Key Points for Selecting Tube Fittings

Tube fittings, also known as double compression ferrules, are efficient sealing joints used for pipe connections. They are commonly used in applications that require higher sealing performance and strength, such as high-pressure systems and vibrating environments. Here is a tube fitting selection guide, we have organized some key factors to consider when selecting tube fittings to help you choose the right ones.

Material Selection:

Stainless Steel: SS316, SS304
Stainless Steel Duplex Steel: F51, F53
Alloy: Chromium-Nickel-Iron Alloy, Monel Alloy, Hastelloy, etc.

Applicable Pipe Types:

Fractional pipe
Metric pipe
Metric pipe to fractional pipe

Thread Types:

NPT female thread, NPT male thread
RT female thread, RT male thread
ISO parallel thread
SAE/MS male thread

Connection Types:

Table 1: Tube Fitting Types and Specific Connection Method
Type	Specific Method
Unions	Tube fittings with same diameters on both ends
Conversion unions	One end metric pipe + one end fractional pipe
Reducing unions	Double ferrule tube fitting with different diameters on both ends
Female connectors	One end double ferrule tube fitting + one end female thread joint
Male connectors	One end double ferrule tube fitting + one end male thread joint
Thermocouple connectors	A ferrule type fastening mechanism is adopted to achieve quick and reliable connection between the thermocouple and its extension line or measurement system
Bulkhead unions	Pass through walls, floors, partitions, or other structural surfaces to connect pipes of the same diameter
Bulkhead reducing unions	Pass through walls, floors, partitions, or other structural surfaces to connect pipes of different diameters
Bulkhead male connectors	One end double ferrule tube fitting + one end male thread joint, passing through walls, floors, partitions or other structural surfaces
Bulkhead female connectors	One end double ferrule tube fitting + one end female thread joint, passing through walls, floors, partitions or other structural surfaces
45° male elbows	One end double ferrule tube fitting + male thread, with a connecting angle of 45°
45° adjustable male elbows	One end double ferrule tube fitting + male thread, angle adjustable within a certain range
Union elbows	Both ends are double ferrule tube fittings with the same pipe diameter, with a connecting angle of 90°
Union reducing elbows	Both ends are double ferrule tube fittings with different pipe diameters, with a connecting angle of 90°
Male elbows	One end double ferrule tube fitting + male thread, with a connecting angle of 90°
Female elbows	One end double ferrule tube fitting + female thread, with a connecting angle of 90°
Adjustable male elbows	One end double ferrule tube fitting + male thread, with a connecting angle of 90°
Union tees	Have three interfaces with the same pipe diameter
Reducing union tees	Where two pipe diameters are the same, or three pipe diameters are all different.
Male branch tees	Double ferrule tube fitting on both sides + branch male thread joint
Male run tees	Double ferrule tube fitting on branch pipe and one side pipe+ the other side pipe male thread joint
Female branch tees	Double ferrule tube fitting on two side pipes + branch pipe female thread joint
Female run tees	Double ferrule tube fitting on branch pipe and one side pipe+ the other side pipe female thread joint
Adjustable male branch tees	Double ferrule tube fitting on two side pipes + branch pipe male thread joint, and the branch pipe allows angle adjustment within a certain range when connecting to the pipeline
Adjustable male run tees	Double ferrule tube fitting on the branch pipe and one side pipe + external thread joint on the other side pipe, and the side pipe allows adjustment of the angle within a certain range when connecting to the pipeline
Union crosses	Four interfaces with the same diameter
Caps	Component used to close the end of a pipeline
Plugs	Fittings used to close the end of a pipeline system

Through these steps, you can select tube fittings that suit your specific application needs, ensuring the reliability of the connection and the overall efficiency of the system. If you have any questions during the selection process, please feel free to contact us.