When highly dangerous products are manufactured, occupational health and safety is given top priority. But hermetically sealed processes are not just important for the people involved in making a product, but also for the product itself, because leakage of even just a few grams of active agent can entail major financial losses. As not all substances are equally hazardous or sensitive, their average exposure concentrations in the workplace air are measured over a defined period of time and their toxicities are divided into categories, so-called “Occupational Exposure Bands” (abbreviated to OEB) – the more toxic, the higher the grading.
The potential hazard that a substance poses is measured in micrograms per cubic meter. The following example demonstrates how accurate the measurements are: OEB 5 corresponds to an exposure of less than 1 µg/m3. If you were to extrapolate this figure to the size of the Empire State Building in New York, then no more than one twentieth of a teaspoon of a particular substance would be present in the entire building.
Features of an OEB-compliant dust-tight feeder
- Solid flanges with milled surfaces: all transfer points within the product space are securely sealed
- O-rings at transfer points between the flanges
- Additional seal on agitator seal and on twin radial packing rings
- Sealed sight glass: at the leak tightness control aperture on the gearing mechanism
- Easy to handle cover, hopper and screw tube: quick-release fastenings remain in place on the device when it is being dismantled
- As many standard components as possible
Do you have any questions about “OEB-compliant feeding”? Contact our Head of Sales Antonio Seising.
Successful pressure test for OEB application purposes
Kubota Brabender Technologie has now conducted a pressure test for OEB application purposes on its DDSR20 2.0 and DDSR40 2.0 twin-screw feeders. Built-up pressure was contained virtually without any loss, when the feeders were both idling and in operation. The PETG downspout, including its silicon sealing ring can be regarded as gas-tight when subjected to pressure of up to at least 40 mbar, without requiring any further accessories. The flexible Liquid Silicon Rubber (LSR) sleeves can also withstand pressure of 30 mbar over a longer period without being visibly damaged.