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MD™-Series
Gas Sample Dryers
Perma
Pure MD™-Series gas sample 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
-60°C.
Product
Feature
- Flow
rates up to 4 l/m
- Operating
temperatures to max. 120° C
- Operating
pressures to 100 psi (absolute)
- Straight
or coiled configuration
- Corrosion
resistant
- Standard
dew points to – 25° C, with –
60° C possible in special cases (contact
factory)
- No
loss of analytes
- No
moving parts
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. Visit
the Purge Gas Configurations page to learn more
about the purge methods Perma Pure customers
deploy in their equipment.
Intelligent
Product Numbering System
Perma
Pure offers the MD-Series dryer with three 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 MD dryer according to the selection
guide and the part number table below:
 1
– Series |
|
4
– Shell and Connector Material |
|
|
MD
(Monotube Dryer) Series
|
MD
|
Polypropylene (PP) |
P |
2
– Tubing Size
|
|
Fluorocarbon
(FEP / PVDF) |
F |
|
0.050'
Nafion™ Tubing
|
050
|
FEP Shell, PP Connectors |
FP |
|
0.070'
Nafion™ Tubing
|
070
|
Stainless
Steel |
S |
|
0.110'
Nafion™ Tubing
|
110
|
FEP Shell, Stainless Connectors |
FS |
3
– Dryer Lengths
|
|
Element
Only (for spare part) |
E |
|
12'
(30 cm)
|
12
|
5
– Connector / Spare Part Type
Sample
Gas Connector Type
|
|
|
24'
(60 cm)
|
24
|
1/16'
Compression (MD-050 only) |
1 |
|
48'
(120 cm)
|
48
|
1/8' Compression |
2 |
|
72'
(180 cm)
|
72
|
1/4'
Compression |
4 |
|
96'
(240 cm)
|
96
|
Spare
Part Type
|
|
|
144'
(360 cm)
|
144
|
Element,
PTFE Inserts, EP O-Rings |
P |
|
288'
(720 cm)
|
288
|
Element, PTFE Inserts, Viton O-Rings |
F |
| |
|
Element,
SS Inserts, Viton O-Rings |
S |
Recommended
Sample Gas Flow Rates
- 0-0.2
lpm: MD-050 Series
- 0.1-2
lpm: MD-070 Series
- 1-4
lpm: MD-110 Series
Notes:
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.
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