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Vacuum freeze drying is a method of preserving a wide variety of
products with minimal loss of their original physical qualities.
This is achieved by converting the water contained in a product
directly from ice to vapour.
Typical products suitable for freeze drying are:
The process has also been used by libraries to preserve
and restore moisture damaged books and documents, and by pharmaceutical
companies to prepare drugs. |
Telstar Model LioAlfa |
A wide variety of freeze dryers are available, from small laboratory
models to large industrial units that handle 1000kg per cycle. Freeze Dry Systems Ltd
are also agents for the internationally known Telstar and Cuddon brands.
 Freeze Dry Systems Ltd are pleased to
announce the arrival of the first in a line of water vapour trapping
products designed and manufactured from our factory in Auckland. The FDS
Trap-EzeŽ -50ēC Refrigerated Cold Trap.
The FDS Trap-EzeŽ has been designed to
maximise flexibility of use by incorporating pipework fittings
(KF10/16/25, hose fitting, or up to 1 BSP connector) in the clear
acrylic trap cover using a conventional trapping flow and return
configuration. This means the unit can be used in-line before an oil
sealed vacuum pump in many applications including freeze drying,
concentrating, degassing, and many other operations. During 2004, a
-85ēC two stage version will become available.
The FDS Trap-EzeŽ utilises a stainless
steel trap collector of four and six litres depending on model, a
temperature indicator, and CFC free refrigeration system. A Teflon
coated version is also available where solvents, chemical, or organic
vapours are present.
For those who are amazed at how easy it
is to destroy expensive vacuum pumping equipment it is obvious that any
products that do not reach the pump cannot cause a problem. This common
place truth is all too often overlooked. Water at any vacuum pressure
from atmospheric to 33mbar, and water, solvent, chemical, or organic
vapours above 1mbar are most often pumped at pressures creating large
quantities of vapour. The condensation of these vapours before they
reach the pump offers two important benefits:
| 1.
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Additional protection
provided to the pump assists the lubrication of bearing
surfaces during severe processes. |
| 2. |
The inlet condenser produces
clean recovered liquids. |
At pressures below 1mbar, the pump
usually has to deal with high boiling point vapours, i.e. vapours of
high relative molecular weight. With the exemption of a very small
quantity of water vapour and even with gas ballasting, vapours are
usually not expelled from the pump. It is highly recommended for these,
they are condensed in a cold trap before they enter the pump. Typical
cold traps are either low temperature refrigerated types or the more
conventional liquid nitrogen based variety. In these situations some
sludge and particulates tend to form in the oil regardless of all
preventative measures. Adding to this tendency is the wide range of
pumping applications a single pump will experience in a typical
industrial, commercial, or laboratory setting.
Contact
us
now to discuss your vacuum and freeze drying needs.
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