Skip to main content

Pumps




Pumps:
            Pumps are such a device, which transfer liquid from one place to another place by pressure difference.

Types of pump:
1.      Centrifugal pump
2.       Reciprocating pump

Centrifugal pump:
                        The pump which raises water or a liquid from a lower level to a higher level by the action of centrifugal force is known as centrifugal pump. A centrifugal pump is a rotodynamic pump that uses a rotating impeller to increase the pressure of a fluid. Centrifugal pumps are commonly used to move liquids through a piping system. The fluid enters the pump impeller along or near to the rotating axis and is accelerated by the impeller, flowing radially outward into a diffuser or volute chamber, from where it exits into the downstream piping system. Centrifugal pumps are used for large discharge through smaller heads.


                                        
                                            
                                                    Figure (1): Centrifugal pump  

  
                 
                                          
                                    Figure (2):  Impeller

Working principle:

A centrifugal pump works by converting kinetic energy into potential energy measurable as static fluid pressure at the outlet of the pump. This action is described by Bernoulli's principle. With the mechanical action of an electric motor or similar, the rotation of the pump impeller imparts kinetic energy to the fluid through centrifugal force. The fluid is drawn from the inlet piping into the impeller intake eye and is accelerated outwards through the impeller vanes to the volute and outlet piping.


CWP:

Circulating Water Pump is briefly known as CWP. In APSCL the CWP are used for water circulation through out the system. One CWP have a capacity of 40,000 tones/hour and weight of 126 tones. Its power consumption is about 6 MW.

Main parts of CWP:
Ø  Pump casing
Ø  Shaft
Ø  Journal and Thrust bearings
Ø  Diffuser
Ø  Impeller
Ø  Electric motor

Application of centrifugal pump in power station:

Ø  Circulating water pump
Ø  Feed water pump
Ø  Condensate pump
Ø  Fire fighting pump
Ø  Demi water pump
Ø  LP and HP heater pump
Ø  Dosing pump etc.

Reciprocating pump:
                        A reciprocating pump is also known as a positive displacement pump, as it discharges a definite quantity of liquid during the displacement of its piston or plunger.

Comparison of Centrifugal and reciprocating pump:

Serial No:
Centrifugal pump
 Reciprocating pump
01
Suitable for large discharge and smaller heads.
Suitable for less discharge and higher heads.
02
Required less floor space and simple foundation.
Required more floor space and heavy foundation.
03
Maintenance cost is less.
Maintenance cost is high.
04
Can handle dirty water.
Can not handle dirty water.
05
Can run at high speed.
Can not run at high speed.
06
Its delivery is continuous.
Its delivery is pulsating.
07
No air vessel is required.
Air vessel is required.
08
Need priming.
Does not need priming.
09
It has less efficiency.
It has more efficiency.


Comments

Popular posts from this blog

“Equalizer connection is needed in lap winding armature but not in wave winding “ why ?

The equivalent circuit of a four point – pole dynamo with a simplex winding. The voltage induced in each path is assumed to both to be same and should be if the reluctance of each magnetic path is the same, so that the lines of flux cut by each inductor of each path are the same. However wear of the bearings or deflection of the armature shaft may cause the armature to be closer to some poles and farther from others, thus changing the length of the air gap, and therefore the reluctance of the magnetic circuits of the poles is not identical. This factors cause the voltage in the materials making up the magnetic circuit. These factors cause the voltage in each parallel path differ, and the unequal voltages in turn cause flow of a circulatingcurrent through the windings and brushes , undue heating of the armature and waste the power. To reduce the circulating current, points on the winding which should be at the same potentials are brought to the same potentials by connecting them with …

Turbine

Turbine:

What are the advantages and disadvantages of hydraulic brakes?

Boiler

Boiler


Boiler: A steam boiler is usually a closed vessel made of steel. Its function is to transfer the heat produced by the combustion of fuel to water and ultimately to generate steam.
Types of boiler:
           1. Fire tube or smoke tube boiler            2. Water tube boiler




                                          Figure: Boiler
Fire tube boiler: In fire tube steam boilers, the flames and hot gases, produced by the combustion of fuel pass through the tubes which are surrounded by water. Fire tube boilers are generally used for relatively small steam capacities and low to medium steam pressure. As a guideline fire tube boilers are completive for steam rates up to 12000kg/h and pressures up to 18 kg/cm².Fire tube boilers are available for operation with oil, gas or solid fuel.


                                   Figure: Vrious parts of boiler
Example: Cochran boiler, Locomotive boiler, Scotch marine boiler, Velcon boiler, simple vertical boiler.


Differentiate among progressive die, compound die and combination die.

Progressive die: The dies which performed two or more operations at different stages every time the ram descends is known as Progressive die.
The principle advantage of Progressive die is in the number of operations that can be achieved with one handling of the stock strip. The main disadvantage is that work pieces may become “dished” as they pushed through the die as they generally have very little support.






Compound die: A compound die differs from a progressive die in that it performs two or more cutting operations during one stroke of the press at one station only.

Compound dies are slower in operation than progressive dies but they have advantages for certain jobs, especially where tolerance are close (1)the cutting operation, by the action of the knockout plate ,ensures flatness of the blank.2 Large parts can be blanked in a smaller press if compound dies rather than progressive dies areused.
Combination dies:A die in which a cutting operation is combined with a noncutting operation …

Thermal Power Plant

Why a dc generator fails to build up voltage?

what is the difference between long shunt and short shunt dc generator?

What is basic difference between a Turbine and The Pump?

What are the factors that control the speed of a dc motor? Describe Ward-Leonard system to control the speed of a dc motor