Vessel sight glass Type 334

level indicatormonitoringstainless steel

The Longitudinal sight glass fitting Type 334 is a rectangular/elongated sight glass fitting designed for welding in or on tank walls and containers, offering a large viewing window for monitoring liquid and gaseous media. It combines the functions of round sight glasses and level indicators while allowing customer-specific materials and configurations.

Design & materials
The fitting is equipped with a sight glass plate made of borosilicate glass (similar to DIN 7081) clamped between seals and firmly screwed into a metal frame. Standard material for metal parts is stainless steel 1.4571 (316Ti); alternative materials available on request. Sealing is provided by flat gaskets selected from a wide range of materials to match the application.

• Standard glass: borosilicate (DIN 7081 or per customer specification)
• Standard metal: stainless steel 1.4571 (316Ti); alternative materials on request
• Sealing materials: fiber gaskets and advanced materials such as PTFE (Teflon®), NBR, novaphit® MST-XP, KlingerSil® C4400 and many more (>50 gasket materials available)

Structure (exploded components)

• Screws
• Cover frame
• Glass cushion
• Sight glass
• Gasket
• Base frame

Options

• FEP or Halar® protective/coating for additional chemical resistance
• Mica protection disc to protect the glass against high temperatures and steam
• High temperature version
• Nearly dead-space free version
• Special constructions / custom designs

Dimensions (standard face-to-face / viewing length / weight)

• BL 270 mm — SL 200 mm — Weight 7.4 kg
• BL 340 mm — SL 270 mm — Weight 9.0 kg
• BL 410 mm — SL 340 mm — Weight 10.6 kg
• BL 480 mm — SL 410 mm — Weight 12.2 kg
• BL 550 mm — SL 480 mm — Weight 13.8 kg
• BL 620 mm — SL 550 mm — Weight 15.4 kg
• BL 690 mm — SL 620 mm — Weight 17.0 kg
• BL 760 mm — SL 690 mm — Weight 18.6 kg

Application notes
The Type 334 provides a significantly enlarged rectangular viewing window compared to smaller types, suitable for visual monitoring of both liquid and gaseous media. Standard sight glass material is borosilicate; if process temperatures or conditions exceed borosilicate limits, mica protection discs or special high-temperature constructions are available. FEP/Halar® coatings protect the glass against aggressive chemicals.

Technical specifications

• Denomination: Longitudinal sight glass fitting Type 334
• Nominal pressure (standard): PN 3
• Typical application: welded in or on tank walls (level indicator / sight glass)
• Standard metal: stainless steel 1.4571 (316Ti) — other materials on request
• Standard glass: borosilicate (similar to DIN 7081) — special glasses on request
• Temperature options: 80°C, 130°C, 150°C, 175°C, 180°C, 200°C, 280°C, 300°C, 400°C (standard borosilicate operation limited; high-temperature and protected variants available)
• Media: for liquid and gaseous media
• Total length (BL) range: 270–760 mm (various SL / weight as listed above)
• Accessories / variants: FEP protective coating, Halar® coating, mica protection disc, high-temperature versions, nearly dead-space free versions, special constructions
• Custom made designs possible; extensive choice of gasket materials (>50)