Causes of Freezing Crack of Plate Heat Exchanger of Chiller

In the field of refrigeration, the application of plate type cooler or plate type air conditioning evaporator has already become the development trend in the field of refrigeration. The plate of the heat exchanger will change with the service life, and there will be leakage, erosion, freezing crack and other problems.

In the whole process of specific application, because the design of the unit control system is not perfect or the customer's wrong operation, it is very easy to cause the freezing crack of the plate exchanger. The actual reasons for the freezing crack of the plate heat exchanger of the chiller are as follows:

1.The filtering device which on the plate heat exchanger inlet water pipe is invalid. This will causes the residue in the water supply to enter the heat exchanger, which in turn causes heat exchanger to block, and the amount of water in the PHE is less than the minimum of the unit settings, thereby causing the circulation is poor, and the large temperature difference position will be ice block ,resulting in a plate spalling.

2. The refrigerant saturated suction temperature is too low.

3.The E-heater protection of plate heat exchanger is invalid in Winter.  

Generally, the water chiller will be shut down in winter, because the PHE in unique structure, causing internal water can not completely emptying or drainage. In this situation, the electric heater on the surface of the plate heat exchanger starts to heat the internal refrigerated water to prevent the PHE from freezing and cracking. 

4.Flow switch is invalid. The key function of the flow switch in the chiller is that when the total flow of cold water is less than the pre-set value, the alarm will be turned off to avoid freezing and cracking of the PHE. Generally PHE be installed on the water outlet. If the flow switch failure or human factors shielding the flow switch situation, the unit management procedures can not immediately sound and stop the chiller, resulting in the water output is less than the pre-set value and chiller is still in operation, the refrigerant will cooling the PHE internal water again, and then cause the plate heat exchanger freeze crack.

Secondly, PHE as an air conditioning evaporator, the refrigerant in the saturated state of the internal volatilization temperature is less than -10 ℃ time can not exceed 20 seconds, otherwise, easy to cause the PHE instantaneous penetration cracking, resulting in cracking.

The freezing cracking condition of the chiller plate heat exchanger is very common. We should timely find out the cause of the freezing cracking. For this reason, we can carry out targeted prevention, and then prevent the occurrence of the freezing cracking condition.