As a related service to asbestos air PCM analysis, Seattle Asbestos Test initiated the service of Rotameter Calibration.
The types of rotameter our lab can calibrate include the following typical widely used rotameter types:
low-capacity meters often used as purge meters (A).
higher capacity, "standard" meters (B) both with female threaded connections (left) and screw-on pipe flanges (right);
metal tube or armored rotameters for higher flow capacities (C)
and for low flows including purging (D).
The method we utilize is either Wet Test or Dry Gas Meter depending on the application and the type of rotameter being calibrated. A typical rotameter calibration procedure is as follows:
Procedure of Rotameter Calibration
Adjust rotameter to a low setting representing about 25% of full scale.
Using a stop watch, measure the time required to draw the appropriate volume
of air through the meter. Record temperature, time and pressure differential
on pump and meter, as appropriate on the Rotameter Calibration.
Repeat the above steps for rotameter settings of 50%, 75% and 100% full
Calculate the actual flow rates using the formula provided.
Record the ambient temperature and pressure, and the pressure differential of
the manometer if using the wet test meter on the Rotameter Calibration Form
Put printed label on the rotameter with calibration date, expiration date, and lab and technician information.