Large Diameter Blind Flange

  • Nominal Size (DN): DN650–DN1500 (NPS 26″–NPS 60″)
  • Nominal Pressure: PN20–PN150 (Class 150–Class 900)
  • Sealing Types:RF , RJ , M , FM , T , G
  • Applicable Standards: ASME B16.5, JIS B2220, EN 1092-1, HG/T 20592, etc.
  • Body Materials:304, 316L, Hastelloy C, Alloy 20, 2205, 2507, 904L, 310S, TA2, 20#, etc.
  • Applicable Media & Temperature Range: Water, neutral gases and liquids, alcohol, oil, fuel, steam, organic solvents, acidic and alkaline solutions (196°C to 1000°C)
  • Applicable Industries:Oil and gas, chemical industry, electric power, shipbuilding, food and beverage, pharmaceuticals, municipal water supply and drainage, building HVAC, metallurgy, environmental protection, etc.

Product details

Large-diameter blind flange (BL), also known as blanking flange or pipe end closure plate, is a solid circular flange without central bore, applicable for nominal diameter DN≥650 (NPS 26 and above). It is fastened by bolts and assembled with gaskets to connect matched pipe flanges, achieving tight leak-proof isolation and sealing.
A blind flange bears the full medium pressure inside pipelines, so its thickness is much larger than ordinary flanges with identical pressure ratings. It is widely adopted as a removable fitting for pipeline isolation, pressure testing, as well as temporary and permanent pipe end blocking, commonly used in oil & gas, chemical, power plant and water treatment industries.

Product Specifications

RF (Raised Face) – The most widely used facing type in the market. Compatible with rubber, PTFE, and spiral-wound gaskets. Suitable for general-purpose service across most pressure and temperature ranges.
FF (Flat Face) – Designed with a full-face contact surface. Primarily used with low-pressure cast iron flanges to prevent flange distortion due to excessive bolt loading. Commonly applied in municipal water systems and low-pressure utility lines.
RTJ (Ring-Type Joint) – Features a precision-machined groove for accommodating metallic ring gaskets. Mandatory for high-pressure and high-temperature services (Class 900 and above). The preferred choice for large-bore hydrogen, high-temperature steam, and critical hydrocarbon lines where metal-to-metal sealing is required.
MFM (Male & Female Face) – Utilizes matched male and female mating surfaces. Effectively prevents gasket extrusion under high internal pressure. Recommended for aggressive corrosive media and erosive fluid services.
TG (Tongue & Groove Face) – Employs interlocking tongue-and-groove profiles. Offers excellent gasket retention and sealing stability. Ideally suited for severe service conditions involving strong corrosives, abrasive slurries, or cyclic thermal loading where gasket displacement must be minimized.