Glass Tube RotameterÂ is a Variable Area Flow Meter. A rotameter comprises of a decreased cylinder, commonly made of glass, with a ÃÂÃÂ¢ÃÂ¢Ã¢ÂÂÃÂ¬ÃÂÃ ÂdriftÃÂÃÂ¢ÃÂ¢Ã¢ÂÂÃÂ¬ÃÂ¢Ã¢ÂÂÃÂ¢ made of SS or PTFE. The differential weight over the annulus territory is steady. The buoy travels through the decreased cylinder here and there regarding liquid stream. The vertical situation of the buoy as shown by scale is the proportion of the quick stream rate.