The blind flange is typically a circular flat plate structure with no central opening, featuring bolt holes distributed along the outer circumference that match the corresponding pipeline flange. It achieves complete pipeline sealing by cooperating with the pipeline flange, sandwiching a gasket between them, and fastening with bolts. Its core functions include
I. Product Structure & Functions
The blind flange is typically a circular flat plate structure with no central opening, featuring bolt holes distributed along the outer circumference that match the corresponding pipeline flange. It achieves complete pipeline sealing by cooperating with the pipeline flange, sandwiching a gasket between them, and fastening with bolts. Its core functions include:
1. Media Isolation: Blocks upstream and downstream media flow during pipeline maintenance, equipment replacement, or long-term shutdown of a pipeline section, preventing media leakage or mixing.
2. Safety Protection: Serves as an emergency isolation device in pipelines transporting flammable, explosive, toxic, or hazardous media, reducing safety risks.
3. Temporary Plugging: Used for temporary sealing during pipeline system commissioning or phased construction, facilitating system pressure testing or cleaning.
II. Executive Standards
Common standards for blind flanges include:
●ASME B16.5: Applies to steel pipe flanges and flanged fittings (including blind flanges) with nominal pipe size (NPS) ½~NPS 24 (DN15~DN600) and pressure ratings Class 150~Class 2500.
●ASME B16.47: Divided into Series A (large-diameter flanges, corresponding to API 605 standard) and Series B (corresponding to MSS SP-44 standard). Applicable to large-diameter steel flanges with NPS 26~NPS 60, including blind flange specifications.
III. Key Parameters & Classifications
1. Nominal Pipe Size (NPS): Ranges from NPS ½ (DN15) to NPS 60 (DN1500), compatible with different pipeline sizes.
2. Pressure Rating (Class): Common ratings include Class 150, 300, 600, 900, 1500, 2500, corresponding to different design pressures.
3. Sealing Face Type:
●RF (Raised Face): Most commonly used, with a 2.0mm or 3.2mm raised platform on the surface. Compatible with non-metallic soft gaskets, suitable for medium and low-pressure working conditions.
●FF (Flat Face): The flange face is flush with the plane where the bolt holes are located. Applicable to low-pressure or compact installation scenarios, often used with rubber gaskets.
●RTJ (Ring Type Joint): Designed for high pressure, the flange face is machined with a trapezoidal groove, cooperating with metal ring gaskets. Suitable for high-pressure systems of Class 600 and above (e.g., oil and gas, chemical high-pressure pipelines).
4. Material Classification:
●Carbon Steel Blind Flanges: e.g., ASTM A105, A350 LF2. Low cost and high strength, suitable for ambient temperature, normal pressure, or medium-temperature working conditions with media such as water, steam, and oil products.
●Stainless Steel Blind Flanges: e.g., ASTM A182 F304 (0Cr18Ni9), F316 (0Cr17Ni12Mo2). Excellent corrosion resistance, applicable to pipelines transporting acid-base media, seawater, or high-purity fluids (e.g., food, pharmaceutical, chemical industries).
●Alloy Steel Blind Flanges: e.g., ASTM A182 F5 (Cr5Mo), F9 (Cr9Mo). Suitable for high-temperature, high-pressure, or strongly corrosive working conditions (e.g., power plants, refineries).
IV. Application Scenarios
Blind flanges are widely used in pipeline systems across industries such as petrochemical, natural gas, power generation, water treatment, pharmaceuticals, and food processing. Specific scenarios include:
●Process pipeline isolation;
●High-pressure system sealing;
●Corrosive environment applications;
●Temporary or permanent plugging.
V. Product Advantages
●High Standardization Level: Complies with ASME series standards, ensuring strict guarantees for dimensional accuracy and material performance. Compatible with American standard pipeline systems worldwide.
●Strong Sealing Reliability: Achieves long-term stable sealing of high-pressure, high-temperature, and corrosive media through precision-machined sealing faces and matched gaskets.
●Easy Installation: Simple structure, allowing installation and disassembly without complex tools, facilitating rapid switching of pipeline states (on/off).
As a "safety barrier" in pipeline systems, the design and selection of blind flanges must comprehensively consider system pressure, temperature, media characteristics, and installation environment to ensure compliance with engineering safety and process requirements.
Dec 02,25
The Core Role Of The Tee In Pipeline Systems
In the complex architecture of modern pipeline systems—spanning petrochemical plants, municipal waterworks, HVAC networks, and power generation facilities—the tee fitting is arguably one of the most critical and universally employed components.
Dec 02,25
Corrosion-Resistant Flanges For Chemical And Marine Industries
Flanges are indispensable components in piping systems, serving as the critical junctions that allow for connections, maintenance, and isolation of flow.
Dec 02,25
Characteristics And Common Applications Of Carbon Steel Bending Pipe
The use of bent piping is an essential practice in industrial construction, allowing fluid transfer lines to navigate complex routes, compensate for thermal expansion, and eliminate the need for numerous welded elbow fittings.
SUBSCRIBE NEWSLETTER
