Reducing Unions

Reducing Unions

SIYelectric Reducing Unions are designed to connect two tubes or pipes of different sizes in fluid, gas, instrumentation, hydraulic, pneumatic, and process systems.

Unlike a standard union with the same size on both ends, a reducing union has two different connection sizes, allowing the system to transition from a larger tube or pipe to a smaller one, or from a smaller line to a larger one. This makes it useful when different tube sizes need to be connected without using multiple separate adapters.

Reducing unions are commonly used in instrument tubing, pressure measurement lines, sampling systems, analyzer panels, hydraulic circuits, pneumatic systems, process skids, and industrial fluid control assemblies.

Key Functions

Tube or Pipe Size Transition

The reducing union connects two different tube or pipe sizes in a straight line, helping adapt the system layout without unnecessary extra fittings.

Secure Inline Connection

The union structure provides a reliable inline connection between two different line sizes while supporting stable sealing and convenient installation.

Compact System Integration

By combining the reducing function and union connection in one fitting, it helps simplify tubing layouts and reduce installation complexity in compact panels or skids.

Compatible Instruments and Components

This reducing union can be used with:

• Pressure transmitters
• Differential pressure transmitter impulse lines
• Pressure gauges
• Pressure switches
• Gauge valves
• Needle valves
• Ball valves
• Instrument manifolds
• Sampling lines
• Analyzer systems
• Hydraulic and pneumatic control panels
• Process skids and equipment assemblies

For pressure measurement systems, reducing unions are often used when instrument tubing size does not match the transmitter, manifold, gauge valve, calibration line, or process connection size.

Typical Applications

Pressure Instrument Tubing

Used in pressure transmitter, differential pressure transmitter, pressure gauge, and pressure switch installations where tubing sizes need to be adapted in the same line.

Sampling and Analyzer Systems

Suitable for gas sampling lines, liquid sampling systems, analyzer cabinets, laboratory equipment, and process monitoring skids where different tube sizes must be connected.

Hydraulic and Pneumatic Control Lines

Applied in hydraulic power units, pneumatic panels, actuator control lines, pressure test equipment, and compact machine assemblies requiring size transition.

Process Skids and Equipment Panels

Used in dosing systems, filtration skids, gas panels, water treatment modules, and industrial process assemblies where compact inline reducing connection is required.

Industrial Fluid and Gas Systems

Suitable for compatible water, oil, gas, steam, chemicals, and utility media. Material, connection type, sealing method, and pressure rating should be selected according to actual operating conditions.

Advantages

• Reducing union design connects two different tube or pipe sizes in one inline fitting.
• Helps simplify piping layouts by reducing the need for multiple adapters.
• Suitable for pressure instruments, manifolds, valves, sampling lines, and process tubing.
• Compact structure is suitable for panels, skids, cabinets, and limited spaces.
• Supports fluid, gas, hydraulic, pneumatic, chemical, and industrial process systems.
• Reliable sealing performance helps reduce leakage risk under proper selection and installation.
• Material, tube size, thread type, sealing, and pressure rating options can be selected according to site requirements.