A flowmeter measures and control the flow of a liquid or gas, used especially to control the flow of shielding gases in welding operations. When used on a high pressure cylinder, a flowmeter is usually combined with a regulator into a regulator-flowmeter unit which reduces the high-pressure gas in the cylinder or cylinder manifold to a lower working pressure. The lower pressure is received by the flowmeter and the required gas flow to the welding head is controlled by manual adjustment of a throttle valve.

The flow of shielding gat; is indicated on a flow- meter tube, which is calibrated in liters per minute  (cubic ft per hour) for the particular gas being used. The welder can set the meter for the required flow rate.

The flowmeter tube is calibrated at a positive pressure which normally exceeds any back pressure produced by the welding equipment. This makes it possible to get a true reading of the gas flow.

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