What is the reason why the vegetable freeze dryer suddenly stops cooling during use? "Experience Sharing"

　　I believe that many customers have more or less unknown problems with the vegetable freeze-drying machine when using the vegetable freeze-drying machine equipment. For example, during use, they find that the food, fruits, and medicines in the vegetable freeze-drying machine have not changed, and are still the same as before. As the title says, the vegetable freeze-drying machine does not cool during operation. If you also encounter this kind of problem, don’t worry, let the editor of Dachang analyze the following reasons:

　　The vegetable freeze dryer is to freeze substances containing a large amount of moisture into a solid by cooling them in advance, and then directly sublimating the water vapor from the solid under certain vacuum conditions. The substance itself remains in the frozen ice shelf, and its volume remains unchanged after drying. The loose porous ice absorbs heat during sublimation, causing the temperature of the product itself to drop and slowing down the sublimation speed. In order to increase the sublimation speed and shorten the drying time, the product must be appropriately heated. The entire drying process of the freeze dryer is performed at a lower temperature.

　　Dachang vegetable freeze-drying machine host (refrigeration unit) is not operating normally

　　1. The refrigeration compressor cannot start (the reasons for not working are as follows)

　　Cause:

　　The power supply fails and the voltage is too low.

　　Troubleshooting:

　　According to the instructions of the freeze dryer, turn on the power and reset the relevant contacts if the voltage is normal.

　　2. The motor cannot drag

　　Cause:

　　Due to the overload of the refrigerator, which far exceeds the rated power of the motor, the compressor does not operate or slows down significantly, and the motor makes a buzzing sound. At this time, the power should be turned off immediately for inspection.

　　Troubleshooting:

　　Check whether there is power in the three phases and whether the power supply voltage of the freeze dryer is normal.

　　3. Water pressure alarm shutdown

　　Cause:

　　When the cooling water pressure of the water condenser is lower than the setting value of the water pressure relay, the freeze dryer compressor automatically stops.

　　Troubleshooting:

　　Fire the alarm, check the water pipes, restore the water pressure to normal, and restart the compressor.

　　4. Oil pressure difference alarm and shutdown

　　Cause:

　　1. Poor oil return results in insufficient oil level in the compressor crankcase and the oil pump cannot absorb oil.

　　2. Dirty oil causes the oil pump filter to become clogged.

　　3. The oil pressure difference relay fails.

　　Troubleshooting:

　　1. Replace the oil separator with a new one.

　　2. Change the oil and clean the oil filter.

　　3. Replace the oil pressure difference relay with a new one.

　　5. High pressure alarm shutdown

　　Cause:

　　1. The freeze dryer has too much refrigerant and the exhaust pressure is high.

　　2. The cooling water temperature is high, the flow is insufficient or the water condenser is scaled.

　　3. There is a leak in the low-pressure section of the refrigeration pipeline and air is sucked in.

　　4. The high-pressure exhaust valve is not fully opened or damaged, resulting in poor exhaust.

　　Troubleshooting:

　　1. Release part of the refrigerant.

　　2. Use cooling water whose temperature and flow rate meet the requirements and clean the water condenser.

　　3. Check the refrigeration pipeline of the freeze dryer for leaks.

　　4. Open the high-pressure exhaust valve fully or replace it with a new one.

　　6. Motor thermal protection shutdown

　　Cause:

　　The air return volume of the freeze dryer system is insufficient, and the motor is not fully cooled.

　　Troubleshooting:

　　1. Adjust the expansion valve to increase the circulation of the system to fully cool the motor;

　　2. Check whether the liquid supply pipeline is blocked (liquid supply cut-off valve, dry filter, solenoid valve, filter in front of expansion valve). If blockage occurs, solve it accordingly.

　　3. Check whether the return air pipeline and the suction filter of the compressor are clogged, and repair them if they are clogged.

　　4. Check whether there is a lack of refrigerant. If there is a lack of refrigerant, add refrigerant.

　　7. Condenser performance deteriorates

　　Cause:

　　1. The condenser of the freeze dryer is not defrosted completely, causing the heat transfer performance to deteriorate.

　　2. The product filling volume exceeds the set value.

　　3. The heating amount for sublimation of the product is too large and the sublimation is too fast.

　　Troubleshooting:

　　1. Defrost thoroughly and drain the water cleanly.

　　2. Do not exceed the maximum water capture volume.

　　3. Slow down the heating speed.

　　8. Insufficient or no cooling capacity

　　Cause:

　　1. The expansion valve is opened too large. At this time, the temperature of the shelf or water vapor condenser does not drop to the set value, and the compressor is severely frosted.

　　2、膨胀阀开启过小，此时温度降不下去，但压缩机温度很高，吸气阀处不结霜，吸气压力与搁板或水汽凝结器所对应的蒸发温度比搁板或水汽凝结器的温度低很多。

　　3、冷冻干燥机制冷系统堵塞不畅，如过滤器堵塞、阀门未开启、电磁阀失灵、膨胀阀堵塞等。

　　4、制冷剂充灌不足，此时温度降不下去，且吸气压力低，吸气阀处不结霜。

　　5、压缩机阀板上部或汽缸下部的纸垫被击穿或破裂，或压缩机吸、排气阀片破碎。

　　Troubleshooting:

　　1、调节膨胀阀。

　　2、疏通制冷系统更换零部件。

　　3、充注制冷剂。

　　4、更换纸垫或阀片。

　　九、导热油压力低

　　Cause:

　　导热油中有空气。

　　排除方法：开启循环泵、有软管一端连接在导热油排气口，一端与平衡桶连接，打开排气阀，排尽管路中的空气。

　　十、导热油进出口温差大

　　Cause:

　　1、导热油流量不足(导热油性能下降循环泵性能下降)。

　　2、测温探头有故障。

　　3、有空气混入导热油。

　　Troubleshooting:

　　1、换导热油，修循环泵。

　　2、更换温度探头。

　　3、排空气。

　　十一、循环泵切换

　　Cause:

　　1、压力不稳定。

　　2、冷冻干燥机循环泵已损坏。

　　3、压力继电器已损坏。

　　Troubleshooting:

　　1、排空气。

　　2、更换或修理循环泵。

　　3、换修或修理继电器。

　　大昌蔬菜冻干机

　　蔬菜冻干机的常见故障及其排除是一项基础性工作，冷冻干燥机的正常运转和使用寿命的延长会为企业创造更多的效益。本文结合对客户调试与维修冷冻干燥机的实际，通过制冷系统、循环系统、真空系统等若干方面常见故障的分析，提出了相应解决方法，希望本文对蔬菜冻干机使用厂家有所帮助。

　　以上就是关于果蔬冻干机在使用过程的突然不制冷是什么原因讲解，方法和解决办法仅供参考，如有更详细更好的解决办法可以联系我们，从而一起分享探讨!

　　温馨提示：蔬菜冻干机的常见故障及其排除是一项基础性工作，冷冻干燥机的正常运转和使用寿命的延长会为企业创造更多的效益。本文结合对客户调试与维修冷冻干燥机的实际，通过制冷系统、循环系统、真空系统等若干方面常见故障的分析，提出了相应解决方法，希望本文对果蔬冻干机使用厂家有所帮助。

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