Solar collector comprising transparent hollow plastic microspheres as insulation material

摘要

The hollow plastic microspheres 17 are made by forming a liquid film of thermoplastic or thermosetting plastic composition across a coaxial blowing nozzle 5, applying a blowing gas 10 at a positive pressure to the inner surface of the plastic film to blow the film and form an elongated cylinder shaped liquid film 12 of plastic. A transverse jet 13 is used to direct an entraining fluid 14 over and around the blowing nozzle 5, at an angle to the axis of the blowing nozzle. The entraining fluid 14 as it passes over and around the blowing nozzle 5 fluid dynamically induces a pulsating or fluctuating pressure field at the opposite or lee side of the blowing nozzle in the wake or shadow of the coaxial blowing nozzle. The continued movement of the entraining fluid 14 over the elongated cylinder 12 produces asymmetric fluid drag forces on the cylinder and closes and detaches the elongated cylinder from the coaxial blowing nozzle and the detached cylinder by the action of surface tension forms into a spherical shape 17. The hollow plastic microspheres can be made from low heat conductivity plastic compositions and blown with a low heat conductivity gas and used to make improved insulation materials and composites and insulating systems. The hollow plastic microspheres 17 can be made to contain a thin transparent or reflective metal coating 20 deposited on the inner wall surface of the microspheres.