The function and selection method of throttling capillary in industrial chiller

The function and selection method of throttling capillary in industrial chiller

The capillary tube in the industrial chiller is a pure copper tube with a specified length and a very thin diameter. Its inner diameter is generally between 0.5-2mm. Choose the appropriate length according to the size of the chiller, and then process it into a spiral shape. So what is the role of capillary tube in industrial chiller? The editor of okmarts.com will talk to you in detail.

The capillary tube is one of the throttling devices of the industrial chiller. The role played in the industrial chiller is to throttle, increase the flow resistance of the liquid flowing through the capillary, and finally achieve the purpose of controlling the liquid supply, but it is increasing the liquid flow resistance While controlling the liquid supply, the capillary also has the effect of reducing pressure. When the high-pressure refrigerant flows through the capillary, it will change from high-pressure liquid to low-pressure and high-temperature gas.

Specifically, the inner diameter and total length of the throttling capillary tube of the industrial chiller and the rated pressure difference between the inlet and the outlet are all influencing factors of the throttling capillary tube of the industrial chiller. However, how to calculate it requires a comprehensive cooling temperature and evaporation temperature. The evaporation pressure, etc., should be the same as the outlet pressure of the capillary.

　　 Calculate the inlet and outlet pressure difference to get the inner diameter and length of the capillary, and then select the corresponding capillary. In most cases, this calculation does not have a fixed value. The experimental values obtained by each industrial chiller manufacturer may be different, which is relatively complicated.

The capillary tube can adjust the liquid supply, throttling, pressure reduction, etc., but before the industrial chiller leaves the factory, the length and inner diameter of the capillary tube should be determined and configured, instead of the customer’s own calculation and installation, so the customer should Don't worry about buying enough. However, during the first actual use and trial operation of the machine, slight adjustments can also be made to meet the actual needs of customers.

Capillary tubes are mainly used in small industrial chiller systems with small cooling capacity. Therefore, the selected capillary tube has a small inner diameter and a long length. The flow rate of the refrigerant flowing through the capillary tube will naturally be less, and the pressure will be lower. The actual demand of the chiller determines the value and length of the capillary tube inner diameter.

　　Industrial chillers with large refrigeration capacity mostly use expansion valves as throttling devices. The expansion valves are installed between the refrigerant barrel and the evaporator to throttle and reduce pressure. The expansion valve allows the liquid refrigerant with relatively high temperature and relatively high pressure that has returned through the industrial chiller system to become low-temperature and low-pressure refrigerant vapor through the expansion valve, a throttling device, and then enter the evaporation The device absorbs heat to achieve the cooling effect.