Difference Between Venturi Meter and Orifice Meter ( Venturi Meter Vs Orifice Meter)
1. Simple in construction.
1. Relatively complex in construction.
2. Low space requirement.
2. Occupies considerable space.
3. Relatively cheap.
3. Expensive.
4. Ratio of orifice diameter to pipe diameter can be changed simply by installing a new orifice plate.
4. Ratio of throat diameter to pipe diameter cannot be changed in Venturi Meter.
5. Pressure recovery is very poor.
5. Pressure recovery is very high.
6. Coefficient of discharge is about 0.61.
6. Coefficient of discharge is about 0.98.
7. Larger power loss.
7. Smaller power loss.
8. Fluid is retarded at once.
8. Fluid is retarded gradually.
9. Flow separates from the wall, i.e., flow separation is there.
9. No flow separation (possibility very less).
10. Area is minimum at the vena contracta.
10. Area is minimum at the throat and there is no vena contracta in Venturi Meter.
11. Coefficient of contraction is not unity.
11. Coefficient of contraction is unity.
12. Cannot be used where only small pressure head is available.
12. Can be used where only a small pressure head is available.
Difference Between Variable Head Meter and Variable Area Meter:
1. In variable head meters, the area of
constriction/area of flow is constant and
the pressure drop varies with the flow
rate.
1. In variable area meters, the pressure drop is constant and the area of flow/area of constriction varies with the flowrate.
2. Variables head meters include orifice meter and venturi meter.
2. Variable area meters include rotameters of various designs.
3. Simple in construction.
3. Complex in construction.
4. Relatively cheaper.
4. Relatively costly.
5. Needs straight runs of pipe before and after the meter (i.e., without fittings, valve).
5. Does not need straight runs of pipe before and after the meter.
6. It cannot give direct visual reading of the flow rate.
6. It can give direct visual reading of the flow rate.