gas welding components

8/19/2019 Gas Welding Components

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GAS WELDING COMPONENTS

Oxyacetylenewelding is veryversatile and

almost all metalsand their alloys canbe welded with it.


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Typical Oxyacetylene Welding(OAW) Station


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Oxygen Cylinders

Oxygencylindersare made of

solid drawnsteel anddesigned tohold

compressedoxygen athighpressre forindstrial


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An oxygencylinderhas a right!

handreglatorconnectionthread and

is paintedblac"


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#t has abrsting disc$tted% which

will blow otand let theoxygenescape if the

cylinderpressrebecomes togreat% schas in a $re.


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Acetylene Cylinders

Acetylenecylinderscontain a

porosmaterialsatratedwith acetone

in whichacetylenegas wasdissolved.


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• Cylinders are $lledwith a very porossbstance &monolithic$ller' to help prevent

large poc"ets of preacetylene formforming

• Cylinders have safety

(se) plgs in the topand bottom designedto melt at *+ (*,,+C)


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This is similar to theway carbon dioxideis dissolved in

lemonade. As agas% acetylene isnstable and canself detonate it is

compressedbeyond *- /pa.

• As the pressre isincreased% moreacetylene will be

dissolved0 forexample% one (*)volme of acetonewill absorb

volme ofacetylene atatmosphericpressre1 bt% at *

atmospherespressre% 2-volmes may bedissolved.


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To assist in even distribtion ofacetylene in the acetone% the bottlealso contains &"apo"' $bre% which

gives a celllar constrction to thechamber. The celllar constrctionalso prevents too rapid discharge of

gas.


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• Acetylene cylinder shto3 valves shold onlybe opened *45 to *4trn

• This will allow thecylinder to be closed6ic"ly in case of $re.

• Cylinder valve

wrenches shold be leftin place on cylindersthat do not have ahand wheel.

Acetylene 7alves


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8eglator 9ressre Settings

• The maximm safe wor"ing pressrefor acetylene is * 9S# :


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Acetylene cylindershave a left!handreglator

connection threadand are paintedcrimson.


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sible plgs are$tted to the top ofthe cylinder and in

the event of a $re%this melt at *,,+Cand allow the gasto escape.


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When wor"ing withacetylene cylinder yomst consider thefollowing0

; ever set acetylenereglator pressreabove *,, /pa.

; To prevent drawingot acetone withthe acetylene gas%restrict the draw!o3

rate to *4- of thecylinder=s contentper hor.


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8eglators

8eglators areneeded toredce andcontrol the

?ow of gasesfrom thecylinders.Oxygenreglators

are coloredblac" andacetylenecrimson.


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8eglators allow1

• The contents of thecylinder to be

monitored.• The redction ofcylinder pressre to asafe wor"ing

pressre.• A constant wor"ingpressre to be setand ad@sted.


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9ressre 8eglators safety Tips.

• #nspect all nts andconnections beforese to detect falty

seats that maycase lea"age ofgas.

• efore opening the valve ofa cylinder to which areglator has beenattached% be sre that thepressre!ad@sting screwhas been completelyreleased by trning it to theleft. ailre to do this allowsthe fll cylinder pressre tohit the engage mechanism

of the reglator. >ot onlywill the reglator bedamaged% bt it may alsobrst and in@re the welder.


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• >ever attempt toconnect anacetylene reglator

to a cylindercontaining oxygenor vice versa.


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• ave reglators repaired only bys"illed mechanics who have beenproperly trained.


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oses and Connectors

8einforced rbber hoses and brass $ttingsare sed to transport the gases from thecylinders to the handpiece handle. oses areblac" with right hand $tting for oxygen and

crimson with left!hand $tting for acetylene.


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Care of ose

• Always se a hoseto carry only one"ind of gas. A

combstiblemixtre may resltif it is sed for $rstone gas and then

the other.


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• Test the hose for lea"s fre6ently byimmersing the hose at normal wor"ingpressre nder water. A lea"ing hose is a

serios haDard and a waste of gas. #f thereis a lea" in the connection with the propernipple and nt% ct o3 the hose a fewinches bac" and rema"e the connection.

Eea"s in other locations shold berepaired by ctting o3 the bad section andinserting a hose copling as a splice.


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• Clamp all of thehose connectionsor fasten them

secrely so thatthey will withstandpressre of at least2,, p.s.i. withot

lea"age.

• ose showinglea"s% brns% worn

places% or otherdefects are n$tfor service andnst be repaired or

replaced.


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•


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• andle the hose careflly whenwelding. Avoid dragging it on agreasy ?oor. The hose shold not be

allowed to come in contact with?ame or hot metal. The hose sholdbe protected from falling articles%

from vehicles rnning overit andfrom being stepped on. #t shold notbe "in"ed sharply.


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• At the end of the day or at the end ofthe @ob% roll p the hose and hang itwhere it will be ot of the way.

Spring!loaded hose reels areavailable.


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andpiece

The handpiece(handle)connects to

the hoses andholds thehandpiececontrol

valves.


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Fixer

The mixerscrews ontothe handle.

#t is heregases aremixed by aspiral

action asthey passthrogh tothe welding

tip.


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Welding Tip

Welding tips directthe ?ame to theweld area. They

come in siDes fromG to 5, and thisindicates ten timesthe siDes of the

hole in the tip. orexample a * tiphas *. mm hole.


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Welding Torch and BlowPipe

Oxygen and the fel gas having beenredced in pressre by the gasreglators are fed throgh sitable

hoses to a welding torch which mixesand controls the ?ow of gases to thewelding noDDle or tip where the gas

mixtre is brnt to prodce a ?ame forcarrying ot gas welding operation.


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There are two types of weldingtorches% namely0(i) igh pressre (or e6al pressre)

type.(ii) Eow pressre (or in@ector) type.


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• igh pressreblowpipes ortorches are sed

with (dissolved)acetylene stored incylinders at apressre of G bar.

• Eow pressreblowpipes are sedwith acetylene

obtained from anacetylenegenerator at apressre of ,,

mm head of water(approximately,., bar).


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Typical torch styles

• A small welding torch, with throttle valves

located at the front end of the handle.

Ideally suited to sheet metal welding. Can

be fitted with cutting

• attachment in place of the welding head

shown. Welding torches of this generaldesign are by far the most widely used.

They will handle any oxyacetylene

welding ob, can be fitted with multiflame

!"osebud# heads for heating applications,

and accommodate cutting attachments

that will cut steel $ in. thic%.

• A full&si'e oxygen cutting torch which has

all valves located in its rear body. Another

style of cutting torch, with oxygen valves

located at the front end of its handle.


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Care necessary for blowpipes.

• ever inspect orremove a tip whilethe tbe is hot.Allow the tip andthe tip tbe to cool

at $rst.


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• /eep the ori$ce at the end of the tip clean at alltimes.


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•


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Accessories

Trolley

A trolleyshold be

sed totransportthe weldinge6ipment

and toprevent thecylindersfrom fallingover.


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Eighting


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Tip Cleaners

Tip cleaners areavailable to "eep

the welding tip freeof obstrction. Astraight clean?ame will be easier

to se andprodces betterwelds.


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lashbac" Arrester

This protect against

a fll ?ashbac" andthe danger thatentails.


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• Chec" valves allowgas ?ow in onedirection only

• lashbac" arrestorsare designed toeliminate thepossibility of anexplosion at thecylinder.

• Combination Chec"4lashbac" 7alves canbe placed at the torch

or reglator.


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lash Hard Chec" 7alves.

• These prevents the reverse ?ow ofmixed gases in torch hoses orreglators. The chec" valve permits

forward ?ow of gas and closes whengas begins to ?ow in a reversedirection. The forward ?ow cases a

disc to move overcoming a slightspring tension. owever% a reverse?ow wold case the dis" to seat

tightly against a seal% preventing any


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• lash arrestors are generally made ofa sintered metal alloy. The sinteredstainless!steel $lter prevents ?ame

from moving pstream of thearrestor.


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• >either of these devices protects thetorch or tip. The best way to assrethat accidents don=t happen is for the

welder to follow safety operatingprocedres.


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Table

This strdy

wor"table ismade of steeland fllygalvaniDed for

corrosionprotection. #tincldes aholding clamp

for smallwor"pieces.


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Review

or Cla!! Reci"a"ion


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Class 8ecitation time

* To prevent the occrrence of?ashbac"s% a IIIIIIII sholdbe installed between either

the torch and hoses orreglators and hoses.

A0 a two way chec"

valve.0 ?ame screen.C0 ?ashbac" arrestor.


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. The hose nts for oxygen andacetylene di3er greatly% becase theacetylene hose nt has.

A0 a left hand thread.

0 has a grove ct arond it.C0 may have ACJT stamped on it.


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2. Tre or alse.

An oxygen cylinder has a right!handreglator connection thread and is

painted crimson


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5. Tre or alse K ( A ?int and steel spar" lighter is the

generally sed to light the oxyacetylene

?ame.


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. Acetylene cylinder fse plgs meltat a temperatre of IIIIIIII+C


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L. What is the maximm safe wor"inggage pressre for acetylene gasK

A0 G psig ( "9a)

0 * psig (*,2 "9a)

C0 psig (* "9a)


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-. The color of and oxygen hose on aoxyacetylene welding ot$t is IIIIIIK


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G. The type of safety device is sed ona oxygen cylinder.

A0 A fsible plg

0 A chec" valve

C0 A pressre safety dis"


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M. The color of and acetylene hose ona oxyacetylene welding ot$t is

IIIIIIK


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*,. What type of safety device is sedon a acetylene cylinder.

A0 A spring loaded plg

0 A pressre safety dis"

C0 A fsible plg

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