Calibration of permeation and diffusion devices by an absolute pressure method
Abstract
By following the change in absolute pressure above a permeation device, calibration of such sources can be performed in substantially less than one hundredth the time required using conventional gravimetric procedures. The sensitivity of the Brookhaven calibration procedure is achieved by combining high resolution pressure and temperature measuring instruments with newly designed permeation wafer devices giving low total volume when connected to the pressure measuring device. Using low and ultra-low calibrated permeation devices, the inaccuracies and expense associated with the use of exponential dilution flasks and large quantities of diluent 'zero' gas for providing part-per-billion calibration gases are reduced markedly. In addition, controlled flow rates of noncondensable gases such as carbon monoxide and methane can be provided at microlitre-per-minute rates using porous glass diffusion devices.
- Publication:
-
Calibration in Air Monitoring
- Pub Date:
- 1976
- Bibcode:
- 1976caam.proc..164D
- Keywords:
-
- Air Pollution;
- Calibrating;
- Gaseous Diffusion;
- Permeability;
- Pollution Monitoring;
- Pressure Measurement;
- Carbon Monoxide;
- Flow Velocity;
- Gravimetry;
- Nitrous Oxides;
- Instrumentation and Photography