Author: Jim Ruschmann (Applications Specialist)
Overview
IBCs or intermediate bulk containers have been long used across many industries for many years. For this discussion, the utilization of rigid versus flexible intermediate bulk containers shall be covered.
Rigid IBCs are generally made of stainless steel or less expensive polypropylene. The IBC can be designed having either an integrated, sloped sided, truncated pyramidal discharge or a side door. Most popular for the sanitary industries are the stainless-steel version with truncated pyramidal discharge. For powder processing applications, the slope of the discharge and outlet diameter can be altered, to an extent, as to promote the flow of powders from the IBC to subsequent equipment or processes. Cohesive materials with poor flow characteristics may not be suitable for standard IBC processing without a combination of dynamic flow promotion and discharge control. This requires a special dedicated station and application specific bins.
The flow of powders from the bin is generally controlled by various discharge valve designs. The valves can be designed for metering and dosing. New coaxial combination valves have been designed for gross discharge as well as fine dosing, configured in a gain in weight scheme. This is where the receiving bin or process is placed on load cells and a scale controller to automatically control the action of the valve, with the intent of metering a precise amount of powder from the IBC with high accuracy.
Fig 1: Combination hygienic valve provides gross discharge and fine dosing.
Fig. 2 Standard hygienic metering valve.
Fig. 3 Standard hygienic open/close butterfly valve.
An IBC’s main function is principally short-term storage while affording the contents of the container high protection from external influences. Examples of these include protection from damage from handling the container or collision damage. However, protection from ambient dust and weather, particularly moisture, is a prime reason IBCs are chosen. IBCs can be custom modified with ports for nitrogen flushing, thereby displacing moisture laden air inside the IBC prior to filling. This prevents lumping and agglomeration of the powders stored within the containers.
Sometimes lump formation is inevitable. For this reason, it is entirely possible to integrate a low profile, light weight, and hygienic lump breaker to the discharge port of the IBC.
Fig. 4 Soft agglomerated lumps are easily broken by including a lump breaker installed on the IBC discharge. The low-profile design saves space and eliminates a unit operation.
Not Just Storage…
IBCs have been chosen to maintain batch integrity, facilitate traceability as well as to preclude cross contamination of other substances. Typically, if many powder or powder blends are used in a process, dedicated IBCs are employed.
IBCs afford product containment when integrated to a process such as blending, milling, sifting, roll compaction and dispensary, just to name a few. With the utilization of high containment, split butterfly valves, hazardous powder having high OEB levels can safely be safely handled.
Fig. 5 Split butterfly valves allow the safe dust tight integration of IBCs to various processes when high potency powders are involved. Most often used as an interface between IBC feeding and discharging
IBCs in the modern world of processing allow for a very high of processing efficiency while keeping matters simple. An example of this is the relatively new concept of “in-bin” blending. This is where the IBC becomes the mixing/blending vessel. Various size IBCs can be docked or mounted to a mixing frame and then transported to storage or another process. In-wall mixing frames frees up space in the processing suite while maintaining strict sanitary protocol.
Fig. 6 After blending, the IBC can be hoisted above another unit process or to storage.
Head space permitting, IBCs can be hoisted into place above a mill. Both the feed IBC and receiving IBC can be tightly integrated for high powder containment. A post hoist provides accurate and positive docking of the IBC to the mill feed inlet as well as fixing the IBC to the mill discharge.
Fig. 7 IBCs along with a post hoist provides a simple and safe method of milling and collection of high potency hazardous powders.
Parallel process is another big benefit of the deployment of an IBC based processing system. Various unit operations can be performed simultaneously, thus providing high processing efficiency. Some examples are milling one batch while mixing/blending another. Filling can be accomplished at one station while blending, milling, or sifting in anther station. The limitations of a batch process can mostly be overcome with “flip flop” processing. This is where two mixing stations in parallel work together simultaneously. While one station is mixing an IBC the other station can be docking an IBC in preparation for subsequent mixing. By the time the vessel is docked and ready, the mixing station one has completed the blend/mix cycle and is ready for un-docking and transport.
Conclusion
Agility, flexibility, and efficiency all go together with IBC-based processing. Customers are demanding short production runs, dealing with a multitude of SKU’s, custom processing all in short order. This why custom manufacturers, contract manufacturing organizations and specialty powder producers are considering IBC-based integrated processing systems. Hanningfield has the experience and know-how to offer both simple and complex IBC based processing systems based on the demands of the customer’s specific requirements.
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