ME™–Series Moisture Exchangers

General Details

ME™-Series moisture exchangers from Perma Pure are ideal for both drying and humidifying gas streams. This device uses Nafion® membrane tubing technology to transfer water to or from a gas stream. In either application, ME-Series moisture 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 utility requirements.

Principle of Operation

In drying applications, ME-Series moisture 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.

For humidification, the ME-Series will transfer water vapor from the atmosphere to a dry gas flowing within the tubing. Once again, this process occurs in a fraction of a second and is very stable and repeatable under constant operating conditions. A common application is to humidify calibration gases, which allows calibration of analyzers at humidity levels equal to those seen in samples, providing a more consistent calibration/sample baseline.


Benefits of the ME include:

  • Removes 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
Product Numbering System

Intelligent Product Numbering System

Perma Pure offers the ME 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
ME Moisture Exchanger Series ME
2 – Tubing Size
0.050″ Nafion Tubing 050
0.060″ Nafion Tubing 060
0.070″ 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″ Stainless Steel Compression Fittings (ME-060 Only) COMP2
1/4″ Molded Headers for 1/4″ Compression Fittings (ME-110 only) COMP4
Barbed Ends (1/16″ for ME-050 and ME-060; 1/8″ for ME-070 and ME-110) BB


Nafion is not only highly resistant to chemical attack, it also exhibits highly selective absorption and transfer of compounds. Most substances are retained quantitatively. Although they do not attack or damage the Nafion tubing, some polar organic substances are absorbed and consequently lost. Ammonia and amines are also absorbed and lost to some degree. For retention information on specific chemicals, use the following pull down menu.