How a four-ring lyophilization experimental lyophilizer can shorten the drying time

The four-ring lyophilization experimental lyophilizer is to freeze the substances containing large moisture in advance by implementing refrigeration measures to freeze them into solid substances, and then evaporate the moisture from the products in a vacuum state, while the substances are left in the frozen ice, and the properties and volume of the substances after drying will not change
.

The operating system includes refrigeration, circulation, vacuum, hydraulics, CIP/SIP and control systems, of which the refrigeration system is a core part
of the entire operating process.

In the operation of the four-ring lyophilization experimental lyophilizer, how to quickly freeze-dry the material, the key link is to understand the characteristics of the material and the eutectic point temperature
.

If most of the moisture can be pumped out before the temperature of the material rises to the eutectic point, then the successful lyophilization of the material is not far away
.

The so-called eutectic point is the temperature
at which all the solutions in the material condense.

Usually we can observe
the change of material properties through the lyophilizer observation window during the pre-freezing stage.

When the material begins to freeze, the temperature detected by the electric couple immersed in the material will suddenly rise, which is caused
by the exothermic phenomenon of the icing process.

At this point, the temperature we recorded is roughly close to the eutectic point (or eutectic point) temperature
.

The process of removing more than 90% of the moisture before the eutectic point (or eutectic point) is called the primary drying period
.

It is also important
to judge the time at the end of a drying.

Judging too early or too late can cause a feeling of frostbite, a decrease in dry quality, or a drain
of energy and time.

The most intuitive way is to judge
according to the shape of the material.

After a dry period, most of the moisture is removed
.

Just as the waterline on the wall continues to fall as the flood recedes, we can observe that there is also a waterline above the material that continues to fall until it disappears
.

The waterline disappears, which means that a drying is coming to an end
.

The second method can be judged according to the changing trend of the pressure in the box, when most of it is removed, the pressure in the box will continue to decrease until it appears linear
.

The third method can be judged
according to the change of material temperature.

When most of it is pumped out, we will find that the temperature of the material will be closer and closer to
the temperature of the shelf.

In order to shorten the drying time, in addition to the crystal shape in the pre-freezing stage, the gas can be appropriately incorporated in the sublimation stage, so that the vacuum value fluctuates within a certain range (generally should not exceed 30Pa).


This method makes the heat transfer method no longer rely on heat conduction to focus on it, and also enhances the way of heat convection and accelerates the speed of
moisture analysis.