BE™-Series Braided Exchangers from Perma Pure can dry or humidify gas streams by equalizing the moisture level in the gas stream with that of the surrounding atmosphere using Nafion™ polymer membrane tubing technology to transfer the water. In either application, BE Braided Exchangers will act to achieve equilibrium between the gas inside the tubing and the surrounding atmosphere. This is done without loss of analytes and with no power requirements.

  • Transfers only water vapor
  • Continuously regenerated
  • Adjusts to ambient humidity
  • No purge gas needed
  • Fast response time
  • Variety of connectors available
  • Excellent corrosion resistance
  • Lightweight and portable

Principle of Operation – Drying

In drying applications, BE-Series Braided Exchangers transfer water vapor from a wet gas stream into the surrounding atmosphere. Drying is complete when the sample humidity level is equal to the ambient humidity level. Since drying proceeds as a First Order kinetic reaction, this level can be reached extremely quickly, usually within 100 to 200 milliseconds. This behavior makes the dryer ideal for applications involving a very humid sample at room temperature. Sample humidity can easily be reduced to as low as 10% of its original moisture content with only a short length of Nafion™ tubing.

Intelligent Product Numbering System

Perma Pure offers the BE Series dryer with four sizes of Nafion™ tubing and in a variety of lengths and connection types. Choose the size based on your flow rate and dryness requirement and build your ME according to the selection guide and the part number table below:

1. Series 2. Tubing Size 3. Length 4. Connector Type
Example BE 060 12 Comp2


1 – Series
BE Moisture Exchanger Series BE
2 – Tubing Size
.050 Nafion Tubing 050
.060 Nafion Tubing 060
.070 Nafion Tubing 070
0.110 Nafion Tubing 110
3 – Dryer Lengths
12” (30 cm) 12
24” (60 cm) 24
48” (120 cm) 48
72”(180 cm) 72
4 – Connector Type
1/8” Molded Header (BE-050 and BE-060 Only) * COMP2
1/8” Stainless Steel Compression Fitting (BE-050 and BE-060 Only) * COMP2-SS
¼” Molded Header for ¼” compression fitting (BE-110 Only) COMP4
Barbed Ends (1/16” for BE-050 and BE-060; 1/8” for BE-070 and BE-110) BB


*The Comp2 connector does not fit a standard size compression fitting. If a compression fitting is needed you must order connector type COMP2-SS.

Perma Pure has created a series of short video presentations to describe the basic functionality of some of our products. The videos are posted below.

Nafion™ Tubing Basic Functionality

Perma Pure MD and PD Gas Sample Dryers Basic Functionality