Abb Atom Ab

Petroleum Geo-services Asa-norway

Asea Brown Boveri Ab

Gunnar Molund

Rune Tenghamn

Goran Engdahl

Magnus Zetterlund

Jan Hidman

Ingvar Niemi

Acoustic transmitter

Flextensional acoustic source for offshore seismic exploration

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

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

Growing community of inventors

Vasteras, Sweden

Gunnar Molund