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Jeremy 4th Year > Pressure Regulators and Orifices > Flashcards

Pressure Regulators and Orifices Flashcards

1
Q

In a regulator what are the restricting, the measuring and the loading elements?

A

Orifice is the restricting element

Diaphragm is the measuring element

Spring is the loading element

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2
Q

What effect does turning the adjustment screw have on a regulator?

A

Clockwise = pressure increase

Counter clockwise = pressure decrease

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3
Q

What is the maximum amount of gas vented through a leak limiting device on a 2 psi or less application?

A

1 cubic foot per hour for propane

2.5 cubic feet per hour for natural gas

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4
Q

What is the function of a vent suppressor?

A

Keeps diaphragm from slamming open and shut

Maintains steady pressure

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5
Q

Most controls on residential appliances are rated for a maximum operating pressure of?

A

0.5 psig (14” w.c.)

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6
Q

What is the most common type of appliance regulator that is incorporated into appliance regulators?

A

Servo regulator

It is incorporated into combination gas valves

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7
Q

What is the maximum first stage regulator setting for propane?

A

10 psi

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8
Q

Once the first stage propane regulator is set for 10 psi, the gas enters the second stage regulator where it is reduced to what pressure?

A

11” wc

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9
Q

A dual stage propane regulator reduces pressure to what?

A

11” wc

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10
Q

A regulator must be installed with a manual shut off located where?

A

Upstream of the regulator

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11
Q

In what position should regulators be installed?

A

Horizontally with the vents on the vertical plane

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12
Q

What type of copper is permitted to be used underground?

A
  • Type K

- Type L or G may be used if they are externally coated with a polyethylene or pvc resin

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13
Q

If indoor installation of a propane regulator is required, where must it be located?

A

Within 3 feet of where the gas line enters the building

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14
Q

What are the benefits of a 2 stage regulator system on propane?

A
  • recommend for smaller gas lines
  • gives appliances a more constant delivery pressure
  • provides flexibility for future expansion
  • less chance of freeze up at the regulator
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15
Q

What is the maximum allowed gas pressure in a single family dwelling?

A

2 psig

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16
Q

What are acceptable materials used for venting a regulator to the outdoors?

A

Steel pipe or tubing

Copper tubing

Aluminium tubing

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17
Q

How do you size a vent line on a regulator?

A

At least equal to the connection on the regulator, but minium 1/4”

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18
Q

A diaphragm gas valve or combination gas valve with inlet pressures less than ___ psig used for _____ gas only, may have the vent line terminate where?

A

0.5, natural gas

The vent line may terminate at a constant burning pilot (standing pilot)

19
Q

How do you size the length of a regulator vent line?

A

Increase one pipe size for every 50 feet of vent line length. The increase in size is made at the connection on the outlet of the device

20
Q

Can the vents from 2 or more relief devices be connected into a common vent?

A

Yes

21
Q

All outdoor vent terminals must have what?

A

Termination fitting installed that will prevent water, insects or other foreign material from entering the vent pipe

22
Q

Where must a propane appliance regulator with a leak limiter be installed?

A

In a well ventilated area such as outside

23
Q

What is one problem that can occur from an undersized regulator?

A

Too low outlet pressure

24
Q

What is one problem that may occur when a regulator is over sized?

A

Noisy during operation

25
Q

Where does external freeze up occur on a regulator?

A

In the atmospheric chamber above the diaphragm or over the regulator vent

26
Q

What can you do to reduce external regulator freeze up?

A

Install the regulator in such a manner that moisture entering the atmospheric chamber through the vent opening is at a minimum

27
Q

Regulators installed outdoors must have the vent pointing where?

A

Down

28
Q

As gas pressure decreases what happens to the temperature of the gas?

A

It drops as well

Pressure drop = temp drop

29
Q

A regulator with a lot of frost on the exterior head and body is a good indication of what?

A

Undersized regulator

30
Q

What must every aerated burner have?

A

An orifice

31
Q

What are the 2 basic functions of an orifice?

A

Regulates gas volume

Controls velocity

32
Q

What are the most commonly used orifices?

A

Plug orifices

33
Q

What color are natural gas pilot orifices?

What color are propane pilot orifices?

A

Silver metal color

Dark brown or black

34
Q

What is considered to be high pressure gas?

A

Over 14” w.c.

35
Q

When may a dual stage regulator be used on a propane system?

A

For temporary applications only

36
Q

Pressure controls without relief devices should be vented how?

A

Seperatly

37
Q

How far must a regulator vent termination be from a moisture exhaust duct (dryer vent)?

A

3’ (1m)

38
Q

For inlet pressure on a regulator of up to 5 psi, the discharge set point on the line relief shall be what?

A

No less than 2 times and no more than 3 times the operating pressure (outlet pressure) of the regulator

39
Q

For inlet pressure on a regulator of greater than 5 psi, the discharge set point on the line relief shall be what?

A

No less than one and a half times and no more than 2 times the operating pressure (outlet pressure) of the regulator

40
Q

What are the calorific values of propane and natural gas?

A

Natural gas = 1000 Btu/cubic ft.

Propane = 2500 Btu/cubic ft.

41
Q

What orific size would you need if you used a number 37 drill bit?

A

35 orifice (2 sizes smaller)

42
Q

How is an orifice drilled?

A

In the direction of gas flow

43
Q

What is the equation for clocking the meter?

A

(Size of proving dial / number of seconds)

Multiply by 3600

Multiply by 1000 for Natural Gas
Multiply by 2500 for Propane

Jeremy 4th Year (13 decks)

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