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ROCHFORD - Typically, there are two major problems which arise during the transfer of powder; excess dust and waste. Excess dust is a hazard to operator health, as well as to the working environment (and can even result in fatal explosions when mismanaged).
Picture: An example application using vacuum transfer for the contained transfer of powder from an IBC to a tablet press.
Meanwhile, waste material results in poor overall efficiency; a problem also caused by excessive manual handling during processing.
Hence in this regard waste is two-fold, it is physical waste (loss of material) and it is time waste (loss of production) both of which negatively impact the overall efficiency of a process. Thus, if an engineer can overcome the problems associated with excess dust and waste, then the efficiency of a process can be maximised to improve hygiene and ultimately profitability.
Solutions for Powder Transfer
There are three simple solutions to improve powder transfer; vacuum transfer, gravity feed and the use of valves - all of which are common in pharmaceutical, food, chemical and other types of process. By selecting the most appropriate method for your application, a process can be easily enhanced.
Lean-phase vacuum conveying is a very efficient and contained method of powder transfer. From pick-up point to discharge, it is possible to maintain a fully enclosed process, preserving the integrity of the system and protecting both the operators and the environment.
The system also minimises waste due to the fully enclosed nature of the pipe-work (no product loss) and the ability to transfer powder at high rates (up to 4,000 kgs/hr). Given these features, a vacuum conveying system is an excellent method for powder transfer as it overcomes the problems outlined above.
The use of gravity feed is another simple, yet effective method of powder transfer. Using a hoist it is possible to raise one container above another and discharge directly or indirectly from the outlet of ‘Container A’ to the inlet of ‘Container B’. For example, if you are looking to transfer powder from one IBC to another, but mill the product in between, this is possible with gravity feed.
Using a hoist it is possible to position an IBC above a cone mill, with another IBC beneath it.
The IBC can then be discharged into the mill, which mills the powder directly into the IBC below.
This removes the need for manual handling, whilst creating a dust-free, fully-contained method for transferring powder.
It’s flexibility, simplicity and reliability makes gravity feeding an excellent method of powder transfer, which can be used across a wide range of applications.
Picture: Hoists can be used to lift IBCs for the gravity discharge of powders.
However, it should be noted that this is not always a suitable option as ceiling height or other obstructions in the process room may restrict the operating height available.
Butterfly and rotary valves can be an extremely simple and effective method for controlling the flow of powders during transfer.
Valves are dust-tight, and easy to install and maintain.
The butterfly valve design provides positive control of powders stored in silos and the rotary valve can provide constant regulated powder transfer.
Another variation is the split butterfly containment valve, which is specifically designed to ensure the operator is never exposed the the product during transfer.
Picture: Butterfly valves and split valves can be used for the contained transfer of powders.
The above solutions can often be used in combination with one another, to provide the ultimate in contained powder transfer. For example, a vacuum conveyor can pick up powder from an IBC and transfer to another IBC, with the use of a valve to control the flow of powder and help maintain a strict closed-system design. A hoist is also often integrated to provide a mixed vacuum/gravity system, to combine the benefits of these to approaches. Hence these solutions, by themselves or in combination, offer the ultimate in process efficiency and containment by overcoming the problems associated with powder transfer; they contain excess dust and eliminate waste.
© Hanningfield Process Systems Ltd / BulkInside
This article is published by Hanningfield Process Systems
Founded in 1987, Hanningfield Process Systems are experts in the design and manufacture of stainless steel process equipment for the pharmaceutical, food, chemical and allied industries. Hanningfield specialise across 5 distinct areas; material conveying, ...View company page