1. Unit 22
Ag mechanics
Using gas equipment

2. Gas welding equipment The use of gas equipment in Ag mechanics:
Heating for shaping
Cutting for fabrication
Welding joining metal together using fusion
Fusion is the melting together of metal
Gas welding equipment
Fuels and gases used in the shop are
Pressure is applied to reduce volume
Compressed:
Burns easily
Acetylene and propane
Flammable:
Oxygen
Accelerator:

3. SAFETY Store fuel gas separate form oxygen
Always check for leaks after changing cylinders
Do not use OIL around regulators
Turn systems ON and OFF correctly
Watch for fumes from metal being worked some are toxic
Wear proper protective equipment
Always cap cylinders when moving

4. EQUIPMENT A device that has two or more outlets for equipment On it.
Manifold:
A device that has only one outlet for equipment, usually on
A cart. Sometimes called a portable.
Rig:
Rig equipment:
To hold cylinders, and be able to move
Cart:
Chain:
To hold the cylinders to the cart for safety
Oxygen cylinder:
Contains the accelerator oxygen
Contains the gas that burns
Fuel cylinder:
Regulators:
Reduce high cylinder pressure to lower working
Pressure.
Hoses:
To transfer gases to the torch
Torch:
Body and attachments to cut, heat, and weld

6. Special features Fuel gas: Left hand threads Red colored hoses
Maximum working pressure 15psi
2 piece bottle with melt out pugs
May have a special valve
Oxygen:
Right hand threads
Green hose
One piece bottle very thick – must withstand 2,200 psi
Double seating bottle valve

7. Parts of a torch

8. Startup: Lighting: Handout from Mr. Williams
Check to make sure needle valves on the body are turned off
Make sure “T” handles are backed off
Turn on bottle valves
Do not stand in front of “T” handles
Fuel gas - 7
Set regulators
Oxygen – 40 psi
Lighting:
Open fuel gas needle valve on the body slightly
Use a friction lighter to ignite
Open the fuel gas more to get a good flame
Open the oxygen needle valve on the body
Adjust to get a neutral flame

9. Too much blue inner cone too much fuel gas
Carbonizing:
Blue colored inner cone no hissing sound equal combustion
Neutral:
Light blue colored inner cone hissing sound too much
oxygen
Oxidizing:

10. Shutdown: Mr. Williams Shut off needle valve on body, let the oxygen
Blow the flame out
Shut off fuel gas:
Shut off oxygen:
Shut off needle valve on the body
Shut off bottles:
It doesn't make any difference.
Bleed off lines
Open oxygen first, high pressure, then shut off
Open fuel gas next drain and shut off
Back off “T” handles on regulators