Testing For Leaks; Operating Precautions - ESAB SCT-4200 Serie Instrucciones

TESTING FOR LEAKS

Every cutting outfit should be thoroughly tested for
leaks after it is first hooked up, and at regular intervals
thereafter. After all connections have been made, make
sure all valves on the torch handle are closed. Then
adjust regulators, or open station valves, to apply 60
psi oxygen pressure and up to 10 psi fuel gas pressure
on the hoses.
Using Leak Test Solution (P/N 998771), or any other
solution suitable for oxygen service, check for leaks at
the cylinder valves, the cylinder-to-regulator connec-
tions, the regulator-to-hose connections, and the hose-
to-torch connections. If bubbling at any point indicates
leakage, tighten the connection. If this does not stop
the leakage, close the appropriate cylinder valve, open
the corresponding torch valve to remove all pressure
from the line, and finally release the regulator pressure-
adjusting screw by turning it counterclockwise; then
break the leaky connection, wipe metal seating surfaces
with a clean dry cloth, and examine them for nicks and
scratches. Remake the connection(s) and retest. Do
not try to light the torch until you are satisfied that all
connections are gas-tight.
After lighting the torch and adjusting the flames, use leak
test solution to check for leakage at all torch valves and
at the nozzle nut.
LIGHTING AND FLAME ADJUSTMENT
1. Open the fuel gas valve about one turn and light
the gas at the nozzle with a friction lighter. DO NOT
USE A MATCH. Use of a match can seriously burn
your hand.
2. Open the preheat oxygen valve until a neutral flame
is obtained.
3. Then open the cutting oxygen valve and adjust
flames with the fuel gas valve. Flames are hottest
when inner cones are shortest. Do not throttle the
preheat oxygen valve unless flames blow off, or burn
away from the nozzle.
NOTE: Because of the several factors involved (injec-
tor, nozzle size, gas pressures) the adjustment
procedures given above do not apply in all situ-
ations. However, this is a good rule-of-thumb if
you want preheat flames at maximum effective-
ness. You should usually be able to keep one
preheat valve wide open if regulator oxygen
pressure has been set correctly for the nozzle
in use.
SHUTTING OFF
Release the cutting oxygen valve lever. Then close the
fuel gas valve, and finally the preheat oxygen valve.
If operations are to be stopped for half-hour or more, all
pressure should be released from the torch, hoses, and
regulators by doing the following:
1. Close each cylinder or station valve.
2. Open torch valves.
3. After relieving the gases, back out the pressure-
adjusting screw of each regulator and close the
torch valves.

OPERATING PRECAUTIONS

Backfire: Improper operation of the torch may cause
the flames to go out with a loud "pop". Such a backfire
may be caused by contact of nozzle with the work, by
spatter from the work, by the use of incorrect gas pres-
sures, or by leakage at the cutting nozzle seats due to
dirt or nicks on seats or to a loose nozzle nut.
Flashback: Under certain circumstances, the flame may
not "pop" out (backfire) but instead burn back inside
the torch with a shrill hissing or squeal. This is called
a "flashback". A flashback should never occur if (1) the
equipment is in good condition; (2) preheat ports on cut-
ting nozzles or welding tips are cleaned frequently; (3)
operating pressures are correct; and (4) throttle valves
are adjusted properly. Should a flashback occur, IMME-
DIATELY shut off the torch. Allow it to cool off for at least
a minute. Then check your nozzle or tip, gas pressure,
readjust regulators if necessary, and relight the torch. If
flashback recurs, send the torch to your distributor or to
ESAB Remanufacturing Center, 411 S. Ebenezer Road,
Florence, SC 29501 for repair.
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