New Non-contacting Ultrasonic Open Flow Monitor

Pulsar Process Measurement (UK) announce the launch of FlowCERT, a new noncontacting ultrasonic open channel flow measurement system that uses unique and patented technology to achieve measurement accuracy that was previously impossible, helping companies to achieve the MCERTS standards.
FlowCERT consists of a dedicated control unit, which makes calculations to BS3680 across every regularly used flume and weir type, and offers datalogging and RS485 digital communications. This is coupled with a choice of sensor, either Pulsar’s high-frequency dBMACH3 transducer or their patented DUET.
DUET is a new concept in ultrasonic measurement featuring two transducers mounted on a common frame, one higher than the other. Both transducers fire together, but the echoes returning from the flow surface are only processed at the lower unit.
By constantly monitoring the phase difference between the two transducers, DUET dynamically compensates for any changes in the speed of sound between the transducers and liquid surface. The speed of
sound varies with temperature, and conventional temperature compensation
equipment does not react quickly enough to be really effective. Temperature variations provide the major source of process inaccuracy when using ultrasonic equipment, so by completely removing temperature
effects, DUET is a significant breakthrough. In tests, against a temperature variation of more than 30ºC, DUET plus FlowCERT achieved
linear measurement accuracies of ±0.5mm.
FlowCERT also offers 32-point linearisation and velocity x area flow calculations where no primary measurement device exists, with the addition of Pulsar’s Speedy velocity sensor. Speedy is available either as a "wedge” sensor to be fitted to the bottom of a channel or pipe, or as a pipe sensor. In both cases the Doppler effect is used to calculate
the liquid flow velocity.