The Components Of A Freeze Dryer
The vacuum freeze dryer, also named lyophilization machine, is composed of a drying box and six systems as refrigeration, a vacuum, a media heat exchange circulation, an automatic control, pneumatic, and an in-situ cleaning and disinfection system.
1. The components of a freeze dryer — drying box
The drying box of a freeze dryer is a vacuum-sealed and low-pressure container, with all materials made of stainless steel. The box of a freeze dryer can withstand positive and negative pressure and meets the requirement of steam sterilization. The sealing of the freeze dryer box is made of high- and low-temperature-resistant silicone rubber.
1) Box: The box of the freeze dryer is rectangular and has a high space utilization rate, a drain port at the bottom, and an observation window on the side. The freeze dryer box is also equipped with a pressure gauge, temperature measuring resistor, air release valve, gas leakage valve, safety valve, spray inlet joint.
2) Shelf: The energy required for food cooling and heating is transmitted through heat transfer media to the shelf and then to the food. The freeze dryer shelf uses special hollow plywood, which has high strength and good sealing. Inside the freeze dryer box installed the shelf assembly. The uppermost layer of the shelf should be set as a heat radiation compensation plate to ensure that the food space in the freeze dryer is under the same temperature environment. In addition, both sides and the back of the shelf are equipped with a rail to avoid food plates or food separating from the shelf.
3) Box door: Automatic locking device for the cylinder is adopted for the freeze dryer door which ensures the vacuum required. When the vacuum pump is working, the air and water vapor in the vacuum drying chamber passes through the water trap, enters the vacuum pump, and is discharged from the system through the pump’s exhaust port.
2. The components of a freeze dryer — media heat exchange circulation system
The energy required to cool down and heat up the food is driven by the circulation pump and transferred through the heat exchange medium of the freeze dryer. The cooling source is provided by the refrigeration system and the heating source by the heating tank.
When the freeze dryer temperature rises, the steam enters the heating tank to heat the medium, and the pneumatic three-way regulating valve is used to adjust the mixing ratio of the heat medium from the heating tank and the shelf return heat medium, and the cooling water of the plate heat exchanger is used to open and close the valve to control the shelf temperature. The freeze dryer system has a plate heat exchanger, pneumatic regulating valve, cooling water solenoid valve, circulation pump, pipeline, solenoid valve, temperature sensor, etc.
3. The components of a freeze dryer — automatic control system
It has functions such as freeze-drying curve setting, vacuum pump testing and control, media temperature, food temperature, and water trap temperature control, dry state detection, path removal, in-situ cleaning and sterilization, automatic protection and alarm.
4. The components of a freeze dryer — pneumatic system
The main use of the system is to control the pneumatic valve.
5. The components of a freeze dryer — in-situ cleaning and disinfection system
Used for cleaning and steam sterilization of box traps of the freeze dryer.