Experiment No: 01 Test on Gear/Vane/Piston pump and plotting performance characteristics

Experiment No :01 Test on Gear/Vane/Piston pump and plotting of performance characteristics

Aim: To study performance characteristics of positive displacement pump (Vane pump).

Apparatus:   Vane Pump Test Rig, Tachometer
Precautions:    
Ensure all the instruments/ equipment are proper and calibrated.
Theory:
            The function of a pump is to convert mechanical energy into hydraulic energy. It is the heart of any hydraulic system because it generates the force necessary to move the load. It is important to note that pumps create flow not pressure. Pressure is created by the resistance to flow
Classification of Pump:

Vane Pump: The vane pump is a device that works on the principle of positive displacement. Consisting of a series of vanes that are mounted to a rotor that provides circulation with the main cavity, the vane pump makes it possible to force liquid through a pipe or duct system at the rate desired by the operator.

Fig: working of vane pump

Diagram:       

Fig : Vane Pump Test Rig

Procedure: 
1.      Firstly the pressure of the system is adjusted to a suitable value with the help of the Pressure relief valve.
2.      After this the flow in the system is adjusted with the help of Flow control valve.
3.      Observe the readings of the vacuum gauge and the watt hour (Watt-hr) reading on the energy meter.
4.      Also note down the Speed of motor Shaft by Using Tachometer
5.      The system pressure is now adjusted to a new value and the procedure is repeated for at least three to Four  readings.
6.      Now efficiency is calculated for each reading by calculating power input and output power
7.      After Performing all experiment, Set Pressure Relief Valve to 0 kg/cm².
8.      Unplug Power Cord of the trainer  from Power Socket ..
 
Experimental Procedure:
1)      Ensure again that connections are proper and electronic display respond gentle pressure at cantilever.
2)      Adjust ‘0.0’ reading on display with empty pan hooked.
3)  Place calibration weight in pan and observe the display reading.
4)  Keep on adding the weight and record the reading.
5)  Reverse the procedure by removing the weight one by one.

          Observation Table:

Sr. No.	Vacuum Gauge (mm of Hg) P1	Delivery Pressure Gauge (Kg /cm2) P2	Actual Flow (LPM) QA	Difference Energy Meter (watt-hour)	Pump Shaft Speed (RPM) N
1.
2.
3.
4.

Calculation :

1.      Out put power  P_o

P1 = mm of Hg = ___ mm of Hg x 13.56 x 10^-4  kg/cm² 

P2 =  kg/cm² 

P =P1 + P2  kg/cm²   =  ____ * 9.8* 10⁴ N/m²

Flow  = LPM = ____*  10^-3 / 60  m³/sec

P_O = Pressure  * Flow

P_O = P  * Q  watt

2.      Input Power   Pin  = Power consumption in 1 min * 60

            Pin = _* 60 =    Watt

3.      Efficiency η  = Out Put  /In Put

η % = P_o/P_in  *100

4.      Theoretical Discharge Q_T

Swept Volume  from manufacture catalog V_D  =3.5 cm³/rev.

Q_T = V_D * Speed (RPM)  cm³ /min 

Q_T  =  ---  *  10^-3  LPM

5.      Volumetric Efficiency 

η _V %   = Q_A /Q_T

 

Sr. No.	Total Pressure P kg/cm2	Shaft Speed (RPM)	Actual Flow (LPM) QA	Theoretical Flow (LPM) QT	Volumetric Efficiency  %	I/P	O/P	Overall Efficiency  %
1.
2.
3.
4.

INSTRUCTIONS

Change the observation table readings 5 times and Plot the graphs

· η Vs Pressure

· Input Power Vs Pressure

· Flow Vs Pressure

Graph: Plot the graph

·         η V_s Pressure

·         Input Power Vs Pressure

·         Flow Vs Pressure

 

Conclusion:  

1.As vane pump is a positive displacement pump, though the pressure increases the flow  remains almost constant.

2. Efficiency of pump goes on increasing with increase in pressure to certain point then it will decrease. 

3. Power required to drive the pump is linearly proportional to the pressure.