| 摘要 |
PURPOSE:To enable nitrogen of ultra high purity having a quite less amount of not only O2 or CO2, CH4 but also some impurities such as H2 or He or the like to be always stably supplied by a method wherein a device for manufacturing product nitrogen is provided with a product nitrogen gas taking-out pipe for gasifying a part of product liquid nitrogen and taking out it as a product nitrogen gas and a back-up pipe having an evaporator extending from a back-up tank storing a part of the product liquid nitrogen to a product nitrogen gas taking-out pipe. CONSTITUTION:A back-up pipe 33 branched from a liquid nitrogen taking-out pipe 24 and extending to a pressurizing tank 30 supplies liquid nitrogen of ultra-high purity to the pressurizing tank 30. A back-up pipe 34 extending toward the back-up tank 31 feeds liquid nitrogen of high purity pressurized under an action of an evaporator 30a to the back-up tank 31. A back-up pipe 35 extending from the back-up tank 31 to a product nitrogen gas taking-out pipe 26 gasifies the liquid nitrogen of utlra-high purity fed out of the back-up tank 31 at an evaporator 32 and supplies it as a product nitrogen gas of ultra-high purity of substantial normal temperature to a product nitrogen gas taking-out pipe 26. It is always possible to perform a stable supplying of the product nitrogen gas of ultra-high purity.
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