27423 Scrub Module for CPEC200


The 27423 Scrub Module for the CPEC200 is an accessory to the CPEC200 Closed-Path Eddy-Covariance System. It is used to provide a source of zero air (air that contains no CO2 or H2O) to the CPEC200 for zeroing the EC155 gas analyzer. More often, a compressed-gas cylinder of zero air is used for this purpose; however, the CPEC200 scrub module may be preferable in locations where acquiring and replacing gas cylinders is not convenient. 

The CPEC200 scrub module consists of a pump and a three-stage molecular sieve. The pump is powered via a cable (included) that connects to the CPEC200 system enclosure. The first stage molecular sieve should be replaced once a year to ensure the zero air is free of CO2 and H2O.

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Detailed Description

The CPEC200 Scrub Module provides a source of zero air to the CPEC200. Ambient air enters through an inlet at the base of the module, flows through a first stage molecular sieve, goes through a small pump, and flows through two more stages of molecular sieve. Zero air then emerges from the exhaust or outlet port.

The outlet port should be connected to the CPEC200 System Enclosure via tubing with 0.25 in. Swagelok® connections (pn 21823-L). The molecular sieve in the first stage cylinder should be replaced once a year to ensure the quality of zero air. Molecular sieve 13X with 1.6-2.5 mm bead diameter is recommended. Approximately 400 g (dry basis) is needed to refill one cylinder.


Volume 480 cm3 (29.29 in.3) for each molecular sieve cylinder
Power 2 W (typical)
Dimensions 39.4 x 34.3 x 20.3 cm (15.5 x 13.5 x 8.0 in.)
Weight 9.6 kg (21.1 lb)

Frequently Asked Questions

Number of FAQs related to 27423: 5

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  1. The molecular sieve is a direct replacement for the old magnesium perchlorate bottles. The molecular sieve may be used for any Campbell Scientific analyzer that used the old bottles.

  2. The molecular sieve is a non-hazardous material that can be shipped to any country.

  3. The molecular sieve has been demonstrated here by our engineering department to be effective at removing CO2 and H2O from the air sample. The change was made for two reasons:

    1. It was a safer alternative than using the previous chemicals.
    2. Increased shipping regulations for the chemicals limited the number of suppliers. 
  4. The bottles of sieve for drop-in replacement contain the pellets and a membrane on top. The membrane is necessary to keep the pellets contained while allowing gas to pass over the zeolite. The bottle has the same footprint as the old magnesium perchlorate bottles. The amount in each bottle is listed on the bottle. The amount of sieve needed for each analyzer is the following:

    • The EC150 needs 22 g (drop-in bottle).
    • The IRGASON® needs 22 g (drop-in bottle).
    • The EC155 needs 22 g (drop-in bottle).
    • The AP200 needs 500 g (refill).
    • The 27423 needs 1000 g (refill).
    • The 31022 needs 500 g (refill).
  5. Yes. For more information, refer to the "CPEC200 Scrub Module Installation, Operation and Maintenance" appendix in the CPEC200 Closed-Path Eddy-Covariance System Instruction Manual.

Listed Under

Common Accessory for the following products: