Type 336 - PN 6 | oval tank sight glass | ACI Industriearmaturen GmbH

Tank Sight Glasses / Level Indicators Type 336 - PN6

Oval Sight Glass for welding into vessels and tanks

The ACI container sight glass Type 336 is a container sight glass in an oval form and due to its geometry, it can be used not only for the observation of processes, but also as a filling level indicator.

As glass material, we use borosilicate glass tried and tested in industry, but we can also supply also high-performance materials such as quartz or sapphire glass for exceptional loads on request. In its original condition, borosilicate glass is already highly resistant to most acids. If there are strong alkali media, it is possible to use one of our customised mica layers to protect the glass surface. Alternatively, we also use protective layers made of KEL-F, FEP or PTFE foil.

As sealing material, we use high-quality flat seals made of proven raw material. For example, for many applications we use the robust and economical aramid fibre seals C4400 by the company Klinger. For chemically and thermally more challenging operating conditions, we recommend novaphit MST by Frenzelit and comparable graphite compound materials. Soft seals made of silicone, EPDM or NBR are also part of our product range. For food uses and very aggressive media, we fit your individually adapted fitting with pure PTFE, expanded or solid, PTFE with inserts (glass fibre or glass beads) or special seals such as Garlock Gylon.

For the flange materials, you have the choice of our usual high-quality types of steel and stainless steel, without exception with pressure device approval and tested according to all current standards. Apart from standard types of steel such as S235, or stainless steel 1.4571 or 1.4541, we also use the alloy 1.4404 that is often used internationally. High-performance alloys such as Hastelloy or duplex steels can also be supplied on request.

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

Lloyd´s Register design appraisal

with Lloyd´s Register design appraisal


Optional versions are possible.

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, or special materials

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:

250 - 670 mm

Nominal pressure:

Operating pressures up to 6 bar

(Vacuum version available on request)

Special feature:

A Lloyd's Register design appraisal is available.


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 (130°C)

Graphite (280°C)

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Type 336 - PN 6 | oval tank sight glass