Dual-Ball Rotameters

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.
Ordering Information           Online Ordering

Measuring Range (ml/min)	Cat.No.
235 to 2350 and 500 to 5000	320-235-4600
4 to 49 and 24.5 to 245	320-5-245
5 to 5000	320-5-4600

Dual Ball Rotameter Operating Instructions

Field Rotameters

Features Easy-to-read scales Rugged and portable Low cost Provisions for panel mounting Multiple flow ranges

Field Rotameter Operating Instructions (PDF)

Instrucciones de Operación Catálogo No. 320 Series (PDF)

Applications

• Low flow and high flow air samplers
• Gas analyzers
• Chromatography systems

About Field Rotameters

These small and lightweight, single ball rotameters represent a new and durable design of portable air flowmeters. SKC Field Rotameters are crafted of see-through acrylic with tapered hose connectors attached to solid brass fittings. A removable section of Tygon^® tubing with a Luer taper adapter is included. A float ball is clearly visible behind decaled graduations on the rectangular face. The easy-to-read scales are ideal for performing routine verifications of air flow easily in the field with reproducible results.

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.

Ordering Information           Online Ordering

Measuring Range (L/min)	Scale	Full Scale Accuracy	Cat. No.
0.05 to 0.5	2"	± 5%	320-2A05
0.1 to 1.0	4"	± 3%	320-4A1
0.4 to 5.0	4"	± 3%	320-4A5
4 to 20	4"	± 3%	320-4A20L
4 to 50	4"	± 3%	320-440
5 to 30	4"	± 3%	320-530
3 to 30	4"	± 3%	320-100 †

† Fitting adapted for use with QuickTake Sample Pumps


Field Rotameter Spec. Sheet (PDF)

Field Rotameter Operating Instructions (PDF)

Instrucciones de Operación Catálogo No. 320 Series (PDF)

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The ball-type flowmeters and rotameters built into most air sampling pumps are primarily intended to serve as flow indicators and are, therefore, of low accuracy. These flowmeters as well as rotameters must be calibrated against a primary standard such as a film flowmeter or electronic calibrator (Defender) to verify accuracy.

When using a rotameter at a different temperature and pressure than when it was calibrated, the following formula can be used to calibrate the new flow rate: Q2 = Equivalent flow rate in L/min or ml/min at calibration location Q1 = Measured flow rate in L/min or ml/min P1 = Pressure in mm Hg at sampling location P2 = Pressure in mm Hg at calibration location T1 = Temperature in degrees Kelvin (degrees Celsius + 273) at sampling location T2 = Temperature in degrees Kelvin (degrees Celsius + 273) at calibration location

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This page was last modified July 17, 2008