FDG type vacuum freezing and drying machine

Main characteristics of FDG series vacuum cryogenic drying equipment The vacuum system is in combination structure of water-sealed pump + oil-sealed pump. The extraction of pre-vacuum is performed by oil-sealed pump group of large power and the vacuum for operation remains by water-sealed Roots pump group of small power so as to reduce energy consumption. Meanwhile, the water-sealed pump group can remove vacuity instability of the system due to poor water-removal performance of oil-sealed pump and emulsification deterioration of the pump oil. Heating is conducted in closed water circulation system, where three-way adjusting valve is used for automatic adjustment of heat supply to the water circulation system to precisely control temperature of the heating plate. Besides, nitrogen is used for automatic pressure-keeping to ensure the working temperature of the hot water reaching 120°C. The rear-installed and side-installed water-catching cold trap is adopted. Compared with the outside-installed cold trap, the former one has advantages of short canal, lower resistance, and smooth steam canal, uniform and high-efficient water-catching. The cold trap uses special method of ammonium single-phase circulating refrigeration. It is more stable in supplying refrigerating liquid and easier in operation than the general method of liquid supply.