Rotameter flow meters are devices that can measure the flowrate of liquids and gases. Generally, the rotameter is a tube made of plastic, glass or metal combined with a float, which responds linearly to the flowrate of the fluid in that tube. OMEGA™ laboratory rotameters are far more versatile due to the use they make of correlation equations. Advantages of the rotameter include the long measurement range, low-pressure drop, simplicity of installation and maintenance, and linear scale of measurement. For the advantages listed above, the rotameter is the most widely-used variable-area flowmeter. It consists of a tapered tube; as fluid passes through that tube, it raises the float. Greater volumetric flow exerts more pressure on the float, lifting it higher. In liquids, the velocity of the flowing liquid combines with buoyancy to raise the float; for gases, buoyancy can be neglected and the float height is set mostly by the velocity of the gas and consequent pressure. Generally, the tube is mounted vertically; with no flow, the float rests at the bottom, but once fluid passes upwards from the bottom of the tube, the float will begin to rise. Ideally, the heights that the float mov...