Abstract: A device for transporting magnetic particles in a selected direction has a support surface extending in the selected direction, a magnet arranged to generate a magnetic field for retaining the particles on the support surface such that the magnetic field on the support surface has high- and low-field bands and a magnetic field gradient zone between the high- and low-bands, means for advancing the high- and low-bands relative to the support surface in a direction having a component in the direction of the gradient, wherein along the high-field band at least first and second magnetic poles of opposite polarity are arranged such that a first magnetic path on the support surface from the first pole to the second pole is shorter than a second magnetic path on the support surface crossing the gradient zone from the first pole to any other nearest pole of opposite polarity.

Abstract: The invention features an excavating device for excavating a hole in a geological formation, which excavating device includes: a body rotatable inside the hole along a rotation axis; a nozzle arranged on the body to jet a stream of an abrasive fluid onto a surface in the geological formation in order to generate the hole, wherein the stream has at least an radial velocity component and one parallel to the rotation axis. The excavating device further has a distance holder arranged on the body to ensure a predefined distance between the nozzle outlet and the surface; wherein the distance holder has a trumpet shaped inner surface section facing the geological formation, which trumpet shaped inner surface section is provided with an opening for allowing the stream to pass through. The opening in the trumpet shaped inner surface section is defined by a recess that is formed in the inner surface of the wall of the distance holder, whereby the nozzle is arranged to discharge in the recess.

Abstract: A Tool for excavating an object, the tool having a jetting system arranged to impinge the object to be excavated with a jetted stream of a drilling fluid mixed with abrasive particles, the jetting system being provided with at least a mixing chamber with a drilling fluid inlet, a second inlet for abrasive particles, and an outlet nozzle for releasing the drilling fluid mixed with the abrasive particles; a recirculation system arranged to recirculate at least some of the abrasive particles, from a return stream of the fluid mixed with the abrasive particles downstream impingement of the jet with the object back to the jetting system, whereby the abrasive particles have a magnetic material, which recirculation system has a separator magnet for separating the abrasive particles from the return stream and for transporting the particles to the second inlet; and, a piece of magnetic material that is provided in or in the vicinity of the mixing chamber such as to draw a part of the magnetic field generated by the s

Abstract: A nozzle unit for generating an abrasive jet. The nozzle unit has a first nozzle connected to a pressurized carrier fluid supply; a mixing chamber in which the first nozzle discharges; and a second nozzle connected to the mixing chamber. An abrasive particle inlet discharges in the mixing chamber. A proportion of the cross sectional area of the first nozzle opening (A1) and the cross sectional area of the second nozzle opening (A2) is in a range of 0.50-1.0.

Abstract: The invention features an excavating device for excavating a hole in a geological formation, which excavating device includes: a body rotatable inside the hole along a rotation axis; a nozzle arranged on the body to jet a stream of an abrasive fluid onto a surface in the geological formation in order to generate the hole, wherein the stream has at least an radial velocity component and one parallel to the rotation axis. The excavating device further has a distance holder arranged on the body to ensure a predefined distance between the nozzle outlet and the surface; wherein the distance holder has a trumpet shaped inner surface section facing the geological formation, which trumpet shaped inner surface section is provided with an opening for allowing the stream to pass through. The opening in the trumpet shaped inner surface section is defined by a recess that is formed in the inner surface of the wall of the distance holder, whereby the nozzle is arranged to discharge in the recess.

Abstract: A system and method for making a hole in an object, the system having jet means for generating an abrasive jet formed of a mixture of a fluid and abrasive particles, and for blasting the abrasive jet with an erosive power into impingement with the object in an impingement area, thereby eroding the object in the impingement area. The system further has a rotating means for moving the impingement area along a selected circular trajectory in the hole about its circumference, and modulation means for modulating the erosive power of the abrasive jet while the impingement area is being moved along the selected trajectory.

Abstract: A Tool for excavating an object, the tool having a jetting system arranged to impinge the object to be excavated with a jetted stream of a drilling fluid mixed with abrasive particles, the jetting system being provided with at least a mixing chamber with a drilling fluid inlet, a second inlet for abrasive particles, and an outlet nozzle for releasing the drilling fluid mixed with the abrasive particles; a recirculation system arranged to recirculate at least some of the abrasive particles, from a return stream of the fluid mixed with the abrasive particles downstream impingement of the jet with the object back to the jetting system, whereby the abrasive particles have a magnetic material, which recirculation system has a separator magnet for separating the abrasive particles from the return stream and for transporting the particles to the second inlet; and, a piece of magnetic material that is provided in or in the vicinity of the mixing chamber such as to draw a part of the magnetic field generated by the se

Abstract: A device for transporting particles containing a magnetic material in a selected direction, the device having: a support member having a support surface for supporting the particles, the support surface extending in the selected direction; a magnet arranged to generate a magnetic field for retaining the particles on the support surface whereby the magnetic field on the support surface is arranged to have a high-field band, a low-field band, and a magnetic field gradient in a gradient zone between the high- and low-field bands whereby the magnetic field strength in the high-field band is higher than that in the low-field band; means for advancing the high- and low-field bands relative to the support surface in a direction having a component in the direction of the magnetic field gradient on the support surface, whereby the high-field band is followed by the low-field band; whereby along the high-field band at least a first magnetic pole and a second magnetic pole of opposite polarity are arranged such that a f

Abstract: A tool for excavating an object, the tool comprising a jetting system having nozzle means arranged to receive a fluid and abrasive particles via an abrasive particle inlet, and arranged to impinge the object to be excavated with a jetted stream of the fluid mixed with the abrasive particles, the tool further having a recirculation system arranged to recirculate at least some of the abrasive particles from a return stream, downstream impingement of the jetted stream with the object to be excavated, back to the jetting system via the abrasive particle inlet, the abrasive particle inlet having an entrance window whereby filtering means re provided in a path fluidly connecting the return stream with the entrance window, for keeping the abrasive particle inlet free from objects of the same size or larger than the size of the entrance window, which filtering means is passable for the abrasive particles.

Abstract: A jet cutting device having a cutter head provided with a nozzle for ejecting a stream of fluid against a body so as to create a selected cut in said body. The cutter head is provided with a deflector having a deflection surface arranged to deflect the stream of fluid ejected by the nozzle into a selected direction in accordance with the position of said cut to be created.

Abstract: A jet cutting device comprising a cutter head provided with at least one nozzle for ejecting a stream of fluid against a body so as to create a selected cut in said body, is discloded. For each nozzle, the cutter head is provided with a deflector having a deflection surface arranged to deflect the stream of fluid ejected by the nozzle into a selected direction in accordance with the position of said cut to be created.

Abstract: A device for transporting particles of a magnetic material in a selected direction, having a support member having a support surface for supporting the particles, the support surface extending in a selected direction, a magnet arranged to generate a magnetic field retaining the magnetic particles on the support surface, the magnetic field having at least one region of reduced field strength at the support surface relative to a field strength of the magnetic field at the support surface outside said region, and drive means for moving each region of reduced field strength relative to the support surface in a direction having a component in the selected direction.

Abstract: A drilling assembly for drilling a borehole into an earth formation is disclosed having a drill string extending into the borehole and a jetting device arranged at a lower part of the drill string, the jetting device is provided with a mixing chamber having a first inlet in fluid communication with a drilling fluid supply conduit, a second inlet for abrasive particles and an outlet which is in fluid communication with a jetting nozzle arranged to jet a stream of abrasive particles and drilling fluid against at least one of the borehole bottom and the borehole wall. The jetting device is further provided with an abrasive particles recirculation system for separating the abrasive particles from the drilling fluid at a selected location where the stream flows from the at least one of the borehole bottom and the borehole wall towards the upper end of the borehole and for supplying the separated abrasive particles to the second inlet.

Abstract: A device for transporting particles of a magnetic material in a selected direction, having a support member having a support surface for supporting the particles, the support surface extending in a selected direction, a magnet arranged to generate a magnetic field retaining the magnetic particles on the support surface, the magnetic field having at least one region of reduced field strength at the support surface relative to a field strength of the magnetic field at the support surface outside said region, and drive means for moving each region of reduced field strength relative to the support surface in a direction having a component in the selected direction.