strip sight glass installed on pipeline
edge detail long slot sight glass
Long Sight Glass — Strip / Slot Sight Glass for Inline Visual Inspection - Image 3
Long Sight Glass — Strip / Slot Sight Glass for Inline Visual Inspection - Image 4

Long Sight Glass — Strip / Slot Sight Glass for Inline Visual Inspection

Long sight glass (strip/slot window) for inline inspection. Stainless housings, borosilicate slot glass, flanged and custom lengths. Datasheet & COA available.

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Description

Long sight glass (also called strip sight glass or slot sight glass) provides an extended viewing window for process lines and vessels. Built for clear, continuous visual checks, our strip sight windows combine durable borosilicate glass and stainless steel housings. They fit flanged and cartridge assemblies and come in custom lengths for level, flow and inspection applications.

Quick overview — what this product does

  • Continuous view: Long rectangular viewing window for an unbroken view of media.
  • Rugged construction: Stainless steel bodies with borosilicate or tempered glass slots.
  • Flexible mounting: Flanged, threaded or cartridge options for easy installation.
  • Custom lengths: Standard sizes and bespoke lengths up to 1500 mm (contact factory).
  • Certs & testing: Batch COA, dimensional reports and pressure testing on request.

Product specifications (typical)

Long / Slot Sight Glass — Specifications

Product type Long / strip / slot sight glass
Window material
  • Toughened sodium silicate glass to DIN 8903 (max. 100 °C)
  • Toughened borosilicate glass to DIN 7081 (max. 243 °C)
Body material Stainless steel 304 / 316; carbon steel optional
Standard lengths 200 mm, 275 mm, 360 mm, 425 mm, 500 mm, 575 mm, 725 mm; custom size
Operating conditions: Nominal pressure 2,5 /6 /10/25 bar, Vacuum

Note: The nominal pressure indicated refers to the design base of the sightglass. When welded into the vessel concerned, the base frame becomes part of the vessel wall. It is necessary, therefore, that appropriate strength calculations are made on all vessels concerned with respect to the design pressure and size of the vessel and in accordance with the relevant design code. If found to be necessary, reinforcement of the vessel wall has to be carried out.
Operating temperatures:
  • 100℃ max. with sodium silicate glass to DlN 8903
  • 243℃ max. with borosilicate glass to DlN 7081

Note: The above indicated temperatures refer to the use of unprotected glass plates, with no protective mica sheets.
Base flange: Boiler plate RSt 37-2/HI /AISI 316 Ti/AISI 316 L
Cover flange: Boiler plate RSt 37-2/HI/AISI304/AISI 316 T/AISI 316 L
Seals:
  • KLINGERsil C4400
  • EPDM
  • Silicone
  • PTFE

Need custom sizes or special materials? Contact us for a quick quote.

Features & benefits

  • Unobstructed inspection: The elongated slot shows flow pattern, level and clarity along a length instead of a small spot.
  • Abrasion resistance: Borosilicate and tempered options reduce scratching in abrasive media.
  • Low contamination risk: Glass window eliminates metallic debris typical of metallic inspection ports.
  • Easy maintenance: Serviceable cartridges and gaskets speed replacement and reduce downtime.
  • Vacuum & pressure capable: Metalized or brazed options available for high-vacuum requirements.

Typical applications

Long sight glass is common in chemical reactors, slurry lines, level gauges for tall tanks, food & beverage sight lanes, water treatment plants, and OEM process equipment where line-of-sight over a distance matters.

Ordering & customization

To order, provide: flange type, bolt pattern, overall length, slot height, glass thickness, and process conditions (P/T, media). For custom orders, upload your drawing (DWG/STEP) via the Request Quote — Upload DWG/STEP form.

Downloads

FAQ

1. What is a strip or slot sight glass?
A strip (slot) sight glass is an elongated rectangular viewing window designed to provide a continuous view of process fluids across a length rather than a point.
2. Can you make custom lengths?
Yes. We manufacture bespoke lengths and slot heights. Contact us with your DWG/STEP for a quote.
3. Which material should I choose for high abrasion?
Choose borosilicate or tempered glass. For extreme temperatures or laser/UV needs, fused silica or quartz may be better.

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