循環(huán)系統(tǒng)由一系列冷卻和加熱換熱器組成，導(dǎo)熱介質(zhì)由循環(huán)泵提供動(dòng)力，部件通過AISI304 不銹鋼管道連接，導(dǎo)熱介質(zhì)通過擱板與產(chǎn)品間實(shí)現(xiàn)熱交換。
The circuit comprises a series of cooling and heating exchangers in series through which a heat exchange medium is circulated by a pump. The components are interconnected by 304 stainless steel pipe work. The medium is circulated through the shelves to effect heat transfer to/from the product.
導(dǎo)熱介質(zhì)為低粘度硅油(5cSt)，保證了在擱板J限低溫情況下溫度的均勻性。
The heat exchange medium is a low viscosity 5cSt silicone oil ensuring optimum shelf temperature uniformity at the ultimate shelf temperature.
冷卻換熱器是釬焊的不銹鋼板式換熱器，減少了導(dǎo)熱介質(zhì)的流量，提高了熱傳導(dǎo)的效率，也降低了泄漏的風(fēng)險(xiǎn)。冷卻換熱器由來自專用壓縮機(jī)的制冷劑直接膨脹制冷，由聚合發(fā)泡物保溫。
The cooling exchangers are a brazed stainless steel plate construction, which minimises the volume of heat transfer fluid and heat exchanger mass to maximise heat transfer efficiency, leakage risks are also minimised. Each one is cooled by direct expansion of refrigerant from a dedicated compressor. The cooling exchangers are insulated externally with a polymer foam.
電加熱器由一個(gè)帶有多根加熱組件的圓柱形AISI304 不銹鋼容器組成，加熱組件是不銹鋼管式加熱器。提供2 個(gè)溫度調(diào)節(jié)安全裝置，以避免硅油過熱。一個(gè)外附在加熱器的外部和一個(gè)在加熱器的內(nèi)部。加熱器采用聚合發(fā)泡材料保溫。
The electrically heated heat exchanger comprises a cylindrical stainless steel vessel fitted with multiple heating elements with stainless steel external protection. Two thermostatic safety switches are provided to minimise the risk of over heating the silicone oil, one attached to the external surface of the heater and one embedded within the heater elements. The heat exchanger is insulated externally with a polymer material.
硅油通過泵循環(huán)。采用屏蔽泵。泵體采用聚合發(fā)泡材料保溫。循環(huán)泵提供的高流速確保擱板溫度均勻。一個(gè)壓力開關(guān)可反饋信號可到PLC，控制泵的操作，與加熱器連鎖。在泵的入口及出口裝有指針式壓力表，用來監(jiān)測泵及系統(tǒng)的運(yùn)行。
The silicone oil is circulated by means of a centrifugal pumping system. A single motor canned pump is used for the Lyomax 1, a twin impeller/motor pump is used for machines from Lyomax 3 to and a single impeller/motor pump for or larger. The pump body is externally insulated with a polymer foam. The pump provides a high rate of flow through the system to ensure a high degree of shelf temperature uniformity. A differential pressure switch provides feedback, to the PLC, that the pump is operating and is also electrically interlocked with the heater to prevent fluid over temperature. Dual pressure gauges are installed on the inlet and outlet of the pump to monitor the pump and system performance.
循環(huán)系統(tǒng)管路上還裝有一個(gè)膨脹罐，以補(bǔ)償不同凍干階段時(shí)硅油的容積的變化。膨脹罐裝有除濕過濾器防止水分進(jìn)入導(dǎo)熱介質(zhì)。膨脹罐液位指示計(jì)（視鏡形式）包括在供貨范圍內(nèi)。
The heat exchange circuit is equipped with an expansion tank to accommodate volume changes between the various stages of the freeze drying process. The expansion tank is fitted with a silica gel moisture trap to prevent water being absorbed by the heat exchange medium. A fluid level indicator (sight glass) is provided.
加熱和冷卻系統(tǒng)可以將導(dǎo)熱流體的溫度控制在-55°C 到+80°C 之間。在穩(wěn)定狀態(tài)下，空載，板層溫度在-40°C 到+40°C 之間時(shí)，板層溫度均勻性為板層之間的溫差為2°C；板層降溫速率為從+20°C 到-40°C 在 60 分鐘之內(nèi)；加熱速率為從-40°C 到20°C 在60 分鐘之內(nèi)。擱板Z低溫度可達(dá)到-55°C。
The heating and cooling systems are automatically controlled to enable the heat exchange fluid to be controlled between -55°C and +80°C. Under steady state, unloaded, conditions the uniformity of temperature across and between shelves is 2°C within the shelf temperature range of -40°C to +40°C. Unloaded, the shelves may be cooled from +20°C to -40°C within 60 minutes for LYOMAX 40 equipped with 2 screw compressors. The ultimate minimum shelf temperature is -55°C
