The major mist collector technologies are; electrostatic, media and centrifugal. A mist collector expert will know when to use a specific mist collector technology and what technologies to avoid for specific applications; for example, we usually will not use electrostatic mist collectors on machines that are machining cast iron - this is because the very fine ferrous dust gets into all parts of the machine and will eventually cause arcing and/or other electrical malfunctions.
 

Electrostatic mist collectors are an attractive option for many machining applications, as they offer low cost and few if any replacement filters that need to be purchased on an ongoing basis. The main filter in an electrostatic mist collector is a washable electronic cell. The technology works by bringing the dirty air in through an impinger, or series of impingers, which remove 80-90% of the mist, particularly the larger droplet. Next, the air is drawn through an ionizing section, which charges the particles of remaining mist in the air.  Those charged particles will then pass through the electronic cell which carries an opposite charge, causing the particles to be collected, like paper clips to a magnet. The charged mist particles are attracted to the electronic cells where they accumulate and drip back down to be recaptured or drained away.  This process is about 95% efficient and offers a low cost, low maintenance option. Various post filter options are available, including carbon for odor control, and HEPA, if there are more stringent filtration requirements.

Most electrostatic mist collectors offer a few key benefits over other mist collection technologies: They do not experience the wear that centrifugal mist eliminators do, which reduces down time as electrostatic mist collectors only have one moving part - centrifugals need to have bushings and bearings replaced periodically and require much more preventative maintenance.  Media based mist eliminators require costly filter replacements, where as electrostatic models do not.

There are several different sizes of electrostatic mist collectors, the smallest being machine mount, and unlike other types of mist collectors, electrostatic units are virtually vibration free, which is key when machining to tight tolerances.  Centrifugal systems have far too much vibration for most machine mount applications, and would require additional expense to have the unit mounted on a stand or other custom installation options.

Media based systems are a great choice for cast metals and other dense ferrous metals, but the flaw with media based systems are that they lose airflow as their filters load, to compensate for this pressure drop, you will need to buy a larger more expensive machine. The expense does not stop there, regular and costly filter replacements are required for the equipment to function properly, failure to replace filters can cause the motor to burn out prematurely.

We like to use electrostatic mist eliminators whenever we can, as it offers the best performance and value for most applications.  We invite you to comment on this post, feel free to ask questions or add information, simply click on the link below that says "comments."