Particle Transport In Tubing

By Morgan Polen - VP of Applications Technology, Lighthouse Worldwide Solution

Airborne Particle Counters (APC) are used for a variety of purposes such as:

• Filter testing
• Cleanroom certification and testing
• Isolator and minienvironment testing and certification.

Often the use of APCs requires the use of tubing for the sampling of the air as the APC may be located some distance from the actual air being sampled. Various factors impact the efficiency of particle transport in tubing. Factors such as sample air velocity, tubing length, tubing material, the number of bends, radius of such bends and tubing diameter need to be considered in selecting and using such tubing. 

Lighthouse Worldwide Solutions has installed particle counters in many different applications throughout the world. This experience along with our application testing has provided us with the information needed to write this paper. Often overlooked is the real world application of installing and using particle counters in operating facilities. It is one thing to have tubing laying flat on the floor extended to 125 ft without any bends. It is another to have the tubing routed up the wall, across a false ceiling into a service chase, then into a cleanroom upthrough a raised floor.

Particle size, particle velocity and tubing diameter are the key factors in determining particle transport effectiveness in tubing. Tubing material is a secondary concern.