MK Products CobraTig 150 XM - Manual (Page 4)

washing, depending on the combustible’s
solubility), followed by purging and inert-
ing with nitrogen or carbon dioxide, and
using protective equipment.
Water-filling just below working level may
substitute for inerting.
A container with unknown contents
should be cleaned (see paragraph
above). Do NOT depend on sense of
smell or sight to determine if it is safe to
weld or cut.
Hollow castings or containers must be
vented before welding or cutting. They
can explode.
Explosive atmospheres. NEVER weld
or cut where the air may contain flam-
mable dust, gas, or liquid vapors (such
as gasoline).
D. Compressed Gas Equipment
The safe handling of compressed gas
equipment is detailed in numerous
industry publications. The following
general rules cover many of the most
common situations.
1. Pressure Regulators
Regulator relief valve is designed to pro-
tect only the regulator from overpressure;
it is not intended to protect any down-
stream equipment. Provide such protec-
tion with one or more relief devices.
Never connect a regulator to a cylinder
containing gas other than that for which
the regulator was designed.
Remove faulty regulator from service im-
mediately for repair (first close cylinder
valve). The following symptoms indicate
a faulty regulator:
Leaks - if gas leaks externally.
Excessive Creep - if delivery pressure
continues to rise with downstream valve
closed.
Faulty Gauge - if gauge pointer does
not move off stop pin when pressurized,
nor returns to stop pin after pressure
release.
Repair. Do NOT attempt repair. Send
faulty regulators for repair to manufac-
turer’s designated repair center, where
special techniques and tools are used by
trained personnel.
2. Cylinders
Cylinders must be handled carefully to
prevent leaks and damage to their walls,
valves, or safety devices:
Avoid electrical circuit contact with cylin-
ders including third rails, electrical wires,
or welding circuits. They can produced
short circuit arcs that may lead to a seri-
ous accident. (See 1-3C)
ICC or DOT marking must be on each cyl-
inder. It is an assurance of safety when
the cylinder is properly handled.
Identifying gas content. Use only cylin-
ders with name of gas marked on them;
do not rely on color to identify gas con-
tent. Notify supplier if unmarked. NEVER
DEFACE or alter name, number, or other
markings on a cylinder. It is illegal and
hazardous.
Empties: Keep valves closed, replace caps
securely; mark MT; keep them separate
from FULLS, and return promptly.
Prohibited use. Never use a cylinder or its
contents for other than its intended use,
NEVER as a support or roller.
Locate or secure cylinders so they cannot
be knocked over.
Passageways and work areas. Keep cyl-
inders clear of areas where they may be
stuck.
Transporting cylinders. With a crane, use
a secure support such as a platform or
cradle. Do NOT lift cylinders off the ground
by their valves or caps, or by chains, slings,
or magnets.
Do NOT expose cylinders to excessive heat,
sparks, slag, and flame, etc. that may cause
rupture. Do not allow contents to exceed 55
degrees C (130 degrees F.) Cool with water
spray where such exposure exists.
Protect cylinders, particularly valves from
bumps, falls, falling objects, and weather.
Replace caps securely when moving cyl-
inders.
Stuck valve. Do NOT use a hammer or
wrench to open a cylinder valve that cannot
be opened by hand. Notify your supplier.
Mixing gases. NEVER try to mix any gases
in a cylinder.
NEVER refill any cylinder.
Cylinder fittings should never be modified
or exchanged.
3. Hose
Prohibited use. Never use hose other
than that designed for the specified gas. A
general hose identification rule is: red for
fuel gas, green for oxygen, and black for
inert gases.
Use ferrules or clamps designed for the
hose (not ordinary wire or other substitute)
as a binding to connect hoses to fittings.
No copper tubing splices. Use only stan-
dard brass fittings to splice hose.
Avoid long runs to prevent kinks and abuse.
Suspend hose off ground to keep it from
being run over, stepped on, or otherwise
damaged.
Coil excess hose to prevent kinks and
tangles.
Protect hose from damage by sharp edges,
and by sparks, slag, and open flame.
Examine hose regularly for leaks, wear,
and loose connections. Immerse pressured
hose in water; bubbles indicate leaks
Repair leaky or worn hose by cutting area
out and splicing. Do NOT use tape.
4. Proper Connections
Clean cylinder valve outlet of impurities that
may clog orifices and damage seats before
connecting regulator. Except for hydrogen,
crack valve momentarily, pointing outlet
away from people and sources of ignition.
Wipe with a clean, lintless cloth.
Match regulator to cylinder. Before con-
necting, check that the regulator label and
cylinder marking agree, and that the
regulator inlet and cylinder outlet match.
NEVER Connect a regulator designed
for a particular gas or gases to a cylinder
containing any other gas.
Tighten connections. When assembling
threaded connections, clean and smooth
seats where necessary. Tighten. If con-
nection leaks, disassemble, clean, and
retighten, using properly fitting wrench.
Adapters. Use a CGA adapter (available
from your supplier) between cylinder and
regulator, if one is required. Use two
wrenches to tighten adapter marked
RIGHT and LEFT HAND threads.
Regulator outlet (or hose) connections
may be identified by right hand threads
for oxygen and left hand threads (with
grooved hex on nut or shank) for fuel
gas.
5. Pressurizing Steps:
Drain regulator of residual gas through
suitable vent before opening cylinder
(or manifold valve) by turning adjusting
screw in (clockwise). Draining pre-
vents excessive compression heat at
high pressure seat by allowing seat to
open on pressurization. Leave adjusting
screw engaged slightly on single-stage
regulators.
Stand to side of regulator while opening
cylinder valve.
Open cylinder valve slowly so that regu-
lator pressure increases slowly. When
gauge is pressurized (gauge reaches
regulator maximum) leave cylinder
valve in following position: for oxygen
and inert gases, open fully to seal stem
against possible leak; for fuel gas, open
to less than one turn to permit quick
emergency shut-off.
Use pressure charts (available from
your supplier) for safe and efficient
recommended pressure settings on
regulators.
Check for leaks on first pressurization
and regularly thereafter. Brush with soap
solution. Bubbles indicate leaks. Clean
off soapy water after test; dried soap is
combustible.
E. User Responsibilities
Follow all Safety Rules.
Remove leaky or defective equipment
from service immediately for repair.
Read and follow user manual instruc-
tions.
F. Leaving Equipment Unat-
tended
Close gas supply at source and drain
gas.
G. Rope Staging-Support
Rope staging-support should not be
used for welding or cutting operation;
rope may burn.
1-3 ARC WELDING
Comply with precautions in 1-1, 1-2,
and this section. Arc Welding, properly
done, is a safe process, but a careless
operator invites trouble. The equipment