OxyFuel Equipment
Section 7
Introduction
Oxyfuel welding is a fusion welding process that uses
oxygen and a fuel gas to provide the heat and
shielding for welding.
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Requirements
An oxyfuel system must:
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2
3
4
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store the two gasses,
regulate the pressure,
set the flow rate,
mix the gasses,
deliver the mixed gasses to the
weld.
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Fuel Gasses
Propane (LPG)
Natural Gas
Acetylene
MAPP
Hydrogen
What are the advantages and
disadvantages of each gas?
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Uses
How many people have used an oxyfuel system?
Is there anything else that it be used for?
Why has the use of oxyfuel welding declined?
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OxyFuel Safety
Remember safety is based on a conscious decision and the
management of hazards.
What hazards are associated with an oxyfuel system?
How do we manage these hazards?
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OxyFuel system
Before learning to use an oxyfuel system, it is important to know the
name and function of each part.
A. Oxygen safety disc
B. Oxygen cylinder valve
C. Oxygen cylinder pressure
gauge
D. Oxygen working pressure
gauge
E. Oxygen regulator
F. Oxygen regulator adjusting
screw
G. Acetylene cylinder safety disc
H. Acetylene cylinder valve
I. Acetylene cylinder pressure
gauge
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OxyFuel System--cont.
J. Acetylene working pressure
gauge
K. Acetylene regulator
L. Acetylene regulator
adjusting screw
M. Acetylene hose
N. Oxygen hose
O. Acetylene torch valve
P. Oxygen torch valve
Q. Torch
R. Welding tip
S. Acetylene cylinder
T. Oxygen cylinder
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Oxyfuel System
Components
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Oxygen Cylinder
What are the characteristics of an oxygen
cylinder?
What are the primary hazards in the use of an
oxygen cylinder?
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Oxygen Cylinder Valve
What is different about an oxygen
valve compared to a water faucet?
How far should it be open when in
use?
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Oxygen Valve—Parts
A. Upper seat
B. Lower seat
C. Safety nut
D. Safety disc
E. Cylinder connection
F. Regulator connection
G. Stem nut
H. Valve stem
I.
Hand wheel
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Oxygen Valve—cont.
Closed
Open
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Acetylene Cylinder
What are the characteristics of an acetylene
cylinder?
What are the primary hazards in the use of an
acetylene cylinder?
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Acetylene Valve
What is different about an
acetylene cylinder valve
compared to an oxygen
cylinder valve?
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LPG Gas Cylinders
How is an LPG cylinder different from an
oxygen or acetylene cylinder?
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Regulators
What is the function of an oxyfuel regulator?
Regulator parts:
A. Pressure adjusting screw
B. Bonnet
C. Needle valve
D. Hose connection
E. Cylinder connection
F. Needle valve seat
G. Diaphragm
H. Spring
I. Nylon thread insert
How does it work?
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Regulators—cont.
Do all regulators have a pressure adjusting screw?
No. Some are fixed pressure.
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Regulators—cont.
What hazards are associated with oxyfuel regulators?
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Regulator Creep
What is regulator creep?
What can cause regulator creep?
What hazards are associated with regulator creep?
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Gauge Not Returning To Zero
Why would a gauge not return to zero?
What can cause this
condition?
What are the possible outcomes of using a
regulator that has a gauge that does not
return to zero?
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Backfires and Flashbacks
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Backfire
What is a backfire when using an oxyfuel torch?
How do you know when a backfire has occurred?
What is the primary cause of backfires?
What are the hazards associated with a backfire?
What should you do when one occurs?
What What is the risk of a backfire?
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Flashback
A. What is a flashback when using an oxyfuel torch?
B. How do you know when one has occurred?
C. What causes flashbacks?
D. What should you do if you suspect one has occurred?
E. What is the potential hazard of a flashback?
F. What is the risk of a flashback?
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Check Valves and Flashback Arrestors
What is the purpose of a check valve?
What does a flashback arrestor do?
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Working Pressure
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Working Pressure
Oxygen and fuel gas working pressure should be set according to
manufactures recommendations for the job being performed.
What factors influence the ideal working pressure?
Can excessive working pressure cause problems when welding?
Yes. What are they?
Can insufficient working pressure cause problems when welding?
Yes. What are they?
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Oxyfuel Torch
What is the purpose of the oxyfuel torch?
Important facts when using oxyfuel torch.
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Hoses and Connections
Are there any unique characteristics of
oxyfuel hoses?
Are there any unique characteristics of
oxyfuel hose connections?
How should hoses be treated?
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PPE
What are the three primary hazards associated
with oxyfuel systems and how are they
managed?
Hazard
Harmful light
Hot metal
Flying molten droplets
Management
Shaded goggles
or face shield
Pliers and gloves
Welding apparel
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Setting Up Oxyfuel System
Extinguish all open flames and stop processes that produce
sparks.
Steps (assuming new system)
1. Secure cylinders
2. Remove caps
3. Crack cylinder valves
4. Connect regulators
5. Open cylinder valves
6. Connect hoses to cylinders
7. Connect hoses to torch body
8. Connect welding tip to torch body
9. Set working pressures
10.Check system for leaks.
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Shutting Down System
Close cylinder valves
Open torch valves
– Leave open until regulator gauges read zero.
– Some sources recommend doing fuel first and oxygen last.
Close torch valves
Release tension on regulator adjusting screw.
Roll up hoses and place torch in a safe position.
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Questions?
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