CENTRIFUGAL PUMP TEST RIG

 

CENTRIFUGAL PUMP TEST RIG

          OBJECTIVE:

 To obtain the efficiency of a centrifugal pump under varying speed.

 

     APPARATUS:

 The apparatus consists of a pump connected with a D.C. motor. The suction pipe is provided with a vaccum gauge for measurement of suction head. While at the discharge side a pressure gauge is fitted for measurement of the delivery head. A variable speed motor drive is provided. A tachometer is provided for the measurement of the revolution of the pump. A swinging arm field dynamometer is connected on motor for measurement of load. A collecting tank is used to find the actual discharge through the pump.

 

    SUGGESTED EXPERIMENTAL PROCEDURE:

 Step1:  Note down the area of collecting tank, position of delivery pressure gauge (Z₂) and arm distance of the spring from the centre of the shaft.

Step2:  Priming the pump-set before starting. Priming means taking the air present in the suction and pressure pipes, volute casing by filling them with water. Ensure to close the aircock / priming adaptor as the air bubbles cease appearing and continous stream of water comes from aircock/ priming adaptor.

 

NOTE: In the supplied apparatus, a self- priming pump is used so the pump does not require priming.

Step3: The speed control on the motor is set to a value and at the same time the flow control valve was adjusted to give the maximum possible discharge.

Step4: Conditions were allowed to steady before the rate of discharge Q, suction head, discharge head, load on the motor and r.p.s. value were recorded.

Step5:  The flow-rate is reduced in stages and the above procedure is repeated.

 

         SAMPLE DATA SHEET:

             Position of delivery pressure gauge (Datum head), Z₂, m     =

            Arm distance, m                                                                     =       

            rg                                                                                            =   9810

            Area of collecting tank, a, m²                                                            =       

 

Run  No

Discharge measurement

Pump Speed (r.p.s)

Suct-ion Head (m)

Delivery head (m)

Total head (m)

Load (N)

Torque Nm

Water power  Po (w)

Input power  P (w)

Effi- ciency h (%)

Initial h1 (m)

Final h2 (m)

Time (sec)

Discharge Q= (m3/         sec)