergence can be seen everyday.
- - Automatic visual indication for exceeding safety levels
- - Strata movement indications on scale
- - High accuracy and simplicity in readings
- - Rapid & simple installation
- - Variable depth installation possible
|No. of Anchors||1 to 4|
|Measuring range||5mm to 30mm|
|Trigger level||5mm to 10mm (adjustable)|
|Hole depth||1 to 10m (more if required)|
|Hole diameter||37mm – 57mm|