Threaded Flanges Product Overview

SIYelectric Threaded Flanges are pipe and instrument connection accessories designed with an internal threaded bore and a flanged outer connection. They allow threaded components to be connected to pipelines, vessels, valves, instruments, or equipment with flange interfaces.

Unlike weld neck or slip-on flanges, threaded flanges do not require welding during installation. This makes them useful in applications where welding is inconvenient, restricted, or unnecessary, especially for small-diameter pipelines, pressure instruments, gauge valves, and threaded instrument connections.

They are widely used with pressure gauges, pressure transmitters, gauge valves, manifolds, threaded pipes, instrument fittings, and process equipment.

Product Description

A threaded flange is a flange with internal threads machined in the center bore. The threaded bore connects with a matching male-threaded pipe, nipple, valve, pressure gauge adapter, or instrument fitting. The flange side is then bolted to a matching process flange with a gasket between the sealing faces.

This structure provides a practical transition between threaded connections and flanged connections.

For instrumentation applications, threaded flanges are especially useful when a pressure instrument or valve has a threaded process connection, but the site connection is a flange. Instead of changing the pipeline or welding a new adapter, a threaded flange can provide a simpler mechanical connection.

Common sealing face options include RF raised face, FF flat face, or other customized designs according to the project requirement.

Key Features

Internal Threaded Connection

The center bore is machined with internal threads to connect male-threaded pipes, nipples, valves, fittings, or instruments.

Flanged Process Connection

The outer flange allows bolted installation to a pipeline flange, vessel nozzle, instrument flange, or equipment connection.

No Welding Required

Threaded flanges can be installed without welding, making them suitable for maintenance, replacement, and small-bore applications.

Suitable for Instrument Connections

Commonly used with pressure gauges, pressure transmitters, gauge valves, needle valves, manifolds, and other threaded instruments.

Stainless Steel Material Options

Available in materials such as SS304, SS316, SS316L, or customized alloys depending on corrosion requirements.

RF Sealing Face Option

The raised face design helps provide reliable gasket sealing when connected with matching RF flanges.

Technical Specifications

Applications

Pressure Gauge Installation

Used to connect threaded pressure gauges or gauge valves to flanged process connections, especially when the pipeline or vessel nozzle is designed with a flange interface.

Pressure Transmitter Connections

Suitable for connecting threaded pressure transmitters, compact transmitters, or instrument adapters to flange-mounted process points.

Instrument Valves and Manifolds

Can be used with needle valves, gauge valves, block valves, and manifolds that have male-threaded connections.

Water Treatment Systems

Applied in filtration systems, pumping stations, dosing lines, and water distribution systems where threaded and flanged connections need to be adapted.

Chemical Processing

Used in chemical pipelines, tanks, reactors, and process equipment where stainless steel threaded flange connections are required. For corrosive media, SS316 or SS316L is usually recommended.

Oil and Gas Systems

Suitable for small-bore instrument connections, pressure measurement points, sampling lines, and auxiliary process connections.

HVAC and Utility Pipelines

Used in chilled water, hot water, compressed air, and general utility lines where threaded components need to be connected to flanged systems.

Advantages

• Connects threaded components to flanged process interfaces.
• No welding required, making installation and replacement easier.
• Useful for pressure gauges, pressure transmitters, valves, and instrument fittings.
• Stainless steel material provides corrosion resistance and durability.
• RF sealing face option supports reliable gasket sealing.
• Custom thread and flange standards can be supplied according to site requirements.
• Suitable for small-bore piping and instrumentation applications.
• Helps simplify installation when the instrument connection and site flange do not match.

Selection Notes

When selecting threaded flanges, confirm the following details:

1. Thread type and size
   Confirm whether the thread is NPT, BSP, G, Metric, or another standard.
2. Flange size and standard
   Confirm flange standard, bolt hole dimensions, pressure class, and nominal size.
3. Sealing face
   Confirm whether the flange face is RF, FF, or another type.
4. Material selection
   • SS304: suitable for water, air, oil, and mild service.
   • SS316 / SS316L: better for chemical, corrosive, coastal, or more demanding environments.
5. Pressure and temperature
   Confirm the working pressure and temperature to ensure the flange, thread, gasket, and connected instrument are suitable.
6. Instrument compatibility
   If used with pressure transmitters or gauges, confirm the instrument process connection, installation direction, and required sealing method.