TO THE TRAINER This PowerPoint presentation can be used to train people about the basics of refrigeration and air condonditioning. The information on the slides is the minimum information that should be explained. The trainer notes for each slide provide more detailed information, but it is up to the trainer to decide if and how much of this information is presented also. Additional materials that can be used for the training session are available on www.energyefficiencyasia.org under “Energy Equipment” and include: Textbook chapter on this energy equipment that forms the basis of this PowerPoint presentation but has more detailed information Quiz – ten multiple choice questions that trainees can answer after the training session Option checklist – a list of the most important options to improve energy efficiency of this equipment
Positive displacement pumps are distinguished by the way they operate: liquid is taken from one end and positively discharged at the other end for every revolution. Reciprocating pump if the displacement is by reciprocation of a piston plunger. Reciprocating pumps are used only for pumping viscous liquids and oil wells. Rotary pumps if the displacement is by rotary action of a gear, cam or vanes in a chamber of diaphragm in a fixed casing. Rotary pumps are further classified such as internal gear, external gear, lobe and slide vane etc. These pumps are used for special services with particular conditions existing in industrial sites.
A centrifugal pump is one of the simplest pieces of equipment in any process plant. The figure shows how this type of pump operates: Liquid is forced into an impeller either by atmospheric pressure, or in case of a jet pump by artificial pressure. The vanes of impeller pass kinetic energy to the liquid, thereby causing the liquid to rotate. The liquid leaves the impeller at high velocity. The impeller is surrounded by a volute casing or in case of a turbine pump a stationary diffuser ring. The volute or stationary diffuser ring converts the kinetic energy into pressure energy.
The pump is mechanical device which conveys liquid from one
place to another place.
It can be defined as a hydraulic machines which converts the
mechanical energy into hydraulic energy.
The pump is power absorbing machine.The power can be
supplied to the pump by a prime mover like an electric motor,
an internal combussion engine or turbine..
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It is classified into positive displacement pumps and
• In positive displacement pumps-its operate on a
principle of liquid discharge or displaced due to the
positive or real displacement of working element.
In rotodynamic pumps-its operate on a principle of the
rise in pressure energy of liquid by dynamic action of
liquid which is carried out by impeller.
Classification of pumps
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Head:Head: Pressure is needed to pump the liquid through the system at a
certain rate. This pressure has to be high enough to overcome the resistance of
the system, which is also called “head”.
.Different Types of Pump HeadDifferent Types of Pump Head
Static Suction HeadStatic Suction Head – It is the vertical height of the center line of pump shaft above
the surface of liquid or it is energy required to lift liquid from sump to pump.
Static Discharge HeadStatic Discharge Head - – It is the vertical height of the center line of pump shaft
to where liquid is delivered or it is energy required to lift liquid from pump to end of
Total Static HeadTotal Static Head - Total head when the pump is not runnig.
h = hs + hd
Total Dynamic Head (Total System Head)Total Dynamic Head (Total System Head) - Total head when the pump is
Velocity headVelocity head-Kinetic energy carried away by the liquid at the end of delivery pipe.
hv = V^2/2g
Manometric head-Manometric head-The total head required to developed by the pump.
Hm = hs +hd +hfs + hfd +hv
Water power (PwWater power (Pw) = Power required by pimp to handle the liquid to devlope
Shaft power(Ps)Shaft power(Ps) –it is the power input by shaft of the pump by motor.
Efficiency = Pw / PsEfficiency = Pw / Ps
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Pump HeadPump Head
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Operations of single acting
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Single Acting Reciprocating Pump
Working of single acting Reciprocating
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Air vessel is a closed
compressed air in the
upper part and liquid
being pumped in the
To get continuous supply of liquid at a uniform rate
To save considerable amount of work in overcoming the
frictional resistance in suction and deliver pipes.
To run the pump at much higher speed without any danger
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Principle: When a certain mass of fluid is rotated by an
external source, it is thrown away from the central axis
of rotation and a centrifugal head is impressed which
enables it to rise to a higher level.
•A device which used to converted mechanical energy
into pressure energy by means of centrifugal force
acting on the fluid,for conveying liquid from one place
to nother is called centrifugal pump.
Working Principle of Centrifugal pump
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Main parts of a centrifugal pump
Suction pipe with foot-valve and a stainer
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Types of centrifugal pumps
According to type of casting
1. Volute type pump
2. Vortex type pump
3. Diffuser type pump
According to number of stages
1. Single stage
2. Multi stage
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How do they work?
• Liquid forced into
• Vanes pass kinetic
energy to liquid: liquid
rotates and leaves
• Volute casing converts
kinetic energy into
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Centrifugal Pump - Working
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Volute Casing: In this type of casing the area of flow gradually
increases from the impeller outlet to the delivery pipe.
Vortex Casing: If a circular chamber is provided between the impeller
and volute chamber the casing is known as Vortex Chamber.
Diffuser Casinng :
The impeller is surrounded by a diffuser.
The guide vanes are designed in such a way that the water from the
impeller enters the guide vanes without shock.
It reduces the vibration of the pump.
Diffuser casing, the diffuser and the outer casing are stationery parts.
Volute and Diffuser casing
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The operation of filling the suction pipe, casing and a
portion of delivery pipe with the liquid to be raised, before
starting the pump is known as Priming
It is done to remove any air, gas or vapour from these
parts of pump.
Priming of a centrifugal Pump
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A rotary pump is a positive-displacement
pump that consists of vanes mounted to a
rotor that rotates inside of a cavity. In some
cases these vanes can be variable length and/or
tensioned to maintain contact with the walls as
the pump rotates
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• Gear pumps are primarily used for high-viscosity liquids. Two or
more gears trap liquid in the space between the gear teeth and the
casing wall and convey it from inlet to outlet. Obviously, it is
essential to minimize paths through which liquid could flow
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Sliding vane pumps
The vanes are a sliding fit in slots cut
in the rotor. The rotor turns eccentric
to the casing, causing the cavities to
decrease in volume.
Vanes can be forced out by
centrifugal force, use springs or utilise
the pressure of the discharge liquid.
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Due to the imbalance of forces, this type of pump often has the
suction arranged at the centre of the Shdft screws and the delivery
at either end, and is often driven through timing gears, which keep
the screws from contacting each other.
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