Since air pollution monitoring instruments are frequently shifted from one site to another during monitoring. It is possible that due to shifting and transporting instruments flow meter (DGM and Rotameter) fitted may develop leaks and can lead to errors in displayed reading of these units.

To check that flow rate indicated by flow meters and DGM are within acceptable range, calibration of these units need to be done regularly. It is desirable that at least one point calibration of flow monitoring device (DGM and Rotameter) is carried out in laboratory before shifting instrument to field for AAQ monitoring. Intermediate flow checks can also be done at place of monitoring in field.

A Portable system for intermediate checking of Dry Gas Meter and Rotameters has been developed to fulfill this requirements as indicated in ISO/IEC/17025:2005.

The AAS 127C an intermediate calibration checking system fitted with master DGM and stop watch along with connector and tubing which can be used for calibration of DGM either in situ of instrument or an independent unit for flow rate in field. Easy to push modular connector provided in calibrator for easy to operate in field. Kit is supplied with needed tools and data sheets. Rotameter calibration can also be checked at selected flow rate range. Provision for fitting of test piece rotameter is existing in AAS 127C. Kit is supplied with calibration certificate issued by NABL accredited Centre for Calibration Services a division of Ecotech Instruments.