Understanding Tube Fittings: Types, Applications and Materials

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Understanding Tube Fittings: Types, Applications and Materials

Understanding Tube Fittings

Like a pipe, a tube is a hollow structure created to offer a contained path for fluids to flow. Tubing is typically made from rolled or extruded metal in this case, although stainless steel is a common tube material for many industrial applications. 

One of the fundamental distinctions between tubes and pipes is that tube fittings are never threaded at the end to create a connection. To the couple, a section of tube to another tube, a section of pipe, or a piece of equipment, a device known as a tube fitting must be used (such as an instrument).

Tubes have thin walls by nature, unlike pipes, which have thick walls. A typical tube’s wall thickness is simply too thin to accommodate threads.

For small-diameter applications, tubes are typically preferred over pipe. The tube is the material of choice for connecting instruments to process piping because skilled workers can easily cut and bend it with basic hand tools and repeatedly break and remake tube connections without compromising the integrity of the seals. The tube is frequently referred to as an impulse tube or impulse line when used as the connecting element between an instrument and a process pipe or vessel.

Tube Fitting Types:

Compression fittings: These fittings slide over the tube and coin and seal on the OD of the tube using a ferrule design.

Cone and Thread Fittings (C&T): The tube ends are threaded and coned (chamfered). The end face of the tube can be positively locked and sealed to the fitting body thanks to the threads.

Butt Weld Fittings: These fittings permanently join the tube end to the surrounding metal at the tube end.

Push-To-Connect Pneumatic Fittings: These fittings allow immediate connections by simply pushing the tube into them.

Tube Fittings Applications:

Application-specific requirements for fitting construction and material specifications make consulting the fitting supplier a smart move for component selection optimization. The majority of tube fittings, however, are compatible with hydraulic or pneumatic systems. Finding the type of fittings best suited for the application requires first determining the fundamental system type.

Hydraulic applications:

Transferring liquid fluids, like water and other chemical solvents, is a function of hydraulic applications. Hydraulic fittings need to have seals that stop liquid leakage and are frequently resistant to rust or other types of potential chemical corrosion.

Pneumatic applications:

Gasses are transferred in pneumatic applications. To stop gas leaks, pneumatic fittings need to have extremely tight seals and be resistant to chemical corrosion.

Other Applications:

Instrumentation Tube Fittings are used in various other applications, like structural design. Since they do not carry fluids, these fittings typically do not need sealing, but they must have physical solid integrity.

Material Compatibility:

The compatibility of the tubing material with the media to be contained is the most crucial factor in choosing the proper tubing for any application. DAWSONS-TECH’s Instrumentation Tube Fittings are made to function on similar materials due to their thermal expansion properties and chemical stability.

It is strongly advised against mixing materials. Galvanic corrosion may occur when two dissimilar materials come into contact. Our entire line of tube fittings is made of stainless steel, specifically SS316, to ensure quality and consistency. For more information, contact us at Dawsons-Tech.