Pre­cise dosing of free-flowing powder

Auger dosers are suited for the dosing of a wide range of pow­ders. Thanks to a spe­cial closing mech­a­nism, tech­nology from Harro Höfliger also reli­ably fills extremely free-flowing powders.

Some­times you are com­pletely absorbed in your tasks. Every­thing is easy and seems to flow by itself – you are “in the flow“. Those who have ever dealt with the filling of pow­ders can even better under­stand the metaphor behind this term. In order to make sure that the powder can be dosed at all, it must flow or be pre­pared to flow. Fre­quently, this is not an easy task, because as diverse as pow­ders are, as dif­ferent are their flow prop­er­ties. Dosing sys­tems have to be designed and adapted accordingly.

A suit­able solu­tion for many pow­ders is the auger doser from Harro Höfliger. It pro­vides pre­ci­sion, flex­i­bility and is even capable of reli­ably advancing cohe­sive pow­ders: Ini­tially, it is located in a con­tainer, with the dosing unit – the epony­mous auger – posi­tioned in the center. Rotating move­ments convey the mate­rial to its des­ti­na­tion, for example the reser­voir of an inhaler.

Closing mech­a­nism of the auger doser

In order to keep the powder moving, the hopper has a spe­cial stirrer for powder flu­idiza­tion. Stirrer and auger have sep­a­rate drives so that the powder can be better con­trolled during dosing stops. How­ever, espe­cially with very well flowing pow­ders, such dosing stops are a real chal­lenge for quite a few auger dosers; the powder may con­tinue to trickle, causing con­t­a­m­i­na­tion and inac­cu­rate dosing results.

There­fore, for more than ten years, Harro Höfliger‘s system has included a spe­cial locking mech­a­nism. The dis­charge opening of the dis­pensing cylinder is open during dosing and will close auto­mat­i­cally when dosing stops. This is done by means of a sleeve which, when closed, rests on the closing cone of the dosing auger so that the powder cannot escape. That way, the powder is kept flowing when – and only when – it is desired.

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Photos: Helmar Lünig