Abstract: Provided are marine acoustic vibrators and methods of using marine acoustic vibrators. An example marine acoustic vibrator comprises a sound radiating surface operable to produce a resonance frequency, wherein the sound radiating surface at least partially defines a marine acoustic vibrator internal volume, wherein the marine acoustic vibrator internal volume comprises a marine acoustic vibrator internal gas having a marine acoustic vibrator internal gas pressure; a compliance chamber, wherein the compliance chamber comprises a compliance chamber internal volume, and a spring function system; a linear motor operable to adjust the compliance chamber internal volume; wherein pressure variations in the marine acoustic vibrator internal volume generated by actuation of the sound radiating surface induce the spring function system and the linear motor to adjust the compliance chamber internal volume such that the pressure variations in the marine acoustic vibrator internal volume are reduced.

Abstract: Disclosed are electromagnetic linear actuators used in acoustic vibratory sources for marine seismic surveying. An embodiment discloses a linear actuator for acoustic sources, comprising: magnetic circuitry comprising a gap; and a coil assembly comprising: a drive coil, wherein at least a first portion of the drive coil is configured to be moved in a linear path in the gap; a pair of ferromagnetic coil guides positioned on either side of the linear path; a first ferromagnetic extension extending laterally from the first portion of the drive coil; and a transmission element coupled to a top side of the first portion of the drive coil. Embodiments also disclose acoustic vibratory sources, marine seismic survey systems, and methods of marine seismic surveying.

Abstract: Disclosed are electromagnetic linear actuators used in acoustic vibratory sources for marine seismic surveying. An embodiment discloses a linear actuator for acoustic sources, comprising: magnetic circuitry comprising a gap; and a coil assembly comprising: a drive coil, wherein at least a first portion of the drive coil is configured to be moved in a linear path in the gap; a pair of ferromagnetic coil guides positioned on either side of the linear path; a first ferromagnetic extension extending laterally from the first portion of the drive coil; and a transmission element coupled to a top side of the first portion of the drive coil. Embodiments also disclose acoustic vibratory sources, marine seismic survey systems, and methods of marine seismic surveying.

Abstract: The invention refers to a driving device for hydroacoustic transmitters, including at least one actuating element (1), arranged to execute a reciprocating movement, wherein the movement of the actuating element (1) includes an increase and a decrease of the distance between two ends thereof, and at least one spring member (5, 27) which is connected to the actuating element (1) at said ends and which extends along a curved line between said ends, wherein the increase and the decrease of the distance between said ends result in a change of the curve of the spring member (5, 27) and thereby a movement of it. The device includes an element (12, 13, 28) for displacement of a mass, which displacement element (12, 13, 28) is connected to the spring member (5, 27) so that the movement of the latter is transmitted to the displacement element (12, 13, 28) and generates a displacement thereof, resulting in said mass displacement.

Abstract: The present invention relates to an arrangement in a valve actuator (101) operating on a valve stem (113) provided with a piston (114) so as to close or open the valve (111), and in order to arrive at a variable area type hydraulic piston/cylinder, it is according to the present invention suggested that in addition to the valve stem piston (114) there could be provided one or more supplemental pistons (124).

Abstract: A drive system for acoustic devices comprising drive devices, the projecting driving studs (14,15) of which are connected to pressure beams (27,28) of the acoustic device, the drive devices comprising a fixture frame (26) inside of which there are located drive units with an intermediate mechanical prestress device (22,23,24,25), the drive units comprising stator and drive cells stacked by means of guide rings (4,5) and guide discs (11), the stator cell comprising a magnetizing coil (1) with a surrounding tube (2) of soft-magnetic material fixed inside a fixture tube (3), and the drive cell comprising a cylindrical magnetic pellet (6) , discs of soft-magnetic material (7,8) and of permanent-magnetic material (9,10) making contact with said magnetic pellet.

Abstract: An electric switching device according to the invention comprises two fixed contacts and one movable contact, referred to jointly as the main contact system. The main contact system is located in an oil-insulated cavity enclosed in a housing. In its direction of movement, the movable contact has an extension in the form of a shaft. The shaft is formed with a hydraulic piston by which the movable contact is operated. The hydraulic piston is surrounded by a cavity in which a piston cavity is formed on each side of the hydraulic piston. The piston cavities are oil-filled. The movement of the shaft is determined by an electrically controlled directional valve. The directional valve receives signals as to whether the electric switching device is to be opened or closed. At a given signal, the directional valve distributes a high pressure to the piston cavity that is to be enlarged.

Abstract: The invention relates to a special embodiment of a plate which is to be able to transmit movement and compressive force as well as possess soft-magnetic properties with low losses and low reluctance. The latter requirement means, inter alia, that the plate, upon loading, will be subjected to a relatively great elastic deformation with an ensuing reduced ability to transmit movement and compressive force. By perforating the plate with a number of evenly distributed holes provided with pellets of a stiff resistant material with an axial length at least as great as the thickness of the plate, movement and compressive force may be transmitted from a compressive force-generating element via the plate to a compressive force-absorbing element without the plate being elastically deformed.

Abstract: In subsea production of oil and gas, a pressurized fluid is needed for operation of valves for the production system. To be able to supply a hydraulic actuator with pressure medium for valve operation without arranging any pressurization from a platform-based pump, a liquid pump has been produced which is driven by rods of a giant magnetostriction material and which may be connected to operating devices and valves at the bottom of the sea. The liquid pump has a high efficiency and has few movable parts. By utilizing the giant magnetostrictive in two alternately operating rods (11) which are arranged in pairs and are surrounded by coils (15) supplied with current, the first rod imparting a movement when magnetic energy is transformed into mechanical energy in the form of a deformation and the second rod dynamically prestressing the first rod together with a load, a piston (12) in a cylinder space (17) of a pump housing (16) may be caused to oscillate for transporting liquid.

Abstract: A specially designed magnetic circuit which is provided which is intended to magnetize cylindrically shaped magnetic materials (1) in the axial direction. The magnetic circuit comprises a magnetizing coil (2), permanent magnets (5, 6), and magnetic return conductors (3, 7) of a ferromagnetic material. The magnetic circuit is well suited to utilize the magnetostrictive properties of a magnetic material.

Abstract: An electrically controlled spring element according to the invention comprises one or more basic spring elements and a mechanical transformer to increase the stretch of the spring element. The basic spring element comprises two mechanically connected elements with an intermediate transmission for power output, each of the elements consisting of a rod pre-magnetized by permanent magnets and consisting of highly magnetostrictive material (Terfenol), a surrounding excitation coil and an outer frame holding the parts together. The magnetic orientation of the pre-magnetization and the coils shall be such that, regardless of the direction of the control current, the electrically controlled excitation is always directed in the same direction as the pre-magnization in one element and is always directed in the opposite direction to the pre-magnetization in the other element.