A 20-year service provider focused on trucking。
Spring, summer, autumn, winter, season, summer again! Now, just in the middle of the summer, katyus need to prepare in advance to repair the air conditioners so that they can open them as the temperature rises。
In air-conditioning systems, the expansion valve is a smaller component, but it plays an important role. It's good and bad, and it's directly related to the cooling effect of air conditioning。
Location of air conditioner expansion valve installation
The swelling valve is also called the throttle or voltage valve and is an important component of the four main components of the air-conditioning system (compressor, condenser, expansion valve, evaporation)。
The dynamic balance of the air conditioning system is determined by an expansion valve sensory temperature and by a pressure differential
The expansion valve works by automatically adjusting the pressure values by temperature differentials and then by balancing the system. Typically, there is a temperature difference between the temperature at the point of export and the evaporation temperature, known as overheat. When the temperature of the evaporation unit is felt, the entire sensor system is under corresponding saturation pressure。
A diagram of the principles of the expansion valve
When the temperature set by the air conditioning system is the same as the temperature of the temperature package, the pressure up and down of the swelling valve is equal and the system is balanced。
When the temperature of the export is too high, the sensory temperature is too high, at which point the pressure value above will increase. The swelling valve pressure plate drives the core down, making the swelling valve more open。
At this point, more liquid freon cores will enter the evaporation unit and become gaseous, reducing the temperature within the evaporation unit and rebalancing the air conditioning system。
On the other hand, when the temperature is too low, the opening of the swelling valve will be reduced, resulting in a decrease in freon entering the evaporation unit, thereby increasing the temperature within the evaporation unit。
The two most common malfunctions of the swelling valves are slurry and ice
An internal tectonic map of the swelling valve
The expansion valve, a mechanical component, is prone to congestion, including blackouts and "freezing"。
Dirt: there are impurities in the system, such as iron chips, welds, fibres, etc。
When the compressor pulls the tank, there is a worn scrap into the air conditioner system, which can easily cause an expansion valve to plug; and fibre impurities, when repairing the air conditioner, must clean up the interface and prevent the stolen material from entering the system, leading to an expansion valve core jamming。
Ice congestion: this is mainly due to excessive moisture in air conditioning systems。
For example:
(1) the air-conditioning system is in a vacuum phase and is not in sufficient time to exhaust the humidity of the air-conditioning system
(2) when adding freon to the system, the air that is connected to the hose is not blown out and the air is entered into the air conditioning system pipe
(3) when lubricating the system, the system enters the air; all of these omissions result in excessive moisture in the system, resulting in an expansionary valve, which prevents the core from moving and leads to malfunctions。
It prevents impurities and air from entering the pipe system to avoid an expansion valve failure
The h-type expansion valve
The size of the swelling valve is small, but it plays an important role, and its pros and cons directly affect the temperature of the indoor environment, as well as the physical feeling of the driver when driving。
When the air conditioning system is too impurities, it is necessary to remove the pipes for cleaning, revacuation and refilling the refrigerants, and to keep in mind that the vacuum should clean the air and seal the pipes, prevent the expansion valves from creating ice congestion and avoid malfunctions. (man/truckhouse quest author: 翟鑫)
