Venting your way to better rotary valve performance — Part I
This two-part article explains how to use venting to improve the rotary valve feedrate to your pneumatic conveying system. Part I discusses how leakage occurs in a rotary valve, how to predict leakage flow, and how to determine your venting needs. Part II, scheduled for the November 1997 issue, covers types of rotary valve vents, discusses selecting a passive or active vent system, explains how to troubleshoot vent system problems, and describes venting solutions in several case studies.
A common yet poorly understood problem with pneumatic conveying systems is inadequate rotary valve venting. The problem is most likely to occur when the rotary valve feeds material against higher pressure, but can also occur when there's no pressure differential across the valve.