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Weld Neck Vessel Sight Glass

The Weld Neck Vessel Sight Glass is designed for direct welding installation on tanks, reactors, pipelines, and process vessels. Featuring a welded neck connection and high-strength transparent window, it provides reliable visual monitoring under pressure, vacuum, and elevated temperature conditions.

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Technical data

Weld Neck Vessel Sight Glass for Tanks, Pipelines and Process Equipment

The Weld Neck Vessel Sight Glass is a robust inspection window specifically designed for welded installation on industrial vessels, reactors, storage tanks, and process pipelines. The weld neck connection provides superior mechanical strength and excellent sealing integrity, making it suitable for demanding industrial environments.

This sight glass assembly allows operators to observe fluid flow, liquid levels, product color, mixing conditions, and process reactions without interrupting production. The direct welded connection eliminates additional flange joints, reducing potential leakage points and improving system reliability.

Manufactured from high-quality stainless steel and equipped with premium transparent viewing materials, the Weld Neck Vessel Sight Glass offers excellent resistance to pressure, vacuum, corrosion, and temperature fluctuations.

Glass options include DIN 7080 borosilicate glass, fused quartz glass, sapphire glass, and tempered safety glass, allowing the sight glass to meet a wide range of industrial operating conditions.

The product is widely used in chemical processing, pharmaceutical manufacturing, petrochemical facilities, food and beverage production, biotechnology plants, water treatment systems, and energy industries.

Weld Neck Vessel Sight Glass— Technical Data

ParameterValue / Standard
Execution StandardDIN 28120 / DIN 28121 (weld-neck / weld-on flanged)
Nominal SizesDN 40 / 50 / 80 / 100 / 125 / 150 / 200
Pressure RatingPN 10 / PN 25 standard — custom up to 70 MPa on request
Glass MaterialBorosilicate 3.3 (DIN 7080) / Tempered Soda-Lime (DIN 8902) / Specialty glass on request
Temperature RangeUp to +280°C (borosilicate) — higher temperature glass available on request
Body / Flange MaterialCarbon Steel RSt37-2 / Stainless Steel 1.4571 / 1.4541 / 304 / 316
Gasket OptionsKLINGERsil C-4400 / PTFE / Silicone / Corrugated ring seal (high PN)
Visible Diameter (d1)48 mm (DN40) to 150 mm (DN200) – see dimension table below
Quality CertificateEN 10204-3.1 Material Certificate (standard) / 3.2 available on request
Connection TypeWeld-on base flange (pre-welded to vessel) + bolt-together cover flange assembly

Weld Neck Vessel Sight Glass— Standard Dimensions

Nominal Size (DN)Visible Diameter (d1)Glass Disc DiameterPressure Rating (PN)Glass Standard
DN 4048 mm~80 mmPN 10 / 25DIN 7080
DN 5058 mm~95 mmPN 10 / 25DIN 7080
DN 8082 mm~125 mmPN 10 / 25DIN 7080
DN 100100 mm~150 mmPN 10 / 25DIN 7080
DN 125120 mm~175 mmPN 10 / 25DIN 7080
DN 150135 mm~200 mmPN 10 / 25DIN 7080
DN 200150 mm~265 mmPN 10 / 25DIN 7080

KEY FEATURES

Thermal Stability

High resistance to thermal shock for extreme temperature environments

Superior Corrosion Resistance

Available in SS304, SS316L, Duplex Stainless Steel, Hastelloy, and other special alloys.

Chemical Resistance

Stable performance in corrosive chemical environments

Reliable Leak-Tight Sealing

Precision-machined sealing surfaces combined with industrial-grade gasket materials ensure long-term sealing performance

Temperature Resistant Construction

Suitable for both low-temperature and elevated-temperature industrial processes.

Custom Design Support

OEM / ODM customization available

Custom Manufacturing Service

We provide tailor-made solutions according to drawings or technical requirements.

TYPICAL APPLICATIONS

FAQ

A: A Weld Neck Vessel Sight Glass is a welded observation window installed directly onto tanks, vessels, or pipelines for visual process monitoring.

A:The weld neck design provides excellent mechanical strength, reduced leakage points, and long-term reliability in industrial applications.

 


A: Yes. The assembly can be designed for pressure-rated service according to operating requirements.


A: Yes. Custom diameters, neck lengths, pressure ratings, and material combinations can be supplied.

A: Yes. LED sight glass lights and explosion-proof illuminators can be integrated for improved visibility.

Need Custom Weld Neck Vessel Sight Glass Solutuions?

Send us your drawings or technical requirements for fast quotation and engineering support.