Technical data

Using a distributor, a maximum of 15 ampoules can be
simultaneously frozen in the cooling bath and connected to the
manifold.
3.5. Separate freezing and drying of liquids in
ampoules (process B)
The refrigeration unit and the vacuum pump are activated via the
control system to pre-cool the ice condenser and to warm up the
vacuum pump. The valve is closed during the warm-up of the
vacuum pump. In case the unit is not equipped with an
electromagnetic pressure control valve, we recommend using a
manual stop valve. Without such a valve, the vacuum pump
cannot be warmed up.
The manifold is equipped with blind plugs for the connection of a
maximum of 48 ampoules. The blind plugs ensure that the
manifold can be pre-evacuated.
The first hose is clamped in the middle with the supplied hose
clamp and the blind plug is removed. The vacuum of the system is
preserved.
The liquid in the ampoule is either frozen under rotation in a
cooling bath or in a deep-freeze.
If shock-freezing is required, we recommend that freezing is
carried out in liquid nitrogen or in a cooling bath.
The ampoule is then connected to the hose and the hose clamp is
removed. Thus the partial pressure in the ampoule is suddenly
decreased and partial thawing during the evacuation process is
avoided.
One ampoule after the other is connected using this method.
The ampoules are sealed in the same way. The hose of the
ampoule to be sealed is clamped and the ampoule is sealed under
vacuum using the blow lamp.
If the ampoule breaks during sealing, the vacuum in the drying
chamber is not affected since the hose is clamped with the hose
clamp.
The remaining glass of the sealed ampoule is removed and the
hose is closed with a blind plug.
In this way, one ampoule after the other can be sealed or new
ampoules can be connected.
24 • Description of the Freeze Drying Processes Operating Manual Freeze Dryer ALPHA 1-4 LSC / ALPHA 2-4 LSC