Abstract: A snow volume-reducing and fluidisation device comprising: a first fixed reservoir (1) equipped with snow fluidising and volume-reducing means (2-6); at least one second reservoir forming a storage basin (11), the volume of said storage basin being at least 20 times preferably 100 times the volume of the first reservoir and said storage basin being at least partly filled, preferably to at least 30% of its volume, with water at ambient temperature; and said fluidisation means (2-6) comprising: snow compacting means comprising mobile dynamic compacting means; and chopping and/or mixing means (2) capable of forcing the snow downwards; and means (3) to inject water derived from the machine reservoir or from the storage basin (11) capable of injecting water above and below said chopping and/or mixing means; and ultrasound generating devices, preferably distributed at several points in the first reservoir in substantially homogeneous manner, positioned below said water injection nozzles.

Abstract: A process of pressurization, of supply for effecting a dive for underwater intervention with a breathing mixture with hydrogen, and of decompression of a person making the dive, wherein the person is pressurized to an absolute pressure P.sub.1 of at least 0.45 MPa with a first type of breathing mixtures not containing hydrogen. The person is supplied at least from this pressure P.sub.1 with a second type of breathing mixtures at pressure P as a function of the depth of dive p to which said person is lowered, which second breathing mixture is of hydreliox type containing hydrogen at a minimum partial pressure of 0.33 MPa, oxygen at less than 4% by volume, helium with a partial pressure of more than 0.1 MPa and other gases such a nitrogen with a total partial pressure of less than 0.09 MPa. Supplying this second type of hydrogenated breathing mixtures in accordance with a composition which would locate the dive in one of the zones of the high pressure nervous syndrome or of narcosis is avoided.

Abstract: Method of underwater arc welding comprising the steps of placing a welding electrode nearby a parent material to be welded, immerged in water; generating a high frequency voltage between the electrode and the parent material for starting a striking arc and supplying a high frequency current to said electrode, after said striking arc has been initiated; generating a welding voltage for producing a weld at the parent material and; simultaneously sustaining the high frequency current, superimposed to the welding current, for stabilizing said welding arc during the time duration of the underwater arc welding.

Abstract: The present invention relates to an arc-welding device for securing studs on metallic elements underwater, and comprising a head containing a chamber and of which the welding bead is obtained by means of a dielectric refractory ring placed around the base of the stud, wherein an annular space is provided between the stud and the ring and neutral gas is blown into the chamber through said space, to drive the water out of the chamber and keep up therein a gaseous atmosphere to facilitate the welding of the studs; the refractory ring is produced from borosilicate glass, rich in silica.

Abstract: The present invention relates to a process and an installation for purification of the helium contained in a mixture of gas, employing a pre-treatment unit to retain the impurities such as water, carbon dioxide gas and heavy organic compounds, and at least one reactor of the chromatographic type located downstream of said pre-treatment unit, said process comprising the following steps of:(a) adjusting the pressure of the mixture of gas until the working pressure of the phase of adsorption is obtained, this pressure being between 10 and 30 bars, and preferably 12 to 15 bars;(b) taking the temperature of the mixture of gas at the outlet of said pre-treatment unit until it is located in the range -15.degree. C./-35.degree. C., and preferably -25.degree. C.;(c) and sending the mixture of gas into the reactor and passing it through an absorbent, which is constituted by a microporous charcoal whose pores are of dimensions less than or equal to 20 .ANG..

Abstract: A method of welding the ends of submerged pipes in a gaseous atmosphere at any depth comprises isolating the ends of the pipes by introducing obturators therein and then introducing the pipe ends into an open topped receptacle which is capped with an underwater personal carrying intervention unit. The closed receptacle is filled with gas and then a sleeve is positioned between the ends of the pipes and welded to the pipes.

Abstract: In a method of welding together two submerged pipe ends, the pipe ends are spaced apart and introduced through orifices into a receptacle by which they can be isolated from the surrounding medium. The spaced pipe ends are connected by a connection sleeve and after isolation are welded to the connection sleeve.

Abstract: Apparatus for handling a submersible device, such as a diving bell, includes a winch mounted on a support structure and having a suspension cable with a free end at which the submersible device is suspended, a guide structure fixed to the support structure and having two guidance ramps, each having a portion thereof extending below a water surface, a traveller having two parallel side members with a guidance device thereon which slidably cooperates with the two guidance ramps, a pulley back including two upper pulleys secured to the guide structure and a movable lower pulley fixed to the traveller with the suspension cable passing over the upper and lower pulleys so as to form n strands, and a locking device for releasably connecting the submersible device to the traveller.

Abstract: Butt-welding apparatus for welding two pipes, e.g. for the shipboard welding of a laid pipe and a towed pipe, comprises a frame for receiving the pipe ends, means for securing the pipe ends relative to the frame and compensation means for causing movement of one pipe relative to the other to compensate for any shrinkage caused by the welding operation and by preheating the pipe ends to be welded.

Abstract: A system for welding the ends of submerged pipes in a gaseous atmosphere at any depth comprises isolating the ends of the pipes by introducing obturators therein and then introducing the pipe ends into an open topped receptacle which is capped with an underwater personal carrying intervention unit. The closed receptacle is filled with gas and then a sleeve is positioned between the ends of the pipes and welded to the pipes.

Abstract: Apparatus for connecting a cylindrical first member to a second member which may comprise: a tubular body attachable to the second member and adapted to receive one end of the first member; a gripping assembly carried by the body and movable from a radially expanded position, in which one end of the first member may be axially received and displaced from the body, to a radially contracted position gripping the exterior of the first member and preventing its axial displacement from the body; an annular seal assembly carried by the body and movable from a relaxed position, in which one end of the first member may be axially received therein, to a compressed position, sealingly engaging the first member; and an actuating assembly carried by the body and operable to move the gripping and seal assemblies to their contracted and compressed positions, respectively.

Abstract: In a method of welding together two submerged pipe ends, the pipe ends are spaced apart and introduced through orifices into a receptacle by which they can be isolated from the surrounding medium. The spaced pipe ends are connected by a connection sleeve and after isolation are welded to the connection sleeve.

Abstract: The ends of submerged pipes are connected using a receiver provided with two apertures through which the pipe ends extend, the receiver being adapted to form a watertight enclosure with an intervention unit and housing means for closing the ends of the pipes comprising two stoppers bearing seal means to be applied against the inner walls of the pipe ends and being maintained spaced apart by a first boom, the receiver including means for supporting a sleeve to be connected to the ends of the pipes and a replacement boom located in the sleeve, the connection being performed by introducing the ends of the pipes to be connected into the receiver through the apertures, at least one of the pipe ends being introduced by movement of the receiver relative thereto, closing the ends of the pipes with the stoppers, causing an intervention unit to descend on to the receiver, providing a watertight enclosure therewith, removing the water from the enclosure and placing it under atmospheric pressure, placing the receiver und

Abstract: In the assembling and laying of an undersea pipe in which the already submerged pipe portion is suspended from a surface support, the end of the submerged pipe portion being supported on a variable inclination laying ramp, and a new pipe section is moved into alignment with the end of the pipe portion and fixed thereto, the submerged pipe portion is so suspended from the surface support that the tension in the pipe portion is maintained substantially constant irrespective of vertical movements of the surface support caused by the action of waves on the surface support.

Abstract: The ends of submerged pipes are connected using a receiver provided with two apertures through which the pipe ends extend, the receiver being adapted to form a watertight enclosure with an intervention unit and housing means for closing the ends of the pipes comprising two stoppers bearing seal means to be applied against the inner walls of the pipe ends and being maintained spaced apart by a first boom, the receiver including means for supporting a sleeve to be connected to the ends of the pipes and a replacement boom located in the sleeve, the connection being performed by introducing the ends of the pipes to be connected into the receiver through the apertures, at least one of the pipe ends being introduced by movement of the receiver relative thereto, closing the ends of the pipes with the stoppers, causing an intervention unit to descend on to the receiver, providing a watertight enclosure therewith, removing the water from the enclosure and placing it under atmospheric pressure, placing the receiver und

Abstract: To enable the release and consequent recovery of a support float which supports a load, e.g. a pipe, as it is lowered to the sea bed, a marker buoy is lowered with the float to be released when the load reaches the sea bed, the marker buoy having an inflated flexible envelope which is trapped in a housing fast with the float and having an opening through which the float can escape only when it has been compressed to a predetermined extent under the effects of a predetermined hydrostatic pressure. The marker buoy is connected to the float by a cable and the float is released from the load either by operations on that cable, or on a release cable connected to the float, on appearance of the marker buoy at the water surface.

Abstract: Rapidly connectable and disconnectable pipe union, comprising a bush on which are fixed one or more pipes provided with a notched flange. It comprises, in addition, a union body on which are fixed one or more pipes. This body comprises an outer threading on which is screwed a nut provided with a toothed rim and a sliding sleeve, connected to the nut by a ring. This nut comprises a toothed rib which meshes behind the notched flange. One application of the present invention is the connection of underwater pipes with one another or onto underwater apparatus by divers or by remotely controlled devices.

Abstract: This invention relates to a union for assembling a smooth pipe end to a bush, composed of two half-unions fitted in each other and assembled by a nut fast with a toothed ring. Each half union comprises a jaw which cooperates with a sliding ring, which ring is displaced by means of a nut fast with a toothed gear. Said jaws comprise on their inner periphery truncated surfaces which cooperate with truncated surfaces carried by said sliding rings to disconnect the half-unions by manoeuvring said lock nuts.

Abstract: A lip-seal for sealing the junction between two parts includes a body for mounting on one part, a sealing lip extending therefrom for application against the other part, and an inflatable chamber defined between the body, the lip and a diaphragm extending between, and connected to, the lip and the body, the arrangement being such that on inflation of the chamber the profile of the lip is modified so that it is moved away from the other part to permit the other part to be assembled with the one part without damage to the lip seal and without premature application of the lip to the other part.

Abstract: This invention relates to a self-propelled machine piloted by operators and working on the sea-bed, such machine comprising on the one hand a self-propelled chassis, comprising an electrically powered hydraulic pumping system driven by a submersible motor fed through a cable connecting the chassis to the surface and, on the other hand, a submarine which fixes itself on a platform connected to the self-propelled chassis, and in which submarine the operators are installed. The platform comprises ramps for precentering and centering the submarine. The submarine is fixed temporarily on the platform by electromagnets, and induction coils enable orders to be transmitted between the submarine and the self-propelled chassis.