| 摘要 |
1463164 Internal resistance heating; resistance heaters GAZ DE FRANCE 1 Feb 1974 [6 Feb 1973] 4865/74 Heading H5H [Also in Divisions F4 and F2] A flow system for recovering heat from a heat source by means of a heat transfer fluid able to pass from the liquid to the gaseous state at temperatures in the region of the heat source, comprises a first porous material able to receive and be traversed by the heat transfer fluid in the liquid state and a second porous material supported on one side by said first porous material and forming a blocking layer such that under the operating conditions prevalent in the system the blocking layer is permeable to the fluid only in the gaseous state. The heat transfer fluid is selected so as not to wet the porous materials, e.g. magnesium, sodium, tin or mercury. As shown in Fig. 1, liquid from a reservoir 42 passes into the hollow axial portion 24 of a T-shaped assembly 12 via a duct 44. The assembly 12 includes a pipe 14 which contains a porous electric heating element 16 having a cylindrical central bar portion 18 enclosing the portion 24. The bar 18 is formed of a first material 20 of porous graphite with pores between 2-50 microns, and a second material 26 also of porous graphite of pore size of the order of 1 micron with a degree of porosity between 8-20%. A further porous material 32 similar to the first material shields the bar. The heat transfer fluid under pressure in portion 24, floods into the first porous material 20 and is heated by an electrical heat source 50, before evaporating into the second porous material 26. The evolved gas flows through conduit 38 to a condenser 40 in order to recover the latent heat of evaporation. A material having a good thermal conductivity, e.g. graphite or aluminium balls may be embedded in the first porous material. Alternatively, particulate material capable of evolving heat may be disposed in the first porous material.
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