Abstract: The invention concerns a method for establishing a plug inside a main pipe, in particular a vertically or slantingly arranged pipe, where said pipe has firs and second ends, and where the plug is arranged inside the pipe at a distance from said first and second ends, where a liquid surface is provided at least inside the pipe, below the level at which it is desirable to establish the plug, where a buoyant layer is established on top of said liquid surface, and where a plug material is placed on top of ‘said buoyant layer as well as a plug established according to the method. The buoyant layer can be granular, liquid or solid material. The plug is made of foam material, expandable material or cement-based material such as concrete.

Abstract: An electroacoustic transducer comprising a magnetic circuit of a magnetically conductive material with a pair of opposed surfaces defining a gap therebetween, the magnetic circuit comprising a magnet inducing a magnetic field in the gap, the magnet having a surface constituting one of the opposed surfaces. The magnetic circuit further comprises a diaphragm and a coil having electrically conducting paths secured to the diaphragm. The coil has portions of its paths situated in the gap.

Abstract: An electroacoustic transducer includes a magnetic circuit of a magnetically conductive material with a pair of opposed surfaces defining a gap therebetween. The magnetic circuit includes a magnet inducing a magnetic field in the gap, the magnet having a surface constituting one of the opposed surfaces. The magnetic circuit further includes a diaphragm and a coil having electrically conducting paths secured to the diaphragm. The coil has portions of its paths situated in the gap.

Abstract: An electroacoustic transducer comprising a magnetic circuit of a magnetically conductive material with a pair of opposed surfaces defining a gap therebetween, the magnetic circuit comprising a magnet inducing a magnetic field in the gap, the magnet having a surface constituting one of the opposed surfaces. The magnetic circuit further comprises a diaphragm and a coil having electrically conducting paths secured to the diaphragm. The coil has portions of its paths situated in the gap.

Abstract: An electric miniature motor having a stator of magnetic soft material and a permanent magnet rotor. The stator has a low electrical conductivity at least in the direction of the rotor shaft to dampen eddy currents in the stator material caused by rotation of the rotor. The magnetizable material of the stator is composed of ring-shaped elements with two sections having their respective diameters so that the elements may be joined co-axially to a tubular stator. This provides the same eddy current damping properties as with a stator composed of segments, but the stator is much cheaper. The coils are formed as flat coils on a flexible foil which are arranged along the internal side of the stator.

Abstract: A contact device consisting of a helical spring which is adapted from SMD mounting, and which is formed with a base portion adapted to be positioned on and attached to a contact face by soldering or gluing, and with a top portion adapted for handling with a tool preferably associated with an SMD apparatus. This provides the possibility of achieving a generally better and less expensive contacting between components, such as acoustic transducers, batteries or the like and printed circuit boards by means of simple features. Constructing the contact device as a screw or helical spring provides a great safeguard against transfer of laterally directed forces or moments from the contact face which destroy the contact face and/or the solder connection with the printed circuit.