Sight glass for industrial applications Type 336

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The longitudinal sight glass fitting type 336 is a lightweight rectangular sight glass fitting that provides an enlarged viewing opening for wall-mounted level indication and general sighting in containers and vessels at relatively low operating pressures (up to 6 barg). It combines features of round sight glasses and level indicators and is available with various materials and protective options.

Design and materials
The fitting is supplied with a sight glass plate made of high-quality borosilicate glass (similar to DIN 7081 or to customer specification) framed between seals and mechanically fixed by screws for permanent tightness and pressure resistance. Standard material for the fitting is stainless steel 1.4571 (316Ti); other materials are available on request.

Sealing and protection
Sealing is achieved with flat gaskets from a broad range of materials. Available gasket materials include common fibre materials and advanced polymers such as PTFE (Teflon®), NBR, novaphit® MST-XP and KlingerSil® C4400, among others. Where borosilicate limits are reached (temperature or aggressive process conditions), the fitting can be equipped with a mica protection disc and/or protective coatings (FEP or Halar®) to shield the glass from high temperature, steam or aggressive chemicals.

Features & options

• Lightweight design with significantly enlarged viewing opening compared to type 330
• Standard material: stainless steel 1.4571 (316Ti); other materials on request
• Sight glass: borosilicate glass (DIN 7081 or customer specification)
• Flat gasket sealing with more than 50 gasket material options (including PTFE, NBR, novaphit® MST-XP, KlingerSil® C4400)
• Optional mica protection disc for high-temperature and steam resistance
• Optional FEP or Halar® coating for chemical resistance
• Nearly dead-space-free design and possibility for special constructions/customisations

Technical specifications

• Maximum working pressure: up to 6 barg
• Standard heat resistance: up to 280 °C (higher-temperature versions available; selectable up to 400 °C)
• Suitable media: liquid and gaseous media
• Total lengths (face-to-face) available: 250, 310, 370, 430, 490, 550, 610, 670 mm
• Nominal pressure (PN): 6
• Temperature options (examples): 80 °C, 130 °C, 150 °C, 175 °C, 180 °C, 200 °C, 280 °C, 300 °C, 400 °C
• Options: FEP or Halar® coating; mica protection disc; high-temperature version; nearly dead-space-free design; special constructions
• Standard components visible in exploded view: screws; cover frame; glass cushion; sight glass; gasket; base frame
• Dimensions & weights (face-to-face BL / viewing length SL / weight):
  • BL 250 mm — SL 180 mm — Weight 5.6 kg
  • BL 310 mm — SL 240 mm — Weight 6.9 kg
  • BL 370 mm — SL 300 mm — Weight 8.2 kg
  • BL 430 mm — SL 360 mm — Weight 9.6 kg
  • BL 490 mm — SL 420 mm — Weight 10.9 kg
  • BL 550 mm — SL 480 mm — Weight 12.2 kg
  • BL 610 mm — SL 540 mm — Weight 13.6 kg
  • BL 670 mm — SL 600 mm — Weight 14.9 kg