1. Gas and Liquid Metering

2. Why Metering? Measuring flow rate and cumulative volume Selling System Control Losses detection Reservoir outlets Pumping stations

3. Accuracy Accuracy of meters depends on:  Linearity: percentage of true reading over a stated flow  Repeatability: ability to indicate the same reading each time the same flow condition  Pressure loss  Resolution  Rangeability

4. Mechanism of Meters All meters are consisted of two parts:  The primary element, which is in contact with the fluid, resulting in some form of interaction.  The second or secondary element translates the interaction between fluid and primary element into a signal.

5. Different Types of Meters Positive displacement meter Turbine meter Orifice meter Magnetic meter Coriolis meter

6. Affecting Factors Fluid properties  Viscosity  Specific gravity Conditions  Temperature  Pressure Flow pattern

7. Positive Displacement Positive displacement meters measure the volume flow rate directly by repeatedly trapping a sample of the fluid. Positive displacement meters can be less accurate than other meters because of leakage past the internal sealing surfaces.

8. (1) (2)(3) (4) (5)(6)

9. Turbine Meter A turbine meter uses a multi-bladed rotor. The turbine rotation is proportional to the fluid velocity A magnetic coil outside the meter produces an alternating voltage. The voltage is then related to the flow rate. They have fast response.

11. Orifice Meter A concentric orifice plate The pressure between both sides of plate is related to the flow rate using Bernoulli's equation.

12. Orifice Meter(cont.) The simplest and least expensive Produces a relatively high pressure drop.

14. Magnetic Meter Insensitivity to  specific gravity  Viscosity  Pressure  Temperature Sensitive to magnetic properties of the liquid.

16. Coriolis Meter The Coriolis meter uses a U- tube sensor Applies Newton’s Second Law Fluid momentum changes natural vibration of the U-tube and twists it. Two sensors detect vibrating velocity of the U-tube at each side and relate it to mass flow.