| 摘要 |
Apparatus for producing a supply of gas at substantially constant pressure P1 includes a pressure swing adsorption plant 1 and an alternative source 3 of gas sharing a buffer vessel 4. A valve 11 is operable to select whether gas flow from plant 1 to buffer vessel 4 is via an unrestricted flow path 14 or via a restricted flow path 12. Gas is also supplied to the vessel 4 from the source 3 when the pressure in the vessel 4 is at or less than P1. During normal operation of the plant gas passes through the unrestricted path 14, but in the event that i) the pressure in the buffer vessel is below P3 where P3 is a predetermined value below P1, ii) there is a recorded failure in the alternative source 3, iii) there is a recorded failure in the supply line 5 or iv) the pressure of the inlet mixture in line 2 is P4 where P4 is a predetermined value above P1, the gas from the PSA plant 1 is switched to the restricted path 12. <IMAGE> |
