Abstract: An air flow producer of non-rectangular shape is adapted for installation in a rectangular opening of a drop ceiling. In preferred form, the producer has a circular housing with an open bottom covered with a grill. A fan with a rotary blade assembly is mounted in the housing to produce a downward air flow, and a circular metal band surrounding the rotary blade assembly defines an air discharge zone centered in the grill and an annular air intake zone surrounding the discharge zone. Flow rates are optimized by positioning the band close to the grill. The grill is preferably integrally molded with a rectangular flange that seats in the drop ceiling opening. The flange supports the housing from the framework and closes the opening to prevent the producer from drawing air from the plenum above the drop ceiling.

Abstract: A process for producing a thermoplastic molding composition is disclosed. The process entails introducing a solid polymeric resin, optionally containing residual moisture, into an extruder, operating under conditions designed to melt the resin and charging water into the melt while in the extruder to yield wet, molten resin that contains water in an amount of at least about 2 percent. The wet, molten resin is then devolatilized to yield dry resin having water content not exceeding 0.3 percent. Molding compositions thus produced have improved properties. In a preferred embodiment, the process results in a molding composition that contains a fine dispersion of a discontinuous phase in a continuous polymeric phase.

Abstract: A system for operating a discharge lamp at partial power by heating the filaments to maintain an operating temperature for the filaments within an operating temperature range. The system comprises a ballast with a resonant circuit having a resonant frequency for supplying power to the discharge lamp and a heating power to each filament of the discharge lamp. The heating power is substantially controlled by an inductor in series with each filament. The ballast with the discharge lamp as a load is characterized by an output having a higher voltage at lower power than at higher power levels. This profile is also suitable for heating the filaments of the discharge lamp, which require more heating power or higher voltage when the discharge lamp is operating at lower power levels.

Abstract: A ballast module, for powering UV lamps in a fluid treatment assembly, that has electronic ballast with a high resonance frequency. The high resonance frequency reduces the size of the components so that the ballast module can be mounted in proximity with the UV lamps where the ballast module is also cooled by the fluid being treated by the UV lamps.

Abstract: A process is described, for treating liquids with radiation. One process involves passing the liquid over an ultraviolet lamp and ballast assembly which is submerged in the liquid. Apparatus for the process has an elongate frame member which is immersed in the liquid. Attached to the frame member and immersed in the liquid is a plurality of ultraviolet lamps and associated ballasts.