The Glass Tube Rotameter consists of a tapered tube, usually made of glass, with a "float" (a shaped weight, made of anodized aluminum or ceramic), which is pushed up by the resistance of the flow and pulled down by gravity. The resistance of a given fluid and float cross-section is only a function of the square of the flow rate, see the resistance equation.

　　A higher volume flow through a given area will increase the flow rate and resistance, so the float will be pushed upwards. However, as the inside of the rotameter is tapered (widened), the area around the float through which the medium flows increases, and the flow rate and resistance decrease until the weight of the float reach a mechanical balance.

　　Floats come in many different shapes, spheres and ellipsoids are the most common. The float can have a chute and be partially colored so that it rotates axially when the fluid passes. This shows if the float is stuck because it only rotates when it is idle. The reading is usually taken at the top of the widest part of the float; the center of the ellipsoid, or the top of the cylinder. Some manufacturers use different standards.

　　The "float" must not float in the fluid: it must have a higher density than the fluid, otherwise, it will float to the top even if there is no flow.

　　The mechanical characteristics of the measurement principle provide a flow measurement device that does not require any electricity. If the tube is made of metal, the float position is transferred to the external indicator through magnetic coupling. This capability greatly expands the application range of variable area flow meters, because the measurement can be remotely observed from the processor used for automatic control.

　　Advantages of Glass Tube Rotameter

　　The Glass Tube Rotameter does not require external power or fuel, it only uses the inherent characteristics of the fluid and gravity to measure the flow rate.

　　The Glass Tube Rotameter is also a relatively simple device, which can be manufactured in large quantities with cheap materials and thus is widely used.

　　Since the area of ​​the flow channel increases as the float moves upward, the scale is approximately linear.

　　Using transparent glass, it has strong resistance to thermal shock and chemical effects.

　　Panel Flow Meter is also our product, welcome to consult and purchase.