The use of these filtration devices provides many benefits. Product purity is increased significantly as is throughput while operating costs, air pollution, and downstream corrosion are reduced. In addition to the clean gas that exits the collector, the liquids may also be recovered and even recycled in some applications.
Mist collection systems can be used for abrasives, coolant, smoke, oil, water and many other materials if properly engineered. Metal finishing and forming industries as well as chemical processing, brine desalination, marine, food processing, paper and pulp, agriculture and many other industries take advantage of mist collectors in daily operations.
They are especially popular in applications where vapor quality is of utmost importance or where space and weight savings are integral. Installed in line, mist collectors have minimal impact on the gas flow of an operating system, another point of interest for many users.
It is, however, important that mist collectors be accessible to technicians as regular maintenance is essential to optimal performance as particulates often adhere to the vapor and become trapped in the collection screen. To accommodate, most demisters are cleanable and relatively easy to replace.
Also known as mist eliminators or demisters, the design of these collection tools can vary significantly but operate off of the same general principals.
The most important feature of a mist collector is the filter. Often several such obstacles are used in industrial collectors to capture droplets contained within a vapor stream. Different structures are used to aggregate the mist into droplets that are heavy enough to drop out or separate from the air stream. Mesh type coalescers, vane packs, or pads made of fabric-like materials are among the most popular filters implemented in mist collectors.
The filter or obstacle must be permeable with very close mesh-like openings through which vapors may pass. Often the smaller the openings the more effective the device is at removing mist from the process stream.
No matter the specific type or size, the filters cause a drop in pressure which draws moisture to the collection area. As aforementioned, mist collectors enable the capture and reuse of the liquids they remove. This necessitates a collection chamber. Often the base of the collector serves as the chamber. Droplets are filtered out through a valve in the bottom while vapors free of mist and debris rise and exit from the top of the compartment.
It is important to consider the end goals, process stream, and materials when selecting a mist collector for industrial use.