INTRODUCTION

In any air sampling application, accurate measurement of airflow is of paramount importance. This necessitates utilization of appropriate technology for flow measurement and periodic calibration and testing of the air flow meters with primary standards, which in turn need to be highly accurate and stable. Soap bubble film technique, wherein the airflow is computed from the time of flight of a soap bubble between two sensors separated by a fixed distance, has been widely accepted for airflow measurement.

Orifice based airflow measurement has been a traditionally accepted technology and continues to be in wide use in lesser demanding applications.

INSTRUMENT DESCRIPTION & APPLICATIONS 

Model PSI-DFC 1 Digital Flow Calibrator & Model PSI–AFCS 1 Air Flow Calibration System are soap bubble film based digital airflow calibration systems, which are fast, accurate and highly reliable, can serve as primary standards in the calibration of air sampling pumps (vacuum or pressure), rotameters, orifices and other flow devices.  

Model PSI-DFC 1 comes in three models designated PSI-DFC 1 L, PSI-DFC 1 M and PSI-DFC 1 H, corresponding to Low, Medium and High flow ranges of 0.1cc/minute to 500.0 cc/minute; 5.0 cc/minute to 5.00 LPM and 100.0cc/minute to 20.00 LPM respectively. Model PSI-AFCS 1 combines the capabilities of all the three models of PSI-DFC 1 into a single instrument. This is achieved by making the three flow cells interchangeable and designing the control system for adapting any one of the three flow cells. Thus Model PSI-FCS 1 is single instrument, which covers the complete flow range of 0.1 cc/ minute to 20.0 LPM.

Model PEM-TLOC-2 Top Loading Orifice Calibrator is an advanced calibrating instrument, which has been designed for in-situ calibration of High Volume Samplers. It utilizes a solid-state pressure sensor, is suitable for flow range of 250 LPM to 2500 LPM and provides a display accuracy of +/-1%. A low cost Top Loading Orifice Calibrator designated as Model PEM-TLOC-1 comes with a U-tube manometer.. Model PEM-OFC-1 Orifice Flow Calibrator is a standard orifice based flow calibrator, which is designed for higher flow range of 10.0 to 120.0 LPM. Since, it utilizes a high precision orifice and also encompasses a temperature sensor and two pressure sensors for measuring the inlet pressure and differential pressure across the orifice, it is capable of accuracy of +/- 1% over its full range. The applications include calibration of high flow rate rotameters.

Model PEM-DFM Digital Flow Meter is a low cost version of PEM-OFC-1 and gives an accuracy of +/- 2%, which is sufficient for many metering applications, which do not warrant the accuracy of the costlier calibrators.