Abstract: An ink jet printer employs a wire mesh gutter electrode assembly and a wire mesh high voltage electrode, each having angled or skewed configurations geometrically related for providing a relatively narrow constricted path for ink droplets, so that charged and partially charged droplets, which are not used for imprinting, traverse a short path and are effectively captured and collected for recirculation and use in the ink recording process.

Abstract: A flat plate solar air heater for installation between light frame structural members, which comprises a pan of sheet stock such as sheet metal with one or more substantially transparent surface sheets to admit solar radiation into a sealed chamber between said pan and the transparent sheets. A louvered structure placed behind the transparent surface sheets reflects high angle solar rays in summer yet admits low angle solar rays in winter into the black-surfaced absorbing chamber. The louvered structure also increases heat transfer to an air stream moving through the chamber, and directs most of the air flow against the absorber surface. The top and bottom of the pan may be chamfered to permit various ductwork connections.

Abstract: A method of separating small diameter non-magnetic particles of different densities by using a low magnetic saturation ferrofluid and a high magnetic gradient to produce levitation by overcoming the magnetic attraction of the particles.Application of a constant gradient field of a level below the magnetic saturation level of the ferrofluid forms the ferrofluid into a density gradient column. Each non-magnetic particle levitates to the level inside the ferrofluid having the same apparent density as the particle.The ferrofluid contains magnetic particles with a mean effective core diameter less than about 50 angstroms and a stabilizing agent layer on the particle exceeding about 50 angstroms. Perfluorinated carriers and surfactants are preferred for their relatively high intrinsic density.

Abstract: A method of separating non-magnetic particles of different densities by using a ferrofluid to produce levitation wherein compensation is made for the magnetic attraction or interaction of the particles by removing particles too small for the desired sharpness of separation or by maintaining the ratio of the interaction force to the separation force outside of theoretical limits.

Abstract: A unitary electrical receptacle or switch for installation after finishing of the surface in which it is to appear, which comprises internal electrical conductors for such a receptacle or switch enclosed by electrically insulating material which is formed into a housing portion and a cover plate portion, with openings in said housing portion for insertion of distribution cable to make the desired electrical contact with the internal conductors, openings in the cover plate portion for insertion of a plug into the receptacle or for protrusion of switching means from switches, and through-holes for connecting the unitary receptacle or switch to a structural member. Means may also be included for firmly connecting the distribution cable to such a receptacle or switch.The housing portion may be designed to straddle a structural member. The flanges formed by the cover plate portion overhanging the housing portion may be provided with shoulders adapted to the thickness of various surfacing materials.