| 摘要 |
<p>An adsorptive trap for monitoring gases and/or vapours comprises a tube (1, 10, 11) (e.g. length about 4-8 cm, internal diameter about 3-5 mm) packed with one or more suitable adsorbents (3,12,18,19) in appropriate amount (e.g. about 0.5 g), each adsorbent being held packed in place between a pair of rigidly fixed porous discs (4,13,20) e.g. porous sintered powder or metal gauze or mesh discs. It has been found that these adsorptive traps provide improved accuracy and precision of measurement as compared with prior art traps in which the adsorbent is relatively loosely packed and retained in the tube. A preferred method of fabricating the traps makes use of thermal contraction and expansion by allowing a previously cooled, contracted, oversize disc to be loosely fitted within the tube and expand on warming to ambient temperature and thereby become rigidly fixed in place.</p> |
