Teledyne 4220 - Manual (Page 137)

4220 Flow Meter
Section 6 Maintenance and Service
6-3
6.2.2 Regenerating the
External Desiccant
Cartridge
Teledyne Isco uses two types of silica gel:
• One looks like small beads or pellets that are blue-black
when dry, pale pink to transparent when saturated.
• The other looks like coarse sand, yellow when dry, dark
green when saturated.
Regenerate desiccant by heating at 212° - 350° (100° - 175°C).
MSDS (Material Safety Data Sheets) for silica gel chemicals are
provided at the back of this manual.
CAUTION
There have been reports of irritating fumes coming from the
desiccant during regeneration. While our attempts to duplicate
the problem have been unsuccessful, we still urge you to use
caution.
• Use a vented oven in a well-ventilated room.
• Do not remain in the room while the regeneration is
taking place.
To regenerate the desiccant cartridge:
1. Carefully snap it out of its bracket.
2. Pull the silicone tubing from the end of the cartridge.
3. Remove one of the end caps from the cartridge by twisting
and pour the saturated desiccant into a metal, ceramic, or
other heat-resistant container.
4. Identify the desiccant and heat it at the proper tempera-
ture two to three hours, or until the blue or yellow color
returns.
5. Do not try to regenerate the desiccant inside the cartridge;
the cartridge is plastic and will melt.
6. Refill the cartridge with the regenerated desiccant (or with
the extra desiccant provided in the accessory package.
7. Replace the end caps.
Notice the filters in the end caps; they keep small pieces of the
desiccant material from falling out of the cartridge. You can clean
these filters from time to time using ordinary dish soap and
water, then allowing to dry.