In our recent investigation into the top OSHA-compliant dust collectors, we discovered that two essential figures determine their effectiveness: CFM and water lift. But when it comes to CFM on a dust collector versus a water extractor, which factor is more crucial? The truth lies somewhere in between.
Understanding CFM on Dust Collectors
CFM may sound like an alluring factor for both vacuum cleaners and blowers. In the context of these tools, CFM stands for cubic feet per minute and measures the amount of air the motor draws in every minute. Take, for example, Makita’s VC4710 dust collector, which boasts a CFM rating of 135. In other words, it has the capability to draw in enough air within a minute to fill a cube with sides measuring approximately 5.1 inches. This data is particularly valuable if the particles you intend to collect are airborne.
Essentially, CFM ensures that the materials keep moving during operation. The higher the CFM value, the larger the area the dust collector can effectively cover.
Understanding Water Lift on Dust Collectors
Suction measurement methods may vary, but water lift, sometimes expressed as a pressure rating, is typically the most familiar term. A quick internet search can help you convert pressure measurements to water lift, although it’s crucial to double-check the units for accurate conversions.
Water lift measures the strength of the vacuum suction. As the motor pulls the water up through the pipe, gravity attempts to pull it back down to its original position. Eventually, they reach a midpoint when the vacuum can no longer lift more water. Our shootout results demonstrated that vacuums, using static water lift tests, can achieve suction of approximately 90″ to 100″.
Editor’s Note: Tube diameters may differ. It’s important to note that our shootout results are based on 2-1/2″ OD tubing and may not align precisely with the manufacturer’s stated test outcomes.
The significance of water lift lies in its ability to determine the vacuum’s debris collection efficiency. CFM is undoubtedly valuable for collecting airborne particles, but when it comes to anything other than suspended materials, strong suction is necessary.
Interestingly, the suction strength needs to closely match what it’s collecting. For example, our dust collector can start picking up wood chips from the floor when they are around 1-1/2 inches away, and it can capture concrete dust when it approaches 1 inch. However, it performs most effectively when the nozzle is a mere 1/2 inch away from the target. Thus, the smaller or lighter the particle, the easier it is for the dust collector to collect it. However, as the particle size increases, proximity becomes critical.
To achieve effective dust collection, both CFM and water lift must work together harmoniously. While higher values are generally more desirable, having a balanced combination of the two is superior to one high rating and the other low. So, rather than solely seeking the highest CFM number available, compare the suction values (water lift, pressure) to identify the best overall balance within the category you are considering.
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