Patent Number: 
Section: claims

1. A device for measuring back pressure in open-ended chemical reactor tubes, comprising:a rigid wand body having upper and lower ends and including a frame member at said lower end;a plurality of hollow tube bodies mounted on said frame member,a tubular elastic sleeve mounted over the outer surface of each of said hollow tube bodies, each tubular elastic sleeve having a top and a bottom;top and bottom ferrules clamping the top and bottom of each tubular elastic sleeve against its respective hollow tube body;an inflation gas path extending to the interior of each tubular elastic sleeve for inflating the respective sleeve;a plurality of paths for providing controlled gas flow through said plurality of hollow tube bodies; anda pressure sensor in fluid communication with at least one of said hollow tube bodies. 2. A device for measuring back pressure in open-ended chemical reactor tubes as recited in claim 1, wherein the top ferrule extends below the frame member. 3. A device for measuring back pressure in open-ended chemical reactor tubes as recited in claim 1, and further including means for adjusting the spacing between the plurality of hollow tube bodies and for fixing the positions of the plurality of hollow tube bodies relative to said rigid wand body. 4. A device for measuring back pressure in open-ended chemical reactor tubes as recited in claim 3, and further comprising an additional hollow tube body mounted on said wand by a flexible mounting means which permits its insertion into a reactor tube independently of said plurality of hollow tube bodies; an additional tubular elastic sleeve mounted over said additional hollow tube body; an additional inflation path extending to the interior of said additional tubular elastic sleeve for inflating said sleeve; and an additional path for providing controlled gas flow through said additional hollow tube body. 5. A device for measuring back pressure in open-ended chemical reactor tubes as recited in claim 1; wherein each of said hollow tube bodies has an outer surface and an inner surface, said outer surface defining a recess, and said inner surface defining an internal fluid path, wherein said inflation gas path includes an inflation tube lying within the recess between one of said ferrules and the hollow tube body.