Flare VS. Bell

Published: February 15, 2021
by Charles Busada
A grouping of coupling types including a flare and bell

The nomenclature of bells and flares varies throughout the industry. We follow a simple definition. 1) A flare is a sloping conical expansion of a tube. Flares assist in funneling an object or carrier into the pneumatic tube system. Flares are usually defined by ID, angle, and length.


Flared tube used in a bank carrier pneumatic system

            Flares are only coupled on the non-expanded part of the tube.                                                  


A bell is a coupling, an expansion of a tube to couple to a similar tube without a sleeve. The ID of a tube is expanded to its OD. The expansion is not sloping (as in a flare) but is parallel. Standard flares have a 2-3″ transition and 3″ parallel section on the small side (see figure above).

 Bells are usually defined by their ID’s and transition length.

We have several blogs on how to couple bells. 

We can flare or bell all of our transparent tubing products to your needs.

A Flared bend where a cup enters the flared side of the bend.

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