Oil & Coolant Mist Collectors
Importance of Machining Mist Collection
Many metalworking applications use oil-based, water-soluble or synthetic coolants in their operations. The use of these coolants creates a mist that can collect on floors, walls, ceilings and local machinery causing a high-maintenance work environment. Floors can become slippery causing a safety hazard. Machinery can become clogged with combinations of mist and dust. Electrical circuitry can be impacted by these mists. Employee health can be impacted by inhalation or ingestion of these mists and it smells bad.
Positive Impact of Mist Collection on Productivity
Mist collection at source creates a safer working environment for employees. The removal of mist from the air also reduces machine maintenance and downtime. In the case of centrifugal collectors the coolant mists can be reclaimed from the air and reused. All these benefits increase productivity and reduce downtime for both workers and machinery.
Types of Mist Collectors
Filtration Methods of Mist Collection
There are 3 different types of filtration used for mist collection:
Media Filter Collectors
This type of mist collector uses a specific media type to filter mist or fumes from the air. Generally a fan will force the airstream through the filtration media, purifying it. The filtered air exits the collector as clean while all impurities are trapped by the filter media. Filter media generally comes in cartridge form and may come in interchangeable media cartridge types to filter differing contaminate types or contaminate combinations such as mist and fumes from the same application.
Centrifugal mist collectors work on the principle of centrifugal force (outward moving force from rotation). Mist-laden air enters a rotating chamber inside a filter. The mist is forced into the filter by the centrifugal force where it collects and combines into larger droplets. The larger droplets are forced through the filter, by the same force, and collected on the inner surface of the rotating chamber where it exits through a drain. Centrifugal mist collectors are highly efficient on water soluble mist applications and can handle high volumes of mist with inexpensive filters. In some applications the coolant can be reclaimed from the mist and reused. However, centrifugal mist collectors are only about 97% efficient for one micron sized particles, and typically require the addition of final stage filters to collect smoke and fine mists. These collectors are generally cheaper to operate but require more maintenance.
In electrostatic collectors the airstream is passed through a section of the collector containing high-voltage electrodes which charge the mist particles and droplets. The airsteam continues to a section of the collector containing oppositely charge collector plates or surfaces. The charged mist particles and droplets are drawn out of the airsteam by attraction to the collector plates. There is generally a pre-filter stage that removes large particles that are too large to be collected by the collector plates. The collector plate must be routinely cleaned either automatically or manually. Electrostatic mist collectors work very efficiently on sub-micron particles down to 0.003 microns. Electrostatic mist collectors generally cost more to initially purchase but negate the need for expensive HEPA filter replacements, so are less expensive to operate. Electrostatic mist collectors are good for continuous operation and offer a very small pressure drop to the airstream.
Collection Methods of Mist Collection
There are 2 different collection methodologies used for mist collection:
Source collection occurs right at the source of the mist creation. These units are typically smaller machine-mounted units or portable unit. They generally have ducting and hoods or inlets to collect the mist at the machining application. Source collectors can also be facility mounted to floors, walls or ceilings and use ducting to collect the mists directly at the machining application. These mist collectors generally use media filtration or centrifugal collection to filter the mist.
Ambient collection is the continuous filtration of the ambient air in a machining environment. These are typically used where disparate sources of mist occur or source collection is not possible. They can also be used in conjunction with source collection methods.
Choosing the Right Mist Collector for Your Facility
Choosing the proper mist-collection system for your application is dependant upon many factors. AIRPLUS Industrial has 30+ years of experience in designing, sourcing, installing and maintaining mist collection systems, we can help you choose the right system for your facility.