| 摘要 |
A stream selector for a process analyzer. The stream selector includes a valve module having two block valves and a bleed valve. In a first mode, the block valves are closed and the bleed valve is open. In a second mode, the block valves are open and the bleed valve is closed. In a third mode, all of the valves are open, thus ensuring that the module is completely purged. A stream-selection valve manifold is made by joining two or more valve modules side by side to form a common outlet and a common passageway, thus ensuring that the manifold is completely purged. The stream selector also provides a single block-and-bleed valve module having a disposal passageway which establishes fluid communication between a vent compartment and an external area suitable for the safe disposal of sample fluids and compressed gas contained in the valve module. The flat-face sealing structure of each valve is very tolerant of scratching and/or irregularities in the sealing structure and of abrasive particulates which may be present in the sample fluid, even to minor structural damage to the sealing structure.
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