Abstract: An improved pulse tube cooler having a resonator tube connected in place of a compliance volume or reservoir. The resonator tube has a length substantially equal to an integer multiple of ¼ wavelength of an acoustic wave in the working gas within the resonator tube at its operating frequency, temperature and pressure. Preferably, the resonator tube is formed integrally with the inertance tube as a single, integral tube with a length approximately ½ of that wavelength. Also preferably, the integral tube is spaced outwardly from and coiled around the connection of the regenerator to the pulse tube at a cold region of the cooler and the turns of the coil are thermally bonded together to improve heat conduction through the coil.

Abstract: A displacer spring and displacer/spring assembly for use in an FPSE and with improved wear characteristics. One embodiment calls for the use of a single machined spring operating alternately in a tension mode and a compression mode and wherein the operating frequency of displacer movement can be controlled therewith to a desired resonant frequency. The machined spring of the present invention provides enhanced structural accuracy which, in turn, leads to the elimination of lateral and side loads as compared to prior art wire-wound helical springs.

Abstract: A displacer spring and displacer/spring assembly for use in an FPSE and with improved wear characteristics. One embodiment calls for the use of a single machined spring operating alternately in a tension mode and a compression mode and wherein the operating frequency of displacer movement can be controlled therewith to a desired resonant frequency. The machined spring of the present invention provides enhanced structural accuracy which, in turn, leads to the elimination of lateral and side loads as compared to prior art wire-wound helical springs.