© SP Industries, Inc.
Rev.004, 12/07
26
Maintenance
Periodic maintenance of your freeze-dryer will lead to enhanced performance and help avoid
difficulties during a freeze-drying cycle. It will also result in increasing the life of the freeze-dryer.
Maintenance should be performed a
minimum
of 4 times a year. Because system use and
application varies from one facility to another you may have to perform system maintenance
substantially more often.
Refrigeration
Ambient
Temperature
Refrigeration unit is constructed assuming ambient
temperature of approx. 25°C. If the ambient temperature is
significantly higher, the amount of refrigerant gas being
condensed as it passes through the condenser will be less.
Voltage
Problems arise due to incorrect supply voltage or from
seasonal voltage drops. Voltage should be checked
periodically to be +/- 5%.
Condenser
(Refrigeration
condenser
located inside
the Dura-Dry)
The condenser must remain clean. Fins may be cleaned either
with a vacuum or with compressed air. When using
compressed air, clean from the inside out. Accumulation of
dust in the condenser significantly reduces the amount of air
passing through to cool the refrigerant.
Vacuum
Cleanliness
In order to pull a good vacuum, the system must be tight,
including good contacts at potential leak sites. Presence of dirt
or particulates decreases the surface to which good contacts
can be made.
DO NOT
use an excess of vacuum grease as it attracts dirt.
Vacuum Pump
Oil
Vacuum pump oil MUST be changed periodically, as it collects
debris and becomes cloudy.
Vacuum pump oil must be free of particles to perform as a
lubricant and a sealant.
Pump oil also needs to be free of water, water vapor, and other
crankcase gasses, which cause the crankcase pressure to
rise, making it difficult for the oil to perform as a sealant and
pull a good vacuum.
