Using Gas Welding Using Gas Welding EquipmentEquipment

Ag IAg I

Ag MechanicsAg Mechanics

Unit 2Unit 2

Competencies to be DevelopedCompetencies to be Developed

Identify major parts of propane and Identify major parts of propane and oxyacetylene welding equipmentoxyacetylene welding equipment

Change oxygen and acetylene cylindersChange oxygen and acetylene cylinders

Turn on and adjust oxyacetylene controlsTurn on and adjust oxyacetylene controls

Light and adjust oxyacetylene torchesLight and adjust oxyacetylene torches

Shut off and bleed oxyacetylene Shut off and bleed oxyacetylene equipmentequipment

Check for leaks in gas equipmentCheck for leaks in gas equipment

IntroductionIntroduction

Many gases will burn, making them both Many gases will burn, making them both dangerous and beneficialdangerous and beneficial

Burning gases are used in ag mechanics Burning gases are used in ag mechanics to do many thingsto do many things Heat, cut, weldHeat, cut, weld

Weld:Weld: to join by fusion to join by fusion

Fusion:Fusion: melting together melting together

IntroductionIntroduction

Gas:Gas: any fluid substance that can expand any fluid substance that can expand without limit.without limit. This expandable nature also means that a This expandable nature also means that a

gas can be compressedgas can be compressed

CompressCompress: apply pressure to reduce in : apply pressure to reduce in volumevolume

Compressed GasCompressed Gas

Dangerous because it is under pressure Dangerous because it is under pressure and trying to get freeand trying to get free

If the gas is flammable there is the If the gas is flammable there is the additional danger that it may explode or additional danger that it may explode or burn out of controlburn out of control

Fortunately, we have suitable equipment Fortunately, we have suitable equipment and techniques available to use and techniques available to use compressed, combustible gasses safelycompressed, combustible gasses safely

Acetylene and PropaneAcetylene and Propane

Most popular for heating, cutting and Most popular for heating, cutting and welding metalswelding metals

They must be mixed with oxygen from the They must be mixed with oxygen from the air or pure oxygen from tanks before they air or pure oxygen from tanks before they will burn.will burn.

Refer to unit 1 for Reducing Hazards in Refer to unit 1 for Reducing Hazards in Agricultural MechanicsAgricultural Mechanics

General Precautions with General Precautions with Compressed GasesCompressed Gases

Wear safety glasses at all Wear safety glasses at all timestimesStore fuel gas cylinders Store fuel gas cylinders separately from oxygen separately from oxygen cylinderscylindersKeep gas cylinders Keep gas cylinders upright and chainedupright and chainedDo not bump or put Do not bump or put pressure on pipes, pressure on pipes, connections, valves, connections, valves, gauges or other gauges or other equipment connected to equipment connected to compressed gas compressed gas cylinderscylinders

When connections are When connections are opened or cylinders are opened or cylinders are changed check for leaks changed check for leaks before using equipmentbefore using equipmentNever use grease or oil Never use grease or oil on equipment—on equipment—spontaneous or instant spontaneous or instant fires may resultfires may resultFollow procedures for Follow procedures for turning systems on and turning systems on and offoffWork only in areas that Work only in areas that are free of materials that are free of materials that burnburn

General Precautions with General Precautions with Compressed GasesCompressed Gases

Screw caps on all Screw caps on all cylinders that do not cylinders that do not have regulatorshave regulatorsKeep equipment or Keep equipment or cylinders that may cylinders that may discharge gas pointed discharge gas pointed away from the operator away from the operator and other peopleand other peopleNever leave clothing Never leave clothing were it can become were it can become saturated by oxygen saturated by oxygen and fuel gasesand fuel gases

Learn to recognize the Learn to recognize the odors of combustible fuelsodors of combustible fuelsProtect gas cylinder Protect gas cylinder storage areas with locked storage areas with locked link fences or concrete link fences or concrete enclosures.enclosures.If gas equipment catches If gas equipment catches fire, immediately turn off fire, immediately turn off the gas at the tanks. If the gas at the tanks. If this is not practical or this this is not practical or this action does not extinguish action does not extinguish the gas fires, evacuate the gas fires, evacuate the area and call for help.the area and call for help.

Gas Burning EquipmentGas Burning Equipment

Shops have either a manifold or portable rig set-Shops have either a manifold or portable rig set-upupManifold: Manifold: pipe with two or more outletspipe with two or more outletsRig:Rig: self contained piece of apparatus self contained piece of apparatus assembled to conduct an operationassembled to conduct an operationOxyacetylene:Oxyacetylene: a shortened version of the words a shortened version of the words oxygen and acetyleneoxygen and acetylene It refers to equipment and processes where the two It refers to equipment and processes where the two

gases are used togethergases are used together

Shops may also use propane and oxygen Shops may also use propane and oxygen torches and propane furnacestorches and propane furnaces

Oxyacetylene EquipmentOxyacetylene Equipment

Major partsMajor parts CartCart CylindersCylinders ValvesValves RegulatorsRegulators GaugesGauges HosesHoses Torch assembliesTorch assemblies

TorchTorch

Mixes gases and discharges them to Mixes gases and discharges them to support a controllable flamesupport a controllable flame

CylinderCylinder

Long, round tank with extremely thick Long, round tank with extremely thick walls built to hold gases under great walls built to hold gases under great pressurepressure

Valves and RegulatorsValves and Regulators

Control the flow of gasControl the flow of gas

GaugeGauge

Measures and indicates the pressure in Measures and indicates the pressure in the hose, tank or manifoldthe hose, tank or manifold

HosesHoses

Flexible lines that carry the gasesFlexible lines that carry the gases

Made of rubber reinforced with nylon or Made of rubber reinforced with nylon or there material to withstand high pressure there material to withstand high pressure and heavy useand heavy use

Red= acetyleneRed= acetylene

Green= oxygenGreen= oxygen

The RigThe Rig

Acetylene SideAcetylene Side Acetylene cylinderAcetylene cylinder

Red or brownRed or brown Cylinder valveCylinder valve Red cylinder pressure Red cylinder pressure

gaugegauge RegulatorRegulator Hose pressure gaugeHose pressure gauge Red hoseRed hose Acetylene valve on Acetylene valve on

torchtorch

Oxygen sideOxygen side Oxygen cylinderOxygen cylinder Green cylinder Green cylinder

pressure gaugepressure gauge RegulatorRegulator Hose pressure gaugeHose pressure gauge Green hoseGreen hose Oxygen valve on torchOxygen valve on torch Torch mixing chamberTorch mixing chamber Torch tipTorch tip

Setting UpSetting Up

AcetyleneAcetylene Left hand threadsLeft hand threads Color coded red (brown in our shop)Color coded red (brown in our shop)

Oxygen cylindersOxygen cylinders Right hand threadsRight hand threads Color coded greenColor coded green

Before attaching regulators to cylinders, Before attaching regulators to cylinders, crack the crack the cylinder cylinder by turning the gas on and off quickly to blow out by turning the gas on and off quickly to blow out any dustany dust

When attaching regulators, hoses, gauges or torch When attaching regulators, hoses, gauges or torch connections, the connectors must be threaded in the connections, the connectors must be threaded in the correct direction. The red color coding and opposite correct direction. The red color coding and opposite threads for acetylene are means of preventing the threads for acetylene are means of preventing the accidental mixing of acetylene and oxygen except in the accidental mixing of acetylene and oxygen except in the torch its selftorch its self..

Setting UpSetting Up

All connections are gas tight when All connections are gas tight when screwed on properlyscrewed on properly

Caution!! Oxygen and acetylene valves on Caution!! Oxygen and acetylene valves on torches seal with light finger pressure. torches seal with light finger pressure. Over tightening will damage the seats of Over tightening will damage the seats of the valves. A the valves. A seatseat is the point where the is the point where the movable part of the valve seat seals off movable part of the valve seat seals off the gas.the gas.

Turning On the Acetylene and Turning On the Acetylene and OxygenOxygen

Use the following sequence to turn on the gases.Use the following sequence to turn on the gases.

DO NOT STAND IN FRONT OF GAUGES WHILE DO NOT STAND IN FRONT OF GAUGES WHILE THE GAS IS BEING TURNED ON!!!THE GAS IS BEING TURNED ON!!!

Step 1: Close the acetylene valve on the torchStep 1: Close the acetylene valve on the torch

Step 2: Close the oxygen valve on the torchStep 2: Close the oxygen valve on the torch

Step 3: Turn the acetylene regulator handle Step 3: Turn the acetylene regulator handle counter clockwise until no spring tension is feltcounter clockwise until no spring tension is felt

Step 4: Turn the oxygen regulator handle counter Step 4: Turn the oxygen regulator handle counter clockwise until no spring tension is felt.clockwise until no spring tension is felt.

Turning on Oxygen and AcetyleneTurning on Oxygen and Acetylene

Step 5: Open the oxygen cylinder valve slowly until the Step 5: Open the oxygen cylinder valve slowly until the pressure gauge responds. Open the valve all the way.pressure gauge responds. Open the valve all the way.Step 6: Open the acetylene cylinder valve slowly half a Step 6: Open the acetylene cylinder valve slowly half a turnturn

NEVER open the acetylene cylinder more than half a turn. This NEVER open the acetylene cylinder more than half a turn. This is so it can be shut off quickly in the case of emergency.is so it can be shut off quickly in the case of emergency.

Step 7: Open the oxygen torch valve an 1/8 of a turn. Step 7: Open the oxygen torch valve an 1/8 of a turn. Turn the oxygen regulator handle clockwise until the Turn the oxygen regulator handle clockwise until the pressure gauge reads 10 psipressure gauge reads 10 psiStep 8: Open the acetylene torch valve an 1/8 of a turn. Step 8: Open the acetylene torch valve an 1/8 of a turn. Turn the acetylene regulator handle clockwise until the Turn the acetylene regulator handle clockwise until the pressure gauge reads 5 psi. Close the acetylene valve.pressure gauge reads 5 psi. Close the acetylene valve.

Turning on Oxygen and AcetyleneTurning on Oxygen and Acetylene

Step 7 & 8 purge the lines and set Step 7 & 8 purge the lines and set regulators to a safe starting pressureregulators to a safe starting pressure

Purge the lines:Purge the lines: remove undesirable gases remove undesirable gases

This makes the unit pressurized and ready This makes the unit pressurized and ready to go.to go.

Testing for LeaksTesting for Leaks

Leak test should be performed when first setting Leak test should be performed when first setting a rig up, when cylinders are changed or if the a rig up, when cylinders are changed or if the odor of acetylene is present when the rig is not odor of acetylene is present when the rig is not in usein useLeaks should be tested for using a small amount Leaks should be tested for using a small amount of water and nondetergent hand soapof water and nondetergent hand soapThe solution should be rubbed around fittings The solution should be rubbed around fittings and any other places that a leak may exist using and any other places that a leak may exist using a 1” paint brush a 1” paint brush If a leak exist it will cause the soap solution to If a leak exist it will cause the soap solution to bubblebubble

Lighting and Adjusting Torches Lighting and Adjusting Torches

Two types- welding and cuttingTwo types- welding and cuttingTo lightTo lightOpen the acetylene valve an eighth of a turnOpen the acetylene valve an eighth of a turnUse a spark lighter to ignite the torchUse a spark lighter to ignite the torch NEVER use matches or a lighter!NEVER use matches or a lighter! DO NOT point the torch directly into the lighterDO NOT point the torch directly into the lighter DO NOT point the torch towards other peopleDO NOT point the torch towards other people

Open the acetylene valve slowly until the flame is ¼” off Open the acetylene valve slowly until the flame is ¼” off the tip of the torch, increase or decrease the flow until the tip of the torch, increase or decrease the flow until the flame just touches the tipthe flame just touches the tip This flame is called a carbonizing flame.This flame is called a carbonizing flame.

Carbonizing flame is one with excess acetylene.Carbonizing flame is one with excess acetylene.

Lighting and Adjusting TorchesLighting and Adjusting Torches

Turn the oxygen valve on slowly and Turn the oxygen valve on slowly and watch the inner flame shorten. Continue to watch the inner flame shorten. Continue to add oxygen until the long, inner flame just add oxygen until the long, inner flame just fits the cone.fits the cone. This is a neutral flame This is a neutral flame Neutral flame:Neutral flame: one with the correct balance of one with the correct balance of

acetylene and oxygen.acetylene and oxygen. This flame is correct for heating, cutting, and This flame is correct for heating, cutting, and

weldingwelding

Lighting and Adjusting TorchesLighting and Adjusting Torches

If additional oxygen is added, the cone If additional oxygen is added, the cone becomes sharp and the flame noisy. This becomes sharp and the flame noisy. This is an is an oxidizing flame oxidizing flame or one with an excess or one with an excess of oxygen.of oxygen.

It is hottest type of flame but not It is hottest type of flame but not recommend for anything but special types recommend for anything but special types of applicationsof applications

Shutting Off TorchesShutting Off Torches

Torches become a fire hazard if the Torches become a fire hazard if the procedure is not followed when shutting procedure is not followed when shutting them off.them off.

Use gentle pressure on torch valves to Use gentle pressure on torch valves to keep from damaging their soft internal keep from damaging their soft internal parts.parts.

First close the acetylene valveFirst close the acetylene valve

Close the oxygen valve lastClose the oxygen valve last

Bleeding LinesBleeding Lines

Removing all gas from the lines and equipmentRemoving all gas from the lines and equipmentProcedureProcedure

Turn off the acetylene at the cylinderTurn off the acetylene at the cylinder Turn off the oxygen at the cylinderTurn off the oxygen at the cylinder Open the acetylene valve at the torch until both regulators return Open the acetylene valve at the torch until both regulators return

to zero. Close the acetylene valve at the torchto zero. Close the acetylene valve at the torch Open the oxygen valve at the torch until both regulators return to Open the oxygen valve at the torch until both regulators return to

zero. Close the oxygen valve at the torchzero. Close the oxygen valve at the torch Turn all regulator handles counterclockwise until they are easy Turn all regulator handles counterclockwise until they are easy

to turn to turn Coil the hoses over the cart handlesCoil the hoses over the cart handles Store the rig in a suitable place.Store the rig in a suitable place.

REVIEW POP QUIZREVIEW POP QUIZ

1. What color are acetylene hoses?1. What color are acetylene hoses?2. What color are oxygen hoses?2. What color are oxygen hoses?3. Acetylene should be at what pressure to light the 3. Acetylene should be at what pressure to light the torch?torch?4. What is used to check for gas leaks?4. What is used to check for gas leaks?5. What material is used to reinforce gas hoses?5. What material is used to reinforce gas hoses?6. What two gases are used in the agricultural 6. What two gases are used in the agricultural mechanics shop?mechanics shop?7. What is used to compress gases?7. What is used to compress gases?8. How far should the acetylene tank valve be opened?8. How far should the acetylene tank valve be opened?9. Why are compressed gases dangerous?9. Why are compressed gases dangerous?10. Define the term 10. Define the term rigrig..