Powered by Nafion™ tubing, Perma Pure gas dryers selectively remove water from a gas sample. This selectivity for water vapor allows our dryers to remove more moisture than other gas drying solutions, while keeping analytes in the gas sample.
Monotube Dryer Series (MD-Series) gas dryers contain a single Nafion™ tube. The MD-Series can dry a gas to humidity levels as low as –40 °C dew point and is ideal for applications with flow rates up to 4 lpm.
How it Works
Flow your sample gas through the Nafion™ tubing and flow a dry purge gas outside the Nafion™ tubing, countercurrent to the sample gas flow.
While the partial pressure of water in the purge gas is less than in the sample gas, Nafion™ polymer will selectively transfer water and water vapor from the sample gas across its membrane and into the purge gas flow, yielding a drier sample gas at the sample gas output.
Specifications
| Nafion™ Tubing Outer Diameter Options | 0.050″ (MD-050), 0.070″ (MD-070), 0.110″ (MD-110) |
| Max. Flow Rate | 0.2 lpm (MD-050), 4 lpm (MD-070), 4 lpm (MD-110) |
| Housing Materials Available | Polypropylene, Fluorocarbon, or Stainless Steel |
| Max. Operating Temperatures | 80 °C for polypropylene housing, 100 °C for fluorocarbon or stainless steel housing |
| Sample Gas Port – End Fitting Options | Port 1/16″ Compression (MD-050, Stainless Steel Only) |
| Port 1/8″ Compression (All models) | |
| Port 1/4″ Compression (MD-070, MD-110) | |
| Purge Gas Port – End Fitting Size | Port 1/8″ Compression (MD-050) |
| Port 1/4” Compression (MD-070, MD-110) | |
| Purge Gas Recommendations | Purge gas must be drier than sample gas |
| Purge gas can be instrument quality air (max -40 °C dew point) or nitrogen | |
| Purge gas should flow at 2 or 3 times the sample rate | |
| *Alternate methods to using a purge gas are possible, such as recycling the dry sample gas, or pulling vacuum through the purge gas flow path. See website for more information. | |
| Coiled Configurations | Certain models are shipped coiled based on length. See page 4 for nominal diameters. Contact us for custom coiled solutions. |
Performance by Model
MD-050 Model: Flow rates up to 0.2 lpm
MD-070 Model: Flow rates up to 4 lpm
MD-110 Model: Flow rates up to 4 lpm
The performance curves above are based upon a sample inlet dew point of 20°C and purge flow rate of 2x the sample flow rate. Consult our team for operation with sample gases condensing above ambient temperature.
psid (psi-differential) = [sample gas pressure at inlet (psig)] – [sample gas pressure at outlet (psig)], based on atmospheric pressure at outlet.
Materials Options
| MATERIAL CODE | MATERIALS FOR END FITTINGS AND SHELL |
| P | Molded polypropylene fittings, polypropylene shell |
| F | Molded fluorocarbon fittings, fluorocarbon shell |
| FP | Molded fluorocarbon fittings, polypropylene shell |
| S | Stainless steel fittings, stainless steel shell |
| FS | Molded fluorocarbon fittings, stainless steel shell |
| END FITTING CODE | MATERIALS FOR END FITTINGS |
| 1 | 1/16″ Compression (MD-050, Material codes S and FS only) |
| 2 | 1/8″ Compression (All models) |
| 4 | 1/4″ Compression (MD-070 and MD-110 only) |
Part Number: Model – Material Code – End Fittings Code
Example: MD-050-12-P-2
Physical Dimensions by Model
| MODEL | Nominal Coil Diameter | A | B | C | D | E | A | B | C | D | E |
| Material Codes: F, P, FP | Material Codes: S, FS | ||||||||||
| MD-050-12 | — | 1/8“ | 1/8“ | 1/8“ | 14 3/8“ | 11 1/8“ | 1/8” or 1/16“ | 1/8“ | 1/8“ | 13 5/8“ | 11 1/8“ |
| MD-050-24 | — | 1/8“ | 1/8“ | 1/8“ | 26 3/8“ | 23 1/8“ | 1/8” or 1/16“ | 1/8“ | 1/8“ | 25 5/8“ | 23 1/8“ |
| MD-050-48 | 4″ | 1/8“ | 1/8“ | 1/8“ | 50 3/8“ | 47 1/8“ | 1/8” or 1/16“ | 1/8“ | 1/8“ | 49 5/8“ | 47 1/8“ |
| MD-050-72 | 4″ | 1/8“ | 1/8“ | 1/8“ | 74 3/8“ | 71 1/8“ | 1/8” or 1/16“ | 1/8“ | 1/8“ | 13 5/8“ | 71 1/8“ |
| MD-070-12 | — | 1/4” or 1/8“ | 1/4“ | 1/4“ | 14 1/4“ | 10″ | 1/4” or 1/8“ | 1/4“ | 1/4“ | 13 3/4“ | 10 3/4“ |
| MD-070-24 | — | 1/4” or 1/8“ | 1/4“ | 1/4“ | 26 1/4“ | 22″ | 1/4” or 1/8“ | 1/4“ | 1/4“ | 25 3/4“ | 22 3/4“ |
| MD-070-48 | 7″ | 1/4” or 1/8“ | 1/4“ | 1/4“ | 50 1/4“ | 46″ | 1/4” or 1/8“ | 1/4“ | 1/4“ | 49 3/4“ | 46 3/4“ |
| MD-070-72 | 7″ | 1/4” or 1/8“ | 1/4“ | 1/4“ | 74 1/4“ | 70″ | 1/4” or 1/8“ | 1/4“ | 1/4“ | 73 3/4“ | 70 3/4“ |
| MD-070-96 | 7″ | 1/4” or 1/8“ | 1/4“ | 1/4“ | 98 1/4“ | 94″ | 1/4” or 1/8“ | 1/4“ | 1/4“ | 97 3/4“ | 94 3/4“ |
| MD-070-144 | 7″ | 1/4” or 1/8“ | 1/4“ | 1/4“ | 146 1/4“ | 142″ | 1/4” or 1/8“ | 1/4“ | 1/4“ | 145 3/4“ | 142 3/4“ |
| MD-110-12 | — | 1/4” or 1/8“ | 1/4“ | 1/4“ | 14 1/4“ | 10″ | 1/4” or 1/8“ | 1/4“ | 1/4“ | 13 3/4“ | 10 3/4“ |
| MD-110-24 | — | 1/4” or 1/8“ | 1/4“ | 1/4“ | 26 1/4“ | 22″ | 1/4” or 1/8“ | 1/4“ | 1/4“ | 25 3/4“ | 22 3/4“ |
| MD-110-48 | 7″ | 1/4” or 1/8“ | 1/4“ | 1/4“ | 50 1/4“ | 46″ | 1/4” or 1/8“ | 1/4“ | 1/4“ | 49 3/4“ | 46 3/4“ |
| MD-110-72 | 7″ | 1/4” or 1/8“ | 1/4“ | 1/4“ | 74 1/4“ | 70″ | 1/4” or 1/8“ | 1/4“ | 1/4“ | 73 3/4“ | 70 3/4“ |
| MD-110-96 | 7″ | 1/4” or 1/8“ | 1/4“ | 1/4“ | 98 1/4“ | 94″ | 1/4” or 1/8“ | 1/4“ | 1/4“ | 97 3/4“ | 94 3/4“ |
| MD-110-144 | 7″ | 1/4” or 1/8“ | 1/4“ | 1/4“ | 146 1/4“ | 142″ | 1/4” or 1/8“ | 1/4“ | 1/4“ | 145 3/4“ | 142 3/4“ |
Part Number: Model – Material Code
Example: PD-50T-12-MPP
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Links
Nafion™ Polymer Selectivity
Nafion™ tubing is highly resistant to chemical attack and exhibits highly selective absorption and transfer of compounds. Most substances completely retained in the sample. Although they do not attack or damage the Nafion™ tubing, some polar organic substances are absorbed and consequently lost from the sample flow path. Ammonia and amines are also absorbed and lost to some degree, for which our scrubbers may be able to help. For additional retention information on specific chemicals, use the following calculator.