Threaded Flange

Threaded flange is a type of flange that is connected to the external thread of a pipeline through internal threads, and can achieve pipeline sealing without welding. Due to its convenient installation and detachable characteristics, it is widely used in low-pressure, room temperature, and frequently disassembled pipeline systems.

Structure and Installation

The core of a threaded flange is the internal thread design, and the thread specifications are strictly matched with the external threads of the pipeline (such as NPT, BSPT standards). The initial fixation is achieved through thread engagement, and the sealing is completed by the compression of the flange sealing surface and gasket. The sealing surface is mostly flat (FF) or protruding (RF), suitable for non-metallic gaskets such as rubber and asbestos. Some high-pressure models use metal toothed gaskets to enhance sealing performance.

No welding is required during installation, just wrap the thread with raw material tape or apply sealant, manually tighten and reinforce with a wrench, greatly simplifying the construction process, especially suitable for scenarios where hot work is inconvenient (such as gas stations, chemical explosion-proof areas).

Performance characteristics

Flexible disassembly and assembly: No need for cutting or welding, can be repeatedly disassembled for pipeline maintenance or component replacement, saving more than 50% of maintenance time compared to welding flanges.

Cost controllable: The manufacturing process is simple (no need for welding groove processing), and the price is about 60% -70% of the same specification for welded flanges, suitable for low pressure systems with small and medium-sized diameters (below DN50).

Limitations: Threaded seals are prone to failure under high pressure (>1.6MPa) or high temperature (>100 ℃), and leakage is easily caused at the thread due to medium erosion. Therefore, they are not suitable for high-pressure steam or highly corrosive media (such as strong acids and chlorine gas).

Applicable scenarios

Low pressure and room temperature pipelines such as tap water and compressed air;

Branch connections of the fire protection system (for quick maintenance);

Instrument pipelines in explosion-proof areas (to avoid danger caused by welding sparks).

Following ASME B16.5 and GB/T 9114 standards, the materials are mainly carbon steel (A105) and stainless steel (304), which is the preferred solution for low pressure and non corrosive scenarios that balances convenience and economy.