Sea-Bird Electronics SBE 45 MicroTSG, User Manual

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APPLICATION NOTE NO. 71 Revised
March 2008
Desiccant Use and Regeneration (drying)
This application note applies to all Sea-Bird instruments intended for underwater use. The application note covers:
•
When to replace desiccant
•
Storage and handling of desiccant
•
Regeneration (drying) of desiccant
•
Material Safety Data Sheet (MSDS) for desiccant
When to Replace Desiccant Bags
Before delivery of the instrument, a desiccant package is placed in the housing, and the electronics chamber is filled with dry
Argon. These measures help prevent condensation. To ensure proper functioning:
1.
Install a new desiccant bag each time you open the housing and expose the electronics.
2. If possible, dry gas backfill each time you open the housing and expose the electronics. If you cannot, wait at least
24 hours before redeploying, to allow the desiccant to remove any moisture from the chamber.
What do we mean by
expose the electronics ?
•
For most battery-powered Sea-Bird instruments (such as SBE 16, 16 plus , 16 plus V2, 16 plus -IM, 16 plus -IM V2,
17 plus , 19, 19 plus , 19 plus V2, 25, 26, 26 plus , 37-SM, 37-SMP, 37-IM, 37-IMP, 44, 53, 54, 55, Auto Fire Module
[AFM]), there is a bulkhead between the battery and electronics compartments. Battery replacement does not affect
desiccation of the electronics, as the batteries are removed without removing the electronics and no significant gas
exchange is possible through the bulkhead. Therefore, opening the battery compartment to replace the batteries does
not expose the electronics; you do not need to install a new desiccant bag in the electronics compartment each time you
open the battery compartment. For these instruments, install a new desiccant bag if you open the electronics
compartment to access the printed circuit boards.
•
For the SBE 39, 39-IM, and 48, the electronics must be removed or exposed to access the battery. Therefore, install a
new desiccant bag each time you open the housing to replace a battery.
Storage and Handling
Testing by Süd-Chemie (desiccant’s manufacturer)
at 60% relative humidity and 30 °C shows that
approximately 25% of the desiccant’s adsorbing
capacity is used up after only 1 hour of exposure to
a constantly replenished supply of moisture in the
air. In other words, if you take a bag out of a
container and leave it out on a workbench for
1 hour, one-fourth of its capacity is gone before
you ever install it in the instrument. Therefore:
•
Keep desiccant bags in a tightly sealed,
impermeable container until you are ready to
use them. Open the container, remove a bag,
and quickly close the container again.
•
Once you remove the bag(s) from the sealed
container, rapidly install the bag(s) in the
instrument housing and close the housing.
Do not use the desiccant bag(s) if exposed to
air for more than a total of 30 minutes.
Sea-Bird Electronics, Inc.
13431 NE 20
th
Street
Bellevue, WA 98005
USA
Phone: (425) 643-9866
Fax: (425) 643-9954
E-mail: seabird@seabird.com
Web: www.seabird.com
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