Aisin Seiki Kabushiki Kaisha

Aisin Newhard Co., Ltd.

Tatsuo Inoue

Shin Kawano

Shaowei Zhu

Masafumi Nogawa

Takayuki Matsui

Masahumi Nogawa

Akira Tominaga

Yoshimasa Ohashi

Shinji Katsuragawa

Kimio Aoyama

A cryogenic refrigerator includes a pressure feeding device, a refrigeration device, a high pressure passage, a low pressure passage, and at least one heat exchanger at the high pressure passage for refrigerating the refrigerant introduced at the high pressure passage by heat exchange, the heat exchanger including an active pressure drop type heat exchanger for declining pressure of the refrigerant at the high pressure passage before being introduced into the refrigeration device. The active pressure drop type heat exchanger declines the pressure of the refrigerant with a ratio equal to or greater than 5 percent out of 100 percent and refrigerates the refrigerant when a pressure difference between a pressure of the refrigerant before being introduced into the active pressure drop type heat exchanger and a pressure of the refrigerant before being introduced into the refrigeration device is defined as 100 percent.

Cryogenic refrigerator

A rotary valve unit in a pulse tube refrigerator is quiet, and has high durability and improved refrigeration efficiency by restricting the generation of unidirectional flow. A center hole is formed on a sliding plane side as a recessed space in the sliding surfaces between the sliding plane and another sliding plane. Since the second center hole is in communication with a low pressure input port via a communication passage, the leakage between the sliding surfaces of the sliding planes can be introduced to the low pressure input port with low pressure.

Rotary valve unit in a pulse tube refrigerator

In a pulse tube refrigerator the refrigeration efficiency has been improved by reducing the on-off valve loss. A second space in a cylinder member is connected with a second high pressure on-off valve and a second low pressure on-off valve . A buffer side on-off valve is provided between the buffer space (a buffer tank ) and the second space . By opening the buffer side on-off valve before the second high pressure on-off valve or the second low pressure on-off valve is open, the pressure in the second space can be the intermediate pressure. Since the pressure difference when the valves are open is decreased, the on-off valve loss can be decreased.

Pulse tube refrigerator

A pulse tube refrigerator which reduces valve losses in a cycle and improves refrigeration efficiency includes a pressure oscillator, a refrigerating portion, a first middle pressure buffer tank, a first middle pressure buffer side valve, a second middle pressure buffer tank and a second middle pressure buffer side valve. A regenerator in the refrigerating portion and an outlet port and an inlet port of a compressor in the pressure oscillator are connected via a high pressure valve and a low pressure valve respectively. A high temperature heat exchanger of the refrigerating portion and the first middle pressure buffer tank and the second middle pressure buffer tank are connected via the first middle pressure buffer side valve and the second middle pressure buffer side valve. The first middle pressure buffer tank and the second middle pressure buffer tank include different middle pressures which are predetermined between an output pressure and an input pressure of the compressor.

A pulse tube refrigerator includes a compressor, a first heat exchanger, a first regenerator, a first cold head, a first pulse tube, a first radiator, a second regenerator, a second cold head, a second pulse tube, a second radiator, an orifice and a buffer tank which are connected in series. A first cooling part consists of the first heat exchanger, the first regenerator, the first cold head, the first pulse tube and the first radiator. A second cooling part consists of the first radiator, the second regenerator, the second cold head, the second pulse tube and the second radiator. The first radiator forms not only the radiator of the first cooling part, but also the heat exchanger of the second cooling part.

A pulse tube refrigerator includes a refrigerating portion including a regenerator, a low temperature heat exchanger, a pulse tube and a high temperature heat exchanger fluidically connected in this order. A first pressure oscillator includes a first compression source, a first high pressure supply valve, and a first low pressure supply valve. The regenerator is connected with outlet and inlet ports of the first compression source via the first high pressure supply valve and the first low pressure supply valve, respectively. A second pressure oscillator is provided independently of the first pressure oscillator and has a second compression source, a second high pressure supply valve, and a second low pressure supply valve. The high temperature heat exchanger is connected with outlet and inlet ports of the second compression source via the second high pressure supply valve and the second low pressure supply valve, respectively.

A multi-type pulse-tube refrigerating system includes a common compressor,having a sucking port,and a discharging port,, a plurality of paralleled pressure changeover valve units,and,connecting between the sucking port,and the discharging port,of the compressor,, and a plurality of pulse-tube based cryogenic temperature generating devices,and,connected to the respective pressure changeover valve units,and,. Employing such cryogenic temperature generating devices,and,, each of which is void of moving parts, limits vibrations. Moreover, instead of the pressure changeover valve units,and,, employing a common pressure changeover valve unit,for the units,and,makes the refrigerating system more compact.

Multi-type pulse-tube refrigerating system

A pulse tube refrigerator includes a compressor, a first high pressure valve connected with the compressor, a first high pressure passage connecting the outlet port of the compressor with the first high pressure valve, a first low pressure valve connected with the compressor, first low pressure passage connecting the inlet port of the compressor with the first low pressure valve, a regenerator connected with the first high pressure valve and the first low pressure valve, a cold head connected with the regenerator, a pulse tube connected with the cold head a second high pressure valve connected with the pulse tube. The pulse tube refrigerator further includes a second low pressure valve connected with the pulse tube, a high pressure cylinder provided in the second high pressure passage, a high pressure side partition element reciprocally provided within the high pressure cylinder and fluid tightly dividing the high pressure side cylinder into a first high pressure space and a second high pressure space, a low pressure cylinder provided in the second low pressure passage; and a low pressure side partition element reciprocally provided within the low pressure side cylinder and fluid tightly dividing the low pressure cylinder into a first low pressure space and a second low pressure space.

A heat-regenerating type cryogenic cooling apparatus,includes a cryogenic temperature generating part,having a heat regenerator,; and a pressure generating device,connected to the part,, generating pressure vibration of a working gas therein, and having a compressor,with a discharging port,and a sucking port,, a high-pressure line,whose one end is in fluid communication with the discharging port,of the compressor,, a low-pressure line,whose one end is in fluid communication with the sucking port,of the compressor,, a high-pressure open/close valve,connected to the other end of the line,, a low-pressure open/close valve,connected to the other end of the line,, a high-pressure side line,connecting the valve,and the,, a low-pressure side line,connecting the valve,and the part,, and a high-pressure side buffer tank,as a high-pressure source connected to the midportion of the line,. At the instant of the opening of the valve,, the amount of working gas discharged therefrom is the sum of the amount of the working gas discharged from the compressor,and the amount of working gas supplied from the high-pressure side buffer tank,, which prevents lowering pressure in the line,, thereby improving the cryogenic efficiency.

Heat-regenerating type cryogenic cooling apparatus

A higher temperature end of a pulse tube is connected to a lower side of a supporting member so as to position at a lower temperature end of the pulse tube at a lower position. Such a structure prevents free convection of a working gas in the pulse tube, which is a cause of reduced refrigerating efficiency. If a cold head is desired to be contacted with a member to be cooled down from its (lower) side, such a need can be satisfied by mounting the cold head on the lower temperature end of the pulse tube (a lower temperature end of a regenerator).

A pulse tube refrigerator includes a regenerator including a cold end and a hot end, a cold head connected to the cold end of the regenerator, a pulse tube having a cold end and a hot end and connected at its cold end to the cold head, a pressure fluctuation source connected to the hot end of the regenerator, a buffer connected to the hot end of the pulse tube through an orifice, and an auxiliary buffer connected to the hot end of the pulse tube through a buffer side control valve. The buffer and the auxiliary buffer may be replaced by a single buffer connected to the hot end of the pulse tube through an orifice and a buffer side control valve which are arranged in parallel.

A superconducting magnet system, such as an NMR apparatus, is outfitted with a compact-size refrigerator that prevents mechanical vibrations produced by the refrigerator from being transmitted to the superconducting magnet system. The refrigerator is in the form of a pulse tube refrigerator having a cold head and a pressure oscillation generating source. The cold head of the pulse tube refrigerator is connected directly to a vacuum insulation vessel of the superconducting magnet system. Cold generated from the cold head cools a cooling device, for example, a liquid helium tank for cooling the superconducting coil, or a heat penetration reducing device, for example, a liquid nitrogen tank, for reducing heat penetration from outside.

Superconducting magnet system outfitted with cooling apparatus

A pulse tube refrigerator according to the present invention is capable of performing cryogenic operation sufficiently. The cryostat includes regenerators and pulse tubes. Each regenerator has a cold stage at an upper end thereof. Each pulse tube has a low-temperature end portion at a lower end thereof and a high-temperature end portion thereof, the low-temperature end portion being located lower than the cold stage. The cold stage and the low-temperature end portion are connected to each other through a line whose cubic volume is substantially negligible in comparison with that of the pulse tube. Since the pulse tube has working gas of relatively high density in an upper portion thereof and working gas of relatively low density in a lower portion thereof, there is no convection of working gas induced by the gravity. Thus, the cryostat performs cryogenic operation sufficiently without being adversely affected.

A multistage type tube refrigerator comprising a regenerator-side pressure oscillation generator, first regenerator connected to the regenerator-side pressure oscillation generator, first cold head connected to the low temperature side of the first regenerator, a first pulse tube having one end connected to the first cold head and the other end connected by way of a first flow regulating mechanism to a first pulse tube-side phase shifter, second regenerator having one end connected to the first cold head and the other end connected to the second cold head, a second pulse having one end connected to the second cold head and the other end connected to second pulse tube-side phase shifter by way of second flow regulating mechanism, in which the first pulse tube-side phase shifter and the second pulse tube-side phase shifter are controlled independently of each other. Further, the pulse tube refrigerator operated while setting the phase angle of the pulse tube-side phase shifter to -50.degree. to -120.degree. relative to the regenerator-side pressure oscillation generator, while setting the phase angle of the second pulse tube-side phase shifter 15.degree. to -90.degree..

Multistage type pulse tube refrigerator

In a Stirling engine, a thermal isolating space is provided between an expansion space and a heating portion so as to establish a thermal isolation of the expansion space from the heating portion.

Growing community of inventors

Anjo, Japan

Tatsuo Inoue