Hydrophobic Vent Filter Kit

Properties

1.5mm sheets of Porex brand polypropylene (PP) material were used to achieve the desired filtering. The filter is rated at 120 to 50 microns. This means that the outside of the filter accepts particles in ambient air up to 120 microns, but the porosity is reduced so that by the time ambient air reaches the inside of the data logger, only particles smaller than 50 microns are passed through.

Effect on Reaction Time

Any material that limits airflow over a diffusion sensor will have some small effect on sensor reaction time. However, we have discovered in testing that the PP material does not slow down the reaction time when the data logger interval is set to 30 seconds or greater. If a higher rate of reaction time is required, you should consider a sample draw data logging meter with a built-in pump.

Sensor Filter

In addition to the PP filters, all our NDIR diffusion CO2 sensors have an additional filter on top of the sensor. This filter must remain clean and dry to ensure accurate CO2 level readings. If the CO2 sensor filter gets wet, it will no longer accurately read CO2 levels. Under normal conditions, you may be able to simply let this filter dry out to start working again. However, moisture inside the data logger could ruin other components and will void the warranty.

Warranty

While the filters should last a lifetime, under the most extreme conditions it is possible that they may become contaminated. As a rule, PP may be used at temperatures ranging from 200 to 300° F (93°C to 149°C). Thus, PP products can be sterilized in an autoclave. You may also send the data logger to CO2Meter.com for filter replacement.