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A fitting Paige lvl 2 > Orifice flow, Clocking, Gas meters > Flashcards

Orifice flow, Clocking, Gas meters Flashcards

(69 cards)

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1
Q

Clocking formula

A

3600/time per revolution X dial size X (press at meter + atmopheric press / 14.7 (101.324) )X ( (60)gas temp at meter + 460 / gas temp In meter + 460)

X CV

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2
Q

What are the standard Pressure and Temperature conditions

A

14.7 PSI (101.325)
60’F

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3
Q

Absolute temp

A

460 ‘F

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4
Q

What is a gas meter

A

Specialized flow meter used to measure the volume of fuel such as natural gas and liquefied petroleum gas that passes through it

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5
Q

Why do most gas flow meters require pressure and temperature correction

A

To convert the flow rate from operating conditions (ACFM) to standard conditions (SCFM)

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6
Q

What two categories can gas meters be put in?

A

Positive displacement meters
Inferential meters

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7
Q

How do Positive displacement meters measure flow

A

Physically measure quantity by repeatedly entrapping the flow and measuring the number of rotations (more widely accepted for customer billing)

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8
Q

How do Inferential meters measure flow

A

Measure flow by inferring its value from other parameters (Infer – to deduce or arrive at a conclusion)

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9
Q

Name examples of Positive displacement flow meters

A

-Diaphragm/bellows meters

-Rotary meters
Rotary lobed (impeller)
Rotary vane

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10
Q

Name Examples of Inferential meters

A

-Differential pressure flow meters
Orifice meters (or venturi)
Pitot and pitot static tube meters
Vortex shedding meters

-Velocity flow meters
Turbine meters
Ultrasonic flow meters

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11
Q

What meters are used for custody transfer of natural gas and utility billing applications in residential and light commercial

A

Bellows

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12
Q

typical MAOP for a bellows meter

A

10-25 Psi

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13
Q

How is flow rate is limited in a bellows meter

A

Physical size of the meter and its bellows

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14
Q

How does the bellows mater measure gas flow

A

For operation, valves alternate the fill and dump cycle of the two bellows. Attached linkages drive a shaft that is connected to a mechanical counter. The counter records the number of alternating fill/dump cycles.

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15
Q

Bellows turn down ratio

A

100:1

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16
Q

Bellows Class 250 (250 CFH) are typically installed where?

A

Gas utilities on homes

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17
Q

Bellows Class 400 to 1000 (400 CFH to 1000 CFH) are typically used for?

A

Commercial and light industrial sizes are available for higher capacities.

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18
Q

What can rotary lobed gas meters handle for pressure and volume

A

Higher volume and pressure than diaphragm meters,

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19
Q

What is the ideal location for Rotary Lobed gas meters

A

Ideal for use in large scale commercial and industrial medium pressure application

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20
Q

Low pressure rating for rotary meters

A

0-175 psi

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21
Q

High pressure rating for rotary meters

A

0-1,480 psi

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22
Q

Rotary meters turn down ration

A

50:1

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23
Q

What are rotary piston meter (Roots meter), suitable for?

A

They are suitable for Custody Transfer, Fiscal Measurement or Sub-metering.

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24
Q

what is the Most basic form meter called for rotary meters

A

Counter meter

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25
What does one SCF of gas relate to in BTU
1000 BTU NG 2500 BTU propane
26
What is an orifice plate
An orifice plate is a type of differential pressure drop device used for measuring flow rate of a fluid.
27
What is the standard orifice plate for gas pressure measurement
Square-edge, concentric design
28
Where is the identifying mark on an orifice plate
The handle
29
What principle does an orifice plate use
Bernoulli's principle
30
What is the orifice flow formula
1658.5 X orifice eff X Area of orifce (Inches) X square root of (Press drop across orifices / SG )
31
Formula for change in the orifice flow formula
Q2/Q1 = K2/K1 X A2/A1 X square root of P2/P1 X square root of SG1/SG2
32
What changes the discharge coefficient significantly.
The angle of approach to and discharge from an orifice, and the shape of the orifice, changes the discharge coefficient significantly. Thickness can as well
33
What is the value range for most orifices
0.6 - 0.9
34
Where are flange taps most commonly used
2" and bigger pipe
35
Where are corner taps most commonly used
Smaller than 2" pipe
36
Which taps offer the greatest differential pressure for any given flow rate but require precise calculations to properly locate the downstream tap position.
Vena contracta taps
37
Which taps are an approximation of vena contracta taps for large pipe sizes (one-half pipe diameter downstream for the low-pressure tap location).
Radius taps
38
Downsides of tapping a pipe
Weakens the structure and making sure its in the right location
39
Where are tapes located for large pipe
2.5 pipe diameters upsteam and 8 pipe diameters down stream from the orifice plate
40
Where are tapes located for smaller pipes
For smaller pipe the taps used are vena contracta type and are located one pipe diameter upstream (D) and half pipe diameter downstream from the orifice plate.
41
If carefully measured tapes are made in orifice placement it can yield results within
+/-3%
42
SG and CV of NG
.6 1000
43
How do Temp compensated rotary meter work
Temperature Compensated (TC) versions, use an internal mechanical bimetal element inside the index and meter body to correct for temperature fluctuations in the gas.They have 2 totalizers: one Uncorrected and one Temperature Corrected.
44
Where are temp corrected rotary meters commonly used
They are often used on low fixed pressure applications where temperatures fluctuate regularly such as outside in cold climates or if installed inside at ceiling level in a boiler room.
45
How does a Rotary Instrument drive meter work
Instrument Drive (ID) versions permit a pulse transmitter (aka pulser) or Pressure/Temperature (PT) correcting instrument to send uncorrected volume outputs from the gas meter to remote totalizing and recording equipment.
46
What does a Rotary instrument drive meter use
Valving kit to a pressure tap on the outside of the meter Conjunction with a corrector on lines where both pressure & temperature fluctuate substantially.
47
How does a rotating vane flow meter work
A rotating vane flow meter is a type of positive displacement meter feature spring-loaded vanes that divide the spaces between the vanes into discrete volumes and move the gas from inlet to outlet and discharge.
48
How does a piston meter work
A piston meter has a unique inline design consisting of three reciprocating pistons operating within their respective measuring chambers.
49
How does an inferential meter work
Inferential meters measure neither mass nor volume but use a property of the flow stream, such as pressure drop or the displacement of a float, to infer volumetric flow rate.
50
How do differential press flow meters work
Differential pressure flow meters calculate flow by measuring pressure drop over an obstruction inserted in the flow path.
51
Common types of flow elements in differential press flow meters
Common types of flow elements are orifice plates, flow nozzles, venturi tubes, and averaging pitot tubes.
52
How does a venturi(Or orifice) meter work
The venturi (or orifice) meter is a differential pressure flow meter. A constriction in the flow path causes a pressure drop across the meter.
53
What else can a venturi(Or orifice) meter measure
Flue gas
54
What are one the most used (and cheapest) ways to measure fluid flow, especially in air applications like ventilation and HVAC systems.
The pitot tube meter
55
How does the pitot tube meter work
The pitot tube measures the fluid flow velocity by converting the kinetic energy of the flow into potential energy. A Pitot tube measures the difference between the static pressure and the flowing pressure of the fluid in the pipe. The volumetric flow is calculated from that difference using Bernoulli’s principle, taking into account the pipes inside diameter.
56
Why is an averaging pitot tube better
Has multiple holes to get an average reading
57
What is an Annubar
An Annubar is a T-shaped averaging Pitot tube
58
How does a velocity flow meter work
In a velocity flowmeter the flow is calculated by measuring the speed in one or more points in the flow, and integrating the flow speed over the flow area.
59
How does a turbine flow meter work
A turbine wheel rotates a magnet which induces current flow in a coil. The data logger counts the pulses/rotation. The logger calculates flow using the RPM of the turbine wheel and diameter of the pipe.
60
Which meter is better suited to measuring the highest-pressure gas at the highest flow rate
Turbine flow meter
61
Turn down ratio for Turbine flow meter
20:1
62
How does a vortex flow meter work
The majority of vortex meters uses piezoelectric or capacitance-type sensors to detect the pressure oscillation around the bluff body. These detectors respond to the pressure oscillation with a low voltage output signal which has the same frequency as the oscillation.
63
Where are vortex meters used
Vortex meters are used in industrial applications that require little custody transfer of gases.
64
How do ultrasonic meters work
Ultrasonic meters use sensors that transmit and receive a soundwave.
65
Which meter can be used for customer billing (New one)
Ultrasonic meters are so accurate that Measurement Canada has approved their use for customer billing.
66
What is customer transfer
Custody Transfer - transporting the gas from one operator to another. Pipeline to rail to ship etc.
67
What is fiscal measurement
Fiscal Measurement – Measurement of the flow of gas at custody transfer points from the seller to the new owner of the gas. Usually, the point where the financial transaction takes place and the Gov’t gets their cut.
68
What is sub metering
Sub-metering - monitoring and managing energy usage downstream of the point of transfer of ownership. Examples monitor use of energy on a large site, boiler consumption vs process consumption or landlord to tenant.
69
What does one bar equal
1 bar = 100 kPa 1 bar = 14.7 psi (1 atmosphere)

A fitting Paige lvl 2 (25 decks)

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