Loss-in-Weight Dosing
Accurate dosing solutions for discharging applications
Dec has developed specialist expertise in accurately dosing powder out of a storage hopper or directly out of packaging such as big bags, drums or bags and further charging dispensed materials directly into process equipment like reactors or mixers without the need of using any screw feeders or rotary valves.
Dosing is accomplished by installing the discharge station on load cells and by transferring the powder out of the station, using PTS Powder Transfer System® or PFL Powderflex.
The weighing system coupled with the PTS operation and some additional valves allows high accuracy dosing and full discharge of the transfer line at the end of the dosing sequence. The weighing system can be connected to the customer control system and can be used for recipe management with connection possibilities to an MES including batch reporting system.
Dosing out of big bags or hoppers
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The big bag station frame or the hopper are installed on load cells. PTS is connected to the station by flexible hose preventing any interference with the scale. When the dosing weight is reached, the outlet of the station is closed by a valve and the line is emptied by operating the PTS during a few cycles.
A typical dosing accuracy of 0.5-1 kg can be achieved for a big bag of one ton. When handling larger batches, multiple big bag changes are possible with weight accumulation.
For smaller charges, a weighing hopper can be combined with the PFL to achieve accuracy of less than 10 g.
Dosing out of drums or bag stations
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The drum emptying station is installed on a scale and the powder is directly transferred by using a suction lance. Higher containment can be provided when using a DCS® Drum Containment System or a DSC Drum Sealing Cover. The dosing valves are sequenced together with the PTS. The system is semi-automatic as the operator will have to manipulate the lance at the end of the drum emptying. Operating software takes into account the influence of the operator, allowing accuracy to within 50-100 g even over multiple drum changes.
