Longitudinal sight glass fitting type 337 PN 25

Product information

The ACI sight glass of type 337 is used for reliable observation of the liquid level in closed containers such as boilers, tanks, or silos. It is a rectangular inline sight glass with round ends that can be either welded into or onto the container wall.

The fitting is equipped with a sight glass plate made of high-quality borosilicate glass according to DIN 7081 (or according to customer requirements). It is securely encased between seals and firmly screwed in to ensure lasting tightness and high pressure resistance.

Standardly, the sight glass type 337 is made of stainless steel 1.4571 (316Ti) - a material that is characterized by high corrosion resistance and durability. On request, the design is also available in many other materials, suitable for specific requirements and applications.

The sealing of the fitting is done with flat seals tailored to your needs from an extensive range of materials. This offers, in addition to the common fiber seals, also more sophisticated materials like PTFE (Teflon®), NBR, novaphit® MST-XP, KlingerSil® C4400 and many other branded seals.

If the maximum service temperature of borosilicate glass DIN 7081 does not meet your requirements or if the process conditions pose a problem even for the highly resistant borosilicate glass, a mica protection disc specifically adapted for the fitting provides additional protection against temperature and steam. FEP or Halar® coatings additionally protect the borosilicate glass from aggressive chemicals or caustics.

For applications in poorly lit containers, the use of a reflex sight glass according to DIN 7081 (or comparable) is recommended. These glasses are embedded with special prism structures that refract and reflect the incoming light - making the filling level much easier to recognize.

If the container is well illuminated, the medium is very clear, or if the color of the medium should additionally remain visible, a transparent sight glass is the better choice. It allows for an undistorted view and exact optical control of the contents.

Important note: Reflex sight glasses cannot be combined with mica discs and coatings, as the protective mica layer prevents the light refraction necessary for reflection. In contrast, transparent glasses can be easily equipped with mica discs, FEP, or Halar® coating, which is particularly recommended for protection of the glass in aggressive media or at high temperatures.