US 4,068,372 AGranted

Tube expander

AssigneeHitachi, Ltd.

InventorsHideaki Kamohara, Toji Nakatui, Yuji Yoshitomi, Iwao Sasaki, Kenji Shimada

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Abstract

Disclosed is a tube expander adapted for use in fixing tubes to a tube plate of a boiler or a multitubular heat exchanger. The expander incorporates an elastic expanding medium adapted to be inserted into a tube to be expanded radially against a wall of a tube-receiving bore of the tube plate. The expander further includes a pressurizing rod passing through the expanding medium, a pressurizing rod head provided at one end of the pressurizing rod, a back-up ring adapted to be supported straddling said tube receiving bore and slidably passed by the pressurizing rod, and seal rings disposed at both sides of the pressurizing rod. The seal rings are made of a hard elastic material of a hardness greater than that of the expanding medium, and each of them is provided with at its portion confronting the end of the expanding medium with a conical recess.

Claims10

Dependent claims

A tube expander having a tubular, elastic expansion medium having axially opposite end surfaces and adapted to be inserted into a tube which, through a radial expansion thereof, is adapted to be fixed to a tube plate;

a pressurizing rod passing through said expansion medium;
a pressurizing rod head provided at one end of said pressurizing rod;
a back-up ring adapted to be supported by an end of said tube plate straddling a tube-receiving bore of said tube plate, said back-up ring being telescopically received by said pressurizing rod;
and seal rings each disposed to abut respective ones of said end surfaces of said expansion medium, said seal rings being of an elastic material having a hardness greater than that of said expansion medium and telescopically received by said pressurizing rod, and at least one of said seal rings having a conical recess at its portion confronting the end surface of said expansion medium.

1 more element

Dependencies are inferred from the claim text.