One of the easiest to use flow meters on the market today, the rotometer functions based on very basic but very effective principles. Like all flow meters, it is meant to gauge the rate of flow as well as other substance characteristics of a liquid or gas passing through a piping system. It is often connected to an alarm system, which when activated sends the message to a valve that alters the flow rate if something is wrong. The number of industries that utilize rotometers are vast because they are so easily applied to many piping applications.
The basic design involves fundamental physics; gravity and pressure work together to move the parts of a rotometer and provide a visual reading for the operator of the piping system. The body is a vertical tube made of glass or clear plastic that is sometimes accented by metallic fittings and may also be round, rectangular or triangular in shape. When the substance flows through it the pressure of the flow moves the small but dense ball inside it. When the ball is moving up it is because of the high intensity of flow which is powerful enough to counteract the gravity that would keep the ball at the bottom of the flow. When the flow is gentle and slow, they ball remains at the bottom of the tube. As long as a rotometer is kept vertical it will read the flow accurately and without using any additional power source.
Like a flow indicator, the rotometer does not give any digital or analog readout but is read by first hand sight alone. Many processing industries utilize these cheap but efficient tools, which are named for the ball within the tube that rotates when a substance is passing through and it moves to do the reading.