What is “3rd staging” and why is it an unacceptable design practice?
In an acceptable “two stage system”, the pump feeds a master divider (first stage) which in turn feeds the secondary dividers (second stage). In a three stage system, the secondary feeds the third stage dividers. One of the positive attributes of a Series-Progressive distribution system is the ability to inform the operator/user of a blockage anywhere in the system by signaling a lube fault when the cycling activity stops due to blockage. A third- stage divider is sometimes so far away from the central pumping source, and/or cycles so infrequently, that the high pressure necessary to signal a blockage cannot be generated due to the compressed volume of lubricant in the lines between the pump and the blockage beyond the third-stage divider.
