Electrically Controlled Liquid-Crystal Heat Valve.
Patent, Filed 26 May 92, patented 29 Jun 93,
DEPARTMENT OF THE NAVY WASHINGTON DC
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An improved electrically controlled thermotropic liquid-crystal heat valve to control the flow of heat between two bodies of different temperatures by interposing there between a fluid layer of liquid-crystal material having a nematic temperature range that includes the temperature of both bodies. This type of heat valve has particular application to any free-swimming divers diving garments, to provide some thermal protection against the cold ambient water. The heat valve uses stable liquid-crystal materials encapsulated in a sealed environment, with the valves electrodes being shielded and not in direct electrical contact with the liquid-crystal material. This arrangement essentially completely eliminates the electrochemical effects which can otherwise degrade the liquid-crystal materials, so that the liquid crystal may function for a very long time. The valve is electrically controlled between the respective two different modes of its open and closed conditions, the open mode occurring when a low frequency AC field is applied to one of the liquid crystal materials and the closed mode occurring when a high frequency field is applied to effect reorientation of the molecules of the liquid crystal materials in a direction perpendicular to the applied AC field, precluding establishment of convective flow cells, thereby retarding the transfer of heat.
- Electricity and Magnetism
- Pumps, Filters, Pipes, Tubing, Fittings and Valves