A good point, and there are indeed two common systems, mainly, pressure-based flowmeters which use an orifice and a pressure gauge, and vertical tube flowmeters that have a floating weight in a transparent tube. In the welding world they are used interchangeably. But if there was is a...
(Please excuse me if this is not the right forum for this question)
I have been setting up some old regulators for use with welding gases and need a simple way of converting flow from one gas to another since I often find myself trying to measure flow of one gas with a flowmeter calibrated...