Specification :

Rotameters are variable area flowmeters that provide field accuracy in an easy-to-read instrument. The principle of operation is simple: air flow passes through a vertical, tapered tube and pushes a ball or float having a diameter slightly less than the smaller tube end. As the ball rises, the clearance between the ball and the tube wall increases. The ball becomes stationary when the diameter of the tube is large enough to allow the total air flow past the ball. The flow rate is determined by noting the engraved scale on the tube at the position of the stabilized ball.

An important feature of the SKC dual ball rotameter is the use of two float balls: a light ( black ball) for indicating low flows and a heavy ( white ball) for indicating high flows. The black ball is read until it is off scale, then the white ball is read.

Two float balls give the broadest flow ranges with the highest accuracy possible in a single rotameter, The two balls give an effective reading scale length of approximately 12 inches in a shorter rotameter.

Note: Low flow rotameters can only be used with pulsation-free pumps.

Dual Ball Rotameter Operating Instructions ( PDF)
About Rotameters
SKC Rotameters are secondary standards and should be calibrated by the user with a primary standard calibrator at regular intervals. Since rotameters are affected by temperature and atmospheric pressure, rotameter calibration should be performed under the conditions of use or a mathematical correction should be used.