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Precautions for Each Operation Step of Vacuum Oven

The vacuum oven is one of the important auxiliary drying equipment in the experiment. It has a wide range of applications and more complicated operations. It has higher requirements than ordinary ovens and requires more attention during use.


Ⅰ. Sample placement of the vacuum drying ovens


Please put the materials to be dried evenly on the sample rack in the vacuum drying box and push them into the vacuum drying box.


Precautions:


1. Do not place the sample in the heating state of the vacuum oven, but place it under the state of ensuring that the heating is turned off.


2. When placing samples, a certain space should be reserved around the upper and lower sides to keep the air flowing in the box.


3. If the sample undergoes phase changes during the drying process, it must be installed in a tray to avoid contamination of other samples.


4. If the weight becomes lighter and the volume becomes smaller after the article is dried, a barrier net should be added to the vacuum port in the vacuum drying box to prevent the inhalation of dry matter from damaging the vacuum pump or solenoid valve.


5. Any liquid solvents and items whose ignition point and boiling point are lowered below 150°C under vacuum are strictly prohibited from being placed in the box.


Ⅱ. Close the door of the vacuum oven tightly


Please close the door gently.


Precautions:


1. Do not close it too hard to avoid large vibrations of the vacuum drying box.


2. There are bolts on the door. Make sure that the door is tightly integrated with the silicone seal when closing.


Ⅲ. The vacuum drying ovens should open the vacuum


Please connect the vacuum pump to the vacuum valve, turn on the vacuum pump and the vacuum valve in turn to pump a vacuum.


Precautions:


1. According to the performance of the vacuum pump, the limit value of the vacuum pump when the pressure gauge is pumped shall prevail.


2. After reaching the vacuum level, close the vacuum valve first. If the vacuum valve is not closed tightly, replace it in time, and then turn off or remove the vacuum pump power supply, which aims to prevent back suction.


3. Observe the vacuum pressure gauge to ensure that the value is stable without obvious fluctuations.


4. If the vacuum degree is less than the requirement of dry goods, turn on the vacuum pump power supply and vacuum valve again, and continue to vacuum, which can prolong the service life of the vacuum pump.


Ⅳ. The heating of vacuum drying ovens


Please turn on the heating switch and set the desired temperature.


Precautions:


1. The heating step must be carried out in a stable vacuum state, otherwise it is easy to cause the pressure and temperature difference between the inside and the outside, causing the outside atmosphere to rush into the box and other emergencies.


2. During the heating process, the heating indicator light will stay on. When the set temperature is reached, the heating will stop automatically and the indicator light will go out at the same time. When the temperature is lower than the set temperature, the heating starts again and the heating indicator light is on.


3. The heating indicator and temperature of the vacuum drying ovens must be displayed normally. If the indicator does not light, turn off the power and contact the person in charge of the instrument.


Ⅴ. The temperature setting of the vacuum drying ovens


Plseae set the desired temperature.


Precautions:


1. The setting temperature should not exceed the rated temperature. The ignition point and boiling point of materials under vacuum drop sharply. Unreasonable setting temperature will cause solid materials to agglomerate.


2. The digital display temperature needs to be indicated normally. If it does not display or flickers, jumps and other abnormalities, turn off the power in time and contact the person in charge of the instrument.


3. The operator must wait until the actual temperature is consistent with the set temperature and the heating indicator light of the vacuum drying ovens goes out before leaving.


4. In order to avoid temperature control failure, a dedicated person is required to check whether the instrument is operating normally and pay attention to the changes of the baking materials. If an abnormality is found, it is necessary to turn off the heating, cut off the power supply, open the vent valve, and report it in time.


Ⅵ. Sampling in the vacuum drying ovens


Turn off the heating switch first, and then slowly open the vent valve. When the vacuum is 0, open the vacuum drying ovens door to take out the sample.


Precautions:


1. Do not open the valve to the maximum value at one time when venting, to avoid the impact of external airflow into the vacuum drying box to the sample, causing pollution in the box and between the samples.


2. It is forbidden to open the box door when the vacuum degree is less than 0.


3. When the box door sealing silicone rubber is deformed due to long-term vacuum and the box door cannot be opened, the box door cannot be opened forcibly. The box door can be opened after the sealing silicone rubber ring slowly returns to its original state.


4. After sampling, close the bleed valve in time.

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