Novatec Inc. has introduced a rotating-wheel desiccant dryer called the NovaWheel and its VersaLoad twin-chamber system.
The wheel continuously moves dry desiccant into service, while it regenerates moisture-laden desiccant in the same rotational cycle. Novatec said the wheel dryer is a simpler, smaller, lower-cost alternative to conventional twin-tower dryers.
NovaWheel also delivers less variation in dew point than other wheel dryers, since it uses a steel-link drive chain instead of a belt to drive the wheel, said Mark Haynie, product manager for dryers. “Because belt drives invariably undergo distortion, slippage occurs, causing rotation speed and thus dew-point performance to vary from target settings,” he said.
The dryer also eliminates spikes that can happen with twin-tower dryers during the changeover from one bed to another.
The cylindrical wheel contains a desiccant-impregnated honeycomb divided into three sections. Air from the resin hopper that has been cooled and filtered goes through a blower, then is split into two streams. One stream passes through the moisture-removal section of the wheel, the other through the purge section, where desiccant already has been regenerated and now is cooled down. At the same time, a stream of hot air passing through the third section regenerates desiccant there.
Haynie said the NovaWheel is especially effective with heat-sensitive resins like PET and glycol-modified PET because of its efficient cooling after regeneration. Also, the rotor speed can be adjusted easily to prevent overdrying of materials such as nylon.
In other news, Baltimore-based Novatec said its new twin-chamber system, VersaLoad, enables processors to switch quickly from one resin or color to another for job changeovers without the usual downtime for cleanout and changing resin source points.
VersaLoad has two vacuum chambers and a central mini-hopper for purging compounds, all mounted on a rail over the processing machine. With each chamber connected to a different raw material conveying line, the operator quickly can change over from the job run supplied by chamber “A” by simply moving the system on the rail so the mini-hopper is positioned at the machine throat, and the machine is purged, and then moving the system farther until chamber “B” is positioned at the machine throat.
Even if a third material or color is needed, that change can be accomplished on the fly with one chamber while the other chamber continues to supply material to the machine.
Safety is another benefit, since the operator does not need to climb on the machine to make hose changes.
Each chamber has a see-through reservoir with an externally mounted, variable-height photoelectric level sensor.
Models are available with Novatec's VL self-contained vacuum loader series for operations where a central materials-handling system is not employed.
Tel. 410-789-4811, fax. 410-789-4638, e-mail [email protected]