MICROCRYOGENIC COOLER Russian patent published in 1997 - IPC

FIELD: cooling sensitive elements of various systems, space optical systems in particular. SUBSTANCE: microcryogenic cooler has armature windings in linear motors of piston and expulsor on its stator or rotor, magnetic systems; piston is arranged in cylinder of starter forming compression chamber and expander with expulsor, their magnetic supports and devices prevent motion of piston at end of stroke; expulsor has positive rigidity which ensures frequency of their free axial oscillations in supports. Magnets of large axial length have nonuniform magnetization residual magnetization at end portions is higher than that in the center portion and field with sections of its increase from magnitude in center portion of magnet to maximum magnitude in its extreme parts which creates axial positive rigidities together with field of shorter magnets when they are located under extreme portions; these positive rigidities are equal to axial rigidities of above-mentioned devices. Working strokes of rotor with piston and expulsor do not extend beyond the limits of lengths of sections having increasing field at extreme parts of magnets. Supports perform function of devices which ensure economical resonance mode of operation of engines in optimal frequency range. EFFECT: enhanced efficiency. 6 cl, 5 dwg