Weld-Mount Tank Viewing Port with Slotted Union Closure — DIN & 3A/SMS
A circular sanitary tank viewing port featuring a cylindrical butt-weld mounting neck, a flat viewing glass disc with elastomer seals, and a slotted round union nut closure. Tabulated across 1"–4" (DIN D 28–104 mm; 3A/SMS D 25.4–101.6 mm) in the union-port dimensional drawing and up to DN150 (6") across the series.
Metal Body Material | SS304 (1.4301) / SS316L (1.4404) |
|---|---|
Mounting & Closure | Butt-Weld Tank Neck with Top Slotted Round Union Nut |
Port Construction | Threaded Weld Liner, Flat Sight Glass & Slotted Union Ring |
Scoped Size Range | DN25–DN150 (1"–6") |
Supported Standards | DIN, 3A, SMS, IDF, RJT, BS, ISO |
Size
Product overview
Cylindrical Weld Neck and Slotted Union-Nut Closure
This union-type weld sight glass (model SGU-11) matches the cross-sectional drawing directly: a cylindrical stainless steel weld liner with an external sanitary thread is welded into a tank wall or vessel head, and a slotted round union nut compresses the flat viewing glass lens and elastomer seal ring against the liner seat.
Exact Union-Port Dimensions (1"–4") and Series Scope
The Union-type sight glass drawing tabulates seven sizes from 1" to 4" (1", 1-1/4", 1-1/2", 2", 2-1/2", 3", 4") with overall heights A from 35.0 to 62.0 mm, DIN weld-neck outer diameters D from 28.0 to 104.0 mm, 3A/SMS weld-neck outer diameters D from 25.4 to 101.6 mm, and union nut outer diameters D5 from 63.0 to 146.0 mm. General series specifications also cite DN25–DN150 (1"–6") or DN150.
Stainless Steel Grades and Seal Elastomers
Manufactured in 304 (1.4301) and 316L (1.4404) stainless steel, the port uses silicone, EPDM, Viton, or NBR gaskets (secondary header notes vacuum to 10 bar and -10 °C to 150 °C). Note that the series schedule also includes generic inline tubular sight glass rows.
Pre-Weld Disassembly and Spanner Servicing
Unscrew the slotted union nut with a hook spanner and remove the glass lens and elastomer seals before welding the cylindrical base neck onto the vessel. Reinstall the seals and glass once the weld has cooled.
Technical specifications
Dimensional reference · Union-type sight glass
Weld-Mount Viewing Port with Union Closure: listed sizes and matching drawing symbols.
| Size | A | DIN D | 3A/SMS D | D5 |
|---|---|---|---|---|
| 1" | 35.0 | 28.0 | 25.4 | 63.0 |
| 1 1/4" | 38.0 | 34.0 | 32.0 | 70.0 |
| 1 1/2" | 40.0 | 40.0 | 38.1 | 78.0 |
| 2" | 42.0 | 52.0 | 50.8 | 92.0 |
| 2 1/2" | 47.0 | 70.0 | 63.5 | 110.0 |
| 3" | 52.0 | 85.0 | 76.2 | 125.0 |
| 4" | 62.0 | 104.0 | 101.6 | 146.0 |
Dimensional drawings
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