Flow

Question 1

What is the principle of operation for Transit Time Ultrasonic Meter?

Answer 1

Measures time difference between sound traveling up and downstream.

Question 2

What is the principle of operation of a Doppler shift Ultrasonic meter?

Answer 2

Shifting of frequency that results from the waves emitted by or reflected by a moving object.

Question 3

What is the main differences between the Doppler and transit time meters?

Answer 3

Doppler: needs solid particles or gas bubbles to measure. Liquids only

Transit Time: can’t have solid particles or gas bubbles. Can be a liquid or gas.

Question 4

Considerations to be taken with installation of clamp-on ultrasonic meters

Answer 4

Thermal expansion/contraction and pipe material. (Must be solid material, no air gaps like concrete)

Question 5

Which medium does sound travel faster in, water or air?

Answer 5

Water

Question 6

What kind of ultrasonic meter is needed for small pipe installs?

Answer 6

Axial.
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Question 7

What kind of transit time meter uses multiple probes paths?

Answer 7

Multi-tap

Question 8

Most typical meter construction

Answer 8

Spool piece.

Question 9

What kind of transducer has most accuracy?

Answer 9

Wetted.

Ex right in process.

Question 10

How should an ultrasonic meter be cal’d?

Answer 10

In-line with a prover

Question 11

What is the phase restriction on a transit time ultrasonic meter?

Answer 11

Single phase (either gas only or liquid only)

Question 12

Which law governs a mag flow meter?

Answer 12

Faraday

Question 13

What is the physical arrangement between the flow, magnetic field, and the electric probes?

Answer 13

Flow perpendicular to magnetic field.

Electrodes right angles to magnetic field

Question 14

What must be the characteristics of the flow tube in a mag flow meter?

What must be the characteristics of the process fluid for a mag meter?

Answer 14

Non-conductive

Conductive

Question 15

What is proportional to flow if the magnetic field is excited by an AC signal?

Answer 15

Flow Velocity

Question 16

Main problem with AC excitation?

Answer 16

Noise makes a need for re-zeroing often

Question 17

Problem with the pulsed DC excitation?

Answer 17

Electrochemical polarization

Question 18

Which excitation method uses positive, off, and negative states to help with electrochemical polarization and noise cancelling?

Answer 18

Pulse DC Tri-State.

Question 19

Pros and cons of a vortex shedding meter.

Answer 19

Pros: measures liquids, gases, and steam
Output Hz is linear to flow rate

Cons: can’t be made smaller then 15mm or larger then 16”
Not Bi-directional

Question 20

Vortex flow meter limitations for min and max flow rate?

Answer 20

Min: lowest Reynolds #

Max: where cavitation occurs.

Question 21

For following substances what changes density?
Solid
Liquid
Gas

Answer 21

Solid: temp.
Liquid: temp, pressure.
Gas: temp, pressure, and compressibility.

Question 22

How many pulses do you need if collect to limit the round off to .001%?

Answer 22

10 000 pulses.

Question 23

Formula for basic meter factor?

Answer 23

MF= (proved value/meter under test)(meter)

Question 24

5 common primary differential flow elements?

Answer 24

Venturi tube
Flow nozzle
V-cone
Pitot tube
Orifice plate

Question 25

``` What are the following AGA factors are for what? -AGA 3 -AGA 3 2000 -AGA 7 -AGA 8 AGA 9 -AGA 11 ```

Answer 25

- AGA 3: volumetric orifice plate - AGA 3 2000: mass orifice plate - AGA 7: turbine - AGA 8: compressibility - AGA 9: ultrasonic - AGA 11: mass flow

Question 26

When pipe diameter changes what happens to flow rate and velocity?

Answer 26

Flow rate stays the same. | Velocity changes.

Question 27

What changes density in Solids Liquids Gases

Answer 27

Solids: Temp Liquids: Temp and Pressure Gases: Temp, Pressure, and Compressibility

Question 28

Basic meter factor equation?

Answer 28

Prover value/meter under test X meter

Question 29

Difference between liquid and gas turbines.

Answer 29

Gas turbines have a large diameter diffuser to direct the gas. Liquids use straightening vanes.

Question 30

Ultrasonic: principle of operations of a transit time flow meter

Answer 30

Measures time difference between sound traveling up and downstream

Question 31

What type type of ultrasonic flow meter calculates flow from the difference between Fab and Fba What type type of ultrasonic flow meter calculates flow from the difference between Tab and Tba

Answer 31

- Transit Frequency | - Transit Time.

Question 32

Can a Doppler ultrasonic meter be used on gas?

Answer 32

No

Question 33

What are the limitations for max and min flow rate of vortex meters

Answer 33

Min: lowers Reynolds Max: where cavitation occurs for max

Question 34

List pros and cons of vortex shedding meter

Answer 34

Pros: measures gas and liquid streams. Out Hz is linear to flow. Cons: can't be smaller then 15mm and no larger than 16" Not bi-directional

Question 35

What's the pattern called for moving vortices carried downstream of a stationary object called?

Answer 35

Vortex street

Question 36

Under what Reynolds # does vortex meters need K-Factor characterization?

Answer 36

8000/10 000