Lincoln Electric HARRIS 18790-53H Manual Del Usuario

MODEL 187 METAL POWDER SPRAY TORCH OPERATING INSTRUCTIONS
IMPORTANT:
*These instructions are intended to be an addendum to the Harris Products Group
Gas Welding, Cutting, Brazing& Heating Torches Instruction Manual P/N 9505643
REV-H when operating the Model 187.
*Failure to read and understand these and other recommended instructions can
result in serious personal injury.
*Save these instructions for the next operator. Extra copies are available through
your Harris distributor.
A. PREPARATION
1. BASE METAL PREPARATION
The workplace surface must be absolutely clean and free of all foreign material
contamination. Remove all traces of grease and cuttings oils. Remove any rust or other
mill scale, corrosion or other protective coatings to fully expose the base metal. Physical
removal can be accomplished using belt sanding, wire brushing or grit blasting with
aluminum oxide. Chemical removal may require further cleaning to remove possible
residual contamination.
2. TORCH SYSTEM PREPARATION AND ASSEMBLY
(a) Assemble powder spray attachment to the torch handle. Assemble so that powder
lever will be positioned upward during actual operation. Do not tighten with a wrench.
Gas tight seals can be attained by hand tightening only. If a gas tight seal cannot be
attained by hand tightening alone, inspect and replace any worn or damaged O-ring
seals before proceeding.
(b) Attach Tips and tube. Components should be wiped clean with a clean dry cloth before
assembly and inserting into the body. Do not wipe parts with bare hands, dirty gloves
or other potential sources of contamination. Do not expose parts and or components
of torch system to sources of oil or moisture when blowing out powder from ports and
cavities. Either pure nitrogen or clean dry air are recommended for this procedure. To aim
tip/tube in the desired direction. Turn tip nut one half turn counter clockwise, pull forward
slightly to loosen and then rotate to desired position.
WARNING: Do not attempt to rotate while tip nut is still tightened. Tightening the tip
nut compresses the "O" rings and they could become damaged resulting in a leak. Re-
tighten connection after repositioning.
(c) Back-flush the torch powder system before (and after) each use to remove any
residual powder. Moisture plus dust from the powder during use can combine and clog
internal passages and/or cause valve to stick. To back-flush, remove container a with
any powder, hold powder feed handle down, introduce clean pressurized air or nitrogen
through torch oxygen inlet and intermittently stop flow of gas through the tip with finger.
This action will cause residual powder to be expelled from torch through the torches
powder inlet port. This action should also clear injector port cavity.
IMPORTANT: Do not direct a stream of compressed air or nitrogen into powder container,
tips or injector at rear of tip assembly. If removing of caked powder becomes necessary,
use a soft copper wire. DO NOT USE A CONVENTIONAL TIP CLEANER.
(d) Attach powder container with alloy. Before attaching the container with the desired
alloy powder, invert the torch so that the hopper faces downward. Attach the powder
container to the hopper and tighten clockwise.
NOTE: To check torch for proper operating condition without powder – remove container,
remove powder from powder container and reinstall container. Attach regulators, hose
and light torch using proper procedure. To a slightly carburizing flame and depress
powder feed handle. If torch is clear of powder flame will change toward neutral. If flame
does not change, repeat back-flush and cleaning procedure.
B. SYSTEM SET-UP AND OPERATING INSTRUCTIONS FOR HARRIS MODEL 187
POWDER TORCH
These instructions are intended for experienced operators and those working under the
close supervision of experienced operators. For set-up of The Harris Model 187
Powder Torch system, gas hoses and regulators read, understand and follow the related
recommendations in the Harris Instruction Manual P/N 9505643 REV-F.
WARNING: Failure to follow these instructions can result in serious personal injury.
1. ATTACH HOSES AND GAS SUPPLY
Do so according to the specific instructions found in Harris Instruction Manual P/N
9505643. With the exception of the powder spray system this equipment should
be treated like any other standard oxy-acetylene welding, brazing or heating type
equipment. Inspect for damage, check for leaks, purge, ignite, etc. per the Harris
Instruction Manual. Refer to the Model 18790 Powder Torch Tip Chart below for tip
pressure settings.
18790 TIP CHART
OXYGEN ACETYLENE
PART NO. PRESSURE PRESSURE
(PSIG) (PSIG)
18790-53H 22 - 36 7 - 12
18790-48H 30 - 50 4.5 - 7
18790-45H 43 - 72
2. REGULATOR SETTINGS
Suggested minimum and maximum pressures are given on the tip chart. Resulting flow
rates and BTU values are also listed. Harris suggests operating at the highest individual
tip setting possible for greatest operation efficiency and maximum tip life. Hose diameter,
hose length, overall condition of the equipment, etc. could have an adverse effect the on
the final flow performance indicated on the chart. For best performance. Always finalize
set pressures when gases are at a dynamic, at flow, condition.
3. ADJUSTING THE FLAME
The manufacturer of different alloy powder mixtures may require different flame types.
The three basic different flame types are generally referred to as neutral, oxidizing and
or carburizing. They are obtained by varying the specific ratio of oxygen to acetylene
flowing through the tip.
When the oxygen to acetylene gas mixture, supplied through the torch, is at a one–to–
one ratio (1:1), the flame will have a clearly defined blue-white inner cone and a blue
outer envelope. Generally, the outer envelope has little or no chemical effect on molten
metal during hard facing and flame adjustment is referred to as "neutral". When there
is excess of acetylene, there is a third zone, between the inner cone and the outer
envelope that is an intermediate yellowish or whitish color. This zone is called the
excess acetylene feather. It contains hot gaseous carbon that "carburizes" the preheated
surface of the base metal, lowers its melting point, and liquefies the surface, producing a
glistening effect called "sweating."
Often the amount of excess acetylene is expressed as so many times the length of the
inner cone, both measured from the torch tip. The neutral flame is called a 1X flame.
If the feather is twice as long as the inner cone, it is a 2X flame. If the feather is three
times as long as the inner cone, it is 3X flame. The carburizing or excess acetylene flame
is sometimes called a "reducing" flame because it tends to combine with and reduce the
amount of oxides present on the heated metals surface.
For hard facing with relatively low melting temperatures' like nickel-base alloy powders,
the recommended flame is between 1X and 2X. If higher melting temperature cobalt-
base alloy powders are used, a 3X flame is generally recommended. Since the flame
characteristic will change somewhat when powder is being sprayed, it is recommended
that the operator depress the powder feed handle and make the final adjustment with
powder actually being sprayed. The gases passing through the aspirator of the powder
torch system produce a vacuum that aspirates or draws the powder through the flame
and cools the tip. If the torch flame is being operated at too low a volume (choked back)
the powder deposition will not be as aggressive and as much as it should be for best
results. The tip ends also may be damaged by overheating thereby decreasing the tips
normal life.
4. BACKFIRE AND FLASHBACK PRECAUTIONS
Improper operation of the torch may cause the flame to go out with a loud snap or
pop, which is commonly referred to as a "backfire." If this occurs, turn off gas supply
immediately - acetylene first, then oxygen. Correct issue causing the backfire then torch
can be lighted again immediately by following standard proper lighting sequence and
procedures. A "backfire" may be caused by touching the tip against the work piece, by
overheating the tip, by operating the unit at other than recommended gas pressure and
flow, faulty equipment, ect..
OXYGEN ACETYLENE
FLOW FLOW
(SCFH) (SCFH)
40 - 60 21 - 35
26 - 46 14 - 21
3 - 6 21 - 35 11 - 18
BTU/HR
1524 -
2064
915 -
1238
762 -
1033