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Thermal expansion valve in refrigeration equipment installation and debugging
Release time:2016-10-13 16:36:27
Thermal expansion valve installed correctly or not, also affects the work of refrigeration equipment. Before installation check that the valve is in good condition, especially the temperature sensitive body parts. Because within the thermal, filled with freonor other refrigerants, such as leaks, the Spring forces the valve hole closed, expansive reading does not work. The installation position of the thermostatic expansion valve, must be somewhere near the evaporator valve should be placed vertically, not tilted or upside down installation. At the time of installation, shall take care that the temperature within the liquid, keep temperature within the package. Temperature should be lower than valve installed.
Due to the thermal expansion valve depends on the temperature feel temperature, thermal packages installed, has a big impact on its performance. Thermal packages installed on the evaporator outlet pipe, generally should be kept away from compressor suction port 1.5M and as far as possible in a horizontal pipe sections. Pay specialattention to, thermal packages must not be placed where there is fluid.
When gas-liquid heat exchanger evaporator outlet, usually wrapping the temperature at the evaporator outlet, that is, before the heat exchanger. Also wraps the temperature in gas-liquid heat exchangers on the suction tube behind, but only in the high temperature liquid refrigerant to provide heat, sufficient to enable full evaporation of the refrigerant and refrigerant gas and heat, allow the installation. And in this case, the thermal expansion valve to adjust the work to a very high degree of superheat (not less than 12~20℃), to ensure that the freon evaporation and separated from the oil.
Temperature-sensing method of installing packages, usually placing it back on the gas pipeline of the evaporator, the temperature close to the wall of the dressing close, oxide skin contact should be wiped clean j exposed metal pipes, and if necessary,coated with a layer of lead paint as a protective layer, to prevent rusting. When the suction tube diameter is less than 25mm, the temperature can be tied at the top of round pipe. When the suction tube diameter 25mm, temperature can be tied back tothe underside of the pipe 45 ° to prevent oil collecting at the bottom of the pipe and other factors, influence temperature correct temperature.
Thermal expansion valve adjustment and must be performed in a refrigeration unit running state. If no thermometers at the outlet of the evaporator, compressor suction pressure can be used, as the evaporator ' saturation pressure checking superheat.However due to the suction pipe pressure drop, overheat the calculated degree, there is higher than the actual temperature error. If superheat is too small in the adjustment, namely, flow is too large, you can rotate in a clockwise direction adjusting lever half a circle or a ring (or increasing the spring force, reducing valve opening), reduce the flow, if superheat is too big, that is, insufficient liquid supply, then the adjusting lever can be turned the other way, the flow rate increases. Be careful the whole adjustment process, rotating the adjusting screw turns may not be too many (he turns a round Rod screws, superheat about change 1~2 0 c). Patiently after several adjustments until it meets requirements.
The thermostatic expansion valve, in addition to adjustments according to the measuring instrument, and can be adjusted according to the empirical method. Turn theadjusting screw, change of valve opening and make the return gas pipe just outsideof frost or condensation. Evaporation temperature below 0 ° c for cooling devices, ifthe Exo-frost on swing arms to touch, there is a cool, feeling stuck his hand, indicating that thermal expansion valve opening is suitable. Evaporation temperature at 0.C air conditioning refrigeration devices, condensation Visual judgment.