The dryer filter is an element of great importance within the refrigeration and air conditioning system. The perfect performance of the dryer filter function is properly related to the correct operation of the system. In this way, if the filter drier does not perform its function it will compromise components that have a much higher cost than the filter in the refrigeration system, such as compressors, expansion valves, solenoid valves, pressure regulators causing operating problems in the system. Cooling.
The basic rules for using and replacing a filter drier
New installation
Every time the cooling system is opened, you must change the filter
After the firing of semi-hermetic or hermetic type compressors.
When contamination indicated by the liquid sight glass is suspected
Types of contaminants in the refrigeration system:
Humidity
They are water molecules existing in the refrigeration circuit, with their presence they initiate different types of contaminations which we will describe.
A major problems caused by water, is the freezing in the expansion valve or capillary tube. Due to the low temperature caused by the reduction of the pressure inside the expansion device, the water particles existing together with the refrigerant gas will be frozen preventing the passage of the gas provided under the efficiency of the cooling system.
A cooling system with more than 100 PPM of moisture can cause:
Cobreamento; rust; Freezing of the water in the expansion device; Acid formation; And decomposition of the lubricating oil of the compressor.
By the technical standards the permissible humidity value is 50 PPM so as not to compromise the cooling system.
Acids
Mineral acids - acids that can cause great damage in a short space of time. The most common are: HF (hydrofluoric acid), HCl (hydrochloric acid).
These acids are formed by the high temperatures in the destruction of the refrigerant gas. They require moisture to be activated, and not introduced into the refrigeration system when opened they form inside the system.
Organic acids - are made up of carbon, hydrogen, and oxygen. These acids can cause great destruction inside the refrigeration system.
They are usually generated at the time of burning the compressor.
Solid particles
They are particles from the welding process of the piping and components during assembly, also generated by the wear of the products resulting in the deterioration of the oil at high temperatures (carbonization).
The presence of solid particles is harmful to all moving parts of the refrigeration system. They may cause the expansion valve not to act correctly by depositing material on its seat.
Another important point is that the presence of metal particles breaks the oil film that protects the moving parts in a cooling system.
Greases, lees and varnishes.
These contaminants are generated in the system after the combustion of the compressor. They are molecular mass, similar to the street asphalt. Both lees, varnishes and greases have various components insoluble in the oil and refrigerant solution.
These particles, because they are not soluble, end up being transported by all tubing of the same form of the oil in the down side of the system.
Waxes
In cooling systems, the waxes are introduced through dirty parts or waste assembly. Equipment that works with low temperatures are more harmed by this type of contaminant.
