Recommending and Selecting a Pump

• To optimize system performance, systems should be designed with a low pressure drop in the flow delivery system so that adequate pressure is available to deliver high flow and turbulent conditions in the process.
• This is accomplished in practice by having properly sized delivery piping systems that keep water velocities between 5 and 7 feet per second and pressure losses to less than 3 psi per 100' of run.
• It is also important to minimize the use of unnecessary tees, elbows, valves, and other high pressure drop causing components such as quick connect fittings.
• Laminar and turbulent flow conditions can exist in a process. It is important for heat transfer that turbulent flow exist through the process while laminar flow is acceptable and desirable in the delivery system. See FYI #156 for more information on Turbulent and Laminar flow.

Example: a mold has ten (10) 3/8" ins/outs. To be turbulent, each 3/8" in/out should have 2.5 gpm. Therefore, 25 gpm is required. A 3/4 HP pump (like in an SK-1035LE) rated for 35 gpm is the correct machine for this application.

This chart can be used to help estimate the water flow rate required for a process in order to obtain turbulent flow conditions which promotes heat transfer.