Slide No: ١Yemen LNG Technical TrainingCENTRIFUGAL PUMPS
PROCESS ROTATING EQUIPMENT
(CENTRIFUGAL PUMPS )
CENTRIFUGAL PUMPS
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� Pumps can be divided into two main groups:
• Displacement pumps
• Dynamic pumps
CENTRIFUGAL PUMPS
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CENTRIFUGAL PUMPS
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CENTRIFUGAL PUMPS
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CENTRIFUGAL PUMPS
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Axial horizontal split case pump
BASIC CENTRIFUGAL PUMP PARTS
Casing
CENTRIFUGAL PUMPS
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Multistage axial horizontal split case Pump
CENTRIFUGAL PUMPS
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Single stage axial vertical split case pump
CENTRIFUGAL PUMPS
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Barrel casing
CENTRIFUGAL PUMPS
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Impellers
CENTRIFUGAL PUMPS
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Shafts
CENTRIFUGAL PUMPS
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Bearings
Partially filled
CENTRIFUGAL PUMPS
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Bearings
Grease lubricated
CENTRIFUGAL PUMPS
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Bearings
CENTRIFUGAL PUMPS
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Spherical bearings
CENTRIFUGAL PUMPS
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Sleeve bearings
CENTRIFUGAL PUMPS
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Thrust bearings
CENTRIFUGAL PUMPS
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Stuffing Boxes
CENTRIFUGAL PUMPS
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CENTRIFUGAL PUMPS
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Packing and seals
CENTRIFUGAL PUMPS
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Packing and seals
CENTRIFUGAL PUMPS
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Mechanical seal
CENTRIFUGAL PUMPS
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Wearing Rings:
CENTRIFUGAL PUMPS
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Couplings
Chain coupling
CENTRIFUGAL PUMPS
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Diaphragm coupling
CENTRIFUGAL PUMPS
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Elastomeric coupling:
CENTRIFUGAL PUMPS
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Flexible Disc coupling:
CENTRIFUGAL PUMPS
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Flexible link coupling:
CENTRIFUGAL PUMPS
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Gear coupling
CENTRIFUGAL PUMPS
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Leaf spring coupling:
CENTRIFUGAL PUMPS
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Metallic Grid coupling:
CENTRIFUGAL PUMPS
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Metallic Grid coupling:
CENTRIFUGAL PUMPS
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Pin Drive Coupling:
CENTRIFUGAL PUMPS
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TYPES OF CENTRIFUGAL PUMPS
Volute
Diffuser
Regenerative - Turbine
Mixed-flow
Axial-flow (propeller)
Single stage
Multi stage
Submersible
Can
Horizontal
CENTRIFUGAL PUMPS
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Volute- type pumps:
CENTRIFUGAL PUMPS
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Diffuser-type pump
CENTRIFUGAL PUMPS
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Turbine-type pumps
CENTRIFUGAL PUMPS
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Mixed flow type pumps
CENTRIFUGAL PUMPS
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Axial flow type pumps
CENTRIFUGAL PUMPS
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Single stage and multistage pumps
� There are three common types of multistage
pumps:
- Submersible
- Can
- Horizontal
CENTRIFUGAL PUMPS
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Vertical pumps (submersible)
CENTRIFUGAL PUMPS
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Can type pumps
CENTRIFUGAL PUMPS
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Horizontal
CENTRIFUGAL PUMPS
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HEAD ON A PUMP
� The amount of energy transferred to the fluid in a
centrifugal pump is called the head of the pump.
� Head is not the same as pressure. This is a very
important concept, which will be explained in the
following paragraphs
CENTRIFUGAL PUMPS
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Terms and Definitions
� Pressure:
• Three pressure terms commonly arise in
pumping problems-absolute, barometric,
and gauge pressure.
• A fourth term, vacuum, is used with
installations operating below atmospheric
pressure, but it is not a pressure term in the
same sense as the first three.
CENTRIFUGAL PUMPS
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� Absolute pressure
• is the pressure above absolute zero.
It may be above or below the atmospheric pressure
existing at the point under consideration.
• Barometric pressure is the atmospheric pressure at
the locality being studied and varies with altitude
and climatic conditions.
• Gauge pressure is the pressure above atmospheric
at the locality where it is measured.
• A vacuum is a negative gauge pressure
CENTRIFUGAL PUMPS
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� Head:
• a column of water or other liquid in a vertical pipe exerts a certain pressure (force per unit area) on the horizontal surface at the bottom of the pipe.
• This pressure can be expressed in pounds per square inch (psi) or as the number of feet of liquid, which exert an equal pressure on the same surface.
• The weight of the column of liquid producing the pressure in question is known as the head on the surface.
• Note that is the weight of the liquid acting on the surface that produces the pressure.
CENTRIFUGAL PUMPS
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CENTRIFUGAL PUMPS
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� Static Head:
• In pump application the height of a column of liquid acting on the pump suction or discharge is often termed the static head on the inlet or outlet and is expressed as a certain number of feet of the liquid.
• Static head is a difference in elevation and can be computed for a variety of conditions surrounding a pump installation.
CENTRIFUGAL PUMPS
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�Vapour Pressure:
• Every liquid at any temperature above its freezing point exerts a pressure due to formation of vapour at its free surface.
• This pressure, known as the vapour pressure of the liquid, is afunction of the temperature of the liquid the higher the temperature, the higher the vapour pressure.
• Vapour pressure is an important factor in the suction conditions of pumps handling liquids of all types.
• In any pumping system the pressure at any point should never be reduced below the vapour pressure corresponding to the temperature of the liquid because the liquid will form vapour, which will partially or completely stop liquid flow into the pump.
CENTRIFUGAL PUMPS
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� Static Suction Lift:
• This is the vertical distance, in feet, from the liquid supply level to the pump centreline, the pump above the supply level.
• Horizontal runs are not considered as part of the static suction lift, so far as lift is concerned
CENTRIFUGAL PUMPS
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� Static Suction Head:
• Where the pump is below the liquid supply level a static suction head exists.
• Numerically, it is the vertical distance, in feet, between the liquid supply level and the pump centreline.
CENTRIFUGAL PUMPS
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� Static Discharge Head:
• This is the vertical distance, in feet, from the pump centre line to the point of free delivery of the liquid
• Care must be exercised to see that the point of free delivery is used when computing static discharge head.
• In some layouts the exact point may be difficult to determine. This is discussed in greater detail later in this chapter.
CENTRIFUGAL PUMPS
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� Total Static Head
• Total static head on a pump is the vertical distance, in feet, between the supply level and the discharge level of the liquid being handled.
� Friction Head:
• Measured in feet of the liquid handled, this is the equivalent head needed to overcome the resistance of the pipe, valves, and fitting in the pumping system, friction head exists on both the suction and discharge sides of a pump, and varies with liquid flow rate, pipe size, interior condition of the pipe, type of pipe, and nature of the liquid being handled.
CENTRIFUGAL PUMPS
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� NPSH definition:
Total inlet pressure, in meters or feet of liquid pumped determined at the pump suction connection (i.e. suction flange), minus the vapour pressure of the liquid pumped in meters or feet of liquid pumped at pumping temperature.
� Two NPSH definitions are used in pumping systems :
Net Positive Suction Head available (NPSHa),
Net Positive Suction Head required (NPSHr).
CENTRIFUGAL PUMPS
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�Cavitaion
CENTRIFUGAL PUMPS
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Pitting accompanying cavitation in a Centrifugal pump