Presentation on theme: "Pumps CM4120 D. Caspary February, 2004. Intro to Pumping Classifications of pumps Positive Displacement Pump – Examples and Applications Centrifugal Pumps."— Presentation transcript:
Pumps CM4120 D. Caspary February, 2004
Intro to Pumping Classifications of pumps Positive Displacement Pump – Examples and Applications Centrifugal Pumps – Examples and Applications Pump Curves Outline
History of Pumps First pumps were driven by water wheels or animal powered Water was lifted w/ paddles and dumped at a higher elevation Over 2200 years ago in Greece, Persia, the Orient, some still in use today Electric motor is most common machine in use today, the pump is second most common Agriculture Automobile Construction Chemical Manufacturing Household Hydraulic Systems Submarines Space Station Zeeland to Zimbabwe
Pump Applications Used to increase the potential and/or kinetic energy state of a fluid Liquid – water, chemical, fuels, coolants, refrigerants, hydraulic fluids, boiler feed, condensate return, etc. Vapor/gas – foams, air, other gases Slurries – concrete, quarry slurries, mud for drilling, precipitates, sewage, pulp stock, etc.
Two Primary Classifications of Pumps Dynamic (or Centrifugal) – Use a spinning impeller to induce centrifugal forces, increasing pressure at the discharge side of the housing. Positive Displacement – Transfers a fixed volume of fluid thru the pump housing with each cycle of operation.
Overwhelming majority of all pumps are some type of Centrifugal Pump. Lower initial cost Reduced maintenance costs Positive Displacement Pumps are widely used but for specific applications. Classifications of Pumps
Comparison between Positive Displacement and Centrifugal Pumps
Head vs. Flow Comparison between Positive Displacement and Centrifugal Pumps
Effect of Increasing Viscosity on Flow for Positive Displacement and Centrifugal Pumps
Comparison of Efficiency vs. Head between Positive Displacement and Centrifugal Pumps
Types of PD Pumps – Gear Pumps External Gear Pump High speed Quiet operation Fuel, lubricants, hydraulic fluid power systems, metering No solids Internal Gear Pump Non-pulsating discharge pressure Low NPSHR Low to moderate speed High viscosity fluids
Lobe Pump No metal to metal contact Can handle solids without damaging them Applications are found in food processing, pharmaceutical, personal care, etc. Diaphragm Pump Other Common Types of PD Pumps
Centrifugal Pump “Family Tree” Pumps Centrifugal Positive Displacement Single Stage Multi-Stage Horizontal Vertical Open ImpellerClosed Impeller
How a Centrifugal Pump Works Pump housing must be primed Impeller rotates, imparting an outward velocity to the fluid – kinetic energy Fluid velocity reaches maximum at the outside diameter of the impeller Fluid enters the volute where it is channeled to the discharge Resistance to flow, starting at the volute, reduces velocity creating pressure energy Vapor pressure of fluid causes new fluid to be drawn into the eye of the impeller
A Centrifugal Pump/Driver Installation Electric Motor Pump Housing Coupling Discharge line Suction line External Cooling Stuffing Box and Packing Gland Bearing Support
Single Stage, Horizontal Shaft, Closed Impeller Flowserve Pump Co.
Horizontal, Split Case, Single Stage Fire Pump Patterson Pump, Div. of Gorman-Rupp
Vertical Pumps Carver Pump Co.
Horizontal, Multi-Stage Pump Cut-away
Types of Impellers Closed vane Open vane Open vane, cut impeller
Pump Curve for a Goulds Model HSC centrifugal pump at 3500 rpm When selecting new pump or changing capacity of existing pumps: Capacity for 6 impeller sizes NPSHR Req’d horsepower Efficiency
Pumping Affinity Laws Used for estimating pump performance when changing impeller size or RPM Q 1 /Q 2 =N 1 /N 2 H 1 /H 2 =(N 1 /N 2 ) 2 P 1 /P 2 =(N 1 /N 2 ) 3
P MOT, Driver Input Power P W, Pump Output Power P P, Pump Input power, BHP Pump Efficiency Overall Efficiency
Pump Maintenance Seals Shaft packing vs. mechanical seals Monitor for leaks Bearings Overhung vs. double support Monitor vibration Wetted parts corrosion Cavitation monitor suction-side pressure listen for rattling
References Viking Pump product literature Gorman-Rupp product literature Goulds Pump product literature Flowserve product literature Carver Pump product literature Pump Handbook, Karassik, Krutzsch, Fraser, Messina, McGraw-Hill, 1976 www.pumpschool.com, Viking Pump, Feb. 2004. www.pumpschool.com www.engineeringtoolbox.com, The Engineering Toolbox, March 2004. www.engineeringtoolbox.com
Pumping Terminology Head Gauge head (h g ) Velocity head (h v ) Elevation head (Z) Atmospheric head (h atm ) Total suction head or suction lift (h s ) Total discharge head (h d ) Total head (H) NPSHA NPSHR