Guide to Blind Flanges

 

Introduction – What is a Blind Flange?

A blind flange is a solid disc used to seal the end of a pipeline, valve, or pressure vessel. Unlike other flanges, it has no bore or opening, effectively blocking fluid flow. Blind flanges are essential in piping systems for isolation, maintenance, or future expansion.



Types of Blind Flanges

Blind flanges come in various types based on design and sealing requirements:

  1. Raised Face (RF) Blind Flange – Features a small raised area around the sealing surface, improving gasket compression.

  2. Flat Face (FF) Blind Flange – Has a completely flat surface, ideal for low-pressure applications.

  3. Ring-Type Joint (RTJ) Blind Flange – Designed with a machined groove to accommodate metal ring gaskets for high-pressure sealing.

  4. Custom Machined Blind Flanges – Modified for specific applications with additional tapping or threading.

Blind Flange Dimensions and Standards

Blind flanges are manufactured according to international standards to ensure compatibility. Common standards include:

  • ASME B16.5 – Covers flanges from ½” to 24” with pressure ratings from Class 150 to Class 2500.

  • ASME B16.47 – Used for larger sizes, 26” to 60”, with pressure ratings up to Class 900.

  • DIN (Deutsches Institut für Normung) – European standard for various flange types.

  • JIS (Japanese Industrial Standard) – Used in Asian markets.

  • EN 1092-1 – European flange standard with multiple pressure ratings.

Applications of Blind Flanges

Blind flanges are used across industries for pipeline sealing and system isolation. Common applications include:

  • Oil & Gas – Sealing high-pressure pipelines and pressure vessels.

  • Water Treatment – Used in filtration and wastewater processing systems.

  • Power Plants – Essential in steam and high-temperature piping.

  • Chemical Processing – Used for corrosive fluid containment.

  • Food & Beverage Industry – Stainless steel blind flanges ensure sanitary piping systems.

Advantages of Using Blind Flanges

  1. Complete Flow Restriction – Prevents fluid movement in pipelines.

  2. Easy Maintenance – Allows quick system shutdown and disassembly.

  3. Strength and Durability – Withstands high pressure and temperature conditions.

  4. Leak Prevention – Provides secure sealing, reducing leaks.

  5. Future Expansion Flexibility – Can be removed for adding new pipeline sections.

Material Selection for Blind Flanges

Blind flanges are available in different materials based on system requirements:

  • Carbon Steel – High strength, cost-effective, and used in industrial applications.

  • Stainless Steel – Corrosion-resistant and ideal for food, chemical, and marine industries.

  • Alloy Steel – Enhanced strength and temperature resistance.

  • Copper-Nickel – Suitable for marine and offshore environments.

  • PVC/Plastic – Lightweight, chemical-resistant, and used in non-metallic piping systems.

Blind Flange Pressure Ratings

Blind flanges are rated by their pressure-handling capacity, following ANSI/ASME classifications:

  • Class 150 – Up to 285 PSI at 100°F.

  • Class 300 – Up to 740 PSI at 100°F.

  • Class 600 – Up to 1,480 PSI at 100°F.

  • Class 900 – Up to 2,220 PSI at 100°F.

  • Class 1500 – Up to 3,705 PSI at 100°F.

  • Class 2500 – Up to 6,170 PSI at 100°F.

The pressure rating depends on material, temperature, and system conditions.

FAQs – Common Questions About Blind Flanges

1. When should a blind flange be used?

A blind flange is used to isolate a section of a pipeline, stop fluid flow, or allow for future expansion.

2. Can blind flanges handle high pressure?

Yes, blind flanges are available in high-pressure ratings up to Class 2500, making them suitable for extreme conditions.

3. What gaskets are used with blind flanges?

Gasket selection depends on the flange type:

  • Raised Face Flange – Uses soft gaskets like rubber, PTFE, or spiral-wound gaskets.

  • RTJ Flange – Requires metal ring gaskets.

  • Flat Face Flange – Uses full-face gaskets.

4. What is the difference between a blind flange and a blank flange?

A blind flange is a standalone component with bolt holes, whereas a blank flange (or blind plate) is a solid plate used to cover a flange opening without bolt holes.

5. How do you install a blind flange?

Blind flanges are bolted onto a mating flange using gaskets and fasteners, ensuring a leak-proof seal.

6. Are stainless steel blind flanges corrosion-resistant?

Yes, stainless steel blind flanges (304, 316 grades) offer excellent corrosion resistance for harsh environments.

7. Can blind flanges be custom-made?

Yes, manufacturers offer custom blind flanges with specific materials, coatings, and machining features based on project requirements.

Conclusion

Blind flanges are essential for sealing, isolating, and maintaining pipeline systems across multiple industries. Understanding flange types, materials, pressure ratings, and applications ensures efficient selection for different operational needs.

For expert guidance, refer to ASME, ANSI, DIN, or JIS standards or consult a certified flange manufacturer for custom requirements.

Comments

Post a Comment

Popular posts from this blog

Check Valve (Non-Return Valve): Types, and Pricing

  Introduction A check valve , also known as a non-return valve (NRV) , is a mechanical device that allows fluid to flow in only one direction, preventing backflow. It is commonly used in pipelines, water supply systems, industrial processes, and pumps to maintain directional flow and prevent equipment damage due to reverse flow. Check Valve Symbol The check valve symbol used in engineering diagrams consists of a valve body with an arrow indicating the permitted flow direction and a barrier preventing reverse flow. It is commonly seen in process flow diagrams (PFDs) and piping and instrumentation diagrams (P&IDs). Types of Check Valves (Non-Return Valves) There are several types of check valves (NRVs) designed for specific applications: Swing Check Valve – Uses a hinged disc that swings open with forward flow and closes when the flow reverses. Dual Plate Check Valve – Features two spring-loaded plates that automatically open and close with the...
Read more

Heavy Machinery Bolt Manufacturer in Rajasthan

  Introduction Finding a reliable heavy machinery bolt manufacturer in Rajasthan is crucial for ensuring high-strength, durable, and corrosion-resistant fasteners for various industries. From construction to mining and heavy engineering , selecting the right supplier ensures superior performance and cost-effectiveness. Udhhyog , a leading supplier, provides insights into the best heavy machinery bolt manufacturers in Rajasthan . Importance of High-Quality Heavy Machinery Bolts Ensuring Structural Integrity – High-tensile bolts provide secure and stable connections . Corrosion Resistance – Galvanized and stainless steel fasteners prevent rust and degradation . Load-Bearing Strength – Heavy machinery requires high-strength nuts and bolts . Compliance with Industry Standards – Ensuring adherence to ISO, ASTM, and BIS certifications . Best Heavy Machinery Bolt Manufacturers in Rajasthan 1. Udhhyog – Leading Supplier for Heavy Machinery Fasteners Specialty: High-tensile, stainles...
Read more

SS Pipe Price Comparison: India vs International Market

  Introduction Stainless steel (SS) pipe s play a vital role in various industries, including construction, manufacturing, and oil & gas. This article provides an in-depth price comparison between Indian and global markets, analyzing factors influencing costs and tips for businesses and Udhhyog owners. SS Pipe Price Comparison: India vs Global Markets Stainless Steel Pipe Prices in India (March 2025) Prices in India vary based on grade, thickness, and supplier. Below is an estimated price range: SS Grade Thickness (mm) Price (INR per kg) 202 1.2 – 3.0 200 – 250 304 1.2 – 5.0 280 – 350 316 1.2 – 6.0 400 – 500 409 1.2 – 4.0 180 – 230 Global Stainless Steel Pipe Prices Prices vary across different international markets: Region Average Price (USD per ton) USA 3,000 – 4,500 Europe 2,800 – 4,000 China 2,500 – 3,800 Middle East 2,700 – 4,200 Key Differences: India vs Global Market Raw Material Costs: Nickel & chromium prices affect global rates. Manufacturing Expenses: Labor and...
Read more