Heating cabinet

Respiration dryer on 200l drums with isocyanates, polyols and additives at approx. 120°C

GIEBEL Adsorbers® increase the quality of isocyanate and polyol end products and significantly reduce the effort of rework. When liquefying these substances for the production of plastic products at 70°C and even 120°C in a heating oven, special GIEBEL Adsorbers® protect against moisture and quality degradation.

Barrels in the heating cabinet

To process some isocyanates, polyols and additives, they are stored in a heating cabinet at 70 to 80°C or even at 120°C. This process is used to increase the viscosity and improve processing.
This process serves to increase viscosity and improve processing. The storage time in the heating oven also varies from a few days to the entire life of the drum, i.e. until it is completely emptied directly from the heating oven.

Necessity of an adsorber

Also, when isocyanate and other substances are removed from the heating oven, the air flowing in will contain water and enter the barrel. Contact with water from the air leads to undesirable side reactions. This results in the formation of CO2 bubbles in the molding compound, which remain trapped in the cured molding material. This requires a great deal of post-processing effort in degassing, or dewatering, the finished product.

How the adsorber works

Breathing dryers are used to protect the barrel from moisture. They are screwed directly into the G¾” bunghole thread. All the air drawn in is completely dried.
During extraction, the aspirated air is completely dehumidified. The desiccant turns from orange to green, indicating the saturation status.

Adsorber in heating cabinet

Compared to standard respiratory dryers, which can only be used up to approx. 70°C, the use of a special solution is recommended in the heating cabinet. The advantage lies in its structure. The desiccant used, molecular sieve 4A, is less temperature-sensitive and absorbs water excellently even at temperatures up to 200°C ( Note: Silica gel, on the other hand, will hardly adsorb any water above approx. 70-80°C).

In addition, special valves are used to protect the desiccant. They ensure a long maintenance interval.

Added value and cost advantage – Proven in practice

The technically optimized design of a respiratory dryer ensures effective protection against moisture even at high temperatures. When used under the above-mentioned conditions, the post-processing of the end product is completely eliminated or reduced to a minimum.