Important Operating Notes - ESAB W-300 Manuel D'instructions

SECTION 3

IMPORTANT OPERATING NOTES

1. Pressures given in Tables 2 through 8 are measured at the
regulator using 25-ft. long hoses (1/4-in. I.D. up through size
No. 30 welding/heating head or for cutting up to 3-in. thick
steel; 3/8-in. I.D. for larger heads or cutting nozzles). If longer
hoses are required, only 3/8-in. I.D. hoses should be used
and pressure drop between regulator and torch should be
considered. Use test gauge adaptors to check for proper
pressure at torch if using long hose lengths, or if there are
doubts about the adequacy of gas flows. Do NOT use hose
line check valves when operating No. 55 and larger heads.
2. Head size number on each welding and heating head indi-
cates the rated acetylene flow capacity in cubic feet/hour
(cfh). For example, No. 55A requires about 55 cfh of acety-
lene at the given operating pressures. However, on heating
heads designed for other fuel gases, the size indicates the
approximate equivalent heating capacity in terms of acety-
lene flow. For example, note from Table 3 that No. 100A
and No. 100FG provide the same average heating output
(147,000 Bt/hr) but No. 100FG head really requires about 62
cfh of FG-2, 57 cfh of propane, or 147 cfh of natural gas.
For consumption purposes, the following are the oxygen
fuel gas ratios normally required for welding and heating:
1.1 to 1.5 cfh oxygen/1.0 cfh acetylene
3.2 to 3.6 cfh oxygen/1.0 cfh FG-2
3.5 to 4.5 cfh oxygen/1.0 cfh propane
1.7 to 2.0 cfh oxygen/1.0 cfh natural gas
* Based on that max. hourly flowrate should not exceed 1/7 of cylinder capacity at 70° F.
Example 1/7 (300 of WK cyl.) = 43 cfh max.
*Based on max. continuous withdrawal rate of 110 cfh for 104 lb. cylinder, 1/2 full @ 70o F.
**Based on max. continuous withdrawal rate of 65 cfh for 100 lb. cylinder, 1/2 full @ 70o F.
Withdrawal rate will increase with wind velocity and intermittent usage; reduce with lower temperature.
Head Flowrate, Min. No. of Cylinders Required*
Size cfh WK Cyl (300 cf )
55 55
70 70
100 100
150 150
200 200
250 250
300 300
FG-2 (104 lb. cyl.) Propane (100 lb. of cyl.)
Head Flowrate, Min. No. of
Size cfh Cyl. Req'd*
70 43 1
100 62 1
150 93 1
200 124 2
300 186 2
500 310 3
3. Correct pressure and flow must be maintained for proper
operation of a welding or heating head. If a tip is "starved"
due to insufficient flow of fuel gas, the tip may overheat and
cause backfire or flashback.
An acetylene or a liquefied fuel gas (LFG) cylinder has a
limited capacity for delivering fuel to the tip; therefore, it is
extremely important to manifold 2 or more cylinder when
operating larger heads to assure adequate supply of fuel gas
to the tip. The rate of withdrawal depends on type of fuel
gas cylinder size, the contents remaining, and the outside
temperature. Tabulated below is the number of the more
commonly used cylinders recommended for manifolding
when using larger heads. If using other cylinders or gases,
check with your fuel gas supplier for recommended with-
drawal rate information.
4. The tables show average values based on typical condi-
tions. The type and quality of steel, its surface condition,
and purity of oxygen, etc., will always have a bearing on the
end results.
WLT Cyl. (390 cf )
2 1
2 2
3 2
4 3
5 4
6 5
7 6
Flowrate, Min. No. of
cfh Cyl. Req'd**
40 1
58 1
86 2
116 2
174 3
290 5
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OPERATION