รายละเอียด
Sight Glass
SGN ( Refrigerant : HFC )
Sight glasses are used to indicate:
The SGI/N and SGRI/N are equipped with sensitive indicators that reflects a colour,
depending on the moisture content in the refrigerant.
Type SGN / SGRN
*For Non- flammable HFC refrigerants
* Indicates too high water content in the refrigeration system
* Indicates lack of subcooling
* Indicates refrigerant deficiency
* Flare/solder connection or socket type
HCFC and Non- flammable HFC : | ||||
Type | Version | Connection [in.] | Connection [mm] | Code no. |
SGN 6s | ODF × ODF solder | ¼ x ¼ | — | 014-0181 |
SGN 10s | ODF × ODF solder | 3/8 x 3/8 | — | 014-0182 |
SGN 12s | ODF × ODF solder | ½ x ½ | — | 014-0183 |
SGN 16s | ODF × ODF solder | 5/8 x 5/8 | 16 × 16 | 014-0184 |
SGN 19s | ODF × ODF solder | ¾ x ¾ | 19 × 19 | 014-0185 |
SGN 22s | ODF × ODF solder | 7/8 x 7/8 | 22 × 22 | 014-0186 |
SGN 22s | ODF × ODF solder | 1-1/8 x 1-1/8 | — | 014-0187 |
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Choice of sight glass | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Before choosing a sight glass with moisture indicator, the following should be considered: | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
* Type of refrigerant | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
* water solubility of refrigerant | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
* the level on which a danger signal is required. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Be aware that polyester oil for Non- flammable HFC refrigerants, e.g. R134a, R404A, R407C react with water in a hydrolysis generating acid and alcohol. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
The recommended levels of moisture content are usually between 30 and 75 ppm, where hermetic compressors only tolerate very low moisture content, while semi-hermetic and other compressors normally tolerate higher moisture contents in the refrigerant. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
The color on the sight glass indicator depends on the moisture content of the refrigerant. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
The values under “green/dry” are to be considered as perfect condition meaning full protection against harmful effects from moisture. In other words, the filter drier is working perfectly. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
If the green color starts to fade, the color change has begun and the indicator should therefore be watched more carefully. If the color changes to yellow it is a clear signal that the capacity of the filter drier is exceeded and should be replaced as soon as possible. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
SGN / SGRN for HCFC and Non- flammable HFC refrigerants | ||||||
Moisture content ppm = parts per million | ||||||
SGN / SGRN | ||||||
25 °C | 43 °C | |||||
Green/ dry | Intermed. color | Yellow/ wet | Green/ dry | Intermed. color | Yellow/ wet | |
R22 | < 30 | 30 – 120 | > 120 | < 50 | 50 – 200 | > 200 |
R134a | < 30 | 30 – 100 | > 100 | < 45 | 45 – 170 | > 170 |
R404A | < 20 | 20 – 70 | > 70 | < 25 | 25 – 100 | > 100 |
R407C | < 30 | 30 – 140 | > 140 | < 60 | 60 – 225 | > 225 |
R507 | < 15 | 15 – 60 | > 60 | < 30 | 30 – 110 | > 110 |