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Basics of reciprocating pump

Reciprocating pump

Reciprocating pump is a mechanical device which is used to discharge or transfer liquid from one source to another source with high pressure and fixed volume approx. It is a type of positive displacement pump. Reciprocating pump converts mechanical energy into hydraulic energy by sucking the fluid from the sump into the piston cylinder where the liquid is discharged through the discharge valve.
Now we will discuss the construction of reciprocating pump below the list of main components of a reciprocating pump is piston, piston rod, connecting rod, piston cylinder, rider ring, cross-head, crankshaft, suction valve, discharge valve, piston ring, flywheel, shaft couplings, end cover, cylinder lubrication oil, lubrication oil pumps.
With the help of assembly, of the piston rod, connecting rod and crankshaft converts the rotary motion into the reciprocating motion. And the compression is going on with the help of reciprocating the motion of the piston.
which moves backward and forward motion in a tightly closed cylinder. In the assembly of piston, piston rod, connecting rod and crankshaft connecting rod and crankshaft.  the is directly connected through a cross head. The rotary motion converts to the reciprocating motion with the help of the cross head. As shown in the figure.
reciprocating pump cylinder
Centrifugal Pump

What is the working principle of reciprocating pumps?

Reciprocating pumps work based on the principle of reciprocating motion, which involves back-and-forth movement of a piston or a plunger within a cylinder. These pumps are positive displacement pumps, meaning they displace a fixed amount of fluid with each stroke or cycle.

Here is a general overview of the working principle of reciprocating pumps:

Cylinder and Piston/Plunger:

The pump consists of a cylinder, which is a closed chamber, and a piston or a plunger that fits tightly within the cylinder.

Inlet and Outlet Valves:

The cylinder has inlet and outlet valves. The inlet valve allows the fluid to enter the cylinder from the source, while the outlet valve permits the fluid to exit the cylinder.

Suction Stroke:

During the suction stroke, the piston or plunger moves away from the outlet valve, creating a low-pressure area within the cylinder. This low pressure causes the inlet valve to open, allowing the fluid to enter the cylinder.

Discharge Stroke:

In the discharge stroke, the piston or plunger moves towards the outlet valve, causing the volume within the cylinder to decrease. As a result, the pressure within the cylinder increases, causing the outlet valve to open and allowing the fluid to be discharged from the pump.

Check Valves:

Reciprocating pumps typically have check valves at the inlet and outlet. These valves ensure that fluid flows in the desired direction by allowing flow in one direction while preventing backflow.

Reciprocating Motion:

The reciprocating motion of the piston or plunger is usually generated by a crankshaft mechanism, an electric motor, or other means of converting rotary motion into reciprocating motion.

Repeat Cycle:

The suction and discharge strokes alternate in a continuous cycle, allowing the pump to continuously draw in and discharge fluid.

How do you know which pump is the centrifugal pump and each reciprocating pump?

  • With the help of the pump casing design.
  • In a reciprocating pump mostly, dampener is used to give the uniform flow.

Where is the reciprocating pump used?

Reciprocating pump used for high pressure, high viscosity fluid and control flow (uniform flow).

How many major parts are used in reciprocating pumps?

The parts name I have already mentioned you can check from here.
reciprocating pump is piston, piston rod, connecting rod, piston cylinder, rider ring, cross-head, crankshaft, suction valve, discharge valve, piston ring, flywheel, shaft couplings, end cover, cylinder lubrication oil, lubrication oil pumps

What do you mean by the stroke in the pump?

The stroke is used to control the flow by adjusting the piston movement. The stroke is directly proportional to the flow rate. It is an adjustment setting of a piston and connecting rod (tight or loose). And piston road where we can set the stroke of the piston.

How do you identify which one is single acting and which one is a double acting pump?

A single acting pump, one section line and one line discharge line connection is used in one cylinder. The suction of the liquid will be in backward movement and discharge will only be in forward direction only. Whereas in the double acting reciprocating pump on the same cylinder, two suction lines and two discharge line connections were used.
In the double acting reciprocating pump, the one tine suction and discharge of the liquid complete in backward and same operation will be continued in forward movement. So, the delivery and suction of the liquid in both directions. In the double acting cylinder, the piston movement is between both one section valve and one discharge valve. One section one discharge valve at the start of the cylinder other is the end of the cylinder.

Why use the double acting reciprocating pump?

This type of pump is used for linear flow, high head, high pressure and without more fluctuations in the flow. 

Which pump is used for dodging the chemical in the tank?

Most reciprocating pumps are used for dodging purposes. It is used for control flow and higher pressure. The discharge flow rate required for dozing chemicals is very low and this one can only be handled by reciprocating pumps.

What is the valve condition during the operation of the reciprocating pump?

During the operation of reciprocating pump when the suction is going on in the cylinder suction valve is open and during the discharge of the liquid the suction valve will be closed and discharge valve be open this is sequential process and automatic by the help of low pressure and high pressure in the cylinder.
There are many types of valves used in reciprocating pumps.

How many types of valves are used in reciprocating pumps? 

Suction and discharge valve are a non-return valve. Which is open in one direction only poppet valves, plate valves and nrv etc.   

Why is the dampener used in reciprocating pumps?

Dampener is used for controlling the flow and fluctuation of the liquid.

Which gas is used to dampener?

nitrogen is used for dampeners.

Why priming is not required in reciprocating pumps.

The chance of cavitation in the cylinder is very low because if some bubbles are shocked in the cylinder It is collapse during the discharge or escapes through the discharge valve because the suction valve will be closed during the discharge process. There will be less chance of air pockets in the inside body.

What is the SOP of reciprocating pump single acting?

  • Check the nitrogen pressure in the damper.
  • Check the lubrication of all parts.
  • All types of lubrication have been given in running conditions after that motor starts.
  • The pump operation will start during the start of the motor.
  • Before the start pump all suction and discharge valves should be in open conditions.

What is separation of reciprocating pumps?

Preventive measures for separation of reciprocating pumps. If the pump cylinder pressure goes below the vapour pressure of liquid and dissolved gases will be liberated from the liquid then cavitation takes place. The continued flow of the liquid is not possible due to this separation of liquid taking place.

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