# Pump Presentation

Topics: Fluid dynamics, Centrifugal pump, Pump Pages: 9 (3063 words) Published: February 11, 2013
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OPEN IMPELLER
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SEMI OPEN IMPELLER

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AXIAL IMPELLER

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[pic]ENCLOSED IMPELLER

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The impeller and  the  flow   of  a  typical  radial  flow  pump

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The impeller of a typical axial flow pump
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Single and Double Volutes

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MULTI STAGE PUMP

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RELATIVE LOCATION OF ROTOR AND DIFFUSER OF A PUMP

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CENTRIFUGAL PUMPS

Centrifugal  Pump  Classification
Centrifugal pumps can be classified based on the manner in which fluid flows through the pump. The  manner in which fluid flows  through the pump is  determined by the design of the pump casing and the impeller.  The three types of flow through a centrifugal pump are radial flow, axial flow, and mixed flow. Radial  Flow  Pumps In a radial flow pump, the liquid enters at the center of the impeller and is directed out along the impeller blades in a direction at right angles to the pump shaft Axial  Flow  Pumps In an axial flow pump, the impeller pushes the liquid in a direction parallel to the pump shaft. Axial  flow  pumps  are  sometimes  called  propeller  pumps because  they  operate essentially the same as the propeller of a boat. Mixed  Flow  Pumps Mixed flow pumps borrow characteristics from both radial flow and axial flow pumps. As liquid flows through the impeller of a mixed flow pump, the impeller blades push the liquid out away from the pump shaft and to the pump suction at an angle greater than 90o Multi-Stage  Centrifugal  Pumps A centrifugal pump with a single impeller that can develop a differential pressure of more than 150 psid between the suction and the discharge is difficult and costly to design and construct. A more economical approach to developing high pressures with a single centrifugal pump is to include multiple impellers on a common shaft within the same pump casing.   Internal channels in  the  pump  casing  route  the  discharge  of  one  impeller  to  the  suction  of  another  impeller.  The water enters the pump from the top left and passes through each of the stage impellers in series, going from left to right.   The water goes from the volute surrounding the discharge of one impeller to the suction of the next impeller. A pump stage is defined as that portion of a centrifugal pump consisting of one impeller and its associated components.   Most  centrifugal pumps  are single-stage  pumps, containing  only one impeller.   A pump containing seven impellers within a single casing would be referred to as a seven-stage pump or, or generally, as a multi-stage pump

IMPELLERS OF CENTRIFUGAL PUMPS

Pumps Impellers  can  be  open,  semi-open,  or  enclosed. The  open  impeller  consists  only  of  blades attached to a hub. The semi-open impeller is constructed with a circular plate (the web) attached to one side of the blades. The enclosed impeller has circular plates attached to both sides of the blades.    Enclosed  impellers  are  also  referred  to  as  shrouded  impellers Impellers  of  pumps  are  either Single-Suction and Double-Suction Impellers based on the number of points that the  liquid  can  enter  the  impeller and    also    on    the    amount    of webbing    between    the impeller blades. Impellers   can   be   either   single- suction    or   double-suction. A single-suction impeller allows liquid  to  enter  the  center  of  the blades from only one direction.  A double-suction    impeller    allows liquid  to  enter  the  center  of  the impeller  blades  from  both  sides simultaneously The impeller sometimes contains balancing holes that connect the space around the hub to the suction  side  of  the  impeller.    The  balancing  holes  have  a  total  cross-sectional  area  that  is considerably greater than the cross-sectional area of the annular...