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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 round vessel sight glass Type 320 according to DIN 28120 is used for safe visual monitoring of processes in vessels and systems.
The sight glass fitting is designed for welding in or onto the vessel and enables observation of the vessel interior as well as illumination on request.
In addition, a calculated tightness verification according to EN 1591-1, taking into account the requirements of TA-Luft, is possible.
The vessel sight glass is available in nominal sizes DN 25 to DN 300 and for nominal pressures PN 10 and PN 16.
It is suitable for industrial applications where processes, filling levels or media in pressure vessels and systems need to be reliably visually monitored.
Beyond the definitions of DIN 28120, we also offer Type 320 in the special sizes DN 250 and DN 300. These sizes, which are not defined in the standard, have also been designed based on DIN 28120.
The vessel sight glass Type 320 is manufactured as standard from corrosion-resistant stainless steel 1.4571. Versions made from stainless steel 1.4404 or special alloys such as duplex or alloy materials are also possible on request. This allows the sight glass fitting to be adapted to demanding operating conditions.
As glass material, borosilicate glass according to DIN 7080 is used as standard. Customer-specific versions of the vessel sight glass are also available on request; further details can be found in the data sheet.
For sealing the vessel sight glass, flat gaskets from a broad range of materials are available. Depending on the application, classic fibre gaskets as well as materials such as PTFE (Teflon®), NBR, novaphit® MST-XP, KlingerSil® C4400 and other branded gaskets are available. This allows the sight glass to be specifically adapted to temperature, pressure and medium.
If the temperature resistance of borosilicate glass according to DIN 7080 is not sufficient for the application, or if steam and process conditions have a particularly strong effect on the sight glass, a matched mica protection disc provides additional protection. For aggressive chemicals or alkaline solutions, the sight glass can also be supplemented with FEP coatings or Halar® coatings.
The DIN 28120 sight glass Type 320 can be equipped on request with SGW sight glass wipers, SVI spray devices and/or LED lights for Ex and non-Ex areas as well as mica protection discs.
The vessel sight glass Type 320 is suitable wherever processes in pressure vessels, tanks, silos, boilers or reactors need to be safely observed and visually monitored.
Typical applications include vessel and apparatus engineering, the chemical industry, petrochemicals as well as biogas plants and fermentation processes.
| 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.
