In the fields of pharmaceuticals, food processing, and biological research, lyophilization (freeze-drying technology) has become a core process for high-value material treatment due to its ability to retain material activity and quality. As the key equipment to realize this technology, lyophilizers (freeze-dryers) are widely used in various high-end production and research scenarios. This article will systematically explain the technical principles of lyophilization, the structural characteristics of lyophilizers, and their application value in multiple industries in both Chinese and English, providing a comprehensive reference for global users.
Lyophilization, also known as vacuum freeze-drying, is a drying technology that combines low-temperature freezing and vacuum sublimation. Its core principle is to first freeze the material below the freezing point (usually -20℃ to -50℃) to convert free water and bound water in the material into solid ice, then place the frozen material in a high-vacuum environment (10-30Pa). Under the joint action of low temperature and vacuum, the solid ice in the material directly sublimes into water vapor without passing through the liquid phase. Finally, the water vapor is condensed and collected by the refrigeration system, realizing the deep dehydration of the material.
（冷冻干燥，又称真空冷冻干燥，是一种结合低温冻结与真空升华的干燥技术。其核心原理是先将物料降温至冰点以下（通常为 - 20℃至 - 50℃），使物料中的自由水与结合水转化为固态冰；随后将冻结后的物料置于高真空环境（10-30Pa）中，在低温与真空的共同作用下，物料中的固态冰不经过液态，直接升华为水蒸气；最后通过制冷系统将水蒸气冷凝收集，实现物料的深度脱水。）
The entire lyophilization process is divided into three key stages: pre-freezing, sublimation drying, and desorption drying. Each stage has strict requirements for temperature, vacuum degree, and time control, which directly affect the final quality of the material (such as activity retention rate and moisture content).
（整个冷冻干燥过程分为预冻结、升华干燥、解析干燥三个关键阶段，每个阶段对温度、真空度、时间控制均有严格要求，直接影响物料的最终品质（如活性保留率、含水量）。）
二、Structural Composition and Core Systems of Lyophilizers (冻干机的结构组成与核心系统)
A standard lyophilizer is composed of four core systems: refrigeration system, vacuum system, heating system, and control system. Each system coordinates with each other to ensure the stable operation of the lyophilization process.
（一台标准的冻干机由制冷系统、真空系统、加热系统、控制系统四大核心系统组成，各系统协同工作，确保冷冻干燥过程稳定运行。）
Refrigeration System (制冷系统)
The refrigeration system is responsible for providing low-temperature conditions for material freezing and water vapor condensation. It usually adopts a cascade refrigeration compressor (composed of high-temperature stage and low-temperature stage compressors), which can achieve a wide temperature control range of -60℃ to room temperature. In the pre-freezing stage, it cools the material to the set freezing temperature; in the sublimation and desorption stages, it condenses the sublimated water vapor into liquid water or solid ice to prevent water vapor from entering the vacuum pump and damaging the equipment.
（制冷系统负责为物料冻结与水蒸气冷凝提供低温条件，通常采用复叠式制冷压缩机（由高温级、低温级压缩机组成），可实现 - 60℃至常温的宽范围控温。在预冻结阶段，将物料冷却至设定冻结温度；在升华、解析阶段，将升华产生的水蒸气冷凝为液态水或固态冰，防止水蒸气进入真空泵损坏设备。）
Vacuum System (真空系统)
The vacuum system is the key to realizing ice sublimation. It is mainly composed of a Roots pump and a rotary vane pump (or a scroll pump). The rotary vane pump first reduces the pressure in the freeze-drying chamber to a low vacuum (about 1000Pa), then the Roots pump further improves the vacuum degree to 10-30Pa. Maintaining a stable high vacuum environment can reduce the sublimation temperature of ice, ensure that ice sublimes at low temperature, and avoid material damage caused by ice melting.
（真空系统是实现冰升华的关键，主要由罗茨泵与旋片泵（或涡旋泵）组成。旋片泵先将冻干腔体内压力降至低真空（约 1000Pa），再由罗茨泵进一步将真空度提升至 10-30Pa。维持稳定的高真空环境，可降低冰的升华温度，确保冰在低温下升华，避免冰融化导致物料损坏。）
Heating System (加热系统)
The heating system provides the sublimation heat required for ice sublimation and the desorption heat required for bound water removal. Common heating methods include shelf heating and radiant heating. The shelf heating method uses electric heating plates installed in the material shelves to transfer heat to the material through conduction; the radiant heating method uses infrared heaters to radiate heat to the material. The heating rate is usually controlled at 0.5-2℃/h to avoid excessive local temperature of the material and ensure uniform drying.
（加热系统为冰升华提供所需的升华热，为结合水脱除提供所需的解析热，常见加热方式有隔板加热与辐射加热。隔板加热方式通过安装在物料架内的电加热板，以传导方式将热量传递给物料；辐射加热方式通过红外加热器，以辐射方式向物料传递热量。加热速率通常控制在 0.5-2℃/h，避免物料局部温度过高，保证干燥均匀。）
Control System (控制系统)
The control system is the "brain" of the lyophilizer, which is composed of a PLC controller, a touch screen, and various sensors (temperature sensor, pressure sensor, weight sensor). It can real-time monitor parameters such as temperature in the freeze-drying chamber, vacuum degree, and material weight, and automatically adjust the working status of the refrigeration, vacuum, and heating systems according to the preset process curve. Advanced lyophilizers also support remote monitoring and data storage functions, which is convenient for process traceability and quality control.
（控制系统是冻干机的 “大脑”，由 PLC 控制器、触摸屏及各类传感器（温度传感器、压力传感器、重量传感器）组成，可实时监测冻干腔体内温度、真空度、物料重量等参数，并根据预设的工艺曲线，自动调整制冷、真空、加热系统的工作状态。高端冻干机还支持远程监控与数据存储功能，方便工艺追溯与质量控制。）
三、Application Fields of Lyophilizers (冻干机的应用领域)
Lyophilizers, relying on the advantages of lyophilization technology (high activity retention rate, good material shape, long shelf life), are widely used in pharmaceuticals, food, biological research, and other fields.
（冻干机依托冷冻干燥技术 “活性保留率高、物料形态好、保质期长” 的优势，在医药、食品、生物科研等领域应用广泛。）
Pharmaceutical Industry (医药行业)
In the pharmaceutical industry, lyophilizers are mainly used for the production of freeze-dried pharmaceuticals, such as freeze-dried vaccines, antibiotic powder injections, and enzyme preparations. Lyophilization can retain the biological activity of pharmaceuticals (for example, the activity retention rate of freeze-dried vaccines can reach more than 90%), and reduce the moisture content of pharmaceuticals to 1%-3%, which can effectively inhibit the degradation of pharmaceuticals and extend the shelf life to 1-3 years. At the same time, freeze-dried pharmaceuticals have good solubility and can be quickly dissolved after adding water, which is suitable for emergency medication scenarios (such as freeze-dried cephalosporin antibiotics, which can be dissolved within 30 seconds after adding water).
（在医药行业，冻干机主要用于冻干药品生产，如冻干疫苗、抗生素粉针剂、酶制剂等。冷冻干燥可保留药品的生物活性（如冻干疫苗活性保留率可达 90% 以上），并将药品含水量降至 1%-3%，能有效抑制药品降解，保质期延长至 1-3 年。同时，冻干药品溶解性好，加水后可快速溶解，适合急救用药场景（如冻干头孢类抗生素，加水后 30 秒内即可溶解）。）
Food Industry (食品行业)
In the food industry, lyophilizers are used to produce high-end freeze-dried foods, such as freeze-dried fruits, freeze-dried vegetables, and freeze-dried instant soups. Lyophilization can retain more than 85% of the vitamins and nutrients in food (for example, freeze-dried strawberries retain more than 90% of vitamin C), and the food maintains its original shape and texture. After rehydration, it can quickly restore the taste of fresh food. In addition, freeze-dried foods have low moisture content and do not require preservatives, which can be stored at room temperature for 1-2 years, reducing storage and transportation costs.
（在食品行业，冻干机用于生产高端冻干食品，如冻干水果、冻干蔬菜、冻干速食汤等。冷冻干燥可保留食品中 85% 以上的维生素与营养成分（如冻干草莓维生素 C 保留率超 90%），且食品保持原有形态与纹理，复水后能快速恢复新鲜食品的口感。此外，冻干食品含水量低，无需添加防腐剂，常温下可储存 1-2 年，降低储存与运输成本。）
Biological Research Field (生物科研领域)
In the field of biological research, lyophilizers are important equipment for the preservation of biological samples, such as serum, cells, and nucleic acid samples. Freeze-drying can extend the shelf life of biological samples (for example, freeze-dried serum can be stored at room temperature for more than 5 years, while refrigerated serum can only be stored for 6 months), and ensure the activity of samples (for example, the survival rate of freeze-dried cells can reach more than 80% after rehydration). At the same time, freeze-dried samples are small in size and light in weight, which is convenient for long-distance transportation without cold chain support.
（在生物科研领域，冻干机是生物样品保存的重要设备，如血清、细胞、核酸样本等。冷冻干燥可延长生物样品的保质期（如冻干血清常温下可保存 5 年以上，而冷藏血清仅能保存 6 个月），并保证样品活性（如冻干细胞复水后存活率可达 80% 以上）。同时，冻干样品体积小、重量轻，无需冷链即可长途运输，方便异地科研合作。）
四、Key Factors for Selecting Lyophilizers (冻干机的选型关键因素)
When selecting a lyophilizer, users need to comprehensively consider the following factors according to their own application scenarios and needs to ensure that the selected equipment meets the actual production and research requirements.
（用户在选择冻干机时，需根据自身应用场景与需求，综合考虑以下因素，确保所选设备符合实际生产与科研需求。）
Capacity (处理量)
The capacity of the lyophilizer is usually measured by the area of the material shelf (such as 0.5㎡, 1㎡, 2㎡) or the maximum material weight (such as 5kg, 10kg, 20kg). Small laboratories usually choose small lyophilizers with a shelf area of 0.5-1㎡; medium-sized enterprises choose medium-sized lyophilizers with a shelf area of 1-3㎡; large-scale production enterprises choose large lyophilizers with a shelf area of more than 3㎡ or customized multi-chamber lyophilizers.
（冻干机的处理量通常以物料架面积（如 0.5㎡、1㎡、2㎡）或最大物料重量（如 5kg、10kg、20kg）衡量。小型实验室通常选择物料架面积 0.5-1㎡的小型冻干机；中型企业选择 1-3㎡的中型冻干机；大型生产企业选择 3㎡以上的大型冻干机或定制化多腔冻干机。）
Temperature and Vacuum Performance (温度与真空性能)
For materials with high requirements for low temperature (such as biological preparations), lyophilizers with a minimum pre-freezing temperature of -50℃ or lower should be selected; for materials requiring high vacuum stability (such as high-purity pharmaceuticals), lyophilizers with a vacuum degree of 10Pa or lower and stable pressure control (fluctuation ≤±2Pa) should be selected.
（对于低温要求高的物料（如生物制剂），应选择预冻结最低温度可达 - 50℃及以下的冻干机；对于真空稳定性要求高的物料（如高纯度药品），应选择真空度可达 10Pa 及以下、压力控制稳定（波动≤±2Pa）的冻干机。）
Automation Level (自动化水平)
Highly automated lyophilizers (equipped with automatic process parameter setting, remote monitoring, and data traceability functions) can reduce manual operation errors and improve production efficiency, which are suitable for large-scale production enterprises with strict quality control requirements; small lyophilizers with basic automation functions (manual parameter adjustment, simple data recording) are more cost-effective and suitable for small laboratories with low production volume.
（自动化程度高的冻干机（具备自动工艺参数设定、远程监控、数据追溯功能）可减少人工操作误差，提升生产效率，适合质量控制要求严格的大型生产企业；具备基础自动化功能（手动参数调节、简单数据记录）的小型冻干机性价比更高，适合产量较低的小型实验室。）
After-Sales Service (售后服务)
Lyophilizers are high-precision equipment, and after-sales service (such as installation and commissioning, regular maintenance, and spare parts supply) is crucial. Users should choose manufacturers with perfect after-sales service systems, such as providing on-site installation and commissioning within 72 hours, regular maintenance guidance, and spare parts supply within 48 hours, to ensure the long-term stable operation of the equipment.
（冻干机属于高精度设备，售后服务（如安装调试、定期维护、备件供应）至关重要。用户应选择售后服务体系完善的厂家，如 72 小时内上门安装调试、提供定期维护指导、48 小时内备件供应等，保障设备长期稳定运行。）
五、Future Development Trends of Lyophilizers (冻干机的未来发展趋势)
With the continuous development of technology in the pharmaceutical, food, and biological fields, lyophilizers will develop in the direction of high efficiency, energy saving, intelligence, and customization.
（随着医药、食品、生物领域技术的不断发展，冻干机将向高效化、节能化、智能化、定制化方向发展。）
High Efficiency (高效化)
By optimizing the structure of the freeze-drying chamber (such as adopting a multi-layer shelf design) and improving the performance of the vacuum and refrigeration systems, the drying time of the lyophilizer will be shortened by 20%-30%, and the production efficiency will be significantly improved.
（通过优化冻干腔结构（如采用多层物料架设计）、提升真空与制冷系统性能，冻干机的干燥时间将缩短 20%-30%，生产效率显著提升。）
Energy Saving (节能化)
The application of frequency conversion compressors, heat recovery systems, and other technologies will reduce the energy consumption of lyophilizers by 15%-25%. For example, the heat recovery system can recover the heat generated by the refrigeration system and reuse it in the heating system, reducing energy waste.
（变频压缩机、热回收系统等技术的应用，将使冻干机能耗降低 15%-25%。如热回收系统可回收制冷系统产生的热量，重新用于加热系统，减少能源浪费。）
Intelligence (智能化)
The integration of artificial intelligence (AI) technology will enable lyophilizers to automatically optimize the process curve according to the characteristics of different materials, predict potential equipment failures, and realize unmanned operation. For example, the AI system can adjust the heating rate and vacuum degree in real time according to the moisture content change of the material, ensuring the best drying effect.
（人工智能（AI）技术的融入，将使冻干机具备根据不同物料特性自动优化工艺曲线、预测设备潜在故障、实现无人化操作的能力。如 AI 系统可根据物料含水量变化，实时调整加热速率与真空度，确保最佳干燥效果。）
Customization (定制化)
In response to the special needs of different industries (such as explosion-proof requirements in the chemical industry, cleanroom requirements in the pharmaceutical industry), manufacturers will provide more customized lyophilizer solutions, such as explosion-proof lyophilizers, sterile lyophilizers, etc., to meet the diverse application needs of users.
（针对不同行业的特殊需求（如化工行业的防爆要求、医药行业的洁净室要求），厂家将提供更多定制化冻干机解决方案，如防爆冻干机、无菌冻干机等，满足用户多样化应用需求。）
In conclusion, as the core equipment of lyophilization technology, lyophilizers play an irreplaceable role in promoting the development of high-end industries such as pharmaceuticals and food. With the continuous innovation of technology, lyophilizers will further improve their performance and expand their application fields, providing stronger technical support for global industrial upgrading and scientific research progress.
（综上所述，冻干机作为冷冻干燥技术的核心设备，在推动医药、食品等高端行业发展中发挥着不可替代的作用。随着技术的不断创新，冻干机将进一步提升性能、拓展应用领域，为全球产业升级与科研进步提供更强有力的技术支撑。）