INSTRUCTIONS for
These INSTRUCTIONS are for experienced operators. If you are not fully familiar with the principles of operation and safe practices for gas regulation equipment, we urge you to read our booklet “Precautions and Safe
Practices for Arc Welding, Cutting and Gouging,” Form 52-529. Do NOT attempt to install or operate this equipment until you have read and fully understand these instructions. If you do not fully understand these instructions, contact your supplier for further information.
F-15-333
April, 1996
L-33 FLOWMETER
I. DESCRIPTION AND SPECIFICATIONS
The L-33 flowmeter (P/N 21988) is calibrated to operate
with an upstream (inlet) pressure of 25 ± 1 psig and to
meter any one of three different gases in cubic feet per
hour (cfh): helium, argon or C-25 (75% argon - 25% carbon dioxide). Each of the two faces of the round plastic
tube has a calibrated scale for one of the above gases.
The flow readings are accurate with ± 5% of the maximum calibrated scale reading for each gas. The range
of each calibrated scale is as follows:
Helium ................................................20 to 150 CFH
Argon/C-25 ...........................................10 to 50 CFH
The L-33 is equipped with standard “B”-size (CGA-032)
inert gas connections (5/8-in — 18 R.H. threads, male
inlet and female outlet). The L-33 will connect directly to
any inert gas or carbon dioxide regulator with matching
threads. If pipeline installation is desired, install a suitable commercially cleaned shut-off valve and a 1/4-in.
NPT (male) x “B” inert gas (CGA-032) (female) fitting
(P/N 74S76) for each L-33 flowmeter to be used.
Also available for pipeline installations are L-33 inert gas
and CO2 flowmeters with 1/4-in. NPT female connections (P/N’s 21989 and 21990 respectively). The CO
flowmeter has a flow range of 20 to 80 cfh and it is calibrated for 80 psig which reduces “freeze-up” possibilities of CO2 at high flows (up to 40 cfh). If higher flow
rates or duty cycles are required, use CO2 heater, P/N
950578.
II. PRESSURE AND FLOW CONVERSIONS
If operating at pressures other than 25 psig, you will not
be reading the actual flow rate from the scale. The true
flow rate is determined by multiplying the indicated flow
reading by the pressure correction factor (see table)
Example: If you are operating a 25 psig calibrated L-33
flowmeter from 50 psig pipeline and you are reading 40
cfh from the flowmeter scale, the actual flow rate is 40 x
1.28 = 51.2 cfh.
Other Conversions:
1. To convert flow to liters per minute (L/min) multiply
indicated flow reading by 0.47.
2. For inert gas mixtures other than the C-25, consult
your gas supplier for the conversion factor that will
apply to one of the calibrated scales.
Pressure Correction Factor
Inlet 25 psig
Pressure Calibrated
psig Flowmeter
15 0.86
25 —
30 1.06
40 1.17
50 1.28
60 1.37
70 1.46
80 1.54
90 1.62
100 1.70
2
INERT GAS OR CARBON DIOXIDE can cause suffocation in confined spaces.
• Always work in well ventilated area.
• Prevent leaks.
• Follow operating instructions on this sheet.
• This flowmeter must be installed, operated, and main-
tained only by trained servicemen.
• For complete safety information on welding and cut-
ting equipment, read form 2035 (oxy-fuel gas) and 52529 (arc welding). For safety information on gases,
see your supplier.
• Do not use with oxygen.
Be sure this information reaches the operator.
Y ou can get extra copies through your supplier .
SAFETY PRECAUTIONS
These Safety Precautions are for your protection. They summarize precautionary information from the references listed
in Additional Safety Information section. Before performing any
installation or operating procedures, be sure to read and follow the safety precautions listed below as well as all other
manuals, material safety data sheets, labels, etc. Failure to observe Safety Precautions can result in injury or death.
PROTECT YOURSELF AND OTHERS - Some
welding, cutting and gouging processes are
noisy and require ear protection. Hot metal can
cause skin burns and heat rays may injure
eyes. Training in the proper use of the processes and equipment is essential to prevent
accidents. Also:
1. Always wear safety glasses with side shields in any work area,
even if welding helmets, face shields, or goggles are also required.
2. Wear flameproof gauntlet type gloves, heavy long-sleeve shirt,
cuffless trousers, high-topped shoes, and a welding helmet or
cap for hair protection, to protect against hot sparks and hot
metal. A flameproof apron may also be desirable as protection
against radiated heat and sparks.
3. Hot sparks or metal can lodge in rolled up sleeves, trousers
cuffs, or pockets. Sleeves and collars should be kept buttoned,
and open pockets eliminated from the front of clothing.
4. Protect other personnel from hot sparks with a suitable nonflammable partition or curtains.
5. Use goggles over safety glasses when chipping slag or grinding. Chipped slag may be hot and can travel considerable distances. Bystanders should also wear goggles over safety
glasses.
FIRES AND EXPLOSIONS - Heat from a flame
can act as an ignition source. Hot slag or sparks
can also cause fires or explosions. Therefore:
1. Remove all combustible materials well away from the work
area or completely cover the materials with a protective nonflammable covering. Combustible materials include wood,
cloth, sawdust, liquid and gas fuels, solvents, paints and coatings, paper, etc.
2. Hot sparks or hot metal can fall through cracks or crevices in
floors or wall openings and cause a hidden smoldering fire on
the floor below. Make certain that such openings are protected
from hot sparks and metal.
3. Do not weld, cut, or perform any other hot work on materials,
containers, or piping until it has been completely cleaned so
that no substances on the material can produce flammable or
toxic vapors. Do not do hot work on closed containers. They
may explode.
4. Have fire extinguishing equipment handy for instant use, such
as a garden hose, a pail of water or sand, or portable fire
extinguisher. Be sure you are trained in its use.
5. After completing operations, inspect the work area to be sure
that there are no hot sparks or hot metal which could cause a
later fire. Use fire watchers when necessary.
6. For additional information, refer to NFPA Standard 51B, “Fire
Prevention in Use of Cutting and Welding Processes”, which
is available from the National Fire Protection Association,
Batterymarch Park, Quincy, MA 02269.
FUMES AND GASES - Fumes and gases, particularly in confined spaces, can cause discomfort or injury. Do not breathe fumes or
gases from welding or cutting, Therefore:
1. Always provide adequate ventilation in the work area by natural or mechanical ventilation means. Do not weld, cut, or gouge
on materials such as galvanized steel, stainless steel, copper,
zinc, lead, beryllium, or cadmium unless positive mechanical
ventilation is provided. Do not breathe fumes and gases from
these materials.
2. If you develop momentary eye, nose, or throat irritation while
operating, this is an indication that ventilation is not adequate.
Stop work at once and take necessary steps to improve ventilation in the work area. Do not continue to operate if physical
discomfort persists.
3. Refer to ANSI/ASC Standard Z49.1 listed below for specific
ventilation recommendations.
4. WARNING: This product, when used for welding or
1. Always have qualified personnel perform the installation,
troubleshooting, and maintenance work. Do not operate or
repair any equipment unless you are qualified to do so.
2. Keep all oxy-fuel equipment free of grease or oil. Grease, oil,
and other similar combustible materials, when ignited, can burn
violently in the presence of oxygen.
3. Do not abuse any equipment or accessories. Keep equipment
away from heat and wet conditions, oil or grease, corrosive
atmospheres and inclement weather.
4. Keep all safety devices in position and in good repair.
5. Use equipment for its intended purpose. Do not modify it in
any manner.
1. Use the proper gas for the process and use the proper pressure reducing regulator designed to operate from the compressed gas cylinder. Do not use adaptors to mount the regulator on the cylinder. Maintain hoses and fittings in good condition. Follow manufacturer’s operating instructions for mounting the regulator to the gas cylinder.
2. Always secure cylinders in an upright position by chain or strap
to suitable hand trucks, benches, walls, post, or racks. Never
secure cylinders to work tables or fixtures where they may
become part of an electrical circuit.
3. When not in use, keep cylinder valves closed. Have the valve
protection cap in place on top of the cylinder if no regulators is
installed. Secure and move cylinders by using suitable hand
trucks. Avoid rough handling of cylinders.
4. Locate cylinders away from heat, sparks, or flame of a welding, cutting, or gouging operation. Never strike an arc on a
cylinder.
5. For additional information, refer to CGA Standard P-1, “Precautions for Safe Handling of Compressed Gases in Cylinders:, which is available from the Compressed Gas Association, 1235 Jefferson Davis Highway, Arlington, VA 22202.
The following publications, which are available from the American
Welding Society, 550 N.W. LeJuene Road, Miami, FL 33126, are
recommended to you:
1. ANSI/AWS Z49.1 - “Safety in Welding and Cutting”.
2. AWS F4.1 - “Recommended Safe Practices for the Preparation for Welding and Cutting of Containers and Piping That
Have Held Hazardous Substances”/
3. AWS SP - “Safe Practices” - Reprint, Welding Handbook.
cutting, produces fumes or gases which
contain chemicals known to the State of
California to cause birth defects and, in
some cases, cancer. (California Health &
Safety Code §25249.5 et seq.)
EQUIPMENT MAINTENANCE - Faulty or improperly maintained equipment, such as torches, hoses
and regulators, can result in poor work, but even
more important, it can cause injury or death
through fires. Therefore:
GAS CYLINDER HANDLING - Gas cylinders, if mishandled, can rupture or explode violently . Sudden
rupture of a cylinder, valve or relief device can injure or kill you. Therefore:
ADDITIONAL SAFETY INFORMATION - For more
information on safe practices for oxy-fuel welding
and cutting equipment, ask your distributor for a
copy of “Precautions and Safe Practices for Gas
Welding, Cutting, and Heating”, Form 2035. Gas
apparatus safety guidelines are also available on
video cassettes from your distributor.
MEANING OF SYMBOLS - As used throughout
this manual: Means Attention! Be Alert! Your
safety is involved.
Means immediate hazards which, if not avoided,
will result in immediate, serious personal in-
jury or loss of life.
Means potential hazards which could result in
personal injury or loss of life.
Means hazards which could result in minor
personal injury.
2
SP-GA 10/98
III. INST ALLA TION
Using Cylinder Gas: An inert gas or a carbon dioxide
regulator must be used. The regulator should be
equipped with a delivery pressure gauge graduated in
increments of 1 or 2 psi so that the pressure to the flowmeter can be set to 25 psig ± 1. Be sure to read the
complete instructions packed with the regulator before
connecting. Position the regulator so that the flowmeter
will end up in a vertical position. Connect hose to the
outlet connection of the flowmeter. Tighten all connections firmly with a wrench.
Using Pipeline Gas: Connect the flowmeter to regulator or station valve. Be sure to align the flowmeter in a
vertical position. Connect delivery line to the flowmeter
outlet connection and tighten all connections firmly with
a wrench.
NOTE: If operating the flowmeter with solenoid valve
operation, the solenoid valve must be located
upstream. It is recommended to connect at least
a 10-ft. long 5/16 or 3/8-in. I.D. hose between
solenoid valve and flowmeter. Do NOT place
valve immediately upstream of flowmeter. The
hose should cushion the sudden release of gas
pressure when the valve opens to prevent
breaking the metering tube and other parts.
IV. OPERATION
From Regulator:
1. Close the flowmeter valve and then SLOWL Y open
the cylinder valve.
2. Turn in the regulator pressure-adjusting screw until
the regulator delivery pressure gauge reads 27 - 30
psig.
3. Open valve (torch or other gas-using device) downstream of the flowmeter.
4. Open flowmeter valve to the desired flow and readjust regulator to deliver exactly 25 psig. It may be
necessary to manipulate both the regulator pressureadjusting screw and the flowmeter valve to get the
exact pressure and flow condition.
5. Close the downstream valve.
After setting up and before starting operations, test all
connections for leakages using Leak Test Solution (P/
N 998771) or a soap-and-water solution. Bubbling of the
solution will indicate leakage and should be corrected
before starting work.
From Pipeline
1. If pipeline pressure is not delivering a pressure of
25 psig ± determine the desired flow by using the
correction table on the front page. Correction factors for in between supply pressures can be interpolated.
2. With flowmeter valve closed. SLOWL Y open the station valve.
3. Open valve (torch or other gas-using device) downstream of flowmeter and then open flowmeter valve
and adjust to the corrected flow reading.
4. Close downstream valve and leak-test the entire setup as described above.
V . MAINTENANCE
If equipment does not operate properly, stop work
immediately and investigate the cause of the malfunction. Maintenance work must be performed by
an experienced person. Do not permit untrained persons to inspect, clean, or repair this equipment. Use
only recommended replacement parts.
T est for Leakage
Periodically , all joints of a flowmeter should be tested for
leakage. Wipe the metal-to-metal seating surfaces of
the inlet nipple and outlet connection with a clean greasefree cloth. Connect flowmeter as directed by the installation procedures, making sure flowmeter valve is closed,
and apply 25 psig pressure to the flowmeter . Using Leak
Test Solution (P/N 998771), or a soap-and-water solution, check flowmeter for leakage as follows:
1. Apply leak test solution on all flowmeter parts including the inlet connection. Also, place a film of leak
test solution over the opening of the outlet connection. Leakage will be indicated by bubbling of the
solution.
2. Close gas supply valve and open flowmeter valve
to release all gas from flowmeter. If leakage was
noted, have the flowmeter repaired. Wipe off the leak
test solution thoroughly with a clean oil-free cloth.
Safety Relief Device
A safety relief device is mounted on top of the flowmeter
which will pop and release gas in case of overpressure.
It is not a resealable relief device. If the safety relief device does vent, close the cylinder valve or inlet supply
valve immediately. Gas remaining in the regulator will
be released through the relief device. Have the regulator supplying the gas repaired and checked over thoroughly .
NOTE: The safety relief device is designed for protect-
ing the flowmeter; not hose or equipment downstream.
General
The following are recommended for maintaining the L33 in good working condition:
1. Replace “O”-rings periodically or whenever there
are signs of leakages. Before installing new "O"-
3
rings, lubricate lightly with silicone lubricant P/N
17672 (1 oz. tube).
2. Wipe the metal seating surfaces on the inlet and outlet connections. Replace if seats are scored. When
replacing, apply a single turn of 1/4-in. wide Teflon
tape on the male 1/4-in. NPT threads.
3. Clean the polycarbonate inner tube with mild soap
and water only and dry thoroughly. To remove the
tube, unscrew the hex retainer. Carefully tilt the flowmeter to slide the tube and ball out (ball should not
pass through the bottom of the tapered tube). Pull
the float stop off of the retainer, make sure holes
through stop are clear.
4. Clean the polycarbonate outer tube (21561) with
water
or alcohol and dry thoroughly. To remove tube, un-
screw it counterclockwise from the brass body .
5. Clean dirt, chips, or any other foreign matter from
valve stem (639400) with alcohol or mild soap-andwater or wipe off with a clean lint-free, oil-free cloth.
6. The bursting-disk (92Z08) and the two washers
(92Z07) should be replaced whenever the flowmeter
is overhauled and, of course they must be replaced
whenever the disk has ruptured due to overpressure.
Handle the replacement disk carefully . It is a very thin
copper foil that will crinkle easily. Use only one disk
and it must be sandwiched between the two washers. Do not tighten the cap (31Z86) more than 20 in.lbs. Overtightening may damage the disk.
7. Leak test the reassembled flowmeter as described
above.
VI. REPLACEMENT P ARTS
Replacement parts for L-33 flowmeter as currently manufactured are keyed in the illustration below . When ordering,
supply both part number and description. DO NOT ORDER BY PART NUMBER ONLY. Parts can be ordered from
your welding equipment distributor or from ESAB Welding & Cutting Products, Customer Service Department, Florence, SC.
LABEL
954393 (AR+HE)
954392 (CO2)
DISK- 92Z08
O-RING - 526185
BALL - 53A61
CALIB. TUBE - 32145 (AR& HE)
O-RING - 18308
O-RING - 996526
CAP - 31Z86
SCREEN - 17726
WASHERS - 92Z07
RET AINER - 21562
STOP - 186W46
TUBE - 21561
O-RING - 21696
32144 (CO2)
INLET CONNECTION
19X63
(P/N 21988 ASS’Y ONLY)
O-RING - 86W51
L-33 Flowmeter Assembly with “B”-size (CGA-032) Male Inlet Connection - P/N 21988
L-33 Flowmeter Assembly with 1/4-in. NPT Female Inlet Connection - P/N 21989
CO2 Flowmeter Assembly with 1/4-in. NPT Female Inlet Connection - P/N 21990
F-15-333 4/96 2M Printed in U.S.A.
STEM - 639400
V ALVE BODY - 639401
KNOB - 639402
SCREW - 185W79
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