Pulse tube refrigerator

A pulse tube refrigerator comprising:

• a compressor that generates a high-pressure working gas by compressing a low-pressure working gas;
• a high-temperature side regenerator that has a high-temperature end and a low-temperature end, the high-temperature end being connected to the compressor;
• a low-temperature side regenerator that has a high-temperature end and a low-temperature end, the high-temperature end being connected to the low-temperature end of the high-temperature side regenerator;
• a high-temperature side pulse tube that has a high-temperature end and a low-temperature end, the low-temperature end being connected to the low-temperature end of the high-temperature side regenerator, the high-temperature end being connected to the compressor;
• a low-temperature side pulse tube that has a high-temperature end and a low-temperature end, the low-temperature end being connected to the low-temperature end of the low-temperature side regenerator;
• and
• a gas flow passage that is connected to the high-temperature end of the low-temperature side pulse tube and the compressor, such that a working gas flows in the gas flow passage, wherein
• the gas flow passage includes:
• a tube having a tube end portion;
• a first flow passage having a first outlet connected to the high-temperature end of the low-temperature side pulse tube and a second outlet formed through the tube end portion, the second outlet on an opposite end of the first flow passage from the first outlet;
• a second flow passage connected to the compressor, the second flow passage having an outlet on an opposite end of the second flow passage from the compressor;
• and
• a housing that gastightly accommodates the tube end portion, the second outlet of the first flow passage and the outlet of the second flow passage, wherein the housing and the tube end portion together form a gastight space filled with the working gas,
• wherein the second flow passage is formed as a through-hole through the housing and arranged coaxially with the second outlet of the first flow passage, the outlet of the second flow passage arranged axially spaced apart from the second outlet of the first flow passage to form a gap between the second outlet of the first flow passage and the outlet of the second flow passage, the gastight space communicating with the second outlet of the first flow passage and the outlet of the second flow passage through the gap, and
• wherein the gas flow passage is configured to prevent gas leakage between the gastight space and the first outlet of the first flow passage, and configured to ensure the working gas passes through the second outlet of the first flow passage between the outlet of the second flow passage and the first outlet of the first flow passage.