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PRINCIPLE OF OPERATION
MDH™- Series
Gas Dryer
User Manual
8 Executive Drive
Toms River, N.J. 08755
Phone: 732/244-0010
Fax: 732/244-8140
e-mail: [email protected]
Web Site: www.permapure.com
PERMA PURE
Perma Pure’s heated MDH-Series gas dryers
were specifically created to dry gas samples with
dew points higher than ambient temperature
without requiring separate heating elements or
insulation. Proprietary Nafion technology selectively removes only water from sample gases,
leaving the rest of the gas sample unaffected.
Unlike chillers and condensers, Perma Pure’s
MDH dryers remove water directly from the vapor
phase, preventing the loss of water-soluble gases
through dissolution in condensate.
Designed to handle gas flows of up to 1.5 lpm,
the heated MDH-Series gas dryers can dry gases
with as much as 30% water by volume. The
compact design can be incorporated easily into
analyzer cabinets or used as a stand-alone
device. The dryers are currently available for use
with 110 VAC.
MDH™-Series gas dryer units consist of a Perma
Pure MD-Series dryer encased in a housing with
half of the dryer heated to a constant temperature
of 80°C to prevent condensation.
The dryer consists of a single Nafion
®
tube within
a fluorocarbon shell. Dry purge gas flowing over
the exterior surface of the Nafion tubing continuously extracts water vapor from the gas stream
inside the tubing. The driving force is the difference in water concentration on the opposite side
of the tubing wall. The purge gas then carries the
water vapor away.
and 12 VDC power sources.
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If condensation forms in the unit:
- Decrease or stop sample flow and increase
purge flow until unit dries out
If unit does not heat:
- Check wiring connections
- Confirm power source is operating
(Refer to Figure 1)
1. Connect the 2 wires to a 110 VAC power
source and let the unit heat for 15 minutes
2. Secure sample inlet and outlet connections
using insulated fitting for sample inlet
3. Connect purge inlet and outlet fittings
4. Start purge flow(purge air must be -40°C dew
point air, nitrogen or other gas)
5. Start sample flow. Sample must be maintained
at constant temperature from its origin to
prevent condensation
WARNING
Do not obstruct vent holes
INSTALLATION GUIDELINES
TROUBLESHOOTING
When installing MDH-Series gas dryers, the following
rules apply:
- Sample pressure higher or equal to purge pressure
- Sample gas pressure not to exceed 80 psig and 10
psig for purge gas
- Purge air of -40°C dew point at a flow rate of 15
times sample flow
- Purge air must flow countercurrent to sample
Model Number: MDH-110-96F-4
Nafion Tube OD/ID: 0.108"/0.086"
Length: 96 inches
Nafion Dryer Housing: Fluorocarbon
Enclosure: Polycarbonate
Thermostat Set Point: 80° C
Power Requirements: 110 VAC, 0.3 Amps,
30 Watts
Figure 1
SETUP
HEX NUT
HEX NUT
Model Numbers:
MDH-070-48F-410, MDH-070-48F-412
MDH-070-72F-410, MDH-070-72F-412
MDH-070-96F-410, MDH-070-96F-412
MDH-110-48F-410, MDH-110-48F-412
MDH-110-72F-410, MDH-110-72F-412
MDH-110-96F-410, MDH-110-96F-412
Nafion Tube OD/ID: 0.108"/0.086"
Length: 96 inches
Nafion Dryer Housing: Fluorocarbon
Enclosure: Polycarbonate
Thermostat Set Point: 80° C
Power Requirements: 30 watts,
110 VAC, 0.3 A, or 12 VDC, 2.5 Amps.
1. Connect the 2 wires to the appropriate 110
VAC or 12 VDC power source and let the unit
heat for 15 minutes.
rev. 9/2012
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