Abstract: In a Vuilleumier heat pump, hot and cold displacers are supported by coil springs in respective buffer chambers. Further, there are respectively provided forced vibration systems of the hot and cold displacers using, as exciting force, force applied to respective displacer rods due to a difference between a pressure fluctuation of a working gas in an inner working space and a pressure in the buffer chambers. A linear motor is also provided to drive the hot displacer so as to reciprocate. It is thereby possible to provide the Vuilleumier heat pump in which a mechanism for driving the hot and cold displacers can have a small-sized and simplified structure, and no restriction is imposed on an arrangement of hot and cold cylinders.

Abstract: A cryocompressor includes a check valve arranged in a circuit connecting a compression chamber defined by a piston disposed in a cylinder with an annular gap small enough to provide an expected sealing effect to a buffer chamber also defined by the piston in the cylinder, a cross sectional area of the annular gap between the piston and the cylinder being larger on the side of the compression chamber than on the side of the buffer chamber.

Abstract: A refrigerator comprising a cold finger having an expansion space and a first compression space defined by a displacer, a regenerator connected to the expansion space and the first compression space, a cylinder having a second compression space and a buffer space defined by a piston, and a communicating tube connecting the first compression space to the second compression space. The working space thus defined is filled with the working gas so that a thermodynamic cycle can be generated in the working gas within the working space to generate coldness within the expansio space by reciprocatingly moving the piston and the displacer with a predetermined phase relationship therebetween. The refrigerator further comprises a first passage having a check valve between the working space and the buffer space, and a second connecting passage connecting the drain space and the buffer space.

Abstract: A gas cycle machine includes a moving coil composed of a first moving coil portion and a second moving coil portion opposing to the first moving coil portion and a magnetic circuit is constituted such that magnetic flux in a first gap in which the first moving coil portion is disposed passes through the first moving coil portion inwardly and magnetic flux in a second gap in which the second moving coil portion is disposed passes through the latter outwardly. Magnetic flux of a permanent magnet passes through the first and the second gaps in opposite directions, respectively, and, therefore, a closed magnetic circuit is composed of the permanent magnet, a cylinder of soft iron and an annular disc, which eliminates the necessity of providing a large circular disc as in the conventional engine.

Abstract: A refrigerator has a reciprocation portion including a piston and a portion of a linear motor and having an angular resonance frequency W defined by the following equation: ##EQU1## where m=total mass of the reciprocation portionSp=area of a working surface of the pistonPa=amplitude of pressure variation of a working gas in a compression space of the refrigerator.alpha.=phase difference between a displacement of the piston and pressure variation of the working gas in the compression spaceS=stroke of the pistonKs=spring constant of a support spring of the pistonand an a.c. power source for driving the reciprocation portion, the power source has an angular frequency W.sub.o substantially equal to said angular frequency W with an acceptable error therebetween being .+-.10%.

Abstract: A cryogenic compressor wherein a compression space and a buffer space which are partitioned off from each other by means of a reciprocating piston are directly connected together through a passage which is provided with a check valve that allows a gas to flow only from the buffer space to the compression space and a purification chamber filled with a purifying substance. Thus, when the pressure within the compression space is about to become lower than the pressure within the buffer space, the gas is led from the buffer space to the compression space via the passage which connects these spaces directly to each other through the check valve, and even if this gas has been contaminated, it is purified by the purifying substance charged in the purification chamber and therefore the contamination of the working gas is prevented.

Abstract: In a vibration-reducing apparatus for a direct-acting type stirling engine, a change of pressure caused by the reciprocal movement of a displacer is applied to a power piston to produce a mechanical force, and the mechanical force is converted into an electric power by a direct-acting type electric generator which is directly connected to the power piston so as to effect reciprocating movements with the power piston.

Abstract: A seal-ring type shaft-sealing device for sealing a highly pressurized fluid such as gas and liquid has a seal ring whose inner circumference is previously formed ovally and is held so as to incline the longitudinal axis of the ellipse to the gravity force direction in the revolutional direction of the rotating shaft at an angle smaller than 90.degree. thus improving the floating characteristic and eliminating the irregular distribution in temperature during operation. The device can be used, for example, in a turbine generator.