VW Type Rock Bolt Stress-meter
Model: SJ-1350

│ DESCRIPTION │
VW Rock Bolt Stressmeter is to measure the axial force transmitted to the rock bolt to verify the effectiveness of the rock bolt (effective length, quantity and stress of rock bolt). It is designed to measure accurate axial force applying to the rock bolt to be reinforced and installed for strengthening the rock at the construction field such as tunnel, mining, hanger, cable tunnel, etc.

│ CHARACTERISTIC │
Model 1350 VW rock bolt stress-meter is equipped with each high precise VW strain sensor at 4 areas divided by four in total length of the anchor inside the rock bolt anchor to fix the grouting in the tunnel rock and it was treated by waterproof anti-humidity and anti-corrosion.

When the rock is subject to load due to its development, relaxation and joint, fine strain is made in the anchor due to the axial force. The built-in VW strain sensor will absorb all of these displacements. The gauge body inside is equipped with the adjusted VW at approx. 1,800Hz. When horizontal displacement occurs, it is detected by strain gauge to make it magnetized and the VW resonant frequency will generate the frequency to transmit to the output device. The output device will display the frequency as a required engineering unit.

Our VW rock bolt stress-meter can calculate the stress distribution area and the size easily and accurately using 4 measuring points method for which the material mechanics concept was introduced. Also, it is equipped with the precise resistance temp sensor to calibrate the gauge’s thermal expansion coefficient due to the temp change. The rock bolt anchor is manufactured in 2-6m length for optional use depending on the construction field conditions.

The rock bolt anchor is made of high carbon piping steel material with the inside diameter Ø16.2 × outside diameter Ø27.2mm, so that it can be easily installed in the ordinary hole size with the inside diameter Ø38mm at tunnel.
The VW rock bolt stress-meter has cleared the inaccuracy occurring at the electric sensor and it is easy to measure the error or tolerance caused in the manual machine type. Precise and semi-permanent measurement is possible due to the waterproof and anti-corrosion treated.

│ 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, Data-logger, and Multiplex Module for measurement of automation).
It is compatible with any other company products. (except temp sensor)