Reciprocating pump Working principle

Summary

A reciprocating pump is a device that increases the head of a liquid, enabling it to exit at a higher elevation. Essential concepts to understand this process include the head and Bernoulli's theorem. A reciprocating pump consists of a suction pipe, a piston-cylinder mechanism, and a delivery pipe. The crank's rotation, usually powered by an electric motor, transforms rotary motion into a reciprocating motion of the piston, creating a vacuum to draw liquid in and exerting pressure to push it out through non-return valves. This video explains the mechanism in detail, including the roles of the crankshaft and pistons in maintaining unidirectional flow and how different heads like suction and delivery are measured.

Highlights

• Reciprocating pumps elevate liquid from low to high head 💧
• A crank mechanism converts rotary motion into reciprocating motion 🔄
• Non-return valves in place to maintain directionality of flow 🌊
• Understanding head and Bernoulli’s theorem is critical for pump operation 🎓

Key Takeaways

• A reciprocating pump increases liquid head for higher elevation discharge 🚰
• Key concepts: Understanding head and Bernoulli's theorem is vital for grasping how these pumps work 📚
• The mechanism includes a suction pipe, piston-cylinder, and delivery pipe connected through a crank system 🔄
• Electric motors drive the crank, converting rotary into reciprocating motion to operate the pump ⚙️
• Non-return valves ensure the liquid flows in one direction, preventing backflow 🚫

Overview

Reciprocating pumps serve the essential function of transporting liquid from lower to higher elevations by increasing the 'head' or the pressure level of the liquid. This process is crucial in numerous engineering applications where water or other fluids need to be moved upwards efficiently.

The pump's mechanism is ingeniously simple yet effective: It involves a piston-cylinder setup where a rotational to reciprocating motion transformation takes place, thanks to a crank system. This motion creates a vacuum that allows liquid to be sucked up through a suction pipe, pushed through with increased pressure, and exits through a delivery pipe.

Non-return valves play a pivotal role in ensuring that the liquid only travels in the intended direction, preventing backflow which could cause inefficiencies or damage. Understanding the role of various components, such as the piston, crankshaft, and valves, as well as the underlying principles like Bernoulli's theorem, is key to mastering how reciprocating pumps work.

Chapters

• 00:00 - 00:30: Introduction to Reciprocating Pumps The chapter introduces students to reciprocating pumps. It begins with a welcome message and music, then explains that reciprocating pumps are devices used to move liquids from a low head to a higher head by adding energy.
• 00:30 - 01:00: Concept of Head and Bernoulli's Theorem The chapter explores the concept of 'head' and Bernoulli's Theorem. It emphasizes that understanding these concepts is crucial for the lecture. The speaker notes that there is another lecture specifically dedicated to explaining the concepts of 'head' and Bernoulli's Theorem for those unfamiliar with them. The focus then shifts to the operation of a reciprocating pump, a device that takes liquid from a low head or low height and delivers it at a higher head from the exit.
• 01:00 - 01:30: Explanation of Reciprocating Pump Diagram The chapter explains the SCHC diagram of a reciprocating pump. Key components include a suction pipe dipping into a sump, which is the source of liquid to be transported. The diagram features a piston-cylinder mechanism, with the cylinder and piston as integral parts.
• 01:30 - 02:00: Mechanism of the Pump Components The chapter discusses the mechanism of pump components, particularly focusing on a piston rod that only moves in a reciprocating motion (left and right, to and fro). This piston rod connects to a connecting rod via a pin joint, which is further connected to a crank.
• 02:00 - 02:30: Crank and Piston Motion The chapter titled 'Crank and Piston Motion' explains the conversion of rotary motion into reciprocating motion using a crank and piston mechanism. It highlights how an electric motor provides power to the crank, which then rotates and converts rotary motion into the reciprocating motion of the piston. The chapter also mentions a delivery pipe through which the liquid exits the cylinder, emphasizing the movement and outflow of liquid through this system.
• 02:30 - 03:30: Function of Inlet and Outlet Valves The chapter discusses the functioning of inlet and outlet valves. It explains how these valves are designed to allow liquid to flow in one direction only. The inlet valve can pivot and open like a flap to let liquid into the cylinder when pulled inside, while preventing reverse flow. Similarly, the function of the outlet valve is implied to operate on a similar principle.
• 03:30 - 05:30: Working of Reciprocating Pump The chapter explains the unidirectional operation of the outlet valve in a reciprocating pump. It highlights how the valve can only open in one direction, allowing liquid to flow out when pushed, but prevents the liquid from returning. This mechanism ensures that the liquid can move outwards but cannot flow back in the opposite direction.
• 05:30 - 06:00: Explanation of Suction and Delivery Head The chapter delves into the concepts of 'Suction' and 'Delivery Head' as part of understanding how a reciprocating pump works. It starts by explaining the restrictions concerning the inlet wall and how it only opens on one side. The focus then shifts to the operational mechanics of a reciprocating pump, emphasizing the piston’s movement. The piston moves in a reciprocating motion between two extreme points known as the top dead center and the bottom dead center. As the crank rotates in a clockwise direction, it initiates the movement necessary for the pump's function.

Reciprocating pump Working principle Transcription

• 00:00 - 00:30 [Music] hello students today we will learn that how a reciprocating pump works okay reciprocating pump is a device which is used to take a liquid from low head liquid with low head and by addition of energy it is made to exit with higher
• 00:30 - 01:00 head content remember this thing that the concept of head and bernales Theorem is a must to understand this lecture in case you don't know the concept of head and Balm then it is described in my another lecture which is particularly dedicated for concept of head and B theorem okay so reciprocating pump is a device which takes a liquid from low head or low height you can say and ultimately delivers it with higher head from the exit of the reciprocating pump
• 01:00 - 01:30 okay now this is the schc diagram of the reciprocating pump you can see it consist of a suction pipe you can see this as I'm showing by the arrow this is a suction pipe which is dipping inside a sump what is sump sump is the source of liquid from where the liquid is to be pulled so that it can be moved to its destination like this okay this is the suction pipe and there is a piston cylinder mechanism you can see this is the cylinder and this Gray colored entity is the piston this piston is
• 01:30 - 02:00 connected to a piston Rod this piston Rod is constrained to move only in left and right direction to and fr only reciprocating motion can be executed with this piston rod and so as the Piston can also execute only the reciprocating motion this piston Rod is ultimately connected by the help of a pin joint to a connecting rod you can see okay and this connecting rod is further connected to a crank okay okay
• 02:00 - 02:30 so the process is of such kind that in case this crank rotates this crank is rotated by the help of providing power it usually by the help of an electric motor so when this crank rotates then due to its rotation the rotary motion converts into reciprocating motion of the Piston like this okay now further there is a delivery pipe delivery pipe is the pipe through which the liquid outflows from this cylinder and ultimately comes out from the exit of delivery pipe which higher head contain
• 02:30 - 03:00 now you can see there are two wolves implanted over here this is the inlet wve and this is the outlet wve these are non-r walles it means that this Inlet wall is pivoted over this end I am showing by the of Arrow okay so it can open inside like this like a flap it can open inside but it cannot open in opposite side so when liquid is pulled inside when liquid is pulled inside then it automatically opens and liquid goes inside the the cylinder okay similarly
• 03:00 - 03:30 this Outlet valve is there it can open only outside like this this direction as I am showing by the help of Arrow okay but it cannot open in opposite side so in case a liquid is pushed then it will open and liquid go out but in case liquid wants to go back return back it cannot do that because the inlet the outlet wall can open only in one side same thing in case the water the liquid wants to go toward opposite side it
• 03:30 - 04:00 cannot happen also with the inlet wall because it can also open only in one side that's it now we will learn that how the reciprocating pump works it is very simple to understand remember that piston always executes reciprocating motion between two dead centers there are two extremities between which this piston can reciprocate those are the top dead center and the bottom dead center like this okay now imagine that this crank starts rotating and rotating in clock clockwise Direction now what will
• 04:00 - 04:30 happen in case it it starts rotating like this since it is rotating like this so it will pull the Piston okay when the Piston is pulled then inside the cylinder a vacuum is created a void is created due to that vacuum the water is pulled Inside by opening the inlet wall automatically because Inlet wall can open inside like this it will open like a flap it is pivoted over here and liquid will be pulled inside now further when the crank rotates more then the
• 04:30 - 05:00 Piston will start moving toward the bottom that Center so this wall will close but since when it is pushing the water water cannot go back opening this inlet valve in opposite side because it is constant only to open in inside but this valve can open this Outlet wall so water will push this wall open it and will go away and ultimately come out from the delivery end like this once again when piston will move toward the right hand side by the help of this crank then vacuum due to that vacuum the
• 05:00 - 05:30 water will be pulled inside since this inlet valve can open in corresponding one side therefore automatically the water will open this wall and go inside and with further movement when water is pushed this wall will open that will automatically close and water will ultimately reach to its destination this is how the reciprocating pump works so simple to understand now in case we take the center of this cylinder okay in case we take the center of the cylinder and this is the level of water of the sump
• 05:30 - 06:00 sump level it is called sump level so the distance between this Center of cylinder and the sump level is called as suction head denoted by HS and the distance between this delivery end of this delivery pipe and the center of cylinder is called as delivery head okay so hope you would have understood the working of reciprocating pump