The reciprocating pump is a positive displacement pump, i.e., initially, a small amount of liquid is transported into a chamber and physically displaced and forced with pressure by moving mechanical elements.
If the mechanical energy is converted to hydraulic energy by sucking fluid into a cylinder, in which a piston rotates and stresses the liquid to improve its hydraulic energy, the pump is called reciprocating pump.
These reciprocating pumps are used to raise the energy level of the water and in the initial period, they do not require any kind of priming for their functioning.
Double acting reciprocating pump:
In a Double-acting reciprocating pump, each stroke of the piston carries out both the functions, suction as well as delivery.
Thus the double-acting reciprocating pumps require two suction pipes and two delivery pipes.
When there is a suction stroke on one side of the piston, other side has supply stroke.
For the complete revolution of the crank, there are two delivery strokes, in these two delivery strokes, water is delivered to the pipe by the pump.
Type of Reciprocating Pump:
A piston pump is a positive displacement pump, in which the high-pressure seal rotates with the piston.
These type of reciprocating pump are used to move liquids or compressed gases; it performances on different types of pressures.
The two types of piston pumps are lift and force pumps; operated by hand or by the engine.
This reciprocating pump is also a positive displacement pump, in which a high-pressure seal is fixed and a smooth cylindrical plunger is passed through the seal.
This is absolutely different from the piston pumps and used at high pressures.
A diaphragm pump is an optimistic displacement pump that uses a rubber, thermoplastic or Teflon diaphragm and appropriate valve interactions on both sides of the diaphragm to pump a fluid.
Components of Reciprocating Pumps:
a) Piston or plunger: A piston or plunger that rotates in a closely fitted cylinder.
b) Crank and connecting rod: Crank and connecting rod mechanism operated by a power source.
The power source gives the rotary motion to the crank; with the help of a connecting rod, we translate the motion by rotating it to the piston in the cylinder.
c) Suction pipe: One end of the suction pipe is liquid in the inlet of the cylinder and dips in the other end.
d) Delivery pipe: One end of the supply pipe is linked with the delivery part and the opposite end on the discharge level.
e) Suction and delivery values: These values are introduced at the suction end and supply end, respectively; these values are non-return values.
Working of Reciprocating Pump:
The reciprocating pump is very simple to function and works like an I.C engine.
First, the piston has the function of providing suction pressure, in order that the liquid can be lifted up or sucked with great pressure.
Then comes the compression part which is able to present the required pressure energy for the fluid.
In this part, the piston has to do numerous work in order that the liquid could be compressed correctly and its pressure could be raised to the specified degree.
The inlet and outlet valves open at a fixed pressure that is determined by the manufacturer.
In single-acting type, it sucks from one side and moves only to that side, but in the dual reciprocating pump, in which each stroke has the function of simultaneous suction and discharge.
This pump can be used as a compressor, however, we have to rearrange a good valve that may function with good frequency.
Note: The alternating pump is a positive displacement pump which implies that the fluid can only transfer in a single direction, never transfer backwards.
This pump always begins with the outlet valve open, otherwise, the pressure will proceed to rise and this will also break the pipeline or pump; but when the relief valve is fitted then this stress will likely be lowered.
Reciprocating Pump Diagram:
Advantages of Reciprocating Pump:
- It gives a high suction lift.
- This pump does not require priming.
- Also has high efficiency.
- No priming necessary in this pump.
- It can deliver water at high pressure.
- This pump can operate in a wide pressure range.
- It has a constant rate of discharge.
Disadvantages of Reciprocating Pump:
- High wear and tear, therefore requiring very high maintenance.
- The flow is not uniform, so we have to fit a bottle at both ends.
- The flow is very low and cannot be used for high flow operation.
- More heavy and bulky in shape.
- The initial cost is very high in this pump.
- More parts mean higher initial costs.
- High maintenance cost.
- No uniform torque.
- Low discharge capacity.
- Hard to pump viscous liquids.
Reciprocating pump applications:
- Oil and gas industry.
- Power plants.
- Petrochemical and Refinery.
- Sugar industry.
- Soap and Detergent Industries.
- Food and Beverages.
- Water treatment plant.
- Cryogenic application.
Frequently Asked Questions:
What is the principle of reciprocating pump?
The reciprocating pump operates on the principle of pushing liquid by a piston that performs a revolving motion in a closed fitting cylinder.
How does a reciprocating pump work?
It works by the action of a piston, a plunger or a diaphragm, the liquid is driven by pulling the liquid into a chamber or cylinder; this liquid is then discharged in the required direction using a check valve.
What is the difference between centrifugal and reciprocating pump?
The centrifugal pump is one of the rotary pumps that use the kinetic energy of the impeller while the reciprocating pump is a positive displacement type pump that is forced by the piston.
What are the main parts of reciprocating pump?
1. Suction Pipe.
2. Suction Valve.
3. Delivery Pipe.
4. Delivery Valve.
6. Piston and Piston Rod.
7. Crank and Connecting Rod.
Reciprocating pumps are suitable for moving clean, non-abrasive fluids, as well as abrasive slurries.
In fact, the low velocity of the reciprocating pumps makes it resistant to corrosion in abrasive-slurry applications.
Pumps maintain high efficiency when pumping is carried at extremely high liquidity and can easily handle 50% volumes of entrainment gas.