PARTICLE CONTAMINATION BELOW A ROBOT ARM IN A CLEANROOM

Experimental velocity and particle concentration data have been obtained near a circular cylinder robot arm in a chamber that simulates a vertical unidirectional flow Class 10 cleanroom. The airflow field around the robot arm has been characterized using a hot wire anemometer. Both mean velocities and turbulence spectral data were obtained. Sodium chloride particles were injected through small holes below the arm to simulate particles generated by moving joints. Results indicate that the turbulent wake near the arm causes an unsymmetrical widespread dispersion of the particles from a single point source on the arm. Particles disperse much stronger along the cylinder axis than normal to the cylinder near the injection point.