Rotameter FAQ and Calibration Information

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This page contains calibration tables as well as other supporting information for users of MATHESON Rotameters.

Use the Contact Us link at the top of the page if you have any questions or comments.  Thank you.



MATHESON Flowmeter Operation Instructions


MATHESON Flowmeter Calibration Information


Rotameter FAQ

How do I read the ball float in the tube?

Take the reading from the middle of the ball.


How do I take a reading with two ball floats in the tube?

Read the top ball until it goes above the top of the chart, then read the lower ball. (The black ball is glass and the silver ball is stainless steel).

how to read a rotameter with two floats


Why are there two ball floats in the FM-1050 tube?

The flow range of the tube is extended with two ball floats instead of one.


What are the units for 0-150 scale on the FM-1050?

The 0-150 scale is in millimeters. Calibration charts for the specific gas and pressure can be found above.


Why are there different FM-1050 calibration charts for different pressures?

The pressure that you choose is the pressure that is in the tube. Most people have the valve on the inlet and the rotameter flows to an instrument or process at atmospheric pressure so in that case you would use the 0 PSIG charts. Do not use the pressure supplying the rotameter if the valve is on inlet. If your valve is on outlet of the rotameter then either use a pressure correction factor or use a calibration chart corresponding to the pressure in the tube. We have many charts that are for 20 PSIG and 50 PSIG.

rotameter calibration with valve on inlet

rotameter calibration with valve on outlet

Need a flowmeter or other related specialty gas equipment?

specialty gas equipment

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