Series of materials dryers for the plastics processing sector has been expanded in order to include the option of two drying hoppers, each with independent temperature control.

Wittmann UK has expanded its Drymax C30 Series of materials dryers for the plastics processing sector in order to include the option of two drying hoppers, each with independent temperature control. Besides the currently available configurations of the Drymax C30 with one drying hopper, either as a hopper mounted unit or beside-the-press unit, and as a compact dryer mounted on a frame and attached to the drying hopper, the Drymax C30 can now be supplied with two hoppers mounted on a frame with casters. In this configuration the Drymax C30 is available in several combinations of hopper sizes of 20, 30, 50 and 70 litres.

The Drymax C30 dryer generates a dry air capacity of 30m3/h and guarantees throughputs up to 20kg/h depending on the material to be dried.

The dual hopper version of the Drymax C30 offers all the features of the single hopper unit with the added flexibility to dry two materials independently using a single dryer.

The Drymax dryer uses the principals of adsorption and is equipped with two independent desiccant beds for a constant dry air supply.

By means of reverse flow direction between process and regeneration air, the dryer is able to achieve a constant process air temperature and dew point of - 60 deg C, independent of the ambient air condition.

The Drymax microprocessor control has been developed and optimized by Wittmann for drying applications and performs extensive monitoring and temperature control tasks in addition to the automatic and independent adjustment of airflow through the two drying hoppers.

The integrated SmartFlow function controls two motorized flappers to divert the airflow based on the material throughput of each drying hopper.

In conjunction with the embedded material saver function, the set point of the process heaters are lowered as soon as a press stoppage is detected in order to avoid over-drying and thermal degradation of the material residing in the drying hopper.

Should an increase of the material consumption be indicated via a rising temperature differential in the hopper, the microprocessor automatically raises the drying temperature to the original set point and the SmartFlow motor valve increases the air flow according to the material throughput.

By using electrically driven switch-over valves in the dryer and SmartFlow valves no compressed air supply is required for the operation of the Drymax C30 dryer.