The reciprocating pump works on the principle of positive displacement. A reciprocating piston pump consists of a piston that moves back and forth in a cylinder. The piston is connected with a crankshaft with the help of a connecting rod. This piston moves as the connecting rod move due to the motion of the crankshaft.
What is reciprocating pump and how it works?
Reciprocating pump is a positive displacement pump where certain volume of liquid is collected in enclosed volume and is discharged using pressure to the required application. Reciprocating pumps are more suitable for low volumes of flow at high pressures.
What is the purpose of reciprocating pump?
2.2.
Reciprocating pumps are used where a precise amount of fluid is required to be delivered, also where the delivery pressure required is higher than can be achieved with other types. The fluid is moved by the means of a piston that travels in a cylinder.
How does a single acting reciprocating pump work?
Single-acting reciprocating pump: This has one suction valve and one discharge valve. When the piston is moved backward, suction happens and when it moves forward, the delivery valve opens up to discharge the liquid.
How do you start a reciprocating pump?
Pump Start-up Procedure
- Line up the pump valves.
- Ensure that the drain valve is closed.
- Open the suction valve.
- Open the vent valve to bleed off gases when liquid comes from the vent valve close it again.
- Open the gland-seal valve (if fitted).
- Commission the bearing and oil cooling systems (if fitted).
What type of flow does reciprocating pump have?
continuous flow
Explanation: The reciprocating pump has a continuous flow. It has a constant discharge even if head on the delivery side varies. Explanation: The reciprocating pump runs at a low speed. Its speed is less than 30m/min.
What is difference between Centrifugal pump and reciprocating pump?
The main differences between Centrifugal Pump and Reciprocating Pump are the Centrifugal pump works low medium pressure head and Reciprocating Pump works high medium pressure head.
Where are reciprocating pumps typically used?
Incorporating reciprocating pumps results in repeatable and precise mechanical operations. Industries that commonly use reciprocating pumps include: Oil and gas: Oil and gas industry applications include disposal, offshore oil, production, injection, feed, charge, steam generators, mainline, and field gathering.
How cavitation occurs in reciprocating pump?
Two basic types of cavitation exist in reciprocating pumps: Suction cavitation can result from obstructed, clogged, or otherwise dysfunctional inlet pipes. When the inlet pipe’s optimal flow is hampered, vapor cavities form near the retracting plunger.Disregard of net positive suction head (NPSH) guidelines.
Why reciprocating pumps are self-priming?
What is Self-Priming? If a pump is located beneath the level of the liquid to be pumped, gravity and air pressure ensure that it is constantly filled with the liquid and there can be no ingress of air into the pump or suction line.
What happens to the reciprocating pump when it is a left untouched?
2. What happens to the reciprocating pump when left untouched? Explanation: When left untouched over a period of time, the reciprocating pump undergoes wear and tear. Reciprocating pumps have a good life provided that they are not left untouched.
What are the advantages and disadvantages of a reciprocating pump?
Advantages and Disadvantages of Reciprocating Pump
- This pump is self-priming – Not require filling the cylinders by starting.
- This pump can work in wide pressure range.
- Priming is not necessary in pump.
- Provide high pressure at outlet.
- Provide elevated suction lift.
- They are use for air also.
What limits the suction lift of a reciprocating pump?
Suction Lift: This is the vertical distance that the pump can be above the liquid source. Typically, atmospheric pressure limits vertical suction lift of pumps to 25 feet at sea level.
How do you adjust the flow rate of a reciprocating pump?
The easiest way to change the flow of a reciprocating pump is to change the rate at which the plungers/pistons move liquid through pump valves into the system.
Why reciprocating pump is a positive displacement pump?
The most common form of reciprocating pump is the positive displacement type.These check valves ensure fluid movement is in one direction from pump suction toward the pump discharge. Since a fixed volume of fluid is displaced the rate of flow is directly proportional to speed.
How is the maximum speed of a reciprocating pump determined?
Maximum speed of a reciprocating pump will be determined on the basis of fact that the pressure in the cylinder during suction and delivery stroke, should not fall below than the vapour pressure of liquid, flowing through suction and delivery pipe.
What is the normal efficiency of a reciprocating pump?
The overall efficiency of a reciprocating pump unit is generally above 85 percent throughout its full operating range (see Figure 4).
What is more efficient centrifugal pump or reciprocating pump?
In general, a reciprocating pump is more efficient than a centrifugal pump.Centrifugal pumps can have efficiencies as low as 40 percent on low-flow/high-head service. A reciprocating machine can have efficiencies greater than 90 percent on the same service.
What is the maximum efficiency of reciprocating pump?
85 percent
Explanation: Reciprocating pump is more favourable for small liquid quantities. As the chamber in the liquid is trapped, it has a stationary cylinder which contains a piston and a plunger. The maximum efficiency of the reciprocating pump is 85 percent.
What is separation head in reciprocating pump?
Separation of flow:
In reciprocating pumps, It is likely to occur at a point where the absolute pressure head of the liquid is less than or equal to the vapour pressure head i.e. -7.8 m of water (gauge) or 2.5 m of water (absolute).
What causes high pump discharge pressure?
One common cause of high discharge pressure is the cooling medium (air or water) flowing across the condenser: either there is not enough or the temperature of the cooling medium is too high. This is normally easy to identify with a simple visual inspection of the condenser.
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