Selection and replacement timing of cold storage drying filters | Filter element, molecular sieve, acid blockage, moisture monitoring
The two main functions of a dry filter are: molecular sieve adsorption of system moisture, filter layer interception of welding slag and metal powder, and prevention of ice blockage, acid corrosion, and compressor wear.
The R404A/R507 low-temperature system uses XH-9 molecular sieve, which is compatible with HFC refrigerant and POE oil; Cannot use R22 old molecular sieve, adsorption capacity mismatch.
The Xitelide unit comes standard with a liquid pipe drying filter, which must be replaced after new or major repairs; Normal and stable operation of the cold storage, it is recommended to maintain and replace it once a year.
There are two types of filter blockage: dirty blockage (impurities blocking the filter screen) and acid blockage (oil acidification causing gum to stick to the molecular sieve), both of which can cause large temperature differences and frosting before and after the filter.
Judging blockage: Touch the inlet and outlet of the filter with your hand, there is a significant temperature difference, and the outlet is cold and frosted, indicating poor flow and internal blockage.
Many maintenance technicians only check for ice blockage. Oil acidification causes acid blockage, and there is no obvious frosting in the early stage, which gradually corrodes the motor winding and belongs to hidden faults.
After water ingress, ice blockage, and oleic acid formation in the system, the filter cannot be replaced only once. It is necessary to continuously connect dual filters in series to adsorb water and acidic substances in stages.
Each liquid pipe of the parallel unit is independently equipped with a drying filter. Do not install only one main pipe, as single branch pollution cannot be isolated and spreads throughout the entire system.
For foreign trade tropical high humidity projects, there is a high risk of water vapor entering the site by sea. It is recommended to add a pre filter before commissioning the new machine to protect the expansion valve core.
The filter is a disposable consumable, and after disassembly, the molecular sieve fails to absorb water when exposed to air. The removed filter must not be reused.
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FAQ
What molecular sieve is used in R404A low-temperature system? XH-9 molecular sieve.
2. Intuitive judgment method for filter blockage? The temperature difference between the import and export is significant, and the export is frosted.
How long does it take to replace the dry filter in a normal cold storage? Suggest annual maintenance and replacement.
Can the filter be reused after disassembly? Molecular sieves have failed to absorb water and cannot be reused.
How to deal with severe water ingress in the system? Series dual filters gradually adsorb moisture.
What is acid blockage? Freezing of oleylated gum adhered to molecular sieves caused blockage.
How to arrange the filters of parallel units? Each branch is installed independently.
