Smaller Footprint for ULTRA dryer

Energy Efficient Drying of Pellets Using Vacuum: Part 2

Packaging manufacturer invests in sustainable products and resource-efficient production continued...

Read Part 1.

Vacuum Dryer Reduces Energy Consumption 

This is also one of the keys to the energy efficiency of the vacuum dryer from Maguire. For example, the process does not require energy to be used for the regeneration of molecular sieves. This is also apparent in the test series Greiner Packaging has conducted. "We determined that the vacuum dryer consumed much less energy than conventional molecular sieve dryers“, states Aigner.

"The energy savings are increased significantly by switching to the energy-saving mode that is integrated into the dryer“, explains Paul Edmondson, the head of sales of Maguire Europe. The software logic ensures that only the required amount of heat is provided to the preheating stage, monitoring temperature at both the beginning and end of the heating hopper, to ensure it’s correct for the vacuum drying process requirements.

When the air that reaches the top of the heating hopper reaches a value that is 30 °C below the set point of the target material temperature, the heater and the blower are switched off automatically. They remain in standby mode until the end of the vacuum cycle or until the expiration of a set time. Only then will they turn themselves on again. This operation can be repeated any number of times during a process. “When drying all polymer materials, the ULTRA low energy dryers verifiably consume 50 percent less energy than conventional desiccant dryers “, Edmondson emphasises.

The vertical design of the dryers makes an efficient gravimetric system possible. At the start of processing a batch, the granulate is heated in the heating hopper and then a defined amount of the material is moved to the vacuum chamber. After the first vacuum cycle, the content of the vacuum hopper is emptied into the retention hopper. From there the material is continuously fed into the manufacturing process. The heating hopper is automatically refilled for the subsequent vacuum cycles. Weighing cells in two critical spots allow the entire drying process to be automatically adapted to the manufacturing process integrated with the software control of the dryer. In addition, the output rates are continuously monitored and recorded due to the use of load cells.

Small Footprint

The vertical design of the vacuum dryers offers another advantage: the machines take up less space. "The new vacuum dryers only take up about half of the space of our other dryers, for which the heat hopper has to be placed separately“, explains Aigner. In addition, ULTRA low energy dryers are very slim overall because the size of the heating hopper could be reduced as the granulate remains in it for a comparatively brief amount of time.

"We are excited that energy-conscious companies like Greiner Packaging use Maguire technologies to implement sustainable processes“, emphasises Paul Edmondson. "We are making good progress in positioning the vacuum dryer technology on the market – even against a desiccant drying process that still dominates the mainstream“. Greiner Packaging in Wartberg has tested the ULTRA low energy dryers for a year and has already replaced multiple molecular sieve dryers with new machines in its production department. "Our experiences so far have been positive“, says plant manager Stefan Bürtlmair in conclusion. 

Author: Ralf Mayeris the editor-in-chief of Plastverarbeiter ralf.mayer@huethig.de

Read Part 1.

Further Reading