Pressure Regulators And Orifices Flashcards
The regulator use a fixed orifice opening for what? And a diaphragm for what? And the spring?
Orifice for the restricting element
Diaphragm for the measuring element
Spring for the loading element
What does the restricting element of a regulator do
The orifice limits the maximum flow capacity through the regulator.
Can the orifice be replaced?
The orifice is a fixed opening that may or may not be replaceable.
Benifit of replaceable orifice
Make it easier to increase or decrease regulator capacity without remcing the regulator body from the line.
What allows the flow of gas through the regulator
The spring
What is the diaphragm normally made of?
Neoprene or similar synthetic compounds
The diaphragm is attached to what and what does it measure?
It’s attached to the valve stem and measures the outlet (downstream) pressure
What happens when you increase or decrease the spring tension?
It raises or lowers the outlet pressure. Clockwise increases, counter clockwise decreases
What are regulator vents required for?
The diaphragm is ruptured or has a small hole. The outlet pressure would discharge through the vent to the outdoors.
What is a internal relief device and it’s purpose?
Simply an over-pressure relief valve to relieve excess gas pressure in order to protect the regulator and downstream equipment.
How does the internal relief device work
If the outlet pressure rises higher than the rating of the components downstream, the diaphragm will lift off its seat and vent excess pressure.
Do you set the relief valve?
It’s factory set
What is the maximum amount of gas vented for propane and nat gas?
Propane C3H8 is 1ft³(0.0283m³) per hour
Nat gas CH4 is 2.5ft³(0.0706m³) per hour
4 types of nat gas pressure regulators
Service
System
Appliance
Servo
What is a service regulator
Are used on nat gas service to a building, reducing the service pressure to desired building pressure
Where is a system regulator used
Is used where the gas pressure in the building is higher than required at the appliance
Where is the appliance regulator used
Found on the gas valve train or appliance manifold
What happens without an appliance regulator
Without one manifold pressure is subject to fluctuations of the gas supply piping. Creates difficulty maintaining constant btu inputs.
What is a servo regulator
Most common type of appliance regulator incorporated into combination gas valves
Max psi of first stage regulator
10psi
What does the second stage regulator reduce the pressure to?
It reduces from 10psi from the first to 11” of W.C.
Can dual stage regulators be used on propane systems
Yes, but only temporarily
Regulators should be installed how?
Installed horizontally, with vents on the vertical plane
Maximum pressures for residential, commercial and industrial buildings
Res is 2psig
Commercial is 20psig
Industrial is 65pisg
All outdoor vent terminals must have?
A termination fitting is installed that will prevent water, insects, or other foreign material from entering vent pipe
When sizing an orifice drill bit which side is inserted into the guage
Insert the shank of the drill
