Batch Fluid Bed Processors

Why Choose a Batch Processor?

Customers choose batch fluid processing for a variety of reasons. Perhaps the most common reason is that upstream and downstream processes are already batch processes. In such cases running the fluid bed processor in a batch mode simplifies material handling.

Many customers like (or need) the ability to identify finished product with a specific batch number. This is particularly true for food and pharmaceuticals but has application to the chemical, metallurgical, personal care and other industries as well. The excellent mixing in the batch fluid bed processor assures uniformity of the final product within each batch.

Other customers need to process several products on one piece of equipment, or need to make relatively small quantities of material on a daily or weekly basis.

In other cases, several fluid bed processing steps are required (e.g. dry mixing followed by drying followed by granulation followed by post drying followed by cooling). In such cases a single batch processor is often less expensive and easier to operate than a continuous processor having multiple processing zones.

Batch Fluid Bed Processes

Niro batch fluid bed processors can be configured for mixing, drying, agglomerating, coating, and cooling.

Mixing

The inherent turbulence in the fluidized bed provides fast, efficient mixing with relatively low attrition of feed materials. Mixing is often the first step in a multi step batch run.

Drying

The intimate mixing of air and feed in a fluid bed provides rapid drying of any material that can be fluidized. Air temperature is controlled to provide the fastest drying time consistent with avoiding temperature damage to the product.

Agglomeration and Granulation

By spraying a fine mist of binder solution onto the bed a batch processor can be used to produce an agglomerated or granulated product.

Although granule structure is controlled by the granulation conditions, typically the agglomerates have a large size (mean diameters of 100 to 1000 microns are typical specifications) and fairly open structure. The combination of large size and open structure produces a free flowing, non-dusty material that nevertheless preserves the large specific surface area typical of small particles.

Such granules are advantageous when re dispersion of the material is required (Such as for instant foods, pigments, agricultural chemicals and other materials that will be re dissolved prior to uses). In other cases an open pore structure is important for surface activity (catalysts and desiccants) or to allow lubricants or coolants to circulate within the granule.

Agglomeration can also be used to reduce the bulk density of a product. This is often of interest for packaging reasons.

Coating

Niro Batch fluid beds can be configured as particle coaters. Excellent control of final particle size and of coating thickness can be achieved. Coatings may be used to provide a controlled dissoloution rate (timed release), to coat an expensive active agent on a less expensive substrate, or to add a surface agent needed for downstream processing.

Cooling

Using ambient air or chilled dehumidified air, Niro batch fluid bed units can be used to quickly and uniformly cool a product.

One Pot Processing

By changing the fluidizing air conditions it is often possible to mix, dry, granulate or coat, post dry and cool in a single processor without discharging the material from the unit.

The Niro Multi-Processor™

Niro batch fluid beds can be configured to allow quick changeover from dryer to granulator to coater.

Sizes Available

Niro offers a range of plant sizes, from small bench scale units designed for a few hundred grams to large units capable of 1500 kg batches.

Available Features

Food and Pharmaceutical grade units

These units are designed with sanitation and validation in mind. Processors can be supplied in a variety of surface finishes from industrial to mirror polished. Interior surfaces are designed to minimize crevices, ledges or dead spaces that would be difficult to clean. A variety of clean in place systems can be configured to individual needs. "Through the wall" processing can be provided to isolate the clean product handling area from the mechanical equipment area.

Deflagration Resistant Designs

Rapid combustion is always a concern when handling powders, especially when they are well dispersed in a fluidizing air stream. Niro equips all its batch processors with grounding systems to minimize charge build up. The ground systems are interlocked with the control system.

Combustion is still a possibility however, so Niro offers 2 bar (30 psig) and 10 bar (150 psig) designs to contain deflagrations. A 10 bar design* is standard on our smaller units and available on larger ones.

A 10 bar design will contain the pressures associated with most* deflagrations, eliminating the need for explosion relief ducts.

A 2 bar design* is available on larger units. This design reduces the required size of explosion relief ducts.

In either case, the unit is equipped with deflagration shut off valves to isolate the inlet air preparation and exhaust duct from the pressure build up.

Computerized Control Available

PC based control systems can provide automatic batch records, automatic recipe control, and export of data to your statistical process control system.

Fill and Discharge Options

Two methods are available for filling and emptying the processor. With a removable bowl system the processor bowl is removed from the processor and taken to another location for filling and emptying. A wheeled trolley is supplied for moving the bowl and an automated system is included to lock the bowl into the processor. With this option the processor bowl becomes part of the material handling system.

Gravity feed and pneumatic discharge systems can be supplied. With this approach the feed is poured into the processor via a fill port on the side. Feed is discharged pneumatically using the main processor fan to supply the motive air. Screw Feeders can be included when the feed does not flow readily.

Pilot Facilities

Niro Maintains pilot facilities in the US and in Europe. Rental units are also available for development work.

*Consult our engineering department for guidance on selecting deflagration resistant designs.

The Choice is Yours

Niro offers both batch and continuous fluid bed processors in a variety of configurations. Our engineers can work with you to develop the approach that works best for your application.