In this article, we shall be covering the definition, types, advantages, disadvantages, and applications of a pump. We have also provided a PDF download link for the same.
A pump is a device that is used for lifting the liquid from ground reserves or low level storage to the upper levels or surfaces even from one place to another. Pumps are operated by a mechanism that is rotary and reciprocating in nature and it consumes energy while performing mechanical work which is moving fluid from one place to another. It can be operated by many energy resources which include manual operation, electricity, engine, wind power, etc.
Types of Pumps
A pump can broadly be classified into two categories, and those are:
- Positive Displacement Pump
- Dynamic Pump
There are two Sub-types of Positive Displacement Pump
- Rotary Pump
- Single Rotor Pump (For example, Piston Pump, Vane Pump, Screw Pump)
- Multiple Rotor Pump (For example, Gear pump, Lube pump)
- Reciprocating Pump
- Diaphragm Pump (For example, Fluid Operated Pump, Mechanically Operated Pump)
- Piston Plunger Type Pump
Dynamic Pumps can also be classified into two sub-types
- Centrifugal Pump
- Axial Pump
A reciprocating pump is a hydraulic machine that converts the mechanical energy into hydraulic energy. Here a certain volume of liquid is collected in the enclosed volume and is discharged using pressure as per the required application. Reciprocating pumps are more suitable for low volumes of flow at high pressures.
The reciprocating pump are further classified into two sub-types
- Single-acting reciprocating pump
- Double acting reciprocating pump
Parts of Reciprocating Pump
- Suction Pipe
- Suction Valve
- Delivery Pipe
- Delivery Valve
- Piston and Piston Rod
- Crank and Connecting Rod
- Air Vessel
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 only one-directional flow is possible in this type of valve. This is placed between the suction pipe inlet and the cylinder. During the 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.
Delivery valve is a non-return valve placed between the cylinder and the delivery pipe outlet. It is in a closed position during suction and opened position during the discharging of liquid.
A hollow cylinder made of steel alloy or cast iron. 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 solids from a water source into the cylinder.
Air vessels are connected to both suction and delivery pipes to eliminate the frictional head and to give a uniform discharge rate.
The hydraulic machine which converts the mechanical energy into hydraulic energy is called Pumps. The hydraulic energy is in the form of pressure energy if the mechanical energy is converted into pressure energy by means of a centrifugal force acting on the fluid, the hydraulic machine is called a Centrifugal Pump.
Main Parts of Centrifugal Pump
- Suction pipe with a foot valve
- Delivery pipe
An impeller is a rotating component of a centrifugal pump that transfers energy from the motor that drives the pump to the fluid being pumped by accelerating the fluid in an outwards direction from the center of rotation.
The Casing that receives the fluid being pumped by the impeller, slows down the fluid’s flow rate. A volute is a curved funnel that increases in area as it approaches the discharge port.
Suction pipe with a foot valve and Strainer
A pipe whose one end is connected to the inlet of the pump and another end dips into the water in a sump is known as a suction pipe. A foot valve is found at the end of a pipeline in a suction lift application. They function as a check valve, but they also have a strainer affixed to their open end.
A pipe whose one end is connected to the outlet of the pump and other ends delivers the water at a required height is known as a Delivery pipe.
Working of a Reciprocating Pump
The reciprocating pump consists of a piston that moves forward and backward motions in a tight-fitting cylinder. The movement of the piston is obtained by joining the piston rod to the crank through a connecting rod. The crank is rotated using 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 nonreturn valves, which allow the water to flow in one direction only. The suction valve allows water from the suction pipe to the cylinder and whereas the delivery valve allows water from the cylinder to the delivery pipe only.
When the crank starts rotating, the piston moves in the cylinder. 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 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 the 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.
Working Principle of Centrifugal Pump
The Centrifugal pump acts as a reverse of an inward radial flow reaction turbine. This means that flow in a centrifugal pump is in the radial outward directions. The centrifugal pump works on the principle of forced vortex flow which means that when a certain mass of liquid is rotated by an external torque, the rise in pressure head of the rotating liquid takes place. The rise in pressure head at any point of the rotating liquid is proportional to the square of the tangential velocity of the liquid at that point. Therefore the rise in pressure head is v2/2g.
Thus at the outlet of the impeller, where the radius is more, the rise in pressure head will be more and the liquid will be discharged at the outlet with a high-pressure head. Due to this high-pressure head, the liquid can be lifted to a high level.
Applications of Centrifugal Pumps
- Centrifugal pumps are used in buildings for pumping the general water supply, as a booster and for domestic water supplies.
- The design of a centrifugal pump makes them useful for pumping sewage and slurries.
- They are also used in fire protection systems and for heating and cooling applications.
- Beverage industry: Used to transfer juice, bottled water, etc.
- Dairy industry: Used to transfer dairy products such as milk, buttermilk, flavored milk, etc.
- Various industries (Manufacturing, Industrial, Chemicals, Pharmaceutical, Food Production, Aerospace, etc.) for the purposes of cryogenics and refrigerants.
- Oil Energy: pumping crude oil, slurry, mud; used by refineries, power generation plants.
Advantages of Pump
- Due to no drive seal so there is no leakage in the pump.
- There are very few frictional losses.
- The construction of the pump is Simple.
- Relatively quiet operation.
- Minimum wear in comparison to others.
Disadvantages of Pump
- Produces cavitation.
- Unable to work at high speed.
Applications of Pump
- Pumping Water from one place to another place.
- Aquarium and pond filtering
- This is also used for Water cooling and fuel injection in automobiles
- Pumping oil or gas and operating cooling towers in the energy industry.
- Uses in waste-water recycling, pulp, and paper, chemical industry, etc.
So this is all about Pump, I hope you like my article, by the way, feel free to post your doubts on the comment section I would love to answer those.
In summary, pumps are crucial in many industries as they help move fluids from one location to another. There are various types of pumps to choose from, each with unique advantages and disadvantages depending on the intended use. The commonly used pump types include centrifugal pumps, positive displacement pumps, and axial-flow pumps. Despite the benefits of pumps, such as increased efficiency and reliability, they also come with challenges such as high energy consumption and maintenance requirements. Nonetheless, pumps are still widely used in industries like water treatment, oil and gas, and manufacturing. With advancing technology, pumps are expected to become even more efficient and better suited to meet the diverse needs of various applications.