Many of us have seen the large funnel shaped mass of metal sitting outside of a manufacturing facility, school or processing plant. These are cyclone dust collectors and they come in many shapes and sizes. If you are curious how they work or are wondering which one will be the right one for your process, read on.
HOW THEY WORK
Cyclone dust collectors filter dust by utilizing centrifugal, buoyant and drag force. When dust laden air enters the cyclone at a controlled speed, the heaver dust particles are forced to the outside of the cyclone wall. This friction allows the dust particles to drop to the bottom of the cyclone into a collection device. The spinning air creates a secondary vortex in the middle of the cyclone that that exhausts the clean air out the top. Cyclones operate at various efficiencies depending on factors such as height to width ratio, water pressure drop, cfm and inlet type.
Most cyclone collectors never operate at peak efficiency. In order to reach maximum efficiency, all the factors mentioned above need to measured precisely and the cyclone manufactured to the specifications based on those measurements. If designing a new system, these measurements can be estimated closely with a knowledgeable engineer and precise measurements of duct length runs and sizes. However, the expense of manufacturing a custom cyclone collector to match these measurements is cost prohibitive. Instead, purchasers should look for a cyclone that shows efficiency based on CFM to water pressure drop and choose the appropriate cyclone for their application.
Efficient cyclones are capable of filtering 90% of particulate down to 15 microns. Options for collecting more particulate may consist of adding an additional cyclone in a series increasing the efficiency an additional 90%, making the total efficiency 99% down to 15 microns. If smaller particulate size is the issue for additional filtration, a bag house filtration system can added to a single cyclone or after the secondary cyclone.
THE INVOLUTE INLET
The involute inlet is an important part of any cyclone dust collection system. The involute initiates the cyclonic action of the dust laden air when entering the dust collector. This allows the clean air vortex to exhaust without the disruption of particulate entering the cyclone. Without this feature, dust laden air would enter the cyclone directly into the exhaust vortex removing much of the efficiency.
DO YOUR HOMEWORK
If you are in the market for a cyclone dust collector, there are some steps you can take to insure you obtain the efficiency that you require for your application. Know your CFM requirement. This is calculated by knowing how much airflow you require at each pickup point within your system. This can be a single pickup point or several. Know your water pressure drop. This is calculated by understanding how much force it will take to move the air at the CFM you require. If these calculations are beyond your knowledge, make sure to hire an engineer who is knowledgeable in dust collection or a dust collector manufacturer that has the engineering experience and willingness to assist you in making these important calculations.