Views: 114 Author: Site Editor Publish Time: 2019-08-13 Origin: Site
Cyclone Filter Cyclonic Separation is a means of separating different liquid phases (different liquid densities), or, separating particles from a gas stream. Cyclone separators often form part of a pre-cleaning stage prior to a gas or liquid being discharged. This article focuses on the gas cyclone separator.
A cyclone separator has several colloquial names. These names include dust separator , dust collector , dust extractor , cyclone extractor and cyclone separator. Generally, smaller units are referred to as ‘dust’ separators or extractors, whilst large scale industrial separators are referred to as ‘cyclone separators’.
Gas Cyclone Separators
Gas cyclone separators are grouped into two main categories, reverse-flow and axial-flow.
Reverse flow cyclone separators are cone shaped. Gas enters the top of the separator body, flows downwards, then flows back upwards and is discharged.
For axial flow ( straight through) cyclone separators, gas enters at one end and is discharged at the opposite end. Axial flow separators are not as common as reverse flow separators.
Small cyclone separators have a higher efficiency rating, but the associated pressure drop is high and the volumetric flow rate is low. Gas velocity through small separators is also very high and this will lead to a high level of erosion if the gas stream contains abrasive particles.
Large cyclone separators have a lower efficiency rating, but the associated pressure drop is low and the volumetric flow rate high. A large diameter separator is not suitable for removing fine particles from a gas stream.
There are many advantages associated with cyclone separators, some of these include:
Cheap to purchase.
Low maintenance.
Suitable for high temperatures.
Suitable for liquid mists.
Do not require much space.
Some disadvantages are associated with cyclone separators, but these disadvantages can be reduced in severity if the correct separator is selected for the correct application. Disadvantages may include:
Increased operating costs associated with the pressure drop (assuming large pressure drop).
Inefficient when handling small/fine particles.
Not suitable for ‘sticky’ substances.
Material selection is a very important consideration when choosing a separator for a specific application. Some process systems may contain erosive or corrosive flowing mediums, so it is necessary to add a protection layer to the cyclone’s internal surfaces.
Suitable materials for protecting the separator within erosive systems might include materials such as ceramic or some form of enamel. Separators operating within corrosive systems may have some form of enamel or poly-based material coating to protect the cyclone metal body beneath.
Cyclone separators are utilised in many applications due to their low cost, simple design and high efficiency. Cyclone separators require no bags or filters and require only low maintenance.
A typical application would include a saw mill. Saw mills generate a lot of dust which must be extracted from the mill. Dust is drawn into the main extraction system by a negative pressure created by a fan -usually a centrifugal fan-. The dust laden air then passes through a cyclone separator where most of the wood dust is separated from the air stream; the clean air is then discharged directly to ambient air whilst the wood dust is recycled or disposed of.
