The production line of our FD vacuum freeze-drying equipment is made up of several systems: food pre-freeze system, drying warehouse system, heating system, vacuum system, refrigeration system, material transmission system, pneumatic system, cleaning and sterilizing system.

• The vacuum system is a combination network of a water-loop pump unit and oil-sealed pump unit. At the early stage of vacuum process, air is removed quickly by the high power oil-sealed pump unit. After that, the working vacuum condition is maintained by a low power Roots water-loop pump unit. This process has several advantages: firstly, energy consumption is reduced, secondly moisture can be removed by water-loop pump unit to maintain a working vacuum condition. Thirdly, unstable vacuum degree performance of oil-sealed pump unit can be avoided. The unstable vacuum degree performance is because the oil-sealed pump has a poor drainage ability, the pump oil is emulsified by the water.
• A closed circulating water system or steam heating is adopted. The heat supply from water circulation system is automatically controlled by three-way valve. Thus, the temperature of the heating plate can be accurately controlled, and the pressure of the nitrogen is automatically adjusted to maintain the working temperature of the hot water at 120℃.
• Back and side vapor condensation cold trap is adopted. Compared with separated and external cold traps, it has the advantages of short channel, low resistance, simple water and vapor path design, uniform and high efficiency of vapor condensation. A special ammonia single phase cycling refrigeration system is adopted in the vapor condensation cold trap which has better performance and operability than traditional units.