Asea Brown Boveri Ab

Abb Atom Ab

Abb Research Ltd.

Goran Engdahl

Gunnar Molund

Rune Tenghamn

Dag Wikstrom

Knut Asskildt

Lars Kvarnsjo

Ingvar Niemi

Jan Hidman

Arrangement in a valve actuator

Drive system for acoustic devices

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. The electric switching device can be provided with an auxiliary contact mechanism which can be placed either in the fixed contacts and/or in the movable contact. The electric switching device is provided with a bistable mechanism comprising wedge-shaped pistons biased by means of springs. The wedge-shaped pistons, in case of drop-out of pressure, lock the movable contact in the existing position via the shaft.

Electric switching device

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.

Device for transmission of the movement and force of a

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. The giant magnetostrictive material may be an alloy containing the rare earth metals terbium (Tb) and dysprosium (Dy) and iron (Fe), for example Terfenol-D with the stoichiometric composition (Tb.sub.x Dy.sub.1-x Fe.sub.1.9-1.98).

Liquid pump driven by elements of a giant magnetostrictive material

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.

Magnetic circuit

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.

Growing community of inventors

Taby, Sweden

Goran Engdahl