MD-Series Gas Dryers
Perma Pure MD™-Series gas dryers use exclusive Nafion selectively
permeable membrane tubing to continuously dry gas streams removing only
water vapor. These dryers operate over a wide range of temperatures,
pressures and flow rates, and dry to dew points as low as -45°C.
Principle of Operation
MD-Series gas dryers transfer moisture from one gas stream to a
counter-flowing purge gas stream, much like a shell-and-tube heat
exchanger transfers heat. Water molecules permeate through the Nafion
tube wall, evaporating into the purge gas stream. The water
concentration differential between the two gas streams drives the
reaction, quickly drying the air or gas.
Purge gas should be dry (-40°C dew point) air or other gas. If no
dry gas is available, a portion of the gas dried by the MD-Series dryer
can act as the purge gas in a split-stream or reflux method. Perma
Pure offers three MD-Series dryer product lines as follows:
| Model Number |
MD-050 |
MD-070 |
MD-110 |
| Nafion Tube OD/ID |
0.053"/0.042" |
0.072"/0.060" |
0.108"/0.086" |
| Available Lengths1 |
12,24,48,72,96 or 144 inches |
| Housing Materials |
Stainless Steel or Fluorocarbon or Polypropylene |
| Maximum Flow Rate |
200 cc/min |
4 LPM2 |
4 LPM2 |
1MD-050 dryers are not offered in 96 and 144 inch lengths.
2MD-070 and MD-110 offer approximately the same drying
performance. Specify MD-110 when pressure drop is a concern, MD-070 to
minimize dead volume. For higher flow rates, please see our
PD-Series dryers. |
