New impeller on the market

Over the past couple of years, Chemineer has developed new impeller systems for a range of increasingly specialised applications. Martin Rigden, technical product manager for agitators, said: 'We have introduced the Bakker Turbine (BT-6) gas dispersion impeller, which is particularly suitable for applications with variable gas flow rates. The BT-6 provides the benefit of constant power draw so that changes in mass transfer during processing are much smaller than with other impellers.'

It works by forcing gas to the vessel wall and distributing it throughout the entire liquid volume, bottom to top, for greatly improved mass transfer and uniformity. With it has been developed an efficient dispersion mechanism that can handle:

Suitable for even the highest flow rates, the minimal power draw of the BT-6 shows only minimal variation to changes in liquid viscosity, says Chemineer. It also remains constant for Reynolds numbers well below 1000, which for typical industrial applications corresponds to viscosities of several thousand centipoises.

For tall tanks, the radial pumping BT-6 can be utilised as the primary gas dispersion impeller, mounted directly above the gas sparger in the bottom of the tank. Combined with axial flow impellers, this configuration combines highly efficient gas dispersion with excellent top-to-bottom blending.

'This design is an example of what has been achieved over the last two years – a mixer that provides the benefit of constant power draw so that changes in mass transfer during processing are much smaller than with other impellers,' Rigden said. 'Mixer designers and manufacturers need to become more solution-oriented. Customers want to reduce the length of their supply chain, so we must join forces with sister companies or form new partnerships to meet the requirement for a broader range of equipment that is no longer confined to mixing.

'In the UK, the continual problem we all face is the change in the markets. We are now dealing with much lower volumes of high value products, for example pharmaceuticals. We have responded by producing mixers that are better suited to these tasks.

'At Chemineer, we are working in close conjunction with our sister organisations, so that complete packages can be offered, which include pumps, service and vessels, as well as mixers.'

Among the new product developments is Nimix, a mixing system in a totally enclosed, zero-particulate environment, which also benefits from being very low shear, and is completely emission free.

Also new is a range of BTNS Biotech Mixers, designed for sanitary batch processes in the pharmaceutical and biotechnology industries. Unlike most traditional designs that have two steam ports, the BTNS Mixer's single-steam-port provides rapid, even heating and thorough sterilisation to dramatically reduce cleaning time and downtime. All wetted parts, including oversized shafting, in-tank couplings and impellers, are made from 316 stainless steel, then polished to a 32AA finish for total corrosion-resistance and cleaner sanitary surfaces.

Equipped to provide precise mixing power for increased process flexibility and energy efficiency, this latest mixer from Chemineer can be supplied with a standard shaft speed of 350 rpm or with optional variable speed controls for critical batch processing applications.