| 摘要 |
Apparatus is described for supplying and measuring a purge gas flow to a pumping arrangement, the apparatus comprising a manifold (104) having a gas inlet (106) and a plurality of gas outlets (110) each for supplying gas to a respective port of the pumping arrangement, and a flow selector (120) between the inlet and the outlets, the flow selector having a plurality of spaced apertures (130) of various sizes and being moveable relative to the manifold from one position in which a first set of the apertures is aligned with the inlet and the outlets to another position in which a second set of the apertures is aligned with the inlet and the outlets to vary the flow rate of gas into and from the flow selector, and enable the gas flow rate to be measured across the aperture aligned with the inlet. |
