Sultan swings it for Bardon

A Hawk Sultan acoustic wave transmitter from Partech Instruments is providing an accurate and reliable solution to the problem of determining the level of primary crushed material at Bardon Aggregates’ Croft Quarry. Knowing precisely how much crushed granite is in the silo immediately below the primary crusher is key to the efficiency of the quarry’s 2,000 tonnes/h crushing operation.

Various technologies for measuring the surface level in the silo had been tried in the past but none had proved wholly effective until the installation of the Hawk Sultan acoustic wave remote transducer in 2004. Suspended within the silo, the Hawk Sultan constantly monitors the surface level with the results being transferred to the central control station located above the crusher. Here a graphic display module provides a visual image of the volume of aggregate within the silo.

The Hawk Sultan is an ATEX-compliant, non-intrusive acoustic wave transmitter that uses a range of transducer frequencies. In operational mode the transducer emits a high-powered acoustic pulse that is reflected back from the surface of the material being measured. The reflected signal is processed using purpose-designed software that includes ‘bin mapping’ for the rejection of false echoes and echoes from structures within the silo.

The transmission of these high-powered, low-frequency pulses ensures that losses due to vapour and dust between the transducer and the target are kept to a minimum. According to Partech, it is the use of frequencies that are substantially lower than other systems that allows the Sultan to operate in applications that would defeat other ultrasonic devices.

Les Lee, engineering manager at Croft Quarry, confirmed that the company had used other ultrasonic technologies in the past but without securing the accuracy of readings required. Typical problems encountered included false readings reflected from the surfaces of the stone and readings loosing their way due to dust.

‘Since the Hawk Sultan was installed the system has worked perfectly and has proved to be very responsive to level changes within the silo. Overfeed was always a problem but this is now being successfully addressed,’ he said.

As a result of this success, Bardon have ordered a further Hawk Sultan system for the fine-dust bin in the phase 4 screening plant at Croft.