2. Pump
A pump is a device used to move fluids such as liquids or slurries. It
increases the mechanical energy of the fluid. The additional energy can be
used to increase-
Velocity ( flow rate )
Pressure
Elevation
4. Positive Displacement
Constant volume of fluid is captured in cavities (an expanding cavity on the
suction side and a decreasing cavity on the discharge side)
within the pump and mechanical energy moves it from inlet to discharge.
It produces the same flow at a given speed (RPM) no matter the discharge
pressure.
A relief or safety valve on the discharge side is necessary as ,if operated
against a closed discharge valve, it will continue to produce flow until the
pressure in the discharge line are increased until the line bursts or the pump is
severely damaged - or both.
5. Dynamic Pumps
These pumps operate by developing a high liquid velocity and converting the
velocity to pressure in a diffusing flow passage.
Dynamic pumps usually have lower efficiencies than positive displacement
pumps, but also have lower maintenance requirements.
Dynamic pumps are also able to operate at fairly high speeds and high fluid
flow rates.
6. Rotary Pumps
In rotary pumps the chamber moves from inlet to discharge and back to inlet.
A wide variety available like:
Gear pumps, Screw pumps, Lobe pumps, Cam pumps, Vane pumps
Rotary pumps produce relatively constant output.
Types:
Single Rotor
Multiple Rotor
8. Features and Applications :
Precise transfer and metering.
High Speed
High pressure
No overhung bearing loads
Relatively quiet operations
Design accommodates wide variety of materials
No solids allowed
10. Features and Applications :
Slow Speed
Simple and Rugged design
Easy maintenance
Capable of pumping solids and floating debris
Minimum head as no collection sump required
Constant high efficiency with variable capacity
Long lifetime
12. Features and Applications :
Pass medium solids
No metal-to-metal contact
Reduced lift with thin liquids
Long term dry run (with lubrication to seals)
Non-pulsating discharge
Mainly used in food applications
13. Reciprocating Pumps
In a reciprocating pump, a volume of liquid is drawn into the cylinder through
the suction valve on the intake stroke and is discharged under positive
pressure through the outlet valves on the discharge stroke using a piston or
plunger.
Types:-
Piston Pump
Plunger Pump
Diaphragm Pump
15. Features and Applications :
Wide Pressure range.
Pressure can be controlled without affecting flow rate.
Only handles low flow rates.
Capable of moving viscous fluids, slurries, and abrasives with proper valve
design.
Pulsating discharge
Typically heavy and bulky
17. Features and Applications :
Wide Pressure range.
Pressure can be controlled without affecting flow rate.
High maintenance and operating costs
Capable of moving viscous fluids, slurries, and abrasives with proper valve
design.
Pulsating discharge
Typically heavy and bulky
19. Features and Applications:
Good dry running characteristics..
Good suction lift characteristics.
Good self priming capabilities.
Capable of handling highly viscous fluids.
Highly efficient up to 97% efficient.
20. Axial Flow Pumps
Axial flow pumps are also called propeller pump. These pumps develop
most of their pressure by the propelling or lifting action of the vanes on the
liquid.
Typically used in:
wet-pit drainage,
low-pressure irrigation,
storm-water applications
22. Centrifugal Pumps
A centrifugal pump consists of an impeller and an intake at its centre.
These are arranged so that when the impeller rotates, liquid is discharged by
centrifugal force into a casing surrounding the impeller.
The casing is there in order to gradually decrease the velocity of the fluid which
leaves the impeller at a high velocity. This velocity is converted to pressure which
is needed to discharge the fluid.
24. Centrifugal Pumps
Most common type of kinetic pump.
They are almost always more economical to own, operate and maintain.
Centrifugal pumps have the following features:
Pulsation free transfer without alteration of flow rate and total head.
High reliability in operation due to low number of moving parts.
High operating speed, directly coupled to high-speed electric motors.
Small dimensions and therefore low space requirement.
Low operating costs.
Excellent performance control by speed adjustment.
Applications with moderate to high flow and low head.
25. Terms you should know:
Flow
It is a volume measure to establish pump capacity.
Horse power
Term used to express amount of power available to drive a pump.
Brake Horse power
Term used to express amount of power required to drive a pump.
Pump efficiency
It indicates percentage of Brake horse power converted into useful work.
Shut off Head
Term used to express head developed by pump at zero flow
26. Terms you should know:
Head
A measure of the energy possessed by water at a given location in the
water system expressed in feet or a measure of the pressure
or force exerted by water expressed in feet.
Discharge Head
This is the vertical distance that you are able to pump
liquid. For example, if your pump is rated for a maximum head of 18
feet, this does not mean that you are restricted to 18 feet of pipe. You
can use 300 feet, so long as the final discharge point is not higher than
18 feet above the liquid being pumped.
27. Terms you should know:
Net Positive Suction Head Available (NPSHA)
The absolute pressure at the suction port of the pump.
NPSHA is a function of your system and must be calculated.
NPSHA = HA ± HZ - HF + HV – HVP
where HA = The absolute pressure on the surface of the supply tank liquid.
HZ = The vertical distance from the surface of the water to the pump
centerline.
HF = The friction formed in the suction piping
HV = The velocity head at the pump's suction
HVP =The vapour pressure of the water at its pumping temperature
