What is the more commonly used method of four-ring lyophilization experimental lyophilizer?

The processing process of the four-ring lyophilization experimental lyophilizer records the change of shelf temperature and product temperature with time to obtain a lyophilization curve
.

The more typical lyophilized curve system divides the shelf heating into two stages, and the shelf temperature remains low during a large number of sublimations, and according to the actual situation, it can generally be controlled between
-10 and +10.

In the second stage, the shelf temperature is appropriately raised according to the nature of the product, and this method is applied to the product with
a lower melting point.

If the performance of the product is not clear, the performance of the machine is poor or its work is not stable enough, it is more prudent
to use this method.

If the eutectic point of the product is high, the vacuum degree of the system can be maintained well, and the refrigeration capacity of the condenser is sufficient, a certain heating rate can also be used to raise the shelf temperature to the allowable maximum height temperature until the end of lyophilization, but it is also necessary to ensure that the temperature of the product in a large number of sublimation shall not exceed the eutectic point
.

If the product is unstable to heat, the two-stage plate temperature should not be too high
.

In order to increase the sublimation speed of the first stage, the shelf temperature can be raised to above the allowable height limit temperature of the product at one time; After the basic end of the large number of sublimation stages, and then reduce the plate temperature to the allowable maximum temperature, although the latter two ways make a large number of sublimation speed have some improvement, but its ability to resist interference is correspondingly reduced, the sudden reduction of vacuum and refrigeration capacity or power failure may make the product melt
.

Reasonably and flexibly mastering a method is still the more commonly used way
of lyophilizers.

The steps when using the four-ring lyophilized experimental lyophilizer are as follows: 1.
The preparation of the sample should be expanded as much as possible, which must not contain acid-base substances and volatile organic solvents; 2.
The sample needs to be completely frozen into ice, if there is a residual liquid collar, it will cause a gasification eruption; 3.
Note that the cold trap is about minus 65 degrees, which can be used as a low-temperature refrigerator, but it is necessary to wear thermal gloves to avoid frostbite; 4.
Before starting the vacuum pump, check whether the water valve is tightened, whether the inflatable valve is closed, and whether the contact surface between the plexiglass cover and the rubber ring is clean and free of dirt and well sealed; 5.
Under normal circumstances , the aircraft shall not be used continuously for more than 48 hours; 6.
During the freezing process of the sample, the temperature gradually decreases, and the sample can be taken out and warmed up for a period of time (still in a frozen state), which is continuously boring to shorten the boring time
.