The Basics about Pump(s)-to-System(s) - Pump Systems Problems, Pump Repair, Pump Installation, Pump Help & Resources

The Basics about Pump(s)-to-System(s)

Written by Dr. Lev Nelik, P.E., APICS

Page 2 of 2

Computerizing the Process

This process can be computerized, as illustrated in a simplified example of a positive displacement pump operating against two systems (two branches). Underlying programming formulas are:

H = h₁ + k₁ x Q₁² - This is the general equation for a system of branch (1), including static head h₁ and friction with system friction resistance k₁
H = h₂ + k₂ x Q₂² - This is the general equation for a system of branch (2), including static head h₂ and friction with system friction resistance k₂
Q = Q₁ + Q₂ - This is what leaves the pumps splits into branches.

Known/given: Q, k₁, k₂, h₁, h₂ (where h₁ and h₂ are static heads for the two systems, and k₁ and k₂ are friction coefficients for these systems)

Need to find: Q₁, Q₂ and pump head h.

Programming procedure:

Guess h
Calculate Q₁ from (1)
Calculate Q₂ from (2)
Calculate Q = Q₁+ Q₂ and compare with given Q
If calculated flow is different than given, re-guess h and repeat the process until error is small

Only when these fundamentals of the pump(s)-to-system(s) principles are understood are you ready to take the next step - a computerized analysis of complex pumping systems.

A parting quiz: how would a procedure change if two pumps had an entirely different (the ones shown above are for identical pumps) performance curves? The best answer, as usual, will qualify you for a free ticket to attend our Pump School session.

Dr. Nelik (aka "Dr. Pump") is president of Pumping Machinery, LLC, an Atlanta-based firm specializing in pump consulting, training, equipment troubleshooting, and pump repairs. Dr. Nelik has 30 years experience in pumps and pumping equipment. He has published over fifty documents on pump operations, the engineering aspects of centrifugal and positive displacement pumps, and maintenance methods to improve reliability, increase energy savings, and optimize pump-to-system operations. With questions, comments, or to attend his Pump School, he can be contacted at www.PumpingMachinery.com.

Comments (0) Add Comment