Framatome Gmbh

Gerard Boula

Christian Valadon

Jean-Pierre Roinjard

Alain Georges

Yves Faunier

An element (18) of elongate form is fastened onto the tube support plate (8a) of the steam generator nearest the bent parts (10c, 10'c, 10''c) of the tubes (10) of the bundle, in a central free zone of the bundle, in line with the small bends (10'c) of the tubes of the bundle. Anti-vibration bars (15) of a set of bars which are intended to be placed between any two adjacent rows (20) of the bundle of tubes are fastened by their internal end onto a dovetail piece (16) which is attached to the elongate element (18). All the anti-vibration bars (15) intended to come into a space contained between two successive rows (20) of the bundle of the heat exchanger are thus fitted in a single operation. The invention applies in particular to steam generators of pressurized water nuclear reactors.

Heat exchanger including a bundle of tubes which are bent into a U and

The blocking device includes sets of antivibration bars (25, 25') interposed between layers of tubes (24) of the bundle of the steam generator, in the upper part of the bundle, termed the tube bend region. The antivibration bars (25, 25') include parts (25b, 25'b) which project with respect to the tube bend region, and the blocking device includes a linkage of the end parts of the antivibration bars, which include aligned openings. The linkage includes a screw (21) whose head (21a) bears on a first antivibration bar (25) and whose threaded rod (21b) is screwed into a spacer (22). The spacer (22) is fixed either in a second spacer or in a tapped fastening element (23), by a threaded part (22b). The threaded parts (21b) of the screw and (22b) of the spacer pass through the antivibration bars (25, 25') through aligned openings.

Device for antivibrational blocking of tubes of a heat exchanger

The joint region (43) of the parts (27, 29) is surrounded by an enclosure (38) which is mounted in a fluidtight manner around a part of the outer surface of the component (31). The enclosure (38) carries an electron gun (39). A low pressure is created in a chamber (44) defined by the fluidtight enclosure (38) and by the outer surface of the component (31). A relative displacement is produced between the parts (27, 29) and the electron gun (39) to cause an electron beam emitted by the electron gun (39) to scan the joint region (43) during the welding. The process may be used in particular in the field of the manufacture of steam generators of pressurized water nuclear reactors.

Process and device for the electron beam welding of two parts of a

The internal equipment (4) includes a metal ring (13) having an outside diameter substantially equal to the inside diameter of the annular parts (1, 2) and including a plurality of radially extending slots in a part of its width defining interconnected adjacent ring segments, and a device (14) for maintaining and thrusting the metal ring (13) against the inner surfaces of the annular parts (1, 2) in their connection region (11) and including a central support part (21) and a plurality of arms (22) of adjustable length having a radiating disposition around the central part (21). The internal equipment (4) further includes two walls (15, 16) defining a fluidtight chamber (8) inside the parts (1, 2).

Internal equipment for electron beam butt welding of two annular parts

The heat exchanger includes at least one metal retainer hoop (20) having a shape similar to the shape of the bent parts (5b) of the tubes of the bundle, fixed at each of its ends on the spacer plate (10a) located closest to the bent parts (5b) of the tubes, in extension of two anchor rods, (14) and interposed between two successive tubes of a plane row of tubes (18) and including linkage devices (22) for fastening the set of antivibration bars (13) interposed between two adjacent tube rows.

Heat exchanger including means for holding antivibration bars interposed

To permit individual identification of each of the tubes (10) of a steam generator, the tubes are marked with the aid of a binary bar code (12a) formed from circular impressions (24) and the absence of impressions. The impressions, formed without material removal, make it possible to read the bar code with the aid of an eddy current probe. The impressions (24) can be made on the exterior of the tubes (10) during their manufacture, or on the interior of the tubes after they have been fixed to the tube plate (16).

Process for individual identification of the tubes of a heat exchanger

In a heat exchanger, such as a steam generator equipping a nuclear power station, the intermediate inwardly curved parts (14c) of the U-tubes (14) grouped into a bundle forming parallel layers are maintained by antivibration bars (36a, 36b', 36c') placed between each pair of adjacent layers, these bars being interconnected outside the bundle by connecting pins (38a, 38b, 38c). To prevent the fly-off of the assembly formed by the antivibration bars and the connecting pins, at least part of the bars (36a, 36b', 36c') are placed in slots formed in an elongated structure (40) fixed to the spacing plate (34a) closest to the inwardly curved part of the tubes.

Heat exchanger having U-tubes equipped with an anti-fly-off support

The anti-vibration bars are arranged as a plurality of sets of at least two bars (18, 18b), the outer ends of the bars being axially aligned. The outer end parts of the anti-vibration bars have aligned passage orifices (23, 24). The orifice (24) is internally threaded. The ends of the bars are connected by a spindle (20) which is threaded at one of its ends and has a screwing and unscrewing head (20b) at its other end. The spindle (920) is introduced into the aligned orifices (23, 24) and into the bore of a tubular spacer (21) interposed between the anti-vibration bars. After being screwed into the internally threaded orifice (24), the spindle (20) is blocked against rotation.

Device for the anti-vibratory wedging of tubes of a heat exchanger

The process comprises introducing the tubes in the form of horizontal layers (the generator can be positioned horizontally for this purpose), installing anti-vibratory bars on the layers, placing weights on the bars and checking the clearances between the tubes and the bars, so that the tubes falling outside the accepted tolerances can be replaced. This is followed by the installation of the layer of tubes immediately above it. This procedure is repeated until all the layers have been installed. The invention is used in the steam generators of nuclear power stations.

Growing community of inventors

Corpeau, France

Gerard Boula