Abstract: A sealing member for use in a swaging apparatus includes an annular heel from which inner and outer lips extend to define an annular cavity. The outer lip has a first portion extending radially outwardly and axially away from the heel and a second portion extending radially inwardly and axially away from the first portion. In a relaxed condition, the inner lip is angled radially inwardly from the heel. This sealing member can be used on a swaging mandrel in combination with a harder back-up sealing member and a centering sleeve that carries a flange. The flange is tapered to a pointed edge and engages a conical back surface of the heel.

Abstract: A tube is inserted in a bore in a tube sheet, the tube having an outside diameter slightly smaller than the bore. Hydraulic pressure is applied to the tube internally to expand it radially throughout a pressure zone that extends at least up to one end of the bore. The pressure is confined between two axially spaced seals that encircle a mandrel and are engagable with the inner surface of the tube. The mandrel and seals are then shifted to relocate the pressure zone so that it does not reach the end, and increased pressure is applied to produce a firmer contact between the outside of the tube and the bore. Any crevices between the tube and the tube sheet in which corrosion would be likely to occur are thus eliminated. The invention is particularly suitable for use in connection with the heat exchangers of nuclear plants.

Abstract: A swaging apparatus for expanding a tube disposed within a tube sheet to form a leak-proof joint, the apparatus including a mandrel body for insertion in the tube. The body defines a pair of oppositely directed ramps. A pair of seal members that define the ends of an annular volume within which pressurized hydraulic fluid flows between the mandrel and the tube are movable axially along the ramps, the seals preferably being of the O-ring type. When the mandrel is being inserted, the seals are disposed at the smaller ends of the ramps so as to minimize frictional resistance to the insertion. The seal that is inserted first will tend to move, under frictional forces, to the small end of the ramp, being returned to the large end by the force of the hydraulic fluid during a subsequent swaging operation. The other seal member, however, is urged toward the small end of the corresponding ramp by a spring that is overcome by hydraulic forces once the swaging begins.

Abstract: A pneumatic pump includes a pneumatic cycling mechanism that permits the commencement of each successive pumping interval only upon the appearance of a pilot signal. The pilot signal is generated by a pneumatically operated pump timer that determines the pumping interval. The pilot signal is terminated during the pumping interval after a signal timer has timed out. The pump, timers and other pneumatic circuit elements are driven by the same source that powers the pump, and no reference to an externally generated timing signal is required.