C4 - LT#1 Oxy Fuel Equipment

Question 1

The process of gas cutting requires what?

Answer 1

Two gases and a source of ignition

Question 2

What gas has the highest flame temperature?

Answer 2

Acetylene gas

Question 3

What is the first step in putting out a fire in the hoses of an oxyacetylene outfit?

Answer 3

Close both the oxygen and acetylene cylinder valves

Question 4

What CRITICAL point of free acetylene is:

Answer 4

28 PSI (193 KPA) pressure at 21 celsius. If the temperature is increased, the pressure becomes critical at a LOWER temperature.

Question 5

The safety devices on an acetylene cylinder are ______ activated

Answer 5

Heat activated

Question 6

Oxygen valves are opened all the way, acetylene valves are opened

Answer 6

1/4 to 1/2 the way

Question 7

Liquid fuel cylinders are designed to allow the liquid to _______ when the cylinder valve is opened and gas escapes

Answer 7

Boil off or vaporize

Question 8

When cylinders are too low on gas to be used, they should be marked

Answer 8

MT

Question 9

Cylinder valves should always be _____ open momentarily before the regulator is attached and _____ when your work is finished.

Answer 9

Cracked open before attaching the regulator and close when your work is finished.

Question 10

To increase the working pressure, the pressure adjusting screw is turned _______?

Answer 10

Clockwise

Question 11

A grooved hex nut indicates

Answer 11

A left-handed / acetylene regulator

Question 12

The gauge with the higher numerical calibrations indicates:

Answer 12

Cylinder pressure

Question 13

The gauge with the lower numerical calibrations indicates

Answer 13

Working pressure

Question 14

The color of an oxygen hose is usually

Answer 14

Green / black

Question 15

The colour of the fuel gas hose is usually

Answer 15

Red

Question 16

An RFCV placed between the torch and hose has the arrow pointing toward the; between the hose and regulator, it is pointing toward the

Answer 16

Torch, hose

Question 17

When you are using the combination torch for the cutting process, the ____ valve is used to adjust the amount of oxygen mixed with the acetylene for preheating

Answer 17

Preheat oxygen valve

Question 18

If a flashback occurs, the _____ and the _____ valves must be shut down as soon as possible

Answer 18

Torch and cylinder

Question 19

What is one of the main hazards of oxygen?

Answer 19

It accelerates combustion rapidly and raises the combustion temperature of fuel gases, which can cause hazards if the oxygen content is above standard atmospheric % (20.8)

Question 20

The acceleration of combustion is called:

Answer 20

The oxidizing effect. Materials that are not combustible in air will burn readily in oxygen-enriched atmospheres.

Question 21

If oil or grease is brought into contact with pure oxygen under slight pressure, what can occur?

Answer 21

An explosion

Question 22

Acetylene is a compound formed by uniting:

Answer 22

Two atoms of Carbon with two atoms of hydrogen to form C2H2

Question 23

The resulting flame temperature of acetylene + oxygen is

Answer 23

up to 3,300 celsius

Question 24

What does the term unstable mean, in acetylene is an unstable compound.

Answer 24

Unstable means likely to break down (decompose) or undergo a physical change without much provocation or cause. This point is called the “critical point”

Question 25

The “critical point” of free acetylene (explosive and unstable) is:

Answer 25

28 PSI at 21 degree celsius

Question 26

Which fittings are safe with acetylene?

Answer 26

Yellow brass, iron, or steel

Question 27

What is the advantage of MAPP?

Answer 27

Relatively inexpensive when compared to the cost of acetylene. Safer to use and may be safely compressed. Flame temp of 2 900

Question 28

What is the advantage of cuts with natural gas?

Answer 28

It can be piped in. The main constituent of natural gas is methane. Flame temp. of 2540 celsius.

Question 29

What is the main advantage of propane gas?

Answer 29

Safe and easy to handle, it is widely used because of its ability to produce clean cuts at a low cost. Requires 4 1/2 volumes of oxygen to one volume of fuel to produce a neutral flame. Temp is 2540 celsius

Question 30

What is stored in acetylene cylinders to charge the average PSI to around 250 (from the dangerous pressure of 15)

Answer 30

Agamassan - a porous material such as asbestos, charcoal, diatomaceous, a stable liquid to absorb the acetylene gas and is used in the cylinder them safe at high pressures. One volume of acetone will absorb 20 volumes of acetylene gas

Question 31

Should you use grease or oil to lubricate regulators, torches, cylinder valves, or other oxy-fuel gas equipment?

Answer 31

No, never

Question 32

The working pressure of acetylene must be kept below how many PSI?

Answer 32

Below 15 PSI to prevent unstable gas from exploding

Question 33

What do oxy-fuel hoses consist of?

Answer 33

2 or 3 layers of rubber, with a strong fabric between each rubber layer for reinforcement

Question 34

What are the causes of backfire?

Answer 34

1)Obstruction of gas flow at the tip
2)hot tip from being too close to the work
3) working pressure too low
4) faulty connection between the torch and the welding or cutting attachment

Question 35

What is a backfire?

Answer 35

the torch burns back into the welding or cutting tip, making a popping sound. Gases pre-igniting inside of the tip.

Question 36

What is a flashback?

Answer 36

When the backfire goes beyond the tip, through the hose to the regulator. The torch handle may become hot.

Question 37

What are the causes of a flashback?

Answer 37

1) Incorrect adjustment of torch valves
2) grossly unequal oxygen and acetylene working pressures
3) clogged tip along with excessive oxygen pressure
4) failure to purge the lines before igniting the torch

Question 38

What is a Reverse Flow Check Valve?

Answer 38

A device that prevents gases from flowing in reverse inside the torch or hose.

Question 39

What are causes of reverse flow?

Answer 39

1) Using plugged or obstructed cutting or welding tips
2) bleeding the lines by turning off cylinder valves while torch valves are still open
3) no pressure from either the oxygen or acetylene cylinders while the torch is in use

Question 40

If a rubber hose is ruptured or catches fire, what must you do?

Answer 40

Turn off the supply of oxygen and fuel gas, before attempting to put out the fire using a smothering fire extinguisher

Question 41

During the cutting process, steel is reduced to:

Answer 41

Iron oxides

Question 42

What is a gas cylinder of acetylene composed of?

Answer 42

A porous filler such as asbestos, charcoal or balsa wood, then filled with liquid acetone into which the acetylene is dissolved

Question 43

MAPP gas is the compound:

Answer 43

Methylacetylene propadiene

Question 44

Gas cylinders, once emptied are emptied out first, then refilled, why?

Answer 44

In the case the remaining gas is contaminated

Question 45

How to safely store acetylene cylinders?

Answer 45

1) Not near radiators or any other source of heat
2) Storage room must be well ventilated
3) Should be used and stored in an upright position
4) Once a cylinder is empty, it is to be stored in the appropriate location and marked MT

Question 46

What is a manifold system?

Answer 46

When large volumes of acetylene are needed and a single cylinder may not provide enough acetylene at the rate required, if the draw limit is exceeded, the liquid acetone will be drawn

Manifold system connects a number of cylinders together so that the draw limit is increased.

Question 47

What is a manifold system?

Answer 47

When large volumes of acetylene are needed and a single cylinder may not provide enough acetylene at the rate required, if the draw limit is exceeded, the liquid acetone will be drawn

A manifold system connects a number of cylinders together so that the draw limit is increased.