European and American refrigeration technology

High efficiency • Energy saving • Environmental protection • Smart

　　Industrial chillers have gradually become an indispensable auxiliary machine in the field of plastic processing machinery forming mold cooling, which can greatly improve the surface finish of plastic products, reduce surface traces and internal stress of plastic products, and make products do not shrink or deform, which is convenient for plastics The demoulding of the product accelerates the product shaping, thus greatly improving the production efficiency of the plastic molding machine. However, some users still make mistakes in the operation, which affect the normal use of the chiller.

　　Operation error:

　　1. The operators of some air-conditioning host rooms do not strictly adjust the chilled water inlet and outlet pressure drops according to the operating parameters of the unit when they are turned on. They are often adjusted higher than the operating parameters. When the pressure drop is too high, it is not to close the cold water pump outlet valve. It is to open the water inlet and outlet valves of the evaporator of another unit that is not in operation. Excess water is discharged from the evaporator of another unit to reduce the pressure drop, resulting in artificially increasing the operating current of the cold water pump, resulting in waste of electricity.

　　2. When starting up, the water inlet and outlet valves on the evaporator of the non-starting unit are not closed first, causing part of the cold water to flow away from the evaporator of the unit that does not open, which affects the cooling effect of the unit under working conditions.

　　At this time, the flow rate that meets the 49kPa pressure drop of chilled water in and out of the A machine's evaporator is 100kg/s. Since both the A and B evaporators have water flowing through, theoretically the chilled water flowing through the A machine evaporator is only 50kg/s, and the other 50kg /s flows away from the B machine evaporator. This kind of misoperation artificially reduces the cooling capacity of the unit, making it difficult to meet the requirements of various cold applications. At the same time, because the amount of water flowing through the evaporator of the A machine is reduced, the temperature of the A machine's outlet water will naturally be lower, which often gives the operator the illusion that the cooling effect of the unit is good. The pressure drop of the inlet and outlet water of the A machine evaporator will definitely decrease. Some operators did not close the water inlet valve of the evaporator of the B unit and increase the pressure drop of the water inlet and the outlet of the evaporator of the A unit. Instead, they added a cold water pump to solve the problem. The pressure of the inlet and outlet water of the evaporator of machine A is increased, but there is no need to increase the cold water pump. This is equivalent to two cold water pumps working for two evaporators, which is pure waste.

　　The reason for the above misoperation is that the operator does not understand the operating principle of the unit, and is only satisfied with being able to turn on the main engine; the operator is afraid of trouble and is unwilling to adjust the water valve, so this operation is done for convenience.

　　The correct operation method of industrial chiller is:

　　1. Before starting the machine, close the chilled water inlet valve of the non-operating unit to prevent the occurrence of water channeling;

　　2. Open the water inlet and outlet valves on the evaporator of the unit to be operated, turn on the corresponding chilled water pump, and adjust the pressure drop of the inlet and outlet water of the evaporator to about 49kPa.

　　3. After the water pump is started, it is found that the pointer of the water inlet and outlet pressure gauge swings too much, indicating that there is air in the chilled water system and needs to be vented. After the pressure gauge indicates normal, the next operation can be continued;

　　4. No matter how many units are opened during operation, one chilled water pump corresponds to one unit.