190101h Oxyacetylene equipment, heating and cutting

Question 1

What is the chemical symbol for oxygen, acetylene and propane?

Answer 1

Oxygen = O2
Acetylene = C2H2
Propane = C2H8

Question 2

Oxygen is stores at what psi?

Answer 2

2175 psi

Question 3

What happens if an oxygen, acetylene or propane tank leaks?

Answer 3

Take out of service and write a report

Question 4

What’s does the abbreviation “MT” mean?

Answer 4

Empty

Question 5

What psi does the frangible disk bust at?

Which pressurized bottle is it used for?

Answer 5

3200 psi and it’s used for oxygen bottles.

Question 6

How is acetylene made?

Answer 6

Calcium carbide mixed with water.

Question 7

How can you notice acetylene in the air?

Answer 7

It has a garlic like odour at 1% concentration.

Question 8

What does the numbers 15 psi, 28 psi and 250 psi mean when we talk about acetylene?

Answer 8

15 psi is the maximum save working pressure.

At 28 psi the gas with ignite spontaneously.

You can store the gas at a pressure of 250 psi when the bottle is fully filed with a porous filler mass + 40 % aceton.

Question 9

What’s the rate at witch you can draw the acetylene?

Answer 9

1/7 of cylinder capacity per hour.

Question 10

What are fusible plugs and what are they used on?

Answer 10

They allow acetylene to discharge if cylinder starts burning.

Question 11

At what temperate do fusible plugs melt at?

Where are they normally located?

Answer 11

At 100 degrees celcius and are located on

• the conclaved bottom of the cylinder
• the filled passage of the back side of the cylinder valve
• reinforcing college or neck ring
• the shoulder of the cylinder

Question 12

Propane range of flammability is ____%?(fuel/air mixture)

Answer 12

2.4 - 9.5 %

Question 13

Acetylene range of flammability is ____%? (Fuel/air mixture)

Answer 13

2 - 89% fuel/air mixture

Question 14

What do you not want on an oxygen bottle because of the danger it causes? Why?

Answer 14

Oil or grease because it can cause an explosion with out source of ignition.

Question 15

How are propane cylinders filled? What do they have as a safety feature?

Answer 15

You can fill it by volume or by weight.

They have relief valve.

Question 16

How much pressure can a oxyacetylene hose hold?

Answer 16

minimum 400 psi.

Question 17

What types of goggles do we use when working with oxyacetylene?

Answer 17

4# or 5# dark green shade goggle.

Question 18

when is heating or cutting metals, shop ventilation not enough?

Answer 18

When the ferrous metals have a coating of zinc, cadmium, or lead.

Question 19

What way are the threads for bottles with fuels? What about oxygen?

Answer 19

Left handed threads for fuelled bottles. Right handed for threads for oxygen bottles.

Question 20

How much do you open a oxygen valve? What about acetylene valve?

Answer 20

Oxygen valve you open all the way. Acetylene valve a full turn.

Question 21

If you need more volume of acetylene what can you do?

Answer 21

Connect 2 or more bottles together

Question 22

What are the 3 ways you can tell a acetylene hose from oxygen hose?

Answer 22

• Left hand threads
• acetylene fittings have groves
• the colour of the hose could be red

Question 23

What’s the purpose of the check valves in oxyacetylene?

Answer 23

They prevent mixer of oxygen and acetylene in the hoses or regulator.

Question 24

Where is the mixing chamber on oxyacetylene equipment?

Answer 24

Torch handle.

Question 25

What are the 8 steps when purging and leak testing Oxyacetylene? (new bottles)

Answer 25

1 secure cylinder to wall
2 check all fitting and remove oil and grease
3 crack the cylinder valve one at a time to blow dust
4 attach pressure regulator, hoses and torch handle
6 retract regulator screws and open the bottle valves
7 with the torch handle valve closed adjust oxygen and acetylene pressure to 5 psi to check for leaks with approved leak tester.
8 purge each bottle at a time by opening torch valve

Question 26

How do you shut the oxyacetylene? (8 steps)

Answer 26

1 Close oxygen cylinder valve
2 open oxygen torch handle valve to release pressure 
3 retract oxygen regulator screw
4 close oxygen torch handle valve
5 close the acetylene cylinder valve
6 open acetylene torch handle valve to release pressure
7 retract acetylene regulator screw  
8 close acetylene torch handle valve

Question 27

Heating tip sizes range from?

Answer 27

00, 0 , 1 - 10

Question 28

Types of flames you will encounter are?

Answer 28

• acetylene flame
• carbonizing flame
• neutral flame
• oxidizing flame

Question 29

What are the characteristic of acetylene flames?

Answer 29

• yellow and bushy flame
• not a successfully used for heating
• temperate of 800 Celsius

Question 30

What at the characteristics of carbonizing flame?

Answer 30

• white feather is present on the flame cone.
• excess of acetylene
• the temperature is 3000 Celsius

Question 31

What are the characteristics of a neutral flame?

Answer 31

• balance the oxygen and acetylene till the blue flame disappears into cones
• the temperature is 3300 Celsius
• recommended flame for heating and cutting

Question 32

What are the characteristics of a oxidizing flame?

Answer 32

• the flame has excess oxygen
• the flame cones becomes shorter, sharper and pale blue then a neutral flame. The center cone becomes longer then the others. This flame is accompanied by a harsh sound.
• carbon will be removed from steel (softens and burns the material)
• the flame temperature is 3500 Celsius
• avoid oxidizing flames

Question 33

How do you set oxyacetylene regulators? (12 steps)

Answer 33

1 release regulator screw
2 slowly crack open oxygen cylinder valve to full position
3 open acetylene cylinder valve one turn
4 purge each hose individually at 5 psi (regulator 5 psi)
5 set to 2 - 3 psi on each regulator gauge
6 open acetylene torch handle valve 1/4 turn, ignite the torch and then open acetylene torch handle valve all the way
7 increase acetylene pressure with the regulator screw to a point where flame leaves the tip
8 adjust acetylene torch handle valve until the flame returns and is smoke free
9 fully open oxygen torch handle valve
10 return acetylene torch handle valve to fully open position
11 with both torch handle valves wide open, adjust the oxygen pressure regulator screw to obtain neutral flame

Question 34

Explain a back fire and why it happen?

Answer 34

• It’s when the flame backs up into the tip and mixer, resulting in a small explosion.

Causes are:

• to slow of a gas
• obstruction of gas flow
• loose or faulty seat (seals or fittings)
• dirty tip
• hot or worn out tip.

Question 35

Explain continuous back fire or burnback and why it happens?

Answer 35

• it’s continuous combustion in the tip or mixer, indicated by a screeching sound and black smoke.
• torch handle will melt
• shut bottles off immediately

Cause are: grossly unequal pressure, Miley unequal pressure and obstruction, failure to purge each hose, lighting torch with both valves open

Question 36

What is the cutting torch start-up procedure? (5 steps)

Answer 36

1 With all torch handle valves closed, including oxygen preheat valve and oxygen regulator retracted, slowly open cylinder valves,
2 open oxygen torch handle valve fully
3 open acetylene torch handle valve 1/4 turn. Ignite torch and adjust till it’s almost out of smoke
4 open the oxygen preheat valve on the cutting attachment and adjust for a neutral flame
5 depress the oxygen lever and readjust oxygen preheat valve, with the lever depressed, to obtain a neutral flame

Question 37

What’s the proper way of torch cutting?

Answer 37

The thinner the metal the more you angle the torch