Level 2 Block 1 - Gas Meters, Orifice Flow, Clocking Summary Flashcards
Which type of meter uses piezoelectric sensors to detect pressure oscillations caused by flow disturbances?
Vortex Flow Meter
What is the significance of the pressure drop in a vortex flow meter?
The pressure drop is more pronounced at higher flows
Using the appropriate parameters from the following information, what is the calculated appliance input? test dial = 1ft3, time measured for 6 revolutions = 84 seconds, propane gas, meter pressure 5 psig, ambient air temperature 61⁰F, single boiler operating at 68% efficiency.
859,839.75 btu
In the clocking formula, when is temperature correction most significant?
When temperature difference (∆T) is 80℉
What type of meter physically measures the quantity of gas by dividing it into fixed volumes?
Positive Displacement Meter
How is the area of an orifice typically related to its geometry?
It is calculated from the diameter of the orifice
What standard pressure is used for gas measurement calculations, according to B149.1?
14.7 psia
Where are the upstream and downstream taps typically located for larger pipe with flange taps?
2.5 pipe diameters upstream and 8 pipe diameters downstream
What is the purpose of an Instrument Drive (ID) meter in gas flow measurement?
To allow the connection of external instrumentation for pressure and temperature corrections
What constant is used in the orifice flow formula to align units, viscosity, and time?
1658.5
Using the appropriate parameters from the following information, what is the calculated appliance input? test dial = 1ft3, time measured for 3 revolutions = 78 seconds, Gas calorific value = 2,275, Manifold Pressure = 10”w.c., meter pressure = 40 psig, local pressure = 12, gas temperature inside the building = 114⁰F, gas temperature at the meter = 61⁰F.
1,112,147 btu
What type of meter uses Bernoulli’s principle to calculate flow based on pressure differences?
Orifice or Venturi Meter
Which of the following meters uses sound waves to measure gas flow?
Ultrasonic Flow Meter
What is the disadvantage of using vena contracta taps in large pipe installations?
The need to drill through the pipe wall
What happens to the pressure when a flow condition is established in a system with an orifice plate installed?
A pressure drop occurs across the orifice
What is the importance of converting gas flow rate to standard conditions (SCFM)?
To account for variations in temperature and pressure
Using the appropriate parameters from the following information, what is the calculated appliance input? test dial = 2ft3, time measured for 5 revolutions = 75 seconds, Methane gas, Manifold Pressure 3.5”w.c., meter pressure 10 psig, local pressure 14.2, ambient air temperature 75⁰F.
768,049 btu
What is the range of the K factor (coefficient of discharge) for most orifices?
0.6 to 0.9
What does the term “K Factor” in an orifice flow calculation represent?
The coefficient of discharge
What is a key characteristic of a rotary gas meter?
It is ideal for high-pressure, high-volume applications
Which of the following is an example of a positive displacement meter?
Diaphragm (Bellows) Meter
According to Boyle’s law, what happens to the energy in a gas if the gas is compressed?
The energy in a smaller volume is more than 1000 btu
Pressure compensation in the clocking formula is applied when meter pressure exceeds which value?
½ psig
What type of meter measures gas flow by using the velocity of the fluid?
Turbine Flow Meter
