In the example below, a new filling system needed to be installed in the logistics center of a chemical company. At the site, around two and a half million deliveries of various chemicals are filled and refilled every year. The products contain substances from different hazard classes which can be in either solid or liquid form. These include substances which are extremely hazardous for the environment, dyes, toxic, highly toxic and strongly smelling substances, spontaneously flammable substances and peroxides, corrosive substances as well as combustible and ignitable substances. They are filled manually from various bulk containers up to 200 liters in volume into smaller containers ranging from 1 milliliter to as much as 25 liters in volume. Effective operator protection is necessary depending on the degree of risk of the substances. For this reason, the safety concept had to be fully implemented. The special challenge lay in the existing ventilation technology, which only had capacity for a small volume of additional exhaust air.

Alternate exhaust air or recirculated air

Weiss Pharmatechnik GmbH has developed an innovative system with two different air circuit systems for this purpose. The solution combines an ejector air nozzle concept with minimum air throughput rates with a 3-zone pure air curtain technology for maximum contamination protection. 

During the filling of liquids containing solvent, the system is put into the ejector air nozzle mode according to the WIBOjekt principle. It then works in exhaust air mode in order to keep the exhaust air volume low while at the same time expelling the solvent vapors in the best way possible. This enables the systems to manage with around 50 % of the typical air volume and guarantee workplace concentrations of ≤ 1 ppm. 

When potent or toxic powders are being handled, the system operates in recirculation mode using the 3-zone clean air curtain principle in WIBObarrier mode. The shape, direction, velocity and air volume of the WIBObarrier air curtain nozzles are precisely balanced. This perfect interaction produces the ideal flow pattern and creates a stable clean air curtain. The clean air curtain attracts nearby air-borne particles both inside and outside the system like a magnet and routes them directly to the extraction areas on the front and back. Even particles that occur due to a worker reaching into the work area are captured by the clean air curtain and routed to the extractor. The product section of the work area is also blanketed by low-flow, HEPA-filtered clean air. The unidirectional air flow comes out of the unit ceiling and is graded from back t front. This means eddy currents such as those caused by the influence of drafts or operator movements are effectively avoided, as is unintentional product entrainment. Behind the back panel, the recirculated air is triple-filtered through a Class F9, Class H14 and another Class H14 filter. Depending on the toxicity of the substance, the use of a sliding glass panel with glove ports can achieve an OEL of ≤ 10 µg/m3. Thanks to the modular concept, the system can be converted for use with a hinged glass panel with glove ports. This enables an OEL of ≤ 1 µg/m3 to be achieved. Filter replacement is carried out safely and without contamination in accordance with the “safe change” principle.

Standardization for a wide range of hazardous materials

The modular system concept enables workplaces to be standardized with high ergonomics and maximum effectiveness. Different lifting systems with a lifttilt device up to 150 kg, a lifting column and height-adjustable worktops make work easier. Mobile, battery-operated pallet jacks or pallet lifters place containers in the systems, remove them or lift them to an ergonomic height for better handling. This makes the handling of even large containers or pallets easily possible. The system can be operated open, with sliding glass panel or completely closed, which means it is suitable for universal and extremely flexible use for a wide range of hazardous substances.