Pulsar Process Measurement have supplied a high-accuracy DUET transducer array with FlowCERT controller to a Premier Foods owned company in Newport. The superb accuracy achieved has allowed the company to make a substantial saving on effluent charges.

Equipment used:

Companies are charged on both volume and quality of the effluent being discharged and many either fail to appreciate the importance of accurate measurement or simply don’t know how to achieve a high standard of accuracy. The MCERTs scheme has introduced a way to benchmark the accuracy of a complete installation. The project was led by Siris Environmental, who have introduced an ‘MCERTS Compliance Guarantee’ to reassure companies that their installation meets the standard, and in this case they handled design, installation, commissioning and also arranged 3rd party inspection of the installation for MCERTS certification.

“ultrasonic systems work by bouncing a sound pulse from the surface being measured and calculating the distance”

Pulsar’s DUET non-contacting ultrasonic transducer array, together with the matching FlowCERT ultrasonic controller, was chosen for the extraordinary accuracy achievable. Ultrasonic systems work by bouncing a sound pulse from the surface being measured and calculating the distance from the time taken for the pulse to return to a transducer. The accuracy of the measurement depends on the speed of sound, which can vary with temperature. Temperature changes can be compensated for, but a temperature compensation circuit can’t respond immediately and there may be temperature variations in the column of air below the transducer face. DUET uses two transducers a known distance apart, and by comparing the returning signal from both transducers, variation in the speed of sound are dynamically compensated for. This was critical to the success of the project. A 2mm variation in measurement accuracy would results in an error of 40 cubic metres per day.

Paul Wiggins of the Environment Agency also commented: “It is excellent news that an industrial effluent flow monitoring installation meeting MCERTS requirements and using a MCERTS certified flow meter has had such a positive impact. Managing flow is crucial to effective effluent treatment, protecting the environment and can have considerable financial benefits to the industry.”