1. So Far: Mass and Volume Flow Rates Reynolds No., Laminar/Turbulent Pressure Drop in Pipes Flow Measurement, Valves Total Head, Pump Power, NPSH This Week: Bernoulli’s Equation and its Application Pump Sizing, Types of Pumps Conservation of Energy

2. Pump Sizing 1. Volume Flow Rate (m 3 /hr or gpm) 2. Total Head,  h (m or ft) 2a.  P (bar, kPa, psi) 3. Power Output (energy added to fluid) and Input (mechanical shaft power from motor) 4. NPSH Required

3. Centrifugal Pumps Advantages Simple construction, many materials No valves, can be cleaned in place Relatively inexpensive, low maintenance Steady delivery, versatile Operates at high speed (electric motor) Wide operating range (flow and head) Disadvantages Multiple stages needed for high pressures Poor efficiency for high viscosity fluids Must prime pump

4. Centrifugal Pumps What if available NPSH is less than required NPSH? Increase Available NPSH 1. Increase suction static head (pump location) 2. Increase suction side pressure 3. Decrease fluid vapor pressure 4. Reduce friction losses on suction side Decrease Required NPSH 1. Reduce pump speed 2. Select a different pump

5. Centrifugal Pumps Curves created for specific speed, viscosity and density Often, use more charts or correction factors to “fine tune” pump selection Variable speed motor has same effect as impeller size Multiple pump/impeller combinations may work

6. Centrifugal Pumps Closed Impeller Most common, low solids Water, beer, wort Flash pasteurization Refrigerants Open Impeller Lower pressures Solids okay Mash to lauter turn Liquid yeast, wort, hops

7. Positive Displacement Pumps Theory: Volume dispensed independent of delivery head Practice: As delivery head increases, some slippage or leakage occurs Speed used to control flow rate, use of valves could cause serious damage Self-priming Good for high viscosities, avoiding cavitation

8. Positive Displacement Pumps Piston Pump Volumetric EfficiencyHigh Pressures Metering hop compounds, detergents, sterilents Suction Valve Delivery Valve

9. Positive Displacement Pumps Peristaltic Pump

10. Positive Displacement Pumps Gear Pump High Pressures No Pulsation High Viscosity Fluids No Solids Difficult to Clean

11. Positive Displacement Pumps Lobe Rotor Pump Both lobes driven Can be sterilized Transfer Yeast Trub Bulk Sugar Syrup