In pipework a flanged adaptor could be to connect a rubber hose to a flanged steel pipe. The barrel is pressed into the hose (and clamped) and the flange is bolted on to the flange on the pipe.
a flanged stub shaft can be bolted onto the flywheel of an industrial engine.
etc
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It could also describe something to interconnect between different types of flange. Flange bolting varies according to pipe code: a 4in ASA150 flange will not connect directly to a 4in PN16 to BS4504, for example, as the pitch-circle-diameter, number and diameter of the bolts is different. If one wanted to join them, a short piece of pipe with one of each of the above on each end would enable the pipes to be connected.
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