Accurate to the gram - feeding and dosing with a vibrating feeder

When dosing bulk materials in the pharmaceutical, food and chemical industries, the physical and chemical properties of the materials initially determine the suitable or preferred technologies. Fine powders, for example, clump together and compact easily, while coarser-grained powders can form bridges or jams. Sticking of the product or dust formation can lead to weighing errors and loss of quality. Hygroscopic or temperature-sensitive particles require constant ambient conditions - which is why sometimes only integrated drying delivers the desired result. ATEX regulations must be observed in potentially explosive areas. The selected system should be easy and thorough to clean in order to avoid contamination and fulfil the usually high hygiene requirements. The aim is always to find the right dosing system for each process for precise, gentle and segregation-free feeding and filling, which can also be integrated as seamlessly as possible into the existing production chain.

Pneumatic linear vibrators without lag

Vibration technology offers a wide range of solutions, even for demanding dosing requirements and sensitive products. Users can utilise the DosyPack dosing station from NetterVibration to dose bulk materials in a variably adjustable, fast and precise manner or to use it as a feeder for optical sorting systems. The system essentially consists of a storage container and a conveyor mounted on blade springs, which, as a fully installed, customised unit, reduces the installation effort for the user. All product-carrying parts of the dosing station are made of brushed stainless steel, while all other components are made of corrosion-resistant or physiologically harmless materials. The conveyor trough is driven by pneumatic linear vibrators from the NTS or NTK series. These are optionally available lubrication-free or as an ATEX version and the manufacturer customises them to the respective application as required. The pneumatic linear vibrators operate without lag, which enables precise starts and stops and thus forms the basis for exact conveying, as the product flow stops immediately after the vibrator is switched off. The exact delivery rate is determined separately by the frequency and the vibration amplitude. Increasing the pressure increases the frequency, while the oscillation width can be adjusted using an optional exhaust air throttle.

Customised to requirements and processes

The manufacturer adapts the dosing station to the operational requirements - the respective design is customised to the upstream and downstream processes. Depending on the application, an open or closed version with a lid and display window is used, which enables visual inspection. Thanks to its functional design and simple construction, users can clean the dosing station quickly and easily when changing products. This is a prerequisite for use under strict hygienic conditions in the chemical and pharmaceutical industries. The station is designed in such a way that poorly flowing and cohesive powders are precisely dosed and sensitive materials are handled gently. In addition to the centrepieces already mentioned, the lid, quick-release clamp and a pusher for pre-dosing in the trough ensure easy handling.The conveying speed is variable thanks to the use of low- and high-frequency vibrators and can therefore be adapted to different products. The storage containers are also available in different sizes.

Read the complete article (in German) including practical examples here, published in CHEMIETECHNIK 09/2024.

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