What Are the Best (and Worst) Applications for an Electrostatic Air Filtration System?

Electrostatic air filtration systems use a unique method of collecting airborne contaminants, making them an excellent solution for certain industrial applications. However, there are also applications where electrostatic filtration is not the best choice—or may even present a safety hazard.

This guide explains the applications where electrostatic air cleaners perform exceptionally well, where they can be effective with proper design and maintenance, and where other filtration methods are recommended.

Excellent Applications

Oil Smoke

Thermally generated oil smoke is one of the most difficult airborne contaminants to capture because the particles are extremely small, wet, and often sticky. Electrostatic air cleaners excel in these applications because they efficiently collect fine oil smoke while maintaining a low pressure drop.

Common sources of oil smoke include:

Cold Forming

Oil is used to lubricate and cool dies and parts in cold headers and other cold forming equipment. When the lubricant is heated by the rapid compression of metal, it generates oil smoke that must be captured.

Precision CNC Machining

High-speed CNC machining generates significant heat, especially when machining hardened steels, stainless steel, titanium, and other difficult-to-machine materials. Oil-based coolants extend tool life and improve part finish but also create oil smoke and mist, particularly when high-pressure coolant systems are used.

Tool Grinding

Wet grinding of hardened cutting tools generates large amounts of oil smoke and mist due to the combination of high grinding temperatures and oil-based lubricants.

Centerless Grinding

Centerless grinding with oil-based coolants produces both oil smoke and fine grinding dust from the workpiece and grinding wheel, making it one of the most challenging filtration applications.

Food Production

Whether in a commercial kitchen or an industrial food processing facility, heating oils during cooking or manufacturing produces oil smoke that can be effectively collected with electrostatic filtration.

Plastic and Rubber Manufacturing

Certain plastic and rubber manufacturing processes generate oil smoke or sticky hydrocarbon smoke that can eventually form tar-like deposits. While these contaminants are challenging for any filtration system, properly maintained electrostatic air cleaners are often an excellent solution.

Examples include:

• Blow molding
• Plastic extrusion
• Rubber vulcanizing

Heat Treating

Heat treating operations frequently generate oil smoke, especially when parts are coated with oil or quenched after heating. Powdered metal parts often absorb large amounts of oil because of their porous structure, producing significant smoke during processing.

Good Applications

Water-Based Coolant Mist

Water-based coolants can produce an extremely fine mist, particularly in high-pressure machining systems. Electrostatic filtration can work very well in these applications, but selecting the proper equipment and following a regular maintenance schedule is critical.

Because water is electrically conductive, humidity control is also important. Introducing a small amount of conditioned room air before the electrostatic air cleaner helps reduce relative humidity and improve system performance.

Common sources of coolant mist include:

CNC Machining

Many CNC machining operations use water-soluble coolant. As the coolant strikes the cutting tool and workpiece, it atomizes into a fine airborne mist.

Centerless Grinding

Centerless grinding with water-based coolant generates both coolant mist and fine particulate from the grinding wheel and workpiece.

Welding Fume

Although cartridge dust collectors are now the preferred technology for most welding applications, electrostatic air cleaners can still perform well under the right conditions.

Electrostatic filters effectively collect welding fume, but because welding smoke is a dry particulate, it can become re-entrained into the airstream if a power supply fails or an electrostatic cell shorts out. Welding fume also stains electrostatic collection cells. While the discoloration does not reduce filtration performance, it does affect their appearance.

Poor Applications

Explosive Dust

Electrostatic air cleaners are generally not recommended for collecting dry dusts because dry particles can become airborne again if an electrical fault causes the collection cells to lose their charge.

Explosive dusts present an even greater concern. Electrostatic air cleaners operate using high voltage, and if combustible dust bridges between high-voltage and grounded components, it can create an electrical arc capable of igniting many combustible dusts.

Common examples include:

Dry Grinding or Sanding

Grinding aluminum, magnesium, titanium, and many other materials can generate combustible dust that requires a properly designed dust collector with explosion protection.

Food Processing

Facilities handling flour, sugar, cornstarch, grain, spices, powdered milk, or similar bulk powders should use dust collection equipment designed specifically for combustible dust applications.

Woodworking

Wood sanding, sawdust collection, paper dust, cardboard dust, and similar materials are combustible and should be collected using dust collectors designed for combustible dust.

Corrosive Materials

Electrostatic air cleaners use aluminum collection cells, ionizers, and prefilters. Certain airborne contaminants are corrosive to aluminum. Although the system may initially collect these contaminants effectively, the filter components will gradually deteriorate, resulting in expensive replacement costs.

Before selecting an electrostatic air cleaner for any corrosive application, verify that the contaminant is compatible with aluminum components.

Choosing the Right Air Filtration System

No single air filtration technology is ideal for every application. Electrostatic air cleaners are among the best solutions for collecting oil smoke and oil mist, while cartridge dust collectors and other filtration technologies are often better choices for dry dust, combustible dust, and highly corrosive contaminants.

Filtration Systems of Troy, Michigan and Bee Clean Specialties have both serviced SmogHog® and MistBuster® electrostatic air cleaners throughout Michigan for many years. Today, Bee Clean Specialties continues servicing SmogHog®, MistBuster®, Tri-Mist®, Trion®, Aerocology®, and other electrostatic air filtration systems throughout Michigan, Indiana, Ohio, Illinois, Wisconsin, Minnesota, and the surrounding Midwest.

If you have questions about a specific application or need help selecting the right air filtration system, contact Bee Clean Specialties at 888-451-0844.