Test 2

Question 1

T/F Coriolis flowmeters can only measure liquids.

Answer 1

False

Question 2

T/F The density of a liquid is almost independent of the liquid conditions.

Answer 2

True

Question 3

The density of a gas is dependent on what 3 things?

Answer 3

Pressure, temperature and, to a lesser extent, gas composition

Question 4

Define the energy flow rate for volume and mass.

Answer 4

The volume flow rate multiplied by the energy content per unit of volume or mass flow rate multiplied by the energy content per unit mass.

Question 5

T/F Coriolis flowmeters offer direct mass measurement.

Answer 5

True

Question 6

T/F Due to how a Coriolis flowmeter operates (Coriolis force) changes in temperature, pressure, density, viscosity and flow profile have a large role when measuring flow.

Answer 6

False

Question 7

A Coriolis flowmeter consists of a sensor, a transmitter and in many cases, peripheral devices. At a high level, the sensor in a Coriolis flow meter performs what function?

Answer 7

Flow rate, density and temperature

Question 8

At a high level, the transmitter performs what function?

Answer 8

Provide sensor information as outputs, acting like the brain of the system to provide a display, basic menu access, and outputs to interface with other systems.

Question 9

At a high level, peripheral devices perform what functions?

Answer 9

Provide monitoring and alarm or additional functionalities, such as batch control and enhanced density functions

Question 10

List the key design aspects of the Coriolis flow tube.

Answer 10

The diameter, the tube wall thickness, the material of construction, the overall length, and the shape.

Question 11

The different designs of the Coriolis flow tube incorporate different geometries. What is the purpose of the flow tube geometry?

Answer 11

The majority of designs try to employ a geometry that will magnify the effect of the Coriolis forces on the flow tubes to generate a larger signal.

Question 12

List the 8 components of a Coriolis flowmeter.

Answer 12

Flow Tubes, casing, drive coil, flow detectors, temperature detector, flow splitter, processor/transmitter, flowmeter peripherals

Question 13

The flow tubes carry the process fluid and are mostly constructed of what two materials?

Answer 13

Stainless steel or nickel alloy steel

Question 14

What is the purpose of the casing on a Coriolis flowmeter?

Answer 14

Protects the electronics and wiring from external corrosion while providing a redundant(or secondary) containment of the process fluid.

Question 15

T/F The drive coil is energized to keep the flow tubes vibrating at their natural frequency.

Answer 15

True

Question 16

Flow detectors and their magnets are electromagnetic detectors located on each side of the flow tube. What role do the flow detectors play in determining the mass flow through the meter?

Answer 16

Produce a signal that represents the velocity and position at that point on the vibrating tube and measuring the phase difference between these signals, mass flow is determined.

Question 17

The temperature detector is an RTD. What does RTD stand for?

Answer 17

Resistance Thermal Device

Question 18

What is the purpose of the flow splitter?

Answer 18

It’s a component that is located in the inlet process connection and connected to the flow tubes. The flow splitter divides the process flow evenly between the two flow tubes.

Question 19

The Coriolis drive coil, flow detector coils and RTD element is routed to the transmitter. What is another name for the transmitter?

Answer 19

Processor

Question 20

Name seven things that flowmeter peripherals can provide from a Coriolis flowmeter.

Answer 20

Mass flow, temperature, density, volumetric flow data, mass or volume totals, alarm outputs and controls valves or other control components

Question 21

T/F Coriolis flowmeters are not used to control valves or other control components in a system.

Answer 21

False

Question 22

1. A Coriolis meter is comprised of two main components, a _________________ and a _________________________.

Answer 22

sensor (primary element), transmitter (secondary element)

Question 23

T/F Coriolis meters directly infer the gas mass flow rate by sensing the Coriolis effect on a vibrating tube(s).

Answer 23

True

Question 24

T/F The direct relationship between the pressure drop and flow range with the actual flow area through a Coriolis meter means a Coriolis meter will typically be larger than a turbine or orifice meter having similar pressure drops at flowing pressures in the 300 ANSI class and above.

Answer 24

False

Question 25

1-7 Left to Right

Answer 25

1.Process Connection Flange 2. Flow Tubes 3. Left Pickoff Coil and Magnet 4. Drive Coil and Magnet 5. Right Pickoff Coil and Magnet 6. RTD 7. Process Connection Flange

Question 26

The twisting of the flow tubes created by the Coriolis force creates a ___________________ between the signals generated by the two pick-off coils.

Answer 26

phase shift

Question 27

The vibration frequency of the flow tubes is proportional to the flowing _______________ of the fluid being measured.

Answer 27

density

Question 28

The phase shift between the signals generated by the pick-off coils is directly proportional to ______________________________.

Answer 28

mass flow rate

Question 29

T/F The “flowing” density measured by the Coriolis meter is used for gas flow measurement purposes.

Answer 29

False

Question 30

Equations and methods for the conversion of mass to volume are documented in what two standard documents?

Answer 30

AGA Report Number 11, Measurement of Natural Gas by Coriolis Meter and AGA Report Number 8, Compressibility Factors for natural Gas and Other Hydrocarbon Gases

Question 31

The typical operating temperature range of a Coriolis meter is ___________ to ___________________.

Answer 31

-400 F (-240 C), +400 F (+200 C)

Question 32

T/F Flowing gas temperature is not required for the measurement of mass with a Coriolis meter.

Answer 32

True

Question 33

The ______________________ of a Coriolis meter is caused by the stiffening of the Coriolis flow tubes as the fluid pressure in them increases.

Answer 33

flow pressure effect

Question 34

T/F Due to the flow splitter and newer designs any rate of change concern is removed for Coriolis meters.

Answer 34

True

Question 35

Erosion due to high velocity gas flow normally is not a concern for Coriolis meters, but can be an issue if__________________________ are present in the gas flow stream.

Answer 35

abrasive contaminants

Question 36

Coriolis meters are sensitive to pulsations at the _____________________ of the meter’s flow tubes.

Answer 36

resonant frequency

Question 37

Coriolis meters typically operate at resonant frequencies above ______ Hz.

Answer 37

100

Question 38

T/F An out of specification zero shift caused by the build-up of debris in the meter flow tubes impacts the entire flow range of a Coriolis meter.

Answer 38

False

Question 39

T/F Coriolis meters are bi-directional meters.

Answer 39

True

Question 40

T/F Based on independent testing, flow conditioning or minimum lengths of upstream/downstream straight pipe is not required for Coriolis meters.

Answer 40

True

Question 41

As a common practice most Coriolis manufacturers capitalize on the economics and high stability of a _____________ calibration.

Answer 41

water

Question 42

To inspect or re-zero a Coriolis meter, ______________________________ of the meter should be established.

Answer 42

thermal equilibrium

Question 43

Describe the Coriolis Effect as it applies to a Coriolis flowmeter and the flow of fluid through the flow tubes.

Answer 43

The substance to be measured runs through a tube that is caused to vibrate in a perpendicular direction to the flow. Fluid forces running through the tube interact with the vibration, causing it to twist (I.e. deflect): the greater the angle of the twist, the greater the flow.

Question 44

What relationship is used in a Coriolis flowmeter to compute the amount of flow?

Answer 44

The mount of twist in the tube proportional to the flow in the tube.

Question 45

Name the main components of a Coriolis flowmeter.

Answer 45

Flow tubes, a driving mechanism for oscillating the flow tubes, and flow detectors mounted on either side of the driving mechanism for measuring the time or phase difference between the two sides of the flow tubes. Flow Splitter

Question 46

T/F The tube sections between the inlet and the driving mechanism will always resist the driver and the tube sections between the driving mechanism and the outlet will always assist the driver.

Answer 46

True

Question 47

What force is used to cause the flow tubes in a Coriolis flowmeter to vibrate?

Answer 47

Magnetic attraction caused as alternating current energizes the coil which causes a pulsating attraction to the magnet

Question 48

T/F The detector coils and the magnets of the flow detectors are mounted on opposing flow tubes.

Answer 48

true

Question 49

As each coil moves through the uniform magnetic field of the adjacent magnet. The voltage generated creates a ____________________.

Answer 49

Sine Wave

Question 50

The sine waves generated by the flow detectors represent

Answer 50

Represent the motion of one tube relative to the other

Question 51

When there is no flow in the meter, the sine waves are in phase and there is no

Answer 51

Coriolis Effect, or twisting motion, imparted on the flow tubes.

Question 52

Explain how the Coriolis Effect works on the inlet and outlet legs of the meter when fluid is moving though the meter.

Answer 52

The mass flow moving through the inlet legs of the flow tubes generates a Coriolis force that resists the vibration of the flow tubes. As the mass flow moves through the outlet legs, the Coriolis force adds to the vibration of the flow tubes. It is the opposing direction of the Coriolis force between the inlet and outlet legs that results in the twisting motion that is used to measure mass flow rate.

Question 53

The time delay between the two sine waves caused by the twist in the flow tubes is called ___________ and is measured in ______________.

Answer 53

Delta - T, microseconds

Question 54

Fluid flow rate is ___________ proportional to Delta-T.

Answer 54

always directly

Question 55

Delta-T is a function of both ______________ and ___________________.

Answer 55

the phase difference, the frequency of the sine wave signals

Question 56

The flow calibration factor contains two components.

Answer 56

the first component is the proportionality constant between mass flow rate and measured Delta-T. The second component is a constant used to compensate automatically for changes in the temperature of the flow tubes.

Question 57

The flow tube temperature affects the _______________ of the tube material and is compensated for in the __________________ factor.

Answer 57

the stiffness, Flow Calibration

Question 58

T/F Volume flow measurement is accomplished by dividing the instantaneous flow measurement by the simultaneous density measurement.

Answer 58

True

Question 59

Density is defined as

Answer 59

mass per unit volume or mathematically as ρ = m/V ρ (rho) is the density m is the mass V is the volume

Question 60

In a Coriolis flowmeter the volume of fluid in the flow tubes is constant. How is it that the mass of the fluid in the tubes changes?

Answer 60

The only way the mass of the fluid can change is if the density also changes.

Question 61

21. T/F Tube period is the reciprocal of natural frequency.

Answer 61

True

Question 62

Coriolis flowmeters measure density by measuring _______________.

Answer 62

tube period in microseconds per cycle

Question 63

Fluid density is ___________ proportional to tube period.

Answer 63

directly

Question 64

When a Coriolis flowmeter is used to measure gas density it is called a ______________.

Answer 64

densitometer

Question 65

Density is often used interchangeably with ______________.

Answer 65

specific gravity

Question 66

Specific Gravity (SG) is defined as:

Answer 66

As the ratio of the molecular weight of a given sample to an equivalent volume of standard air. SG=D1/D2

Question 67

Measurements of density and specific gravity must be corrected for variations in _________________.

Answer 67

temperature

Question 68

As the mass of the process fluid increases, the natural frequency of the flow tubes _________________.

Answer 68

decreases

Question 69

As the mass of the process fluid decreases, the natural frequency of the flow tubes _________________.

Answer 69

increases

Question 70

Most Coriolis flow tube designs aim to magnify the Coriolis force by the design of ________________________________.

Answer 70

The geometrical form of the flow tubes.

Question 71

The larger the Coriolis Effect becomes the larger the __________________ making it easier to determine mass flow.

Answer 71

the time or phase difference (Delta-T)

Question 72

T/F The need for the magnification of the Coriolis Effect has disappeared due to the efficiency of today’s electronics.

Answer 72

True

Question 73

What impact does the compact tube design on tube oscillation frequencies and why is this an advantage in operating the meter?

Answer 73

Shortens the tube length. Higher oscillation frequencies have the advantage of a better decoupling performance from pipeline vibrations and and external disturbances, which are predominantly in the 50 Hz to 180 Hz range.

Question 74

The main reason for using bent tubes in a Coriolis flowmeter is for _______________________.

Answer 74

thermal expansion of the measuring tube

Question 75

Why do commercially available Coriolis flowmeters with straight tubes use materials other than stainless steel?

Answer 75

Titanium or zirconium materials offer a small temperature expansion coefficient. With these materials, even great temperature differences between the measuring tube and the casing results only small additional axial stress as well as higher stress limits vs stainless steel.

Question 76

T/F A well-designed flow profile is a requirement for the design/use of a Coriolis flowmeter.

Answer 76

False

Question 77

Why is it not a good idea to use the dual flow tube design?

Answer 77

They require flow splitters and are not recommended for applications with fluids that are prone to plugging

Question 78

The single-tube double loop design flowmeter provides the same advantages as the dual-tube design without employing flow splitters. List the disadvantages of this design.

Answer 78

Increased pressure loss and easy drainage of the instrument is impossible

Question 79

How many flow detectors does a Coriolis flowmeter require and where are they located on the flow tubes?

Answer 79

Two flow detectors located at the inlet and outlet sections.

Question 80

What are the advantages of the electrodynamic sensors used in todays flowmeters?

Answer 80

Very good phase accuracy and high reliability

Question 81

In a Coriolis flowmeter, one temperature sensor is used to measure the temperature of the process fluid. Why is a second temperature sensor needed?

Answer 81

Temperature difference between the flow tube and the casing results in an axial force so it is needed to adjust the flow meter reading for this effect.

Question 82

On a gas installation, why is the sensor mounted at a high point in the piping in a vertical (tube/flag up) configuration?

Answer 82

Allows any liquid in the flow stream to drain from the meter, ensuring proper operation.

Question 83

T/F Concentric alignment of companion pipe flanges with the sensor inlet/outlet process connections is important when installing a Coriolis flowmeter.

Answer 83

True

Question 84

T/F A gasket protrusion has no impact on a Coriolis flowmeter installation.

Answer 84

False

Question 85

Why should welding not be done in the immediate area of the sensor?

Answer 85

Prevents possible internal weld scale from entering the sensor which could cause plugging.

Question 86

T/F Coriolis flowmeters should be installed at least 3-4 feet from transformers, motors or other sources of electromagnetic induction.

Answer 86

True

Question 87

Why is it important to make sure the hazardous area specified on the sensor approval tag is suitable for the environment in which the sensor will be installed?

Answer 87

Failure to comply with the requirements for intrinsic safety in a hazardous area could result in an explosion.

Question 88

When are strainers or separator type filters needed when installing a Coriolis flowmeter?

Answer 88

Recommended when the presence of damaging foreign material in the gas stream can be anticipated.

Question 89

Name four things that can affect the accuracy of a Coriolis flowmeter.

Answer 89

Dirt and trash can accumulate in the piping, affecting flow conditions. The inputs into flow computers and other electronic devices can be changed by mistake, causing errors in measurement. Any change in density, viscosity, pressure or temperature can influence a shift in the number of pulses produced per unit volume. Field installation effects can affect the operation of the meter.

Question 90

What is the difference between a “primary” and “secondary” proving device.

Answer 90

A primary device is a volume device such as the bell or volume prover that has had its volume checked and verified against a standard such as NIST in the United States. A secondary device is a device that has been checked against a primary device and is often used to prove another meter.

Question 91

A transfer prover system consists of a _____________ with the field ____________ placed in _____________.

Answer 91

master meter, Coriolis meter, series

Question 92

T/F A transfer prover system can be used to calibrate field meters brought into a shop or the master meter prover can be taken to the field.

Answer 92

True