Preparation for the pilot freeze dryer

　　As we all know, when using the pilot freeze dryer for the first time, we must thoroughly clean the parts of the dryer. Everyone knows that stainless steel parts are washed with ethanol, and plexiglass is washed with physiological saline. Ampoules are cleaned with an ultrasonic cleaner, but what preparation do we need to do before testing the freeze dryer in real operation?
　　The pilot freeze dryer must be pre-frozen before operation and use. The pre-freeze needs to prepare a low-temperature refrigerator, minus 40 degrees Celsius, or minus 80 degrees Celsius low-temperature refrigerator, and place the items to be dried in a low-temperature refrigerator or liquid nitrogen It usually takes about four hours. It can be observed directly from the outside. After the items are completely frozen, the freeze-drying experiment can be carried out. The items are quickly moved into the tray of the pilot freeze-drying machine to ensure the freeze-drying effect.
　　The green vacuum tube connects the main unit and the vacuum pump, and the connection uses international standard clamps. In order to effectively prevent the leakage of air, this type of clamp is specially designed with a sealing rubber ring in the clamp, apply an appropriate amount of vacuum grease on the rubber ring, and then clamp with the clamp to make the connection more closely fit Together, to effectively prevent air leakage. If the clamp is not clamped, it will cause air leakage, which will cause the instrument panel to display a digital display value greater than 20pa during vacuum extraction. At this time, the air tightness of the glass cover of the vacuum pump and the pilot freeze dryer should be checked.
　　There are two power sockets on the right side panel of the main unit of the pilot freeze-drying machine, one is to connect the power cord of the vacuum pump to the main unit, and then the main power supply of the second pilot freeze-drying machine is plugged in.
　　Before the operation of the vacuum pump, you must check whether the vacuum pump oil is added, otherwise it will not run normally. The oil level should not be lower than the center line of the oil mirror. The vacuum pump will have a strong jitter when it is first used, and it will gradually become stable.
　　If the air tightness is not good, you should apply some vacuum grease to the sealing rubber ring above the cold trap, lightly spin the plexiglass cover on the rubber ring, and test the tightness by turning on the vacuum pump. To ensure its integrity.