GB741015A - Improvements in and relating to oscillatory drives more particularly for small refrigerating machines - Google Patents

Abstract

741,015. Reciprocating electric motors. DOLZ, H. July 14, 1953 [July 26, 1952], No. 19472/53. Class 35. [Also. in Group XXVIII] In a reciprocating motor driving a refrigerator pump, the effective capacity in the circuit produced by the inertia of the moving parts is such as to cause resonance with the natural inductance of the electromagnetic winding, so that little or no spring is required. The device may be adjusted to resonance by adjustment of the spring or of a condenser or choke in the circuit. In a practical embodiment. Fig. 4, the coil 1 which is fed with current through coiled conductors 7 reciprocates between the annular poles 19, 22 of a permanent magnet 25. The sliding rod 16, which carries the pump piston 2 and the driving coil, is guided in a sleeve 46, e.g. of graphite, and carries inside the coil, a return spring 12 if one is used. The magnet pole core may be recessed at 24 and also radially slotted to reduce eddy-current losses. Alternative shapes of magnet are shown in Figs. 10 and 11. The pumped fluid enters at tube 45 and passes through the working gap to cool the coil. Further cooling may be achieved by putting non- magnetic conducting rings, e.g. of copper or aluminium around the moving coil at either end of the air-gap. The end clearance of the piston may be adjusted by means of plug 33 in the end of the cylinder. If desired, a compressor may be fitted at each end of the rod 16 or two independent units working towards each other in a common cylinder may be used. Speed reducing levers may be inserted between the load and the driving coil, or the load may be attached to a tapped spring.