Reciprocating Pump is a positive displacement type pump.
Today we will study the complete overview of Reciprocating Pump.
Note: At the bottom of this article you will find the PDF downloadable link and continue your learning offline.
Let’s start with the definition first.
Definition of a Reciprocating Pump:
A reciprocating pump is a hydraulic machine which converts the mechanical energy into hydraulic energy.
Here a certain volume of liquid is collected in the enclosed volume and is discharged using pressure to the required application.
Reciprocating pumps are more suitable for low volumes of flow at high pressures.
Main Parts or Components Reciprocating Pump with their Function:
A reciprocating pump consists of several parts and those are:
- Suction Pipe
- Suction Valve
- Delivery Pipe
- Delivery Valve
- Piston and Piston Rod
- Crank and Connecting Rod
- Air Vessel
Here is the Schematic Diagram of a Reciprocating Pump:
Let’s see all the parts in details:
It is used to suck the water from the water reservoir to the cylinder.
It connects the inlet of the pump with the water tank.
The suction valve is a non-return valve which means the only one-directional flow is possible in this type of valve.
This is placed between the suction pipe inlet and the cylinder.
During suction of liquid, it is opened and during discharge, it is closed.
It is a pipe that is used to deliver the water from the cylinder to the desired location.
It connects the outlet of the pump to the tank where the water is to be delivered.
4. Delivery Valve:
Delivery valve also non-return valve placed between the cylinder and delivery pipe outlet.
It is in a closed position during suction and in opened position during discharging of liquid.
An arrangement of piston and piston rod is inside this cylinder.
Piston and Piston Rod:
A piston is a solid type cylinder part which moves backward and forwards inside the hollow cylinder, to perform suction and delivery of liquid.
Piston rod helps the piston to its linear motion.
Crank and Connecting Rod:
Crank is a solid circular disc which is connected to the power source like motor, engine, etc, for its rotation.
Connecting rod connects the crank to the piston, as a result, the rotational motion of the crank gets converted into linear motion of the piston.
A strainer is provided at the end of the suction pipe to prevent the entrance of the solids particle from a water source into the cylinder. Otherwise, solid particle choked the delivery.
Air vessels are connected to both suction and delivery pipes to eliminate the frictional head and to give a uniform discharge rate.
Working Principle of a Reciprocating Pump With Diagram:
This type of pump is consists of a piston that moves forward and backward in a close-fitting cylinder. The movement of the piston is obtained by connecting the piston rod to crank by means of a connecting rod. The crank is rotated by means of an electric motor.
Suction and Delivery Pipes with a suction valve and a delivery valve are connected to the cylinder. The suction and delivery valves are non return valves, which allow the water to flow in one direction only.
The suction valve allows water from the suction pipe to the cylinder and where the delivery valve allows water from the cylinder to the delivery pipe only.
When the crank starts rotating, the piston moves in the cylinder.
From the above diagram, When a crank is at A, the piston is at the extreme left position in the cylinder. As the crank is rotating from A to C,(θ=0º to 180º) the piston is moving towards the right in the cylinder.
The movement of the piston towards the right creates a partial vacuum in the cylinder. But on the surface of the liquid in the sump atmospheric pressure is acting, which is more than the pressure inside the cylinder.
Thus the liquid is forced into the suction pipe from the sump. This liquid opens the suction valve and enters into the cylinder.
When a crank is rotating from C to A (θ=180º to 360º), the piston from the extreme right position starts moving toward left in the cylinder.
The movement of the piston towards the left increases the pressure of the liquid inside the cylinder more than the atmospheric pressure.
Hence the Suction valve closes and the delivery valve opens. The liquid is forced into the delivery pipe and is raised to a Required Height.
Reciprocating pump Types:
A Reciprocating Pump can be categorized into three Types:
1. According to Mechanism:
- Double-acting Reciprocating Pump
2. According to air vessel:
- Pump with air vessel and
- Pump without air vessel.
3. According to Number of cylinders:
- Single cylinder
- Double cylinder and
- Triple cylinder pump.
Let’s understand one by one in detail:
Single-acting Reciprocating pump:
As the name itself “single” that means there is only one suction and deliver valve, suction and delivery pipe.
The fluid sucks only in one direction that is suction stroke and it delivers that is called deliver stroke.
Double-acting Reciprocating Pump:
Here It has two suction and delivers valve, suction and delivery pipe.
Consider, when the piston in a cylinder is in between then one suction and a delivery pipe is on one side(Piston left) and one pipe at another side (piston right).
Pump with air vessel:
It means a continuous flow of water at a uniform rate. It accumulates water by compressing air in the vessel.
Pump without air vessel:
Pump without air vessel means there is some amount of air present in the water. As per the work requirement at the domestic place, these types of pumps used.
Here only one cylinder is connected to a shaft.
There is a two-cylinder attached to a single shaft. The main difference from the single-cylinder pump is here there is separate suction and the delivery valve is provided to each cylinder.
In this pump, there is a three-cylinder connected to it.
Reciprocating Pump Application:
The main application of Reciprocating pump are:
- Oil drilling operations.
- Pneumatic pressure systems.
- Light oil pumping.
- Feeding small boilers condensate return, etc.
Reciprocating Pump Advantages:
There are four major advantages of a Reciprocating Pump and those are the following:
- High pressure is obtained at the outlet.
- The priming process is not needed in this pump.
- Reciprocating Pump provides high suction lift.
- It is also used for air.
Reciprocating Pump Disadvantages:
The major disadvantages of Reciprocating Pumps are:
- It requires high maintenance, because of more wear and tear of the parts.
- Low flow rate (it discharges a low amount of water).
- They are heavy and bulky in size.
- The initial cost is High.
Here are Some Videos, do Watch this videos I am sure you will get a complete knowledge.
So you completed the topic Reciprocating Pump, I hope now you clearly understand the concept of this pump and how its work.
Do check this article on Reciprocating Pump vs Centrifugal Pump
Here is a shorts Recap:
What are the types of Reciprocating Pump?
1. According to Mechanism.
2. According to Air-Vessels.
3. According to Number of Cylinder.
What are the advantages of the reciprocating pump?
1. High pressure is obtained at the outlet.
2. The priming process is not needed in this pump.
3. Reciprocating Pump provides high suction lift.
4. It is also used for air.
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