Filter Driers (Liquid Line)
The effective functioning of the system of commercial largely depends on the purity of the device. Only clean, dry refrigerant and clean, dry, oil should circulate in the system. OH contaminants such as dirt and water must be removed. Contaminants, should be locked in some part of the system where they can't hurt. Devices used for this purpose may be in separate units. However, they can be combined in a single unit which filters and absorbs. (Adsorption is the ability to collect substances on a surface of the condensed layer.) Screens, filters, adsorbents and water are used as part of a filter-dehydrator.
A General method for removal of moisture from the liquid line land, figure 13-161. Enough drying material should be used for both high and low humidity ranges. If it is fully activated, it can keep the refrigerant as clean and dry. Driers are usually installed in the liquid line.
The usual straight-through the dryer is a cylinder made of brass, copper or steel. It is filled with desiccant chemical, such as activated alumina or silica gel.
These chemicals can adsorb 12% to 16% of their weight in water. Both ends of the cylinder, as a rule, contain the filter elements. End covers equipped with either a flare or soldered joints.
The design of the liquid line drier allows the body to stay in the line. Only on the land cartridge needs changing.
The refrigerant must be dried as follows:
- Less water than 15 ppm, if R-12.
- Less than 25 ppm if R-22 or R-500.
- 5 ppm for R-502.
Corrosion begins:
- 15 ppm water in the R-12.
- 120-page / min. for R-22 or R-500.
- 15 ppm for R-502.
Refrigerant with the specified safe amount of moisture avoids many of the problems in the system. Experience shows that the corrosion, oil breakdown and motor burnouts almost eliminated if the guidelines are followed. Clean the cooling system consists of four main tasks:
- Removal of water.
- Removal of acid.
- Filtration of solid particles floating around,
- Measurement when drying the job is completed.
Driers will process the first three tasks. The indicator of humidity is required for the fourth.
Driers shall be retained permanently, because the oil loses moisture slowly. In addition, insidation in hermetic compressors and in small crevices can free wet for long periods. Filter-drier as a sponge. However, it can become rich, if the dryer is too small. This will leave the refrigerant wet. The moisture indicator is the only way of recognising the wet state.
R-22 driers should be three to five times more than those needed for an equal number of R-12. The greater the ability of the refrigerant hold water, the more land is required. R-500 driers should be as large as R-22 dryers. R-502 driers should be as large as R-12 dryers...
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