August 24, 2017

Normally, measuring the supply current during the mix process controls the concrete viscosity and provides an indication when the correct mix consistency has been achieved. If the power, supplied to the motor, is fluctuating and not at a consistent level, it can be difficult to keep costs at a controllable level and waste concrete was becoming a huge issue. Therefore, a more reliable measurement of the mix viscosity was required.

Our client needed to apply these principles to a large-scale concrete production at Terminal 5 Heathrow.

Measuring Viscosity Of Fresh Concrete By Sensing TorqueThe company made the decision to supply a generator for the concrete production facility. Although it could potentially resolve the issue, it proved to be an expensive option, so they continued looking for a more cost-efficient alternative to control and monitor concrete production.

Firstly, Datum identified a suitable coupling in the driveline for measurement. The Datum Torque Measurement System was installed onto the shaft along with an inductive power coupling. A stator unit was engineered to fit the envelope around the coupling, which provides power for the shaft unit and acts as a receiver for the torque signal. This design is completely non-contact. Torque and Shaft speed signals are transmi!ed from the stator, as RS485 data to the control room. The data is displayed and recorded in the control room as either torque or power.

 Torque Sensor Measures Viscosity of the Concrete Mixture

Data supplied from the shaft provided raw data, indicating of how the mix was performing, as it was being mixed. The data transmi!ed from the shaft showed the sharp rise in torque, as the load is added to the mixer and the drop off in torque (viscosity) as the mix becomes more consistent. Operating staff are able to “tune” the mix by the addition of fluid to attain the desired consistency in the shortest time. The repeatability of the data from the torque signal has allowed a reduction in the time required to achieve this.

Torque Test Data Heavy Duty Mixer Cycle

Following successful proving trials on the first mixer, a second system was ordered and installed. Once the first unit was installed, a second Torque measuring system was installed on the second batcher, due to the successes of the first.