How to Maintain Vacuum Freeze Dryer
1. Maintenance of vacuum freeze dryer in use
The surface area of the sample should be enlarged as far as possible, and no acid-base substances or volatile organic solvents should be included in the sample. Samples must be completely frozen to ice. If there is residual liquid, it will cause gasification spray. Note that the cold trap is about 65 degrees below zero. It can be used as a cryogenic refrigerator, but it must be operated with insulating gloves to prevent frostbite. Before starting the vacuum pump, check whether the outlet valve is tightened, whether the inflatable valve is closed, whether the contact surface between the plexiglass cover and the rubber ring is clean, clean and well sealed. Normally, the machine can not be used continuously for more than 48 hours. During the freezing process, the temperature of the sample decreases gradually. The sample can be taken out and warmed up for a period of time (still in the freezing state) and dried continuously to shorten the drying time. Vacuum freeze dryer LCD display, Chinese interface, with sample drying curve. After the imported compressor is equipped with a heat exchanger, the refrigeration capacity is increased and the water catching capacity is improved. The cold trap has large opening, no inner coil and sample pre-freezing function. The pre-cooler can be used as a diversion bucket to speed up drying. The cold trap and the operating surface are all stainless steel, corrosion resistant, smooth and transparent bell jar. Transparent bell-jar drying room, safe and intuitive. Stainless steel sample rack, common sample disc spacing adjustable. The design is novel, the volume is small and the operation is convenient, and the occupancy of the laboratory table is reduced. Nitrogen inflatable valve is optional.
2. Maintenance of vacuum freeze-drying mechanical switch
Turn on the main power switch on the left side of the vacuum freeze-drying machine case, and the air pressure is 110 pk. Press the main switch key on the control panel for more than three seconds, and the temperature is shown as the actual temperature of the cold trap. Start the refrigerator and pre-cool it for more than 30 minutes. Put the sample into the sample rack, cover it with plexiglass cover, and start the vacuum pump. After the pressure digital display is stable, the temperature and pressure values are recorded. Record the temperature and air pressure before shutdown of vacuum freeze drying machine. Hold the inflatable valve on the control panel and close the vacuum pump immediately. When the air pressure digital display is atmospheric pressure, open the plexiglass cover and take out the sample. Turn off the refrigerator, hold down the main switch key for more than three seconds, and finally turn off the main power switch. After the ice in the cold trap is completely turned into water, open the water outlet valve on the left side of the chassis to release water, clean the inner wall of the cold trap with dry cloth, and cover the vacuum freeze dryer with a large sheet of filter paper to prevent dust.