Patent ID: 6869800

Claim:
An instrument comprising (i) a housing for attachment to a vessel or pipeline through which a process fluid is flowing and (ii) a probe having (a) a shaft which may be inserted into or withdrawn from said vessel or pipeline through sealing means associated with said housing, and (b) a container for containing a catalyst or sorbent, said container being fixed to one end of said shaft whereby, by insertion of said shaft into said vessel or pipeline, said container is retractably disposed within said vessel or pipeline; said container comprising an outer container, having walls with orifices therein, and an inner container for containing the catalyst or sorbent, said inner container being disposed within said outer container such that the inner container and outer container are spaced apart from each other to form an unstream and a downstream region between the inner container and the outer container, said upstream and downstream regions being separated from one another by baffle means, whereby, when inserted into a vessel or pipeline through which a process fluid is flowing, at least a part of the process fluid can flow from upstream of said outer container through at least one orifice in the wall of the outer container into said upstream region, through said catalyst or sorbent contained within the inner container, into said downstream region, and thence through at least one orifice in the wall of the outer container to the vessel or pipeline downstream of the container.