Why does direct cooling block ice machine freeze ices slowly

June 27, 2021

Some customers may ask why does the direct cooling block ice machine freeze ices slowly, and Let's analytic the reasons together!

1. The surface of the evaporator becomes dirty, greasy or dusty, and the heat transfer effect decreases. This situation is mainly caused by long idle periods of the device, unqualified water quality, and poor use environment of the device. In addition to the poor heat transfer effect of the evaporator, the surface of the evaporator becomes too thick due to long-term uncleaned dust, and the heat transfer efficiency is also significantly reduced.


2. Due to the poor insulation effect or poor sealing performance of the direct cooling block ice machine, the cold loss is large. Poor thermal insulation performance is due to insufficient thickness of the pipeline thermal insulation layer, uneven thickness of the evaporator plate, and poor thermal insulation effect, mainly due to improper selection of the insulation layer thickness or production process by the manufacturer. In addition, when using the device, the heat insulation and moisture resistance of the heat insulation material may be damaged, which may cause moisture exposure, deformation and even erosion of the heat insulation layer. The thermal insulation performance of the thermal insulation material is reduced, and the effect of directly cooling the ice maker is poor. Another important reason is the poor thermal insulation and sealing performance of the device. Condensation usually occurs around the device insulation, which indicates that the part is not tightly sealed.


3. There is more air or frozen oil in the evaporator of the direct cooling block ice machine, and the heat transfer effect is reduced. Once frozen oil adheres to the inner surface of the evaporator heat exchange tube, its heat transfer coefficient will decrease. Similarly, if there is more air in the heat exchange tube, the heat transfer area of the evaporator will be reduced, its heat transfer efficiency will be significantly reduced, and the freezing effect will be slowed down accordingly. Therefore, in daily operation and maintenance, attention should be paid to eliminating the oil stain on the inner surface of the heat pipe of the evaporator in time to improve the heat transfer efficiency of the evaporator.


4. The block ice machine throttle valve is improperly adjusted or blocked, and the refrigerant flow rate is too large or too small. A blocked valve or throttle will directly affect the flow of refrigerant into the evaporator. When the throttle valve is opened too large, the refrigerant flow is relatively large, and the evaporation pressure and evaporation temperature also increase. Freezing speed of direct cooling ice cube maker will slow down. At the same time, when the throttle valve is opened too small or blocked, the refrigerant flow rate is reduced, the refrigerant volume of the system is also reduced, and the freezing speed is also slowed down.


5. The compressor has low efficiency and the refrigeration capacity cannot meet the ice-making load. The compressor has a long running time, serious wear and tear, an increase in the clearance of the compressor, a corresponding decrease in the sealing performance, a decrease in the gas transmission coefficient of the compressor, and a decrease in the cooling capacity. When the ice making amount is less than the ice making load, the ice making efficiency decreases. The refrigeration capacity of a compressor can be roughly determined by observing the suction and discharge pressures of the compressor. If the compressor's cooling capacity decreases, the usual method is to replace the cylinder liner and piston ring of the compressor. If the replacement is not effective, other factors should be considered, and even the machine is removed for repair and troubleshooting.


6. The cooling capacity of the ice block machine system is insufficient, and the cooling capacity is insufficient. There are two main reasons for insufficient refrigerant circulation. The first is insufficient refrigerant charge. Another reason is that the system has a lot of refrigerant leakage. In this case, you should find out the leak point first, and focus on checking each.