Table 8-4.-Selection of Shielding Gases for Various GMAW and GTAW Applications

gas that moves up the tube, the higher the ball is lifted. Figure 8-11 shows a cross section of the flowmeter.

The shielding gas regulator has a constant outlet pressure to the flowmeter of about 50 psig. This is important because the flowmeter scales are accurate only if the gas entering them is at that approximate pressure. If you use higher inlet pressures, the gas flow rate will be higher than the actual reading. The reverse is true if the inlet pressure is lower than 50 psig; therefore, it is important to use accurately adjusted regulators. With an accurate flowmeter, these regulators can deliver inert gas flows up to 60 cfh. You should read the scale by aligning the top of the ball with the cfh desired.