 Myself, P. B. Ekhande, working as an assistant professor in Department of Mechanical Engineering at Valchiyan Institute of Technology, Sollapur. So today we are going to study regarding the working of the centrifugal pump. Now at the end of this session, students will be able to understand the working of the centrifugal pump. So when we consider the working of the centrifugal pump, we should know regarding the components of the centrifugal pumps also. First we will go through the components of the centrifugal pump and then we will see the working of the centrifugal pump. Now the various components which are required for the centrifugal pump are impeller, casing, suction pipe with the strainer and the foot wall, then delivery pipe and delivery wall. So these are the main components which are required for the construction of the centrifugal pump. So impeller is a part which is rotating, casing is a part which is a stationary part and these are the parts which are connected to the casing portion. Impeller is given a power from the some source called as a prime over or that prime over may be the engine or it may be the electrical motor. So impeller is located or enhanced in the casing portion which is a sort of casting is which is provided with the enolate type of the ship. Then we see regarding the construction of the pump over here, it consists of casing portion. So casing is over here, then there is a impeller which is a rotary part which is located in the centrifugal, located in the housing of the centrifugal pump with the help of the bearings at the end. And these two parts are connected with the help of the another parts which are over here. So this suction pipe is connected to the casing portion at the central location which is called as the eye of the impeller. So from the some portion the water is initially taken at the central location called as the eye portion. Then the delivery pipe that is connected to the housing at this location which is required to carry the water after imparting pressure to this portion. So these are the two parts which are connected to the housing of the centrifugal pump and there are two walls which are provided. One is a suction wall over here and other is a delivery wall. So these two walls are required for the pumps as ancillary parts over there. And these two walls are provided to observe the pressure of the water at the exit portion and the inlet portion. So suction at that there is a suction wall provided which is actually the indication of the pressure at this location which is normally below the atmospheric pressure because vacuum will be created inside this location. The pressure at this location inside this is below atmospheric pressure when there is a working of the centrifugal pump. And when there is no working of the centrifugal pump it is retained at the atmospheric pressure. And on this side we can observe the pressure developed because of the working of the centrifugal pump. So this can be observed with the help of the wall with the help of the pressure gauge provided over here which is a positive pressure. Now the pump which is provided with the impeller along with the vanes portion. So these vanes are covered from one side with the plate and other side is provided with the plate or it may be open type. So vanes are the curved nature type of the plates which are mounted or as a casted part or it may be welded part. So these vanes are mounted in such a condition that there is a convergent zone provided from outer location to the inner location. So like that there is a vane arrangement. The casing which is provided over here that casing is an invalid type of the casing. It is not the circular one. So that casing which is provided is an invalid type because it increases the dimension between or the space between the impeller and the casing inner portion. So when we observe over here the space at this location is the least one. So radius at this location is the least radius. And as it proceeds in the anticlockwise direction there is an increase in the radius or the space increases because of this dimension which is provided for the casing as an invalid portion. This is required again to increase the pressure of the water. Now one principle which is known to us that when the liquid or any working substance passes through the convergent zone there is an increase in the velocity at the cost of pressure. But in this there is a reverse element when the water passes through the divergent zone the kinetic energy is reduced and the pressure is increased. So here the divergent zone is provided for the impeller as well as the divergent zone is available for the water when it passes in the anticlockwise direction. So this is the rotation direction anticlockwise direction for the casing of the pump. Now we will see regarding the working of the centrifugal pump. The water from the tank portion is taken inside this casing portion with the help of say vacuum which is created over here. So pressure acting on this will be the positive pressure water level on that the pressure acting is positive or atmospheric pressure whereas when the this impeller rotates with the very high speed the water which is taken from this inside the pipe portion is thrown in the outward direction with the help of the impeller veins. So the water is thrown in the outward direction so centrifugal force is imparted to that and due to the impelling the water in the outward direction and passing through the divergent zone this kinetic energy will get converted into pressure energy and then the high pressure water is taken through this spacing towards the deliory end and because of that pressure the deliory wall opens and then water goes to the deliory pipe or to the deliory tank portion. So like that the water entry will be there from this side and exit will be from this side or the deliory pipe. So this working is for this is the working for the centrifugal pump which is actually after starting the pump but before starting or when we consider the working principle of that initially the deliory wall will be in the close condition priming will be there for the pump to fill the water inside the casing portion and then the rotation of the pump will have the expelling of the water in the outward direction for that purpose the motor will be connected to the electric collected to the shaft of that centrifugal pump and then that speed will be sufficient to produce the centrifugal head which can initiate the discharge from the deliory wall and the deliory wall will get opened because of that pressure and the water will be discharged to the deliory pipe at high pressure. Before stopping the pump it is necessary to close the deliory pipe because the water has to be retained in the pipe so that the priming is not required frequently. Think of this question, what is priming and why it is required in centrifugal pump? So priming it is a process of filling the suction pipe and casing with the water and removing the air. Now why this is essential in case of the centrifugal pump? If you think of the density of water and the air, if the air is filled in the pipeline and the casing in that case the density of air which is inside this casing and the pipeline for that the centrifugal force of the impeller will not be sufficient to lift the water from the sump portion or that is from the well portion and that is because of the less density of air. But if the water is filled in the pipeline and the casing portion the density of the water is higher as compared to the air and the centrifugal force of the centrifugal pump will be sufficient to lift the water from the sump or that is the well portion. Thank you.