รายละเอียด
Sight Glass
SGI ( Refrigerant : HCFC , mineral oil , R22)
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 SGI / SGRI
* Refrigerants where lubrication is by mineral oil e.g. HCFC
* Indicates too high water content in the refrigeration system
* Indicates lack of subcooling
* Indicates refrigerant deficiency
* Flare/solder connection or socket type
HCFC : Flare ext. × ext. Connection | ||||
Type | Version | Connection [in.] | Connection [mm] | Code no. |
SGI 6 | Flare ext. × ext. | ¼ x ¼ | 6 × 6 | 014-0007 |
SGI 10 | Flare ext. × ext. | 3/8 x 3/8 | 10 × 10 | 014-0008 |
SGI 12 | Flare ext. × ext. | ½ x ½ | 12 × 12 | 014-0075 |
SGI 16 | Flare ext. × ext. | 5/8 x 5/8 | 16 × 16 | 014-0024 |
SGI 19 | Flare ext. × ext. | ¾ x ¾ | 19 × 19 | 014-0028 |
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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. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
SGI / SGRI for mineral oil e.g. HCFC refrigerants | ||||||
Mineral oil e.g. R22 | Moisture content ppm = parts per million | |||||
SGI / SGRI | ||||||
25 °C | 43 °C | |||||
Green/ dry | Intermed. color | Yellow/ wet | Green/ dry | Intermed. color | Yellow/ wet | |
< 150 | 150 – 300 | > 300 | < 250 | 250 – 500 | > 500 |