Accurate Torque Measurement System
The Torqatron is a load cell calibrated to measure torque with an excavator mounted digital readout.
Russell Heale has been involved in the screw piling industry since 1995 and is always striving for improvement through research and development. One important area of progress is in the current calibration and torque measurement procedures, and the development of the innovative Torqatron system.
We are the only Australian manufacturer of load cells for measuring torque for screw pile installation.
The load cells manufactured at Russell Heale Engineering are individually calibrated to their own readout and have to be calibrated to work. The strain gauges in the loadcell are fitted by an expert in this field. They are calibrated to the minimum and maximum torque, and then to up to five intermediate set points. The whole process is repeated 5 to 7 times to ensure that repeatability is well within the specified range. The test bed has NATA certified force measuring equipment fitted. The repeatability has been found to be around the 0.2% range.
Overstatement of Torque
Using other measurement systems we have directly observed errors of up to 50% overstatement of installation torques. We cross checked a 10,000 Nm installation which revealed an actual installation of only 5,000 Nm. These other methods commonly used for measuring torque are the Bourden pressure gauge and pressure transducer systems which measure hydraulic line pressures to determine torque applied.
With these other measuring systems it is difficult to establish the actual losses of the gearbox, or the hydraulic motor, which may vary depending on speed, the torque being applied and the condition of the gearbox or motor itself. This results in an artificially high torque reading, and is not obvious to the operator.
Of course the reason for using screw piles is to have the confidence that the structure built on the site will be solid and stable for many years to come. It is important to be sure that piles are installed to the torques required to handle the loads asked for. The best way to do this is by using the world's best practice torque measurement system, the Torqatron.