Type 337 - PN25 | Tank sight glass | ACI Industriearmaturen GmbH

Oval Sight Glass Type 337 - PN25

Oval sight glass with rounded ends PN 25

The ACI container sight glass Type 337 is a robust series of oval container sight glasses. Due to the use of sight glass panels according to the standard industry norm DIN 7081, it is possible for Type 337 to use sight glass panels of the “transparent” or “reflex” type, as for Type 330. The “transparent” type enables the use of protective layers such as mica, KEL-F, PRFE or FEP to protect the glass surface from chemical and thermal influences, while the “reflex” type ensures a better readability of the liquid level, due to the inset grooves.

Apart from the borosilicate glass described in the industry norm DIN 7081, we also use higher quality materials such as quartz or sapphire if your application requires it, for especially high temperatures or heavy-duty use.

Sealing is provided, like for most of our sight glass fittings, by high-quality flat seals such as KlingerSIL C4400, Frenzelit novaphit MST, or chemically highly-resistant PTFE in an untreated or expanded form. Durable soft seals such as silicon, EPDM or NBR can also be installed in your fitting by the factory.

As flange material, you can choose from our whole catalogue of high-quality types of steel and stainless steel, such as S235, 1.4571 or 1.4541. The internationally widespread stainless steel 1.444 is also available, along with high-performance alloys such as Hastelloy or duplex steel.

If it is necessary to replace the glass or seal, our competent team of technical and sales consultants will help to provide a solution as quickly as possible.

Read on for technical details or watch the product video above in the slider !

Technical details


Base flange:
1.4571, 1.4404, 1.4435, 1.4462, 1.4539, 1.4541, 2.4602, 2.4610, P265GH, Alloy , Super Duplex

Cover flange:
1.4571, 1.4404, 1.4435, 1.4462, 1.4539, 1.4541, 2.4602, 2.4610, P265GH, Alloy , Super Duplex

DIN 912, A4-70

Glass plates:
Borosilicate glass acc DIN 7081
Soda lime glass acc. To DIN 8903

Universal Quality (aramid fiber)
(Other materials available)


oval longitudinal sightglass
for insertion or welding

Nominal size:

176 - 536 mm

Nominal pressure:

Operating pressures up to 25 bar

(Vacuum version available on request)


100°C or 243°C

depending on glass and gasket selection.

Gasket selection:

PTFE (200°C)

FKM (200°C)

NBR (100°C)

C4400 (150°C)

Silicone (200°C)

EPDM (140°C)

Graphite (280°C)


Optional versions are possible.

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Type 337 - PN25 | Tank sight glass