The Role of the Throttling Device of the Chiller

The Role of the Throttling Device of the Chiller

The throttling devices commonly used in chillers mainly include: thermal expansion valve, float regulating valve, manual throttle valve, capillary tube, etc. Except for the capillary tube, the other three throttle valves can control the flow rate of the chiller, evaporator, and refrigerant. Adjust to adapt to the change of cooling load and achieve the purpose of adjusting the cooling capacity. Industrial chiller throttling devices can be divided into the following four types:

1. Thermal expansion valve: According to the change of refrigerant temperature at the outlet of the evaporator and the function of the temperature sensing mechanism, the opening degree of the valve is automatically adjusted to control the refrigerant flow. It is mainly composed of a valve body temperature sensor and a capillary tube. It is suitable for evaporators without free liquid surface, such as dry evaporators and coil evaporators. When choosing a thermal expansion valve, consider the type of refrigerant, the evaporation temperature range, the maximum cooling capacity of the evaporator behind the valve, and the pressure difference between the front and back of the valve.

2. The float expansion valve can control the flow through the change of the liquid level of the chiller, so as to reduce the pressure and adjust the flow. Its automatic adjustment is suitable for evaporators with free liquid surface, for example, flooded evaporators , Low-pressure circulating storage tank,. Its structure is simple, the liquid level of the floating ball fluctuates greatly, and the impact force transmitted by the floating ball to the valve core is large.

3. Capillary. The capillary is a slender copper tube with a diameter of 0.7 to 2.5 mm and a length of 0.6 to 6 meters. It is widely used in small closed refrigeration devices. The liquid supply capacity depends on the pressure and temperature of the refrigerant at the inlet of the capillary, as well as the length and inner diameter of the capillary. Moreover, the thin tube has a simple structure, low price, no liquid storage in the system, less refrigerant charge, poor regulation performance, and the industrial volume does not adjust with changes in working conditions, and is suitable for occasions where the evaporation temperature changes little and the working conditions are stable.

4. Throttle short tube. The short throttle tube is a throttling device with a fixed cross-section throttling orifice. It is widely used in some automotive air conditioners, chillers and heat pumps. It is low in price, simple to manufacture, good in stability, easy to install, and cancels the thermal expansion system. The temperature-sensing package used to judge the size of the refrigeration load has good interchangeability and self-balancing ability. In short, choosing a suitable throttling device according to different types of chillers and their cooling effects can improve the cooling effect of the chiller.

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