310201h Differential Pressure Flow Measurement

Question 1

What is the term for the device that produces the differential pressure in a head type flow meter?

Answer 1

The primary element

Question 2

What is the equation to calculate the flow rate of a gas process using a differential pressure flow element?

Answer 2

Question 4

What is the equation to calculate the flow rate of a liquid process using a differential pressure flow element?

Answer 4

Question 5

Define the term Beta ratio

Answer 5

Beta ratio is the ratio between the diameter of the restriction and the inside diameter of the pipe

Question 6

Define the term pressure head

Answer 6

Pressure head is the vertical distance that a column of the flowing liquid rises in an open-ended tube because of the static pressure.

Question 7

According to the continuity equation, what must happen to the flow velocity as a fluid passes through a restriction?

Answer 7

Flow velocity must increase

Question 8

When using a five-valve manifold to calibrate the differential pen on a chart recorder (using the manifold), what are the required valve positions?
Block valves =
Equalizer valve low side =
Low side vent plug =
Equalizer valve high side =
Bleed valve =

Answer 8

Block valves = closed
Equalizer valve low side = closed
Low side vent plug = removed
Equalizer valve high side = open
Bleed valve = open

Question 9

When using a five-valve manifold to calibrate the static pen on a chart recorder (using the manifold), what are the required valve positions?
Block valves =
Equalizer valve low side =
Equalizer valve high side =
Bleed valve =

Answer 9

Block valves = closed
Equalizer valve low side = open
Equalizer valve high side = open
Bleed valve = open

Question 10

True or false
The flow coefficient (C) is a constant, and is unaffected by changes in the flow conditions that the flow run was designed for

Answer 10

False
Changes in flow conditions require that the flow coefficient be changed

Question 11

What 3 things determine the thickness of an orfice plate?

Answer 11

1. Process pipe size
2. Differential pressure across the plate
3. Flow temperature

Question 12

What type of orfice plate is this?

Answer 12

Concentric orfice plate

Question 13

What type of orfice plate is this?

Answer 13

Eccentric orfice plate

Question 14

What type of orfice plate is this?

Answer 14

Concentric orfice plate

Question 15

What is the purpose of a drain hole on a concentric orifice plate used for gas flow?

Answer 15

To allow entrained liquids to pass through the plate

Question 17

What is the purpose of a drain hole on a concentric orifice plate used for liquid flow?

Answer 17

To allow entrained gas to pass through the orfice plate

Question 18

What are the 2 preferred orfice plates for flows that exhibit a low Reynolds number

Answer 18

Quadrant edge and conical entrance orfice plates are the preferred choices for flows that exhibit low Reynolds numbers

Question 20

Flow conditioning orifice plates can be installed within ____ pipe diameters upstream and downstream of a flow disturbance

Answer 20

Flow conditioning orifice plates can be installed within 2 pipe diameters, upstream and downstream of a flow disturbance.

Question 21

What is one of the major advantages of using an integral orifice plate over a conventional orfice plate?

Answer 21

The major advantage of using an integral orifice plate flowmeter is the elimination of impulse lines because the upstream and downstream pressures are routed through machined passages

Question 22

What is the minimum pipe size recommended when using flange taps?

Answer 22

2 inch / 50mm pipe

Question 23

True or false
When considering Vena Contracta pipe taps, the tap application moves away from the orifice plate as the beto ratio decreases.

Answer 23

True

Question 24

When using a 3 valve manifold to zero adifferential pressure flow instrument, what are the required valve positions?
Block valves =
Equalizer valve =

Answer 24

Block valves = closed
Eqaulizer valve = open

Question 25

What is the major advantage of using a senior orifice changer compared to a junior orifice changer?

Answer 25

The senior orifice changer allows the flow to continue, while the plate is being checked or replaced

A junior orifice changer does not allow you to do this while the process is still flowing

Question 26

What is the preferred slope when installing impulse lines from a primary element to a recorder or transmitter on a liquid service?

Answer 26

1 inch per horizontal foot
Or
8.3cm per horizontal meter

Question 27

When measuring a dirty liquid service, ________ can prevent the process fluid from entering the impulse lines and causing a blockage.

Answer 27

When measuring a dirty liquid service, purging can prevent the processed fluid from entering the impulse lines and causing a blockage

Question 28

When using an orifice plate to measure gas low, what is the preferred location of the pressure taps on the process pipe?
And where should the instrument be located in relation to the process pipe

Answer 28

When using an orifice plate to measure gas flow, the preferred location of the pressure taps is on the top of the process pipe and the instrument should be located above the process pipe

Question 29

When using an orifice plate to measure steam flow in low ambient conditions, what is the preferred location of the pressure tap on the process pipe?
And where should the instrument be located in relation to the process pipe?

Answer 29

When using an orifice plate to measure steam flow in low ambient conditions, the preferred location of the pressure taps is on the top of the process pipe and the instrument should be located above the process pipe.

Question 30

True or false
When using a square root chart in flow measurement, the chart reading indicates the percentage of differential pressure

Answer 30

False, a square root chart indicates percent of flow.

Question 31

The instrument mounted in the picture indicates the measurement of what kind of process?

Answer 31

Liquid or Steam flow

Question 32

What is the major advantage of a digitized flowchart?

Answer 32

The charge information can easily be imported into spreadsheets and reporting software to maximize the information available

Question 33

The instrument mounted in the picture indicates the measurement of what kind of process?

Answer 33

Direct mount for gas flow

Question 35

If the Reynolds number is less than 2000 the pipe flow is _______

Answer 35

If the Reynolds number is less than 2000 the pipe flows laminar

Question 36

If the Reynolds number ranges from 2000 to 4000 the pipe flow is called ______________

Answer 36

If the Reynolds number ranges from 2000 to 4000 the pipe flow is called transitional flow

Question 37

If the Reynolds number exceeds 4000 the flow is called ________

Answer 37

If the Reynolds number exceeds 4000 the flow is called turbulent.

Question 39

What is the formula for finding the volume of a sphere?

Answer 39

Question 41

What is the formula for finding the volume of a displacer?

Answer 41