Upload
ah-tiang
View
245
Download
0
Embed Size (px)
DESCRIPTION
JJ104 Workshop Technology
Citation preview
Oxy Fuel Cutting SystemsBasic Setup & Use
Tim Turner
Typical Torch System Oxygen Cylinder Acetylene Cylinder Method of Securing the cylinders Caps Regulators Backflash arrestors Hoses Torch Body Torch Head Torch Tip Clothing and Eye/Face Protection
Oxygen Cylinders Oxygen is very pure - 99% Pressure is about 2200 psi at 700 F Hydrostatic tested to 3300 psi Forged from a single piece of steel -
no welding Minimum of 1/4” thickness Annealed periodically Stored away from combustibles
– 5’ high wall– 1/2 hour fire rating
K
LK
T S D,E,Y,U,LE
Q ME MBE XAD
MD
R
Oxygen cylinder sizes:
Liquid Oxygen is stored in a dewer flask
Acetylene Cylinders
Acetone - absorbs acetylene under pressure Consumption rate = 1/7 content per hour Fusible plug - 2120 F Temperature has an extreme affect on pressure Let stand upright at least 20 minutes before using Protected valve or cylinder cap Stored away from oxygen and combustibles
– 5’ high wall– 1/2 hour fire rating
WK
WTL
WS
WCL
WC WQ
Acetylene Cylinders C2H2 - Made from calcium carbide and water
Welded construction Monolithic filler - Asbestos fibers, balsawood
(85% porus) Acetone - absorbs acetylene under pressure Fusible plug - 2120 F Consumption rate = 1/7 content per hour Temperature has an extreme affect on pressure Let stand 20 minutes before using Protected valve or cylinder cap Sold by cubic feet - determined by weight of the
cylinders
Oxygen Cylinder Valve
Brass Construction Double back seat - NEVER
LEAVE HALF OPEN Pop off valve - (fragile
disk) Right hand Thread
Acetylene Cylinder Valve
Brass Construction Packed valve - OPEN 1/2 TO 3/4 TURN Hand wheel or tank wrench - NEVER
REMOVE WRENCH during use RH (Male) or LH (Female) Thread
Manifold Systems
Increased Efficiency more stations no downtime
Parts:
Cylinders Hoses - Brass or braided Check valves or hand valves Flashback Arrestors - OSHA Regulators Main valves
Procedure for changing tanks:
Continuous supply of gasses Do not allow empties to be pressurized Valves and/or checkvalves Never unsecure cylinders without protective
caps Check for Leaks MT - DATE
Regulators
Gauges - High and Low pressure Bonnet - weakest point Adjusting screw - Clockwise = On
Single stage - less expensiveDual stage - more accurate - lump on back - 200 psiNozzle Type - low volumeStem type - High VolumeGauges - High and Low pressure - bourbon tubeBonnet - weakest pointAdjusting screw - Clockwise = On
Regulators
Protector Cap
Protects valve from being knocked off Must be in place when Regulators are off
Backflash Arrestor
Torch / Manifold Regulator / torch
Hoses
Acetylene = Red– Notch around nut means LH thread
Oxygen = Green– RH Thread
New Hoses have talc inside - Blow out before connecting to torch
Needle valves
What each does Preheat / Cutting hole pressures Tightening
Torch Body
single stage / dual stage
Cutting Head Preheat oxygen needle valve Seat type / Graphite type - tightening Body to head connection - tightening Oxygen lever - regulator setting, #1 needle
valve setting
Cutting Tips
1 or 2 piece sizes relate to # Drill Sizes Hand / Wrench tight
Rosebud
Tip Cleaners
Acetylene safety Precautions
Never call acetylene “gas” Extremely explosive with air or oxygen Leave wrench on tank
Oxygen Safety Precautions
Never call oxygen “Air” Never allow oxygen to come in contact with
oil, grease, or other petroleum bases Never use oxygen for compressed air Never move cylinders without caps Always secure cylinders
•Setup Procedures for Oxy-Acetylene Systems Do not move cylinders without valve protection Secure cylinders Inspect threads “Crack” Oxygen Valve Attach regulators and tighten Blow talc from new hoses Attach Flashback arrestors, check valves, hoses, check
valves, torch body, torch head, and tip Properly pressurize torch and check for leaks
Procedures for Lighting Oxy-Acetylene Systems SCREW ADJUSTING SCREW OUT Stand to the side of the adjusting screw Open tanks one at a time (Oxygen wide, Acetylene 1/2 turn) Adjust regulators Bleed lines one at a time Fine adjustments made while bleeding the hoses Open the acetylene needle valve and light torch Open high pressure oxygen needle valve wide Adjust to a neutral flame
Shut Down Procedure for Oxy-Acetylene Systems Turn off acetylene needle valve Turn off preheat oxygen needle valve Turn off tanks Bleed lines one at a time TURN ADJUSTING SCREWS OUT Turn off all needle valves
Flame types
Carborizing Neutral Oxidizing
Starting or restarting a cut
Heat the starting pointMove the oxygen hole off the edge of the plate and start the oxygen stream
Resume Cutting
Offhand Cutting Techniques
Rolling your hands– “Pre-load” your wrist and forearm– Roll, don’t slide for a smoother cut
Sliding the torch through your fingers– Apply pressure to torch tubes with thumb and index
finger– Keep other three fingers in fist– Don’t move the torch body hand during stops and
starts.
Beveling Angles
Slide the torch through your fingers toward you.
Only move the hand nearest the flame when continuing the cut.
Keep your other three fingers in your fist. This will keep your hands cooler and allow you to make a better cut.
Safety
Backflash– Turn Oxygen off first
Watch where you cut– Don’t blow molten metal toward another
person– Don’t melt the hoses– Don’t drop metal on hoses– Don’t let hoses lay on hot metal
Headgear Assembly– Forehead pad– Proper adjustment– How to assemble – How lenses go in– Cleaning different types of lenses– Autochange hoods– Shade numbers for various things– Cracked or broken hoods– Hood designs (pipeliner, short, sock, brazing shield, handheld).