The ultimate static mixer selection guide
Static mixers effectively homogenise fluid materials, including granules, gases, liquids and slurries, in a continuous process contained in pipelines or channels.
Specialised designs can mix methane and steam, liquids and gases, and materials with diverse densities, viscosities and inflow rates. They find roles in many different applications, from dispersing flavourings into breakfast cereal to mediating chemical reactions and ensuring the safe dispersal of waste products.
With so many different materials and purposes, the range of inline static mixers is broad. Inline static mixers range from small laboratory units connected to narrow tubing to giants 46-feet across inside power station cooling towers.
There is no substitute for the services of a specialist such as https://www.statiflo.com/, but this guide aims to help you focus on your requirements.
A basic distinction is between mixers for viscous ingredients with laminar flow, such as plug flow reactors, injection moulders and extruders, and those for low viscosity gases and liquids with turbulent flows, such as gaseous mixing and the dispersion of immiscible liquids.
Helical twist (HT) blades achieve medium mixing and are considered general purpose. For demanding applications and larger sizes, GX elements – with X-grid cross bars – are ideal for laminar flows, while GV elements – with corrugated blades in various shapes – are ideal for turbulent ones. Extrusion melt blenders (SMB) are for extruders and injection moulders.
Although good advice is often critical, many mixer assemblies are general purpose, available in stainless or carbon steel and a variety of plastics. Many are designed with provisions for a choice of injectors, samplers, sensors or heat exchange jackets. Steel units are usually bolted into the pipeline, but some plastic units are simply threaded.
Similar designs in larger diameters are typically used in water treatment plants. They are usually bolted or riveted into position. For open water channels, large repeating elements can be designed and assembled.
For more demanding high-pressure scenarios, such as viscous polymer production, you will normally require large steel mixer units that are welded in position. Other units are available in exotic alloys with provision for steam injection heaters.
For desalination, chemical and paper pulp industries look for special corrosion-resistant mixers. Some are constructed of PTFE-lined carbon steel, with removable PTFE elements.
Removable elements within stainless steel modules are also ideal for foodstuff and pharmaceutical industries.