Abstract: Method and apparatus to maintain homogeneity in a mixture of a fluid carrier and a quantity of magnetically permeable particles in which the mixture within a cylindrical container is subjected to the influence of a magnetic field which rotates around the container, and which at any instant is centered about its own axis lying outside the container. The field has an axis with directional components in a circumferential sense and in the axial sense of the container. In the apparatus, the field is produced by electrical coils connected for multiphase operation, side-by-side around the container and each coil is in a circumferentially and axially inclined relationship to the container.

Abstract: In a method of insulating an electrical conductor, the conductor passes upwardly through a coating fluid and a die means which is carried in a vertical position by a supporting fluid force. This force is provided by the supporting force of the fluid or a magnetic force which holds the die in suspension. Freedom for horizontal movement of the die is provided to enable it to move in a manner corresponding to any lateral movement of the conductor, this die movement being controlled by hydrodynamic forces between conductor and die to maintain the concentricity of a fluid layer formed on the conductor.