| 摘要 |
<p>Air is separated by pressure swing adsorption using beds 12 and 14 of adsorbent which are able to be placed in communication with a product nitrogen pipeline 20. The pipeline 20 has a pressure regulator 28 disposed therein and communicates with a buffer vessel 32. A flow restrictor 30 is located in the pipeline downstream of the pressure regulator 28, and a valve means 34 for closing the pipeline 20 between the pressure regulator 28 and the buffer vessel 32. When the valve 34 is in its closed position gas flows into the buffer vessel 32 via a by-pass conduit 36 having a second flow restrictor 38 therein. The valve 34 closes when the pressure in the vessel 32 (and hence the purity of the product nitrogen delivered to it) falls below a chosen value, and the flow restrictor 38 is sized so as to maintain the purity of nitrogen for at least some period of time after the valve 34 closes.</p> |
