| 摘要 |
PROBLEM TO BE SOLVED: To decide the whole of a spring constant easily and set optimum resonance frequency easily, even if there is a difference of specification of a freezer in the stage of its design, in the case of setting the operation frequency of the compressor in a stiring freezer where the double-piston type compressor and an expansion valve are combined. SOLUTION: The operation frequency of a compressor C is set in the range from resonance frequency f0 to f=0.9f0-1.1f0. The resonance frequency f0 (Hz) is decided by f0=(1/2π).[(1/m). Km+(A<2> .P0)/(Vc0+0.7Va0)}]<1/2> , using m (Kg) for mass of the mobile part of the compressor C, Km(N/m) for the mechanical spring constant of a compressor coil spring 26, A(m<2> ) for area of the working surface of a piston 7, P0(Pa) for average pressure of gas within the system, Vc0 (m<3> ) for volume of the compressive space in the neutral position in reciprocation of the piston 7, and Va0 (m<3> ) for volume of the normal-temperature space in the neutral position in reciprocation of a displacer 37.
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