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PPT研究院 POWERPOINT ACADEMY * * AUTOMOTIVE AIR CONDITIONER Drier or Accumulator: The drier, also known as the receiver-drier, is sort of the safety catch for your system. The compressor is only supposed to compress the gas form of refrigerant. However, theres always a chance that some liquid could make it back that far. The drier catches this liquid before it can damage your compressor. * AUTOMOTIVE AIR CONDITIONER Since even the tiniest leak or careless installation can introduce water moisture to the system, the drier absorbs this chemically, using whats called a desiccant (similar to that packet of DO NOT EAT that comes with electronics). The drier also has a filter that catches any gunk that might be in there. * AUTOMOTIVE AIR CONDITIONER Thats pretty much the whole story! Different systems also have sensors here and there to tell pressure and temperature, but they are specific to a make and model of vehicle. * AUTOMOTIVE AIR CONDITIONER 3. Thermal Expansion Valve Another pressure-regulating device is the expansion valve. The expansion valve can sense the pressure and temperature of the refrigerant, which makes it very efficient in controlling refrigerant to the evaporator. There are several different varieties of expansion valves. The most common type is the Chrysler H block valve and is quite efficient. * AUTOMOTIVE AIR CONDITIONER The expansion valve has a capillary tube with a thermal bulb that controls how far open or closed it is. The thermal bulb and the internal pressure of the refrigerant balance to control just the exact amount of refrigerant needed. The thermal bulb is clamped to the output of the evaporator. If not enough refrigerant is flowing to cool the evaporator this bulb will sense it and open more or vice versa.? * AUTOMOTIVE AIR CONDITIONER 4. Receiver-Drier The receiver-drier is placed on the high side of expansion valve systems. Since this type of valve needs liquid refrigerant to function, a receiver is used to ensure that the valve gets