Abstract: A swaging apparatus includes a mandrel to be inserted in a tubular structure that is to be expanded radially. A pair of seals define the axial boundaries of an annular pressure zone between the mandrel and the tubular structure. One or both of the seals includes a support formed by a plurality of arcuate segments elastically held together and presenting a cam surface. A cam member interacts with the cam surface to expand the support radially in response to swaging pressure, thereby preventing inelastic deformation of an elastic member on the high pressure side of the support.

Abstract: In an apparatus for forming leak-proof joints between tubes and a tube sheet by the internal application of hydraulic swaging pressure, the flow of relatively low pressure fluid from a pressure source to an intensifier is permitted or interrupted by a control valve. During a prefill period, a prefill valve causes the low pressure fluid to bypass the low pressure input side of the intensifier and flow directly to the high pressure side and then to a mandrel. Thereafter, the low pressure fluid is caused to enter the low pressure side of the intensifier to increase the pressure in the mandrel during a swaging period. A pressurization sensor, which is connected to the input and output sides of the prefill valve, contains a piston which is movable in response to the difference in the pressures at these two points to produce a termination signal which, after a delay, actuates the control signal at the end of the swaging period.

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 swaging apparatus for expanding a tube radially to form a joint, the apparatus including a mandrel for insertion in the tube. A working fluid is supplied through the mandrel to apply hydraulic pressure to the tube. The mandrel carries a pair of oppositely directed ramps, and a pair of seal combinations that are movable axially along the ramps. The seal combinations define the ends of an annular volume within which the pressurized fluid flows between the mandrel and the tube, each seal combination including a softer primary seal, which may be an O-ring, and a harder backup seal. Positioning sleeves that are axially slidable on the mandrel prevent angular movement of the backup seals relative to the longitudinal axis of the mandrel, thereby maintaining a uniform circumferential extrusion gap between the mandrel and the tube when pressure is applied.

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: In an apparatus for forming leak-proof joints between tubes and a tube sheet by the internal application of hydraulic swaging pressure, the flow of pressurized fluid from an adjustable pressure reduction valve is permitted or interrupted by a control valve. An actuator moves the control valve between its flow permitting and interrupting positions in response to a control signal. In the sensor, which is connected to the input and output sides of the control valve, a piston is movable in response to the difference in the input and output pressures to produce the control signal when a predetermined comparative pressure relationship exists.

Abstract: A method and apparatus for expanding tubes radially, particularly useful for anchoring tubes within a tube sheet in preparation for a subsequent hydraulic swaging operation. The apparatus includes at least one primary expander and at least one seondary expander. The secondary expander is axially positioned within the tube and has a larger cross-sectional area than the primary expander when considered with reference to a plane passing transversely through the tube. The expanders are compressed axially, thereby producing outwardly directed pressure against the interior surface of the tube. The primary expander produces the greatest pressure against the tube due to its smaller cross-sectional area. Axial compressive forces can be applied to the expanders by a draw bar that passes through them.

Abstract: A head that engages a face of a tube sheet has a mandrel extending from it for insertion in a tube. Pressurized test fluid is introduced through a conduit in the mandrel into an annular fluid-flow space between the mandrel and the tube. The fluid, which is confined by seals, flows around one end of the tube to the joint and, if the joint is not tight, emerges at the opposite face of the tube sheet where it can be detected.

Abstract: A high pressure fluid delivery conduit for use at pressures of 30,000 psi or more permitting relative movement of one end relative to the other only when fluid pressure is not applied thereto. The conduit is formed by a plurality of rigid tube-like sections arranged end-to-end and a plurality of movable joints connecting the sections. Each joint has an outer member in which an inner member is rotatably received. Outer and inner passageways defined by the outer and inner members at an interface location, respectively, communicate with each other regardless of the positions of the members. A pair of ring-shaped seals are disposed between the outer and inner members, for radial expansion upon the application of fluid pressure thereto to prevent the escape of the fluid. The seals are arranged on opposite sides of the interface location.

Abstract: In a device for confining a pressurized working fluid within a tube to be expanded radially, a support to be positioned axially within the tube and at least one sealing member encircling the support. The sealing member is deformable so that it expands radially against the inside of the tube upon axial compression by the force of a pressurized working fluid introduced into the tube. A centering means is provided that prevents angular movement of the sealing member relative to the longitudinal axis of the tube, thereby forcing the sealing member to assume a radially centered position within the tube as it expands.