When the term velocity is used in dental suction it should be referring to the speed at which the air is moving through the suction system. The velocity can be very different at many points along the way.

Velocity has a formula: V (velocity) = Volume going through an opening x 114 Size of the opening The volume going through a hole or suction tool is determined by the vacuum level created by the vacuum pump and the size and shape of the hole. A simple chart can be found in the BaseVac web site: www.basevacdental.com

We have previously talked about velocity (date) and how it’s really a combination of air flow and the added power of velocity that moves things around. Similar things happen to air flows in a dental piping collection system. At a given level of vacuum (‘’Hg) a certain flow of air can be moved through a specific diameter of pipe. A pipe is defined by its diameter just like a hole. A good chart for finding air flow is at www.basvacdental.com

Most dry vac manufacturers want larger diameter pipe 4 and 6 inch. The idea here is that a high flow suction pump needs a large pipe to move its large volume through. OK, I agree but only if you can get that much air into the pipe through the tiny holes of the suction tools. Velocity, remember, needs a higher vacuum to really create excitement and movement. The large flow big pump systems tend to be 5-9’’ Hg vacuum energy systems.