CARD – New WITTMANN dryer models
With the acquisition of the Austrian company FarragTech on 1 April, the product portfolio of WITTMANN dryers has been expanded. The new dryer models of the CARD series can cover all drying applications – starting from material throughputs of just 0.16 kg/h up to throughputs of more than 1,000 kg/h. This applies without restriction to all plastic materials including engineering plastics. From ABS and PA to PET: CARD dryers can be used without water coolers.
The name CARD (Compressed Air Resin Dryer) stands for compressed air granulate dryer. The compressed air available at the user’s plant is provided in a pressurized state and normally cooled and/or dried. When the compressed air is depressurized, it generally reaches a sufficiently low dew point. Depending on the quality of the compressed air, the dew point usually lies somewhere between -16 °C and -25 °C, which is sufficient for drying plastic materials. CARD dryers make use of this principle. Adapted to the type of granulate to be processed, the depressurized air is heated by a heater element, then supplied to the granulate. In this way, the plastic granulate is heated up, the moisture is drawn to its surface and absorbed by the dry air.
Dryer sizes up to 70 l container volume (corresponding to about 20 kg/h material throughput) are perfectly suited for use on processing machines, and offer the advantage especially for low throughput rates that no further material transport is necessary. The dried material can be processed directly, and the relatively small quantities of material reaching the machine’s feed opening without any further processing step in between do not cool down on the way.
The smallest dryer models CARD G and CARD G/FIT are available with container volumes of 1 l, 3 l and 6 l and differ from each other by their respective control systems. The CARD G/FIT comes with the new FIT control system, which permits operation via a touch surface and provides some additional functions to improve its energy efficiency. What is more, an integrated material loader can be operated very easily via the FIT control system.
Additional model sizes can be found among the appliances designated as CARD E and CARD S, whose container volumes range from 10 l to 160 l, and which also differ from each other by their control systems. The CARD S is equipped with the FIT control system, and the entire CARD S series comes with a temperature-controlled, digital air quantity regulation as well.
The appliances designated as L or XL are available with container volumes of up to 3,500 l. From the CARD M model upwards – including the CARD L/XL appliances – all CARD dryers are equipped with a second drying circuit. The primary circuit in the lower section of the drying container functions according to the principle of a compressed air dryer. It is supplemented by a secondary circuit, which preheats the ambient air and channels it into the upper second third of the drying container. As a result, the plastic material is preheated, which optimizes the drying process in terms of energy consumption. The CARD XL offers the additional option of using compressed air from an extrusion blow-molding process. For this, the excess blower air is collected in a storage tank and passed on to the compressed air dryer. This enables targeted utilization of blower air which would normally be wasted.
The drying containers are made of stainless steel and come with at least one sight glass window for visual inspection. Depending on their size, the drying containers also have a cleaning door. For filling the dryers – all the way from the CARD 1G with a volume of 1 l up to the CARD 3500XL with a volume of 3,500 l – WITTMANN offers material loaders to match each appliance.