The reciprocating pump is a positive displacement pump, i.e., initially a small amount of liquid is transported into a chamber and physically displaced or forced with pressure by moving mechanical elements.
These reciprocating pumps are used to raise the energy level of the water and it does not require any kind of priming for their functioning.
Introduction to reciprocating pump:
The reciprocating pump delivers high discharge pressure but discharges at a relatively small volume.
It has a moving part which reciprocated in a to and fro manner.
There are two ports – inlet and outlet ports supported with valves that open and close at the appropriate time of the cycle of operation.
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.
When the piston moves the outer dead center to the inner dead center and piston force of the water at outlet or distribution value.
Type of Reciprocating Pump:
1. Piston 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.
The two types of piston pumps are lift and force pumps operated by hand or by the engine.
2. Plunger pump:
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 used at high pressures.
3. Diaphragm pump:
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.
4. 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.
Components of Reciprocating Pumps:
1. Piston or plunger: A piston or plunger that rotates in a closely fitted cylinder.
2. 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.
3. Suction pipe: One end of the suction pipe is liquid in the inlet of the cylinder and dips in the other end.
4. Delivery pipe: One end of the supply pipe is linked with the delivery part and the opposite end on the discharge level.
5. 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 I.C engine.
1. The piston has the function of providing suction pressure, in order that the liquid can be lifted up or sucked with great pressure.
2. Then comes the compression pressure which is required pressure energy for the fluid.
3. In this part, the piston has to do various work in order that the liquid could be compressed correctly and its pressure could be raised to the specified degree.
4. 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 other side, but in the dual reciprocating pump, 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.
- The alternating pump is a positive displacement pump which implies that the fluid can transfer in single direction, never transfer backwards.
- This pump always begins with the outlet valve open, otherwise, the pressure will proceed to rise and will 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:
- Reciprocating pump 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:
- This reciprocating pum has 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.
- They are more heavy and bulky in shape.
- The initial cost is very high in this pump.
- More parts mean higher initial costs.
- It has high maintenance cost.
- No uniform torque.
- It has 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.
Reciprocating pumps are suitable for moving clean, non-abrasive fluids and 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 gas.