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For welding in or on according to DIN 28120
Execution according to DIN 28120 for operating pressures up to 16 barg
Non binding • Usually a response within 24 hours
The Type 320 circular vessel sight glass, in accordance with DIN 28120, is designed for the safe visual inspection of processes in vessels and systems.
The sight glass assembly is designed for welding into or onto the vessel and allows the interior of the vessel to be observed; it can also be fitted with lighting on request.
The circular vessel sight glass is available in nominal diameters from DN 25 to DN 300 and for nominal pressures of PN 10 and PN 16.
It is suitable for industrial applications where processes, levels or media in pressure vessels and systems must be reliably monitored visually.
In addition to the specifications of DIN 28120, we also offer the Type 320 in the special sizes DN 250 and DN 300. These sizes, which are not specified in the standard, have also been designed in accordance with DIN 28120.
The Type 320 vessel sight glass is manufactured from corrosion-resistant stainless steel 1.4571 / 1.4404 or other stainless steels. We also manufacture vessel sight glasses from special alloys such as Duplex / Alloy. This ensures they are designed to withstand demanding operating conditions.
Borosilicate glass in accordance with DIN 7080 is used as the standard glass material. Customised versions of the vessel sight glass are also available on request.
A wide range of materials is available for the flat gaskets used to seal the vessel sight glass. Depending on the application, materials such as PTFE (Teflon®), NBR, novaphit® MST-XP, KlingerSil® C4400 and other branded gaskets are available in addition to classic fibre gaskets. This allows the sight glass to be specifically adapted to the temperature, pressure and medium.
In addition, a calculated airtightness verification in accordance with EN 1591-1 is possible, taking into account the requirements of the TA-Luft.
If the temperature resistance of borosilicate glass to DIN 7080 is insufficient for the application, or if steam and process conditions have a particularly severe effect on the sight glass, a customised mica protective screen provides additional protection. For aggressive chemicals or alkalis, the sight glass can also be fitted with FEP or Halar® coatings.
The Type 320 vessel sight glass is suitable for use wherever processes in pressure vessels, tanks, silos, boilers or reactors need to be safely monitored and visually inspected.
Typical areas of application include vessel and equipment manufacturing, the chemical industry, the petrochemical industry, as well as biogas plants and fermentation processes.
Like many of our sight glasses, the Type 320 sight glass can also be fitted with suitable accessories on request. These include SGW-type wipers, SVI spraying devices, LED lights (for Ex and non-Ex areas) and mica protective screens.
For applications with specific requirements regarding the medium, temperature or corrosion resistance, special versions and additional coatings such as FEP coating and Halar® coating are also available.
| DN (Nominal size) | 25 | 40 | 50 | 80 | 100 | 125 | 150 | 200 | 250² | 300² |
|---|---|---|---|---|---|---|---|---|---|---|
| Outside diameter Da [mm] | 115 | 150 | 165 | 200 | 220 | 250 | 285 | 340 | 395 | 445 |
| Inside diameter Di [mm] | 48 | 65 | 80 | 100 | 125 | 150 | 175 | 225 | 280 | 325 |
| Dimension h1 [mm] | 16 | 16 | 16 | 20 | 22 | 25 | 30 | 35 | 40 | 45 |
| Dimension h2 [mm] | 25 | 30 | 30 | 30 | 30 | 30 | 36 | 36 | 40 | 45 |
| Glass diameter [mm] | 63 | 80 | 100 | 125 | 150 | 175 | 200 | 250 | 300 | 355 |
| Glass thickness at PN 10 [mm] | - | - | - | 15 | 20 | 20 | 25 | 30 | 45 | 45 |
| Glass thickness at PN 16 [mm] | 10 | 12 | 15 | 20 | 25 | 25 | 30 | 40² | - | - |
| Weight at PN 10 [kg] | - | - | - | 9,6 | 11,1 | 14,3 | 21,9 | 30,7 | 44,7 | 59,2 |
| Weight at PN 16 [kg] | 2,8 | 5,4 | 6,0 | 9,7 | 11,3 | 14,6 | 22,4 | 31,8² | - | - |
2) Similar to DIN 28120
The base flange must be welded into the vessel wall without any stress. After welding, it is essential to check the sealing surface for flatness, as heat-induced warping is a common cause of subsequent glass breakage. Glass and gaskets must be removed before welding.
Yes, according to DIN 28120, it can be used up to -1 bar from a strength perspective. However, actual suitability for vacuum applications also depends on other factors, in particular the seal material, the bolt tightening torques and the specific environmental conditions.
DIN 28120 covers pressure classes PN 10 and PN 16 as standard. Furthermore, as the manufacturer, we can design and manufacture reinforced special flanges for virtually any operating pressure. We would be happy to advise you on customised designs for higher pressure classes.
A regular visual inspection of the sight glass is required. In the event of mechanical damage such as scratches, chips or flaking, or if the glass becomes cloudy due to wear, immediate replacement is necessary. It is recommended that the seals are also replaced whenever the glass is changed.
Yes, replacement glasses and seals for Type 320 are also available individually. Due to the standardisation of the fitting, these spare parts are generally available at short notice, and in many cases directly from stock. The product range includes MAXOS® borosilicate glass in accordance with DIN 7080, as well as matching seal sets made from PTFE (Teflon®), NBR, novaphit® MST-XP and KlingerSil® C4400.
