Flat Welding Flanges – Lightweight, Compact, and High-Performance Flange Solutions for Industrial Applications

Overview of Flat Welding Flanges – Compact, Reliable, and Cost-Effective

Flat welding flanges are widely used in pipeline connections, offering efficient sealing solutions for various industrial applications. These flanges come in two main types: plate type flat welding flanges (PL) and neck type flat welding flanges (SO). Both types are designed to provide secure connections while ensuring low leakage and high performance in moderate pressure conditions. Flat welding flanges are commonly employed in industries such as petrochemical, water treatment, and manufacturing.

Types of Flat Welding Flanges

• Plate Type Flat Welding Flanges (PL)
  These flanges are designed for low-pressure connections, typically with a nominal pressure not exceeding 2.5 MPa. They are suitable for relatively mild conditions, such as non-purified compressed air or low-pressure circulating water. The sealing surfaces of plate type flat welding flanges can be smooth, concave-convex, or tenon groove, with smooth surfaces being the most commonly used.

• Flat Welding Flanges with Neck (SO)
  Flat welding flanges with a neck feature a low neck height, enhancing the flange's stiffness and load-bearing capacity. These flanges require significant welding work and electrode consumption but are easier to install onsite. While they are not ideal for high-temperature, high-pressure, or repeated bending applications, they are still widely used due to their convenience and effectiveness in less extreme conditions.

Features of Flat Welding Flanges

• Space and Weight Savings
  One of the key advantages of flat welding flanges is their compact design, which reduces both weight and space requirements. The smaller diameter of the sealing element and the replacement of traditional flange gaskets with sealing rings allow for lower compression pressure, reducing the number of bolts needed and thus lightening the overall weight of the system. This makes flat welding flanges up to 80% lighter than traditional flanges.

• Enhanced Sealing Performance
  The design of flat welding flanges ensures excellent sealing performance with minimal pressure, which reduces the risk of leaks in pipeline systems. This makes them ideal for use in applications where joint reliability is critical.

• Cost-Effective Solution
  Flat welding flanges offer a reliable, space-efficient, and cost-effective solution for pipeline connections, especially in environments with moderate pressure and temperature conditions.

Technical Specifications

• Outer Diameter Range: 75 mm – 2190 mm

• Bolt Hole Center Circle Diameter: 50 mm – 2130 mm

• Bolt Hole Diameter: 11 mm – 30 mm

• Number of Bolt Holes: 4 – 48

• Thread Size: M10 – M27

• Flange Thickness: 12 mm – 58 mm

• Pipe Outer Diameter:

• A (172 mm – 2032 mm)

• B (14 mm – 2020 mm)

• Flange Inner Diameter:

• A (18 mm – 2036 mm)

• B (15 mm – 2024 mm)

• Theoretical Weight of Flange: 0.36 kg – 234.6 kg (DN1800)

• Flange Pressure Range: 0.25 MPa – 4.0 MPa

Applications of Flat Welding Flanges

Flat welding flanges are widely used in various industries that require secure, leak-proof pipeline connections. Key applications include:

• Petrochemical and Chemical Industries
  Ideal for transporting flammable or explosive media, as well as media containing high concentrations of hydrogen sulfide, carbon dioxide, or other harmful gases.

• Oil and Gas Pipelines
  Used in long-distance pipelines for transporting flammable gases or liquefied petroleum gas, particularly in areas where threaded connections are unsuitable.

• Water Supply Systems
  Common in systems for supplying water to high-rise buildings or in indoor hot water pipeline systems, often used with galvanized or lined plastic spiral corrugated compensators.

• Specialized Applications
  Used in environments where space and weight are important considerations, such as offshore platforms and marine environments, where the reduced weight and compact design are essential.

Sealing Principle of Flat Welding Flanges

The sealing of flat welding flanges is achieved through the compression of a flange gasket by the two sealing surfaces. While this offers an effective seal, it also introduces certain challenges. Maintaining a consistent sealing force requires substantial bolt tension, which in turn necessitates larger bolts and nuts. This leads to a larger flange size and increased weight. In offshore environments, this can become a critical issue, as the increased weight and size can be a significant concern. Furthermore, flat welding flanges may require 50% of the bolt load to compress the gasket, leaving only 50% of the load to maintain the pressure. This makes flat welding flanges less efficient in sealing under extreme pressure conditions compared to other flange types.

Supplier of Flat Welding Flanges

LTZC is a trusted supplier of high-quality flat welding flanges with over 30 years of industry experience. We provide flanges that meet the highest standards of durability, sealing performance, and ease of installation. If you're looking for a reliable supplier of flat welding flanges, contact LTZC for the latest pricing and specifications.