Type 318V - Tank sight glass for vacuum | ACI Industriearmaturen GmbH

Sight glass fitting type 318V - PN 2.5 for vacuum applications

Short description - Tank sight glasses type 318V

Our round tank sight glasses type 318V, like our other tank sight glasses, are welded to or in tank walls to allow observation or illumination of the tank interior. ACI tank sight glasses type 318 have been designed based on DIN 28120 for vacuum applications up to an operating pressure of 2.5 bar. A sight glass made of chemically highly resistant borosilicate glass DIN 7080 is clamped between two high-quality stainless steel flanges and thus forms an almost maintenance-free inspection opening. The vacuum is sealed on the media side by means of sealing rings.

Compared to the DIN 28120 design, our Type 318V is considerably flatter and lighter. Due to the use of hexagon head screws, it has significantly fewer protruding edges, which greatly reduces the space required for the sight glass holder. The Type 318V therefore perfectly fills the application range between our Type 317 for pressureless operation and the more solid Type 320 according to DIN 28120.

The fitting is sealed with O-rings or sealing rings in accordance with DIN 11851, which can be selected from an extensive range of materials such as PTFE (Teflon®), NBR, EPDM or silicone.

Should the maximum operating temperature not meet your requirements, or should the process conditions present a problem even for the highly resistant borosilicate glass, there are possibilities (depending on the vacuum) to also work with flat sealing systems. Like other of our sightglasses, the type 318V can be equipped with wipers type SWI or lights.

More technical details about our tank sight glass type 318V can be found in the data sheet or in the product video.

Technical data


Block flange:

1.4571 (factory standard)

Cover flange:

1.4541 (factory standard)

Special materials on request

Sight glass:

Borosilicate glass according to DIN 7080


PTFE, NBR, EPDM, FKM, Silicone




For welding in or on similarly

DIN 28120 but for vacuum applications

Nominal size:

DN 50 to DN 400 (larger sizes on request)

Nominal pressure:

from vacuum to +2,5 bar


depending on gasket selection


Special designs/options

a) With wiper type SWI

b) With spraying device type SV1

c) double glazing

d) Double glazing + heating element

e) With LED or halogen luminaires, also ATEX-certified

h) High-temperature version with quartz glass

i) Plexiglas impact protection window (5mm)

j) Other special designs on request

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Type 318V - Tank sight glass for vacuum