Presentation on pump Roll 132031-132040

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Assignment on pumprajshahi university of engineering and technology

SLIDE REPRESENTATION BY-

NAME ROLL ASFAQUZZAMAN---------------------------- 132031

SIFAT TASNIM--------------------------------- 132032

OISHWARJA FERDOUS ------------------- 132033

RASEL AHMED------------------------------- 132034

ABDUR RAHMAN----------------------------- 132035

MD.RAFSAN JANI PRANTO--------------- 132036

SAJIB RYHAN---------------------------------- 132037

MARUFA SULTANA -------------------------- 132038

MD.MUHAIMANUL ISLAM------------------ 132039

G.M. NAZMUL ISLAM------------------------ 132040

DEPT. OF ME RUET

23/8/2014

Submitted to:-Dr. Mohammad Rofiqul IslamHead of DepartmentDepartment of Mechanical Engineering RUET

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PUMP: A pump is a device that moves fluids

(liquids or gases), or sometimes slurries, by mechanical action.

When a fluid, be it hot or cold, has to be "moved" in a system, pumps are used. In other words, in a more technically appropriate manner, the pump is a machine which has the function of increasing the total (mechanical) energy of a liquid;

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Different parts of a pump:

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Classification of pump:-

Pumps are in general classified as Centrifugal Pumps (or Roto-dynamic pumps) and Positive displacement pumps.

Pumps can be classified by their method of displacement into positive displacement pumps, impulse pumps,velocity pumps, gravity pumps, steam pumps and valveless pumps.

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Centrifugal Pumps (Roto-dynamic pumps):-

The centrifugal or roto-dynamic pump produce a head and a flow by increasing the velocity of the liquid through the machine with the help of a rotating vane impeller. Centrifugal pumps include radial, axial and mixed flow units.

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INTERIOR OF A CENTRIFUGAL PUMP:-

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HERE IS A VIDEO OF A CENTRIFUGAL PUMP:-

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Positive Displacement Pumps:

The positive displacement pump operates by alternating of filling a cavity and then displacing a given volume of liquid. The positive displacement pump delivers a constant volume of liquid for each cycle against varying discharge pressure or head.

The positive displacement pump can be classified as: 

Reciprocating pumps - piston, plunger and diaphragm

Power pumps Steam pumps8/23/2014

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POSITIVE DISPLACEMENT PUMPS:-

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Pump performance data such as this is usually

supplied by the manufacturer before pump selection. Pump efficiencies tend to decline over time due to wear(e.g. increasing clearances as impellers reduce in size).

When a system design includes a centrifugal pump, an important issue it its design is matching the head loss-flow characteristic with the pump so that it operates at or close to the point of its maximum efficiency.

Pump efficiency is an important aspect and pumps should be regularly tested.

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HERE IS A VIDEO OF A positive displacement PUMP:-

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Figure of a centrifugal pump:

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Working procedure of a centrifugal pump:

Standard operating procedure to operate centrifugal pump is:

The first-step in the operation of a centrifugal pump is priming. Priming is the operation in which the suction pipe, casing of the pump and portion of the delivery pipe up to the delivery valve are completely filled with the liquid which is to be pumped, so that all the air from this portion of the sump is driven out and no air pocket is left

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 It has been observed that even the presence of a small air pocket in any of the portion of pump may result in no delivery of liquid from the pump.

The necessity of priming a centrifugal pump is due to the fact that the pressure generated in a centrifugal pump impeller is directly proportional to the density of the fluid that is in contact with it.

Hence if an impeller is made to rotate in the presence of air, only a negligible pressure would be produced with the result that no liquid will be lifted up by the pump

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Centrifugal pump:-

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As such it is essential to properly prime a centrifugal pump before it can be started. The various methods used for priming a centrifugal pump are discussed later.

After the pump is primed, the delivery valve is still kept closed and the electric motor is started to rotate the impeller. The delivery valve is kept closed in order to reduce the starting torque for the motor.

The rotation of the impeller in the casing full of liquid produces a forced vortex which imparts a centrifugal head to the liquid and thus results in an increase of pressure throughout the liquid mass. The increase of pressure at any point is proportional to the square of the angular velocity and the distance of the point from the axis of rotation

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Thus if the speed of the impeller of the pump is sufficiently high, the pressure in the liquid surrounding the impeller is considerably increased.

Now as long the delivery valve is closed and the impeller is rotating, it just churns the liquid in the casing. By opening the delivery valve the liquid is forced to flow out from the pump casing outlet portion.  At the eye of the impeller due to the centrifugal action a partial vacuum is created. This causes the liquid from the sump, which is at atmospheric pressure, to rush through the suction pipe to the eye of the impeller thereby replacing the liquid which is being discharged from the entire circumference of the impeller. The high pressure of the liquid leaving the impeller is utilized to flow the liquid to higher end through the delivery pipe.

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A PUMP ON ITS WORKING STATE:-

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As the liquid flows through the rotating impeller it receives energy from the vanes which results in an increase in both pressure and velocity energy. As such the liquid leaves the impeller with a high absolute velocity. In order that the kinetic energy corresponding to the high velocity of the leaving liquid is not wasted in eddies and efficiency of the pump thereby lowered, it is essential that this high, velocity of the leaving liquid is gradually reduced to a lower velocity of the delivery pipe, so that the larger portion of the kinetic energy is converted into useful pressure energy.

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Usually this is achieved by shaping the casing such that the leaving liquid flows through a passage of gradually, expanded area, the gradually increased cross-sectional area of the casing also helps in maintaining uniform velocity of flow throughout, because as the flow proceeds from the tongue T to the delivery pipe, more and more liquid is added from the impeller. This is how a pump workes.

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Pump Applications:- Pumps are used for many different

applications. Different types of pumps are used in different sector. Some of them are given below:-

Boiler Feed Pumps - built to control the amount of water that enters a boiler. They are centrifugal pumps, and most are multistage.

Fire Pumps - a type of centrifugal pump used for fire fighting. They are generally horizontal split case, end suction or vertical turbine.

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Pool Pumps - used to circulate the water

in a pool. Water Pumps - a type of equipment

used to move water through a piping system. They rely upon principles of displacement, gravity, suction, and vacuums to move water. They can be both positive displacement or centrifugal pumps.

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..…THE END …..

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