Protect Moisture-Sensitive Equipment bySelectively Drying Sample or Carrier Gas

Perma Pure MD™-Series gas dryers use exclusive Nafi on® selectively permeable

membrane tubing to continuously remove only water vapor from gas streams. These

dryers operate over a wide range of temperatures, pressures and fl ow rates while

drying to very low dew points.

Principle of Operation

MD-Series gas dryers transfer moisture from one gas stream to a counter-fl owing

purge gas, much like a shell-and-tube heat exchanger transfers heat. Water molecules

permeate through the Nafi on 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 instrument air or other dry 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

refl ux method. For more infromation about the drying process, including the use of the

sample gas as the purge gas, please visit our website at www.permapure.com.

• Dries continuously

• Removes only water vapor

• Achieves low dew points

• Requires no electricity

• Maintenance-free operation

• No moving parts

• Excellent corrosion resistance

• Short residence time

PERMA PURE

MD™-SeriesGas DryersMD™-SeriesGas Dryers

1 MD-050 Series dryers are not offered in 96 and 144-inch lengths. 2 MD-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 fl ow rates, please see our PD-Series dryers.

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Perma Pure offers three MD-Series dryer product lines:

Bulletin 103

Pressure Drop Calculations:∆ P for MD-050 (inches of water) = Sample fl ow rate (lpm) x length of dryer (inches)∆ P for MD-070 (inches of water) = Sample fl ow rate (lpm) x 0.14 x length of dryer (inches)∆ P for MD-110 (inches of water) = Sample fl ow rate (lpm) x 0.07 x length of dryer (inches) P for MD-110 (inches of water) = Sample fl ow rate (lpm) x 0.07 x length of dryer (inches)

PERMA PURE LLC8 Executive Drive • P.O. Box 2105 • Toms River, New Jersey 08754

(732) 244-0010 • (800) 337-3762 • Fax (732) 244-8140 • www.permapure.com • info@permapure.com

MD™ is a Trademark of Perma Pure LLC. Nafi on is a Registered Trademark of E.I. DuPont

-50

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FLOWRATE (cc/min)

MD-050 Drying Performance

MD-050-12

MD-050-24

MD-050-48

MD-050-72

FLOWRATE (l/min)

MD-070-144

MD-070-96

MD-070-72

MD-070-48MD-070-24

MD-070-12

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0 1 2 3 4

10

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MD-070 and MD-110 Drying Performance

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