Resiprocating pump
- 2. Muhammad Abdul Wajid Sir Hafiz Osama PRESENTED TO:
- 4. Reciprocating pumps are self priming and are suitable for very high heads at low flows. They deliver reliable discharge flows and is often used for metering duties because of constancy of flow rate. The flow rate is changed only by adjusting the rpm of the driver. These pumps deliver a highly pulsed flow. If a smooth flow is required then the discharge flow system has to include additional features such as accumulators. An automatic relief valve set at a safe pressure is used on the discharge side of all positive
- 5. Pumps are used to increase the energy level of water by virtue of which it can be raised to a higher level. Reciprocating pumps are positive displacement pump. The use of reciprocating pumps is being limited these days and being replaced by centrifugal pumps. These are also useful where high heads are required with small discharge, as oil drilling operations.
- 6. A reciprocation pumps consists of a plunger or a piston that moves forward and backward inside a cylinder with the help of a connecting rod and a crank. The crank is rotated by an external source of power. The cylinder is connected to the sump by a suction pipe and to the delivery tank by a delivery pipe. At the cylinder ends of these pipes, non-return valves are provided. A non-return valve allows the liquid to pass in only one direction. Through suction valve, liquid can only be admitted into the cylinder and through the delivery valve, liquid can only be discharged into the delivery pipe.
- 8. When the piston moves from the left to the right, a suction pressure is produced in the cylinder. If the pump is started for the first time or after a long period, air from the suction pipe is sucked during the suction stroke, while the delivery valve is closed. Liquid rises into the suction pipe by a small height due to atmospheric pressure on the sump liquid. During the delivery stroke, air in the cylinder is pushed out into the delivery pipe by the thrust of the piston, while the suction valve is closed. When all the air from the suction pipe has been exhausted, the liquid from the sump is able to rise and enter the cylinder.
- 9. During the delivery stroke it is displaced into the delivery pipe. Thus the liquid is delivered into the delivery tank intermittently, i.e. during the delivery stroke only.
- 10. Piston: Generally made of the mild steel Liner: Made of Mild steel Valves: Made of steel but a little improved from which has the stiffen and less wear and tear are used and brass can also b used.
- 11. Following are the main types of reciprocating pumps: According to use of piston sides ◦ Single acting Reciprocating Pump: If there is only one suction and one delivery pipe and the liquid is filled only on one side of the piston, it is called a single-acting reciprocating pump. ◦ Double acting Reciprocating Pump: A double-acting reciprocating pump has two suction and two delivery pipes, Liquid is receiving on both sides of the piston in the cylinder and is delivered into the respective delivery pipes.
- 13. According to number of cylinder Reciprocating pumps having more than one cylinder are called multi-cylinder reciprocating pumps. ◦ Single cylinder pump A single-cylinder pump can be either single or double acting ◦ Double cylinder pump (or two throw pump) A double cylinder or two throw pump consist of two cylinders connected to the same shaft.
- 14. According to number of cylinder ◦ Triple cylinder pump (three throw pump) A triple-cylinder pump or three throw pump has three cylinders, the cranks of which are set at 1200 to one another. Each cylinder is provided with its own suction pipe delivery pipe and piston. ◦ There can be four-cylinder and five cylinder pumps also, the cranks of which are arranged accordingly.
- 15. According to number of cylinder
- 16. According to existence of air vessels ◦ With air vessels ◦ Without air vessels
- 17. Let A = cross sectional area of cylinder r = crank radius N = rpm of the crank L = stroke length (2r) Discharge through pump per second= Area x stroke length x rpm/60 This will be the discharge when the pump is single acting. 60 N LAQth
- 19. Discharge in case of double acting pump Discharge/Second = Where, Ap = Area of cross-section of piston rod However, if area of the piston rod is neglected Discharge/Second = 60 )( 60 LNAAALN Q P th 60 )2( LNAA Q P th 60 2ALN
- 20. Thus discharge of a double-acting reciprocating pump is twice than that of a single-acting pump. Owing to leakage losses and time delay in closing the valves, actual discharge Qa usually lesser than the theoretical discharge Qth.
- 21. Slip of a reciprocating pump is defined as the difference between the theoretical and the actual discharge. i.e. Slip = Theoretical discharge - Actual discharge = Qth. - Qa Slip can also be expressed in terms of %age and given by 10011001 100% d th act th actth C Q Q Q QQ slip
- 22. Slip Where Cd is known as co-efficient of discharge and is defined as the ratio of the actual discharge to the theoretical discharge. Cd = Qa / Qth. Value of Cd when expressed in percentage is known as volumetric efficiency of the pump. Its value ranges between 95---98 %. Percentage slip is of the order of 2% for pumps in good conditions.
- 23. It is not always that the actual discharge is lesser than the theoretical discharge. In case of a reciprocating pump with long suction pipe, short delivery pipe and running at high speed, inertia force in the suction pipe becomes large as compared to the pressure force on the outside of delivery valve. This opens the delivery valve even before the piston has completed its suction stroke. Thus some of the water is pushed into the delivery pipe before the delivery stroke is actually commenced. This way the actual discharge becomes more than the theoretical discharge. Thus co-efficient of discharge increases from one and the slip becomes negative.
- 24. Centrifugal Pumps Reciprocating Pumps 1. Steady and even flow 1. Intermittent and pulsating flow 2. For large discharge, small heads 2. For small discharge, high heads. 3. Can be used for viscous fluids e.g. oils, muddy water. 3. Can handle pure water or less viscous liquids only otherwise valves give frequent trouble. 4. Low initial cost 4. High initial cost. 5. Can run at high speed. Can be coupled directly to electric motor. 5. Low speed. Belt drive necessary. 6. Low maintenance cost. Periodic check up sufficient. 6. High maintenance cost. Frequent replacement of parts. 7. Compact less floors required. 7. Needs 6-7 times area than for centrifugal pumps. 8. Low head pumps have high efficiency 8. Efficiency of low head pumps as low as 40 per cent due to the energy losses. 9. Uniform torque 9. Torque not uniform. 10. Simple constructions. Less number of spare parts needed 10. Complicated construction. More number of spare parts needed.
- 25. Oil and gas production Pipeline Refinery Chemical processing Power Primary metals processing Mining General industry Hydro testing
- 26. There is no doubt that these pump are best when it comes to providing us with high pressure. Bus as we have seen that there are lost of maintenance which are required in the pump.so we can say these pump are used in places where there is a specific purpose of them to be used. So this was all about the reciprocating pump.
Editor's Notes
- #5: There is a relatively large body of literature from education, psychology, and the private sector that talks about the ways that teams develop (e.g., Friend & Cook, 2003; Tuckman & Jenson, 1977). Most researchers agree that teams generally move through four stages of development. While authors assign some different names to the stages, this module uses the terms that are best known in the field: forming, storming, norming, and performing. Forming refers to the first stage of development in which teams come together and begin to identify what they want to accomplish and how they will work together. Storming refers to the second stage, in which teams encounter some differences of opinion that occasionally lead to a more uncomfortable form of conflict. In stage three, norming, teams develop strategies for working through conflict and using it in more positive and creative ways. Finally, stage four, or performing refers to the highest stage of team development in which teams are highly effective and make excellent use of creative problem solving. It is important to note that teams develop at different rates, and that not all go through the four stages in a linear way. Many effective teams develop their own identities, so that a high performing team may not use all of the structures that we typically see in a newly forming team. Finally, it is important to note that leadership is critical in team development. The leader of a stage one or two team may need to play a stronger role in helping the team establish its structure and processes. By the time a team gets to stage four, however, there is less need for one person to take responsibility for leading the team. At this stage, leadership may be shared by all team members. If possible, slides 5 – 9 should be printed as handouts so that participants can take notes on the presentation.