The Armfield FT18-MkII is a small pilot-scale cross-flow filtration system designed to operate with a range of membrane module configurations. It can operate with as little as 5-10 litres of material but still give data that is useful for process scale-up. It can be used over the full range of cross-flow filtration applications from microfiltration through to reverse osmosis. It is the perfect tool to use, following on from flat sheet membrane trials with the FT17, for further process development and scale-up.
The system uses a high-pressure piston-recirculation pump to circulate product through the filter module of choice.
The triple-piston design combined with high-pressure flexibles minimises pressure pulsation. The operator can use their own feed vessel or this can be specified (FT18-20 option). The speed of the recirculation pump can be adjusted to suit the particular filtration module and the product. The retentate back-pressure valve enables pressures up to 50 bar to be achieved. Accidental system over-pressure is avoided by a bursting disc downstream of the recirculation pump.
There is a permeate back-pressure valve so that accurate transmembrane pressures (TMP) can be set. Pressure sensors are sited on the retentate side on the inlet and outlet of the filter module, as well as on the permeate side. Any temperature gain in the retentate through recirculation at high pressure is removed using a 316 stainless steel shell and tube heat exchanger, which has corrugated tubes for improved heat transfer.