In our previous article about oil mist collector technology, we discussed the pros and cons of centrifugal mist collectors and filter-based mist collectors. Today, we look at the other two most common methods of getting oil mist out of the air.
Electrostatic Precipitator Mist Collectors
An electrostatic precipitator uses high-voltage electricity to impart a positive charge onto the particles of mist carried by an air current. Then, the air is passed between a series of negatively-charged plates, and the positive charge in the mist particles is attracted to the negative charge on the plates. The particles, still being oils, stick to the plates once they hit and are removed from the air flow.
Electrostatic collectors are ideal when:
- Dealing with petroleum-based cutting oils, mist, and smoke, as these are particularly sticky and thus easily removed from the air when they hit the collection plates.
- Seeking a low Total Cost of Ownership — with no expensive filters to replace and almost no moving parts, electrostatic collectors last a very long time.
- Working with particulate
Electrostatic collectors are not as useful for:
- Operating with particulate that has both solid and liquid components. Solid particles tend to bounce off of the collection plates rather than stick, and can re-enter the airflow.
Spiral Tube Oil Mist Collectors
A spiral tube oil mist collector works very much like a cyclone dust collector, forcing the air through a vertical tube in a downward spiral, then upward through the center of that selfsame spiral. Particulate drops out of the airstream at the bottom of the spiral. The difference is that while cyclone dust collectors use this process once, spiral tube mist collectors run the air through several — sometimes dozens — of tubes to make sure that a sufficient percentage of the particulate is removed, and then the air is passed through a HEPA filter to guarantee adherence to air quality regulations. Because the air passing through the filter is already mostly clean, the filters on these collectors last much longer than the filters on an entirely filter-based collector.
Spiral tube collectors are ideal when:
- You need quiet collection. Spiral tube oil mist collectors run very quietly compared to the alternatives.
- You need to collect and recycle the oil: spiral tube collectors inherently gather all of the collected oil in a single easy-access space.