Pressure Regulators And Orifices

Question 1

The regulator use a fixed orifice opening for what? And a diaphragm for what? And the spring?

Answer 1

Orifice for the restricting element
Diaphragm for the measuring element
Spring for the loading element

Question 2

What does the restricting element of a regulator do

Answer 2

The orifice limits the maximum flow capacity through the regulator.

Question 3

Can the orifice be replaced?

Answer 3

The orifice is a fixed opening that may or may not be replaceable.

Question 4

Benifit of replaceable orifice

Answer 4

Make it easier to increase or decrease regulator capacity without remcing the regulator body from the line.

Question 5

What allows the flow of gas through the regulator

Answer 5

The spring

Question 6

What is the diaphragm normally made of?

Answer 6

Neoprene or similar synthetic compounds

Question 7

The diaphragm is attached to what and what does it measure?

Answer 7

It’s attached to the valve stem and measures the outlet (downstream) pressure

Question 8

What happens when you increase or decrease the spring tension?

Answer 8

It raises or lowers the outlet pressure. Clockwise increases, counter clockwise decreases

Question 9

What are regulator vents required for?

Answer 9

The diaphragm is ruptured or has a small hole. The outlet pressure would discharge through the vent to the outdoors.

Question 10

What is a internal relief device and it’s purpose?

Answer 10

Simply an over-pressure relief valve to relieve excess gas pressure in order to protect the regulator and downstream equipment.

Question 11

How does the internal relief device work

Answer 11

If the outlet pressure rises higher than the rating of the components downstream, the diaphragm will lift off its seat and vent excess pressure.

Question 12

Do you set the relief valve?

Answer 12

It’s factory set

Question 13

What is the maximum amount of gas vented for propane and nat gas?

Answer 13

Propane C3H8 is 1ft³(0.0283m³) per hour
Nat gas CH4 is 2.5ft³(0.0706m³) per hour

Question 14

4 types of nat gas pressure regulators

Answer 14

Service
System
Appliance
Servo

Question 15

What is a service regulator

Answer 15

Are used on nat gas service to a building, reducing the service pressure to desired building pressure

Question 16

Where is a system regulator used

Answer 16

Is used where the gas pressure in the building is higher than required at the appliance

Question 17

Where is the appliance regulator used

Answer 17

Found on the gas valve train or appliance manifold

Question 18

What happens without an appliance regulator

Answer 18

Without one manifold pressure is subject to fluctuations of the gas supply piping. Creates difficulty maintaining constant btu inputs.

Question 19

What is a servo regulator

Answer 19

Most common type of appliance regulator incorporated into combination gas valves

Question 20

Max psi of first stage regulator

Answer 20

10psi

Question 21

What does the second stage regulator reduce the pressure to?

Answer 21

It reduces from 10psi from the first to 11” of W.C.

Question 22

Can dual stage regulators be used on propane systems

Answer 22

Yes, but only temporarily

Question 23

Regulators should be installed how?

Answer 23

Installed horizontally, with vents on the vertical plane

Question 24

Maximum pressures for residential, commercial and industrial buildings

Answer 24

Res is 2psig
Commercial is 20psig
Industrial is 65pisg

Question 25

All outdoor vent terminals must have?

Answer 25

A termination fitting is installed that will prevent water, insects, or other foreign material from entering vent pipe

Question 26

When sizing an orifice drill bit which side is inserted into the guage

Answer 26

Insert the shank of the drill