pumps presentation prepared by: nimesh gajjar. outline of presentation difference between pump and...
TRANSCRIPT
Outline of presentation
• Difference between Pump and Compressor
• Definition of pump
• Terminology used in pumps
• Classification of pumps
• Working of different types of pumps
• Application of Pumps
Difference between Pump and Compressor
• A pump is a machine for raising a liquid - a relatively incompressible fluid - to a higher level of pressure or head.
• A compressor is a machine for raising a gas - a compressible fluid - to a higher level of pressure.
What is pump ???
• 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 combustion engine or turbine..
Terminology• Suction head (hs): it is the vertical distance between the liquid level in the
sump and the centre line of the pump. It is expressed as meters.
• Delivery head (hd): It is the vertical distance between the centre line of the pump and the liquid level in the overhead tank or the supply point. It is expressed in meters.
• Static head (Hs): It is the vertical difference between the liquid levels In the overhead tank and the sump, when the pump is not working. It is expressed as meters.Therefore, HS= (hs+ hd)
• Friction head (hf): It is the sum of the head loss due to the friction in the suction and delivery pipes.
hf=(fLV2/2gD).
• Total head (H): It is the sum of the static head Hs, friction head (hf) and the velocity head in the delivery pipe (Vd 2/2g). Where, Vd=velocity in the delivery pipe.
• Manometric head(Hm): It is the total head developed by the pump. This head is slightly less than the head generated by the impeller due to some losses in the pump
• Mechanical efficiency(ηmech): It is the ratio of the impeller hydraulic power to the power of the motor or the prime mover
Classification of Pump cont…
• There are two main categories of pumps kinetic and positive displacement. Almost all pumps fall into one of these two categories. The main difference between kinetic and positive displacement pumps lies in the method of fluid transfer.
Kinetic Pump Positive displacement
imparts velocity energy to the fluid, which is converted to pressure energy upon exiting the pump casing
moves a fixed volume of fluid within the pump casing by applying a force to moveable boundaries containing the fluid volume
Low pressure generated High pressure generated
High volume liquid discharge Low volume liquid discharge
•These pumps operate on the principle of the rise in pressure energy of liquid by dynamic action of liquid.• The dynamic action of liquid is carried out by revolving wheel which has curved vanes on it.•This wheel is known as impeller.•This pump is classified in two types:1)Centrifugal pump2)Jet pump
Centrifugal pump cont….
• Centrifugal pump works on the principle that when a certain mass of liquid is made to rotate along the impeller from the central axis of rotation, it impresses a centrifugal head. It causes the water to move radially outwards at higher velocity and causes the water to rise to a higher level. The motion of water is restricted by casing of pump, it result into pressure build up.
C:\Users\nimy\Desktop\Pump\Lecture\Centrifugal Pump.mp4
• The operation of filling the casing , impeller and suction pipe and the portion of delivery pump upto delivery valve is called priming.
• In case the priming of pump is not done and the pump is not done and the pump is not under the operation, the water present in the pump and suction pipe will flow back to the sump. The space occupied by water will be filled by air.
• If the pump is now started, the air pockets inside the impeller may give rise to vortices and cause the discontinuity of flow. Under these condition, the flow of fluid does not commence and the pump runs dry. It causes the rubbing and seizing of the wearing rings, increases noise level and vibrations and finally may cause the serious damage to pump.
How does Centrifugal pump work _.mp4
Centrifugal pumpAdvantages• Simple in construction and cheap• Handle liquid with large amounts of solids• No valves involved in pump operation• Maintenance costs are lower
Disadvantages
• Cannot handle highly viscous fluids efficiently
• Cannot be operated at high heads
• Maximum efficiency holds over a narrow range of conditions
Jet Pump•This pump is a combination of a surface centrifugal pump, down-hole nozzle, and venturi arrangement. It can be used in small diameter wells that require a lift of 100 feet or less.
•The pump supplies water, under pressure, to the nozzle. The increase in velocity at the nozzle results in a decrease in pressure at that point, which in turn draws water through the foot valve into the intake pipe. The combined flow then enters the venturi where the velocity is gradually decreased and the pressure head recovered. The excess flow is discharged at the surface through a control valve, which also maintains the required re-circulating flow to the nozzle.
Jet Pumps.mp4
RECIPROCATING PUMPS• Reciprocating pump classification
• 1. Sides in contact with water a) Single acting Reciprocating pump b) Double acting reciprocating pump
• 2. Numbers of cylinder used a) Single cylinder pump b) Two cylinder pumps c) Multi-cylinder pumps
Operations of single acting reciprocating pump
Positive Displacement Reciprocating Pumps Working Animation.mp4
Diaphragm Pump
Wilden - How Air-Operated Double-Diaphram Pumps Work.mp4
A diaphragm pump is a positive displacement pump that uses a combination of reciprocating action and either a flapper valve or a ball valve to transfer liquids.
Diaphragm pumps are self priming and are ideal for viscous liquids. Diaphragm pumps transfer almost any kind of slurry, debris laden waste, food processing residual, liquid, stones, sticks, sugar, oil sludge, refinery waste, mud, clay pharmaceutical, industrial fluids
Rotary pumps• 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
Gear pumps
Animation How internal gear pump works.mp4
External Gear Pumps.flv
Gear pump:
it consists of two or more gears which mesh each other. The rotation of these gears provides pumping action .
Spur, helical , herringbone types of gear may be used for the purpose but spur gear are most commonly used.
Vane pump
Phun - Rotary Vane Pump.mp4
Rotary Vane Pump Animation.flv
Vane pump: it consists of stationary casing and cylindrical rotor. The cylindrical rotor contains the sliding vanes which fitted to the radial grooves of rotor as shown as fig. The vanes are free to move away from the centre of rotor due to the spring action .These make tight contact between vanes and casing rotation. Liquid is carried on by the vanes and finally discharge to the delivery side.
Screw pumps
Screw Pump.flv
Screw pump:
Screw pumps are special type of rotary positive displacement pumps.
It consists of pair of screws, one of the screw rotor drives other screw rotor in the stationary casing .
The liquid is carried between screw threads in pair of screws in mesh and is displaced axially as the screws rotates.
Practical Application of PumpsTYPE OF PUMP APPLICATION
Piston pump For low head and more discharge
Plunger pump For high head and less discharge, and for denser liquids.
Bucket pump For low head and suitable for manual operations
Centrifugal pump For continuous flow, high discharge, low head
Multi stage centrifugal pump High discharge
Multi stage centrifugal pumps For high head
Rotary pump For viscous fluid like lubricating oil