Patent GB-674284-A (GB)
Title: Improvements in and relating to thermomagnetic generators and refrigerators
IPC: H01L37/04
Filed: 1950-05-31
Abstract: 674,284. Electric generators. TECHNICAL ASSETS, Inc. May 31, 1950 [May 31, 1949], No. 13568/50. Class 35. [Also in Group XIII] Generators operating by thermally produced changes of permeability of magnetic circuit.-In a thermo-electric generator or magnetic refrigerator operating by thermally produced changes in the permeability of a magnetic circuit or the Curie effect as described in Specifications 655,087, 655,088 and 661,738, [Group XIII], and comprising composite active ferromagnetic elements having graded Curie points heated and cooled by a metallic liquid, eddy-currents are reduced by making the section of tubular elements which are insulated from each other. The elements may comprise a cluster of rectangular tubes carrying the liquid but preferably a pack of flat, mutually insulated tubes is used. In the form shown in Figs. 1 and 2, the composite sections 1, 11 comprise packs of flat tubes whose Curie points vary from top to bottom and are joined to magnetic extensions 2, 2<SP>1</SP> and 3, 3<SP>1</SP>, at either end. At the top or high temperature end, the liquid passes into compartments 4, 4<SP>1</SP>, provided with cooling fins 5, 5<SP>1</SP> and 6, 6<SP>1</SP>, and joined by a tube 7 containing an electromagneticallyoperated piston 8 for oscillating the liquid. at the bottom or low temperature end, the tubes are joined by a refrigerating or cooling tube 14 having external and internal fins. The liquid oscillator may alternatively be at the low temperature part of the apparatus. The magnetic circuit comprises a permanent or electro magnet 15 having pole-pieces 16, 17, carrying A.C. windings 18 and in magnetic contact with the tube assemblies so that flux passes longitudinally through them. The flat tubes are separated by insulating layers 1*. The tubes may be strengthened by longitudinal spacers joining the flat sides of the tube. The piston for reciprocating the liquid may be replaced by a thermal oscillating means shown in Fig. 4. The compartments 4, 4<SP>1</SP> are joined through conical vapour condensing chambers 20, 20<SP>1</SP>, to sealed superheating tubes 23, 23<SP>1</SP> connected at their ends to electrodes 24, 24<SP>1</SP> and 25, 251. Rectified current is fed alternately through the length of each tube so that the liquid is vapour - ized and pushes the liquid. Thermal insulation 26, 26<SP>1</SP> is provided round the tubes which are each braced by an insulated metal sleeve 27, 27<SP>1</SP>. The tubes 23, 23<SP>1</SP> may contain inert gas or may have bulbs connected to their top ends which may contain gas under pressure to produce the desired natural frequency of the liquid body. In a modification, Fig. 6, the magnetic circuit and the liquid circuit are mutually at right angles. The magnetic circuit comprises a permanent magnet 32 with pole-pieces 33 joined to either side of the thermal section which comprises mutually insulated flattened tubes 35 carrying the liquid. The passages 36 inside the tubes open into finned compartments 40 joined by a reciprocating piston chamber 43. At their upper ends the tubes are interconnected by mutually insulated tubes 44 suitably spaced for easy heating or cooling.