VW Type Rod Extensometer
Model: SJ-1390

│ DESCRIPTION │
VW Rod Extensometer is useful to measure the horizontal and vertical displacement of rock or soil in the tunnel or strain of slope or displacement of surrounding ground caused by the stress concentration for excavation work at the tunnel or mining and cable tunnel, etc.

│ CHARACTERISTIC │
Model 1390 VW Rod Extensometer is made up with sensor part having 4 sensors of small VW displacement treated by waterproof and anti-humidity and anchor rod having stainless steel tube to transmit the anchor and displacement for treatment of grouting at tunnel rock to the sensor. When the displacement occurs due to the development or relaxation and joint of rock, it is transferred to VW displacement sensor by anchor rod transforming the tensile force of vibration wire.

If the vibration wire is magnetized by the magnetic coil then the resonant frequency is generated and then this frequency is transmitted to the output device to display the necessary engineering unit, so you can check the displacement velocity, percentage, size and displacement distance easily.

Our VW rod extensometer is designed for slim type so that the measurement anchor can be installed easily in ø38mm which the minimum hold size for installation of rock bolt as 4 measurement points method. VW displacement sensor is designed for total 50mm measurement scope.

When the slab on the reference point sensor head is adjusted setting at normally 25 mm distant point after the grouting of anchor part has been solidified, the tensile force and compression volume can be measured up to each 25 mm exactly and the frequency property for the displacement before delivering the sensor can be easily calculated using the exclusive calibrator for each item to apply the accurate calibration coefficient by recording the result.

The anchor length of VW rod extensometer is 2-6m which is based on longest anchor and it is optional to use depending on the civil engineering designated length or construction site conditions. Also, the precise resistance temp sensor was mounted to compensate the thermal expansion coefficient of the gauge caused by the temp change. The VW rod extensometer has got over any inaccuracy caused in the electric sensor and it is not difficult at all to measure any error or measurement error caused in manual machine type.

It is also possible to do precise and semi-permanent measurement because it was treated by waterproof and anti-humidity.

│ SPECIFICATION │

※ The product spec is subject to change without prior notice in order to enhance the product’s quality.

│ REFERENCE │
This is VW type sensor to output the frequency signal to be connected with the VW sensor output units (Readout, Datalogger, and Multiplex Module for measurement of automation).
It is compatible with any other company products. (except temp sensor)