Explosive atmosphere sight glass Type 391

monitoringweld-onstainless steel

The ACI sight glass type 391 is a circular sight glass fitting with pipe attachment designed for installation on pipelines or sharply curved tanks. It clamps a borosilicate sight glass plate between two high-quality stainless steel flanges with tailored flat seals.

Components

• Screws
• Cover flange
• Glass cushion
• Sight glass (borosilicate glass DIN 7080)
• Gasket
• Base flange with pipe attachment
• Nuts

Options

• Wiper SGW with PTFE or silicone wiper blade
• LED light for Ex and non-Ex areas
• FEP or Halar® coating
• Mica protection (protective shield)
• Custom made design

Nominal pressure

• PN 16
• PN 25
• PN 40

Temperature options

• 80°C
• 130°C
• 150°C
• 175°C
• 180°C
• 200°C
• 280°C
• 300°C
• 320°C
• 400°C

Dimensions / Weights (selected values from drawing table)

• DN 100 — Diameter (PN16): 220 mm; Weight (PN16): 10.5 kg; Inner diameter: 107 mm; Length (standard): 70 mm; s: 3.6 mm; A: 114.3 mm
• DN 125 — Diameter (PN16): 250 mm; Weight (PN16): 14.5 kg; Inner diameter: 132 mm; Length (standard): 70 mm; s: 4.0 mm; A: 139.7 mm
• DN 150 — Diameter (PN16): 285 mm; Weight (PN16): 18.6 kg; Inner diameter: 160 mm; Length (standard): 70 mm; s: 4.5 mm; A: 168.3 mm
• DN 200 — Diameter (PN16): 340 mm (PS max. 10 barg note for larger sizes); Weight (PN16): 28.2 kg; Inner diameter: 207 mm; Length (standard): 70 mm; s: 6.3 mm; A: 219.1 mm
• DN 300 — Diameter (PN16): 460 mm (PS max. 6 barg for very large sizes); Weight (PN16): 55.7 kg; Inner diameter: 310 mm; Length (standard): 70 mm; s: 7.1 mm; A: 232.9 mm
• DN 350 — Diameter (PN16): 520 mm (PS max. 6 barg for very large sizes); Weight (PN16): 78 kg; Inner diameter: 340 mm; Length (standard): 70 mm; s: 8.0 mm; A: 355.6 mm

Quick overview

• Maximum possible pressure up to 40 barg (depending on PN and size)
• Heat-resistant up to 280 °C (various temperature options available)
• Suitable for liquid and gaseous media
• Nominal sizes DN 100 - 350
• Custom made designs possible
• More than 50 sealing materials available
• Accessories available (wipers, LED lights, protective screens, mica discs, etc.)

Technical specifications

• Brand / Manufacturer: ACI Industriearmaturen GmbH
• Model / Type: Circular sight glass fitting type 391
• Product application: For welding on pipelines or installation on curved tanks; suitable for monitoring liquid and gaseous media
• Body material: High-quality stainless steel 1.4571 (316Ti)
• Sight glass material: Borosilicate glass (DIN 7080) — alternative glass types on request
• Sealing: Flat seals in a wide range of materials (fiber, PTFE (Teflon®), NBR, novaphit® MST-XP, KlingerSil® C4400, and many branded seals)
• Coatings / protection: FEP or Halar® coating available; optional mica protective shield for higher temperature/steam protection
• Accessory options: Sight glass wiper (SGW), LED lights (Ex and non-Ex), mica protection, FEP/Halar coatings
• Nominal sizes (DN): 100, 125, 150, 200, 300, 350
• Nominal pressure: PN 16, PN 25, PN 40 (depending on size and design)
• Temperature capability: multiple options from 80°C up to 400°C depending on configuration and protective measures
• Standard face-to-face length: 70 mm (all listed DN)
• Inner diameters (examples): DN100 = 107 mm; DN125 = 132 mm; DN150 = 160 mm; DN200 = 207 mm; DN300 = 310 mm; DN350 = 340 mm
• Typical applications: Process monitoring, tank and pipeline sighting where chemical resistance and temperature/pressure performance are required
• Documentation: Datasheet and info brochure available (PDF)