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7. WORKING PRINCIPLE
7.1.
FREEZE
The product inserted into the equipment can either be previously frozen or can be frozen in the ice condenser. To
freeze it in the condenser, the product is placed into the plate stack (optional accessory), and the condenser is cooled
selecting the option "freezing" on the touch screen, both in semiautomatic mode and in automatic mode.
The freeze temperature is proportional to the solidification point of product. Freezing speed influences the size of the
crystals and, consequently, sublimation speed. Therefore, the most suitable freeze parameters for each product must
be determined. It is advisable to freeze products at a temperature below -20°C for a period of 3-4 hours.
7.2.
LYOPHILIZATION
7.2.1.
IN MANIFOLD
It is used to lyophilize bulk products in glass flasks with a grinding mouth (29/32mm Ø). The products contained in the
flasks (filling a quarter up to maximum half the flask) have to be previously congealed in a rotating bath of alcohol,
freezing the product to the walls of the flask.
When the condenser has reached the programmed temperature, the following steps must be performed:
1. Connect the vacuum unit.
2. Connect the flasks or bottles (with previously frozen product) to the valves connected to the condenser.
3. Open the valves (see Fig. 4).
Then the vacuum is done inside flasks, and the sublimation of the product starts. A pressure of less than 10mbar is
reached within 10 minutes. If this does not happen, the pump will stop and the alarm of the vacuum system will
appear. In this case the valve-flask connections must be reviewed in order to assure that there is no a leak.
If it is necessary to connect additional flasks when the freeze-drying process has already begun, the following steps
must be performed:
1. Close all valves.
2. Connect the new flask and open its corresponding valve.
3. Wait 10-15 seconds in order for the pressure to be restored in the unit.
4. Open the valves of the other flasks.
It is possible to provide external heat by means of an electric heat source, in order to speed up the drying process. The
heat source should be at the suitable distance to apply the radiation heat that the product requires. A hot air heater
directed directly to the flasks may also be used.
At the beginning of the process a layer of ice will form on the outside wall of the flask; this will gradually disappear as
drying out continues. When the exterior of the flask is at ambient temperature, no ice remains in the product (the
process has finished). Once the process has finished, the corresponding valves of the manifold are closed and air
enters in the flasks. So they can be removed.
IM-LYOQUEST-EN-SP-1016a.doc
CONNECTION VALVE
Air inlet
Start vacuum process
Fig. 4
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