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What is Pump and its components, working priciples, and operation of centrifugal pump?

                  I hope you are very happy today. Today I discuss the pumps and their operation, pump types that are used in Irrigation Drainage System.

Definition of Pump:

A pump is a device that is used to convert mechanical or electrical energy into hydraulic energy. A pump is a device that moves liquids or gases by mechanical action. A pump is a device that is used to elevate the liquid or flow from lower to higher locations. A pump is a device that imports energy. The primary function of the pump is used to impart energy to the fluid. A pump is a device in which flow converts from lower to higher pressure. A pump is a device that is used to displace fluid from lower to higher locations. To elevate or lift water from lower to higher levels. A pump is used to move a fluid from one point to another point. A pump is used to impart kinetic energy to fluids.

Operation of Pump:

                               A pump is used to elevate the water from beneath the ground. When the water inlets the pump than first of all passes through the foot valve which is used to reduce the dust from water. The inlet side where water enters is called the Suction side. On the suction side, water pressure is low. Employ centrifugal forces to lift from lower to higher location or from lower pressure to higher pressure. Comprises of an impeller fitted on the shaft within the casing. Liquid led into the eye of an impeller, picked up by the vanes of the impeller and accelerated to the high velocity due to centrifugal force. This liquid discharged into the impeller and then out. A vacuum is created after throwing liquid so more liquid from the sump flow in which creates continuous action of flow kinetic energy needs to convert into pressure energy with the help of guide vanes in the casing. So kinetic energy will be converted into pressure energy. Whenever flow takes place from lower pressure to higher pressure region, separation takes place which can create eddies that could be responsible for energy loss.

Working Principle:

                       Incapable of sucking liquids. Priming is required to run the pump. The pump needs to develop pressure that is impossible in the presence of air. The pressure produced by the pump is directly proportional to the density of the liquid to be pumped. After the process of priming, start the pump and closed the delivery valve until the achievement of a certain pressure head by the pump.

The basic principle on which a centrifugal pump works is that when a mass of liquid is rotated by a rotating impeller in a casing with higher velocity, a centrifugal head is imparted to liquid which develops a pressure head. The pressure head raises the liquid from a lower to a higher level. While moving up a liquid particle with a given velocity to reach the same verticle height through which any particle should fall freely under gravity to attain the same velocity starting from rest.

Components of Pump:      

                                    Components of pumps are given below:

Impeller:

               An impeller is the main part of the pump.it is also called the rotor. It is used to rotate the liquid and finally cause the liquid to leave the impeller by centrifugal force.

Closed / Shrouded Impeller:

            In which shrouds are on both sides between which plain (radial ) or curved vanes are inserted. These impellers have a passage for water entry called the Eye of an impeller. Used to pump pure liquids like oil, acids alkalies, etc. The material should be resistant against the reaction of the material handled.

Semiclosed Impeller:

               In which vanes are fixed on one shrouds only, has less number of vanes with more length to avoid clogging. It is used to pump liquid containing mucks and debris up to some extent only such as sewage water and paper pulp etc.

Open Impeller:

               In which vanes are directly fixed on the web. It is used to pump slurry and liquids having large solid particles like sand, pebbles, etc. It performs a very rough job Therefore should be resistant against wear and impact.

Pump casing:

                     It is required for housing the impeller and bearing. It is used to convert a velocity head into a pressure head. It is used for the guidance of the pumped flow. It is used to create boundaries for the pumped flow.

Pump casing has three type

Volute type casing:

                            The volute-type casing is very commonly used. Its maintenance and other costs are also very cheap due to this it is a very common type of casing. Its construction is also very simple. The water discharged by the impeller enters into a progressively expanding spiral casing. The cross-section area of the casing generally increases from the noise to the tongue until the discharge pipe. This casing produces equal velocity all around the circumstances and it reduce generally the velocity of liquid gradually as it flows from the impeller to the discharge pipe, thus changing the velocity head into pressure head. In this casing, more eddies create so due to this small amount of velocity head is converted into a pressure head, the large amount of velocity head is lost due to eddies formation.

Vortex casing :

                       For the better performance of the pump, sometimes an annular space known as vortex or a new chamber whirlpool chamber is provided between the impeller and volute casing. It is generally formed as a part of the casing, with parallel walls which serve as diffuser without guide vanes.No work is done on water or fluid on this chamber, the energy remains constant except slightly loss by friction. The torque that is produced due to water on this chamber does not change and the velocity of a whirl must vary inversely as it radial distance from the center.

                                                 

Diffuser type casing:

                         In this type of casing, which impeller is surrounded by a series of stationary guide vanes or diffuser rings with guide vanes which by their divergence furnish expanding passage for water gradually to follow after leaving the impeller. In this casing losses of eddies is very small. In this process the direction of flow changed, so the velocity head converted into a pressure head before entering the volute casing. Its construction is so complicated and its maintenance cost is very high. Its efficiency is more than all casing. Due to the high cost of this casing, volute type casing that is cheap mostly used.

Suction Pipe:

               The suction pipe is the pipe whose upper end is connected with the pump on the suction side and the lower end is submerged in the liquid in a sump. The lower end is fitted with a foot valve and strainer.Due to the small pipe length, friction losses are insignificant. It is important in that how far liquid is entering the eye of the impeller.

Delivery Pipe:

                     The delivery pipe is the pipe whose upper end is ended at the supply end or reservoir in which water is collected and the lower end starts from the outlet flange of the pump. Just after the outlet flange a sluice valve and non-return valve is fitted.

Prime mover:

                            Generally, an electric motor is used to drive the pump. An electric motor is generally coupled directly with a pump. An engine is also used in the belt system.