Westinghouse Electric Corporation

David F Olechovsky

Wenche W Cheng

Philip S Brown

Susanta Sinha

Harold T Keller

Raymond P Castner

Douglas G Harman

An apparatus for expanding a tube against the walls of a circumscribing bore, or a sleeve within a tube to effect an interference joint therebetween, is described herein. The tube expansion apparatus generally comprises a fluid mandrel connected to a hydraulic expansion unit for applying a radially expansive force to the tube or sleeve, and a control circuit electrically connected to the expansion unit and fluidly connected to the mandrel for sensing fluctuations in the pressure of the fluid discharged from the mandrel during the elastic and plastic deformation of the tube or sleeve during the expansion process, computing a final swaging pressure on the basis of these pressure fluctuations, and deactuating the hydraulic expansion unit when this final swaging pressure is attained within the tube or sleeve. The invention is particularly adapted for minimizing or eliminating the clearance between the heat exchange tubes of a nuclear reactor, and the baffle plate bores through which they extend. The invention may also be used to generate interference joints between such heat exchange tubes, and a reinforcing sleeve inserted therein.

Tube expansion apparatus

A process for the controlled expansion of a conduit against the walls of a circumscribing structure is disclosed herein. The process generally comprises the steps of applying a radially expansive force to the conduit, while monitoring a variable associated with the elastic and plastic properties of the particular conduit being expanded in order to determine a final swaging force which will complete the expansion process. The process of the invention is particularly useful in eliminating the clearance between heat exchanger tubes and baffle plates in a nuclear reactor, and in sleeving operations wherein an internally inserted sleeve is plastically deformed against a heat exchanger tube in order to affect an interference joint therebetween.

Tube expansion process

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North Huntingdon, PA, United States of America

David F Olechovsky