Procedure –

1. Note down the diameter (D) and stroke length (L) of the piston, wattmeter constant k, distances Z _d and Z _s of the pressure gauges from the pump axis
   
2. Start the motor and open the delivery valve fully
   
3. Measure the discharge Q _actual
   
4. Note down the pressure gauge reading P _d and P _s and also wattmeter reading X
   
5. Measure the number of strokes occurring in a given time and hence obtain the speed of the piston in RPM
   
6. Change the opening of the delivery valve
   
7. Repeat steps 3 to 6 for atleast ten different openings of the delivery valve
   

Formulae
Under ideal conditions the discharge in case of double acting reciprocating pump is given by:

Calculations
Perform the following calculations for each opening of the delivery valve :

Advantages of Reciprocating Pump

The advantages of Reciprocating Pump include the following.
• No priming required
• Pressure and flow rate changes have little effect on performance
• Reciprocating pumps generally operate at higher efficiencies than other pumps, generally reaching levels of 85% or more efficiency
• A reciprocating pump provides a steady, unchanging flow rate

Disadvantages of Reciprocating Pump

The disadvantages of the Reciprocating Pump include the following.
• Pulsating flow
• Typically handles only low flow rates
• High operating and maintenance cost
• Not able to handle dirty water