Patent Number: 
Section: claims

1. A device for measuring back pressure in open-ended chemical reactor tubes, comprising:a wand body having upper and lower ends;a plurality of injector tubes mounted adjacent said lower end;a gas inlet on said wand body;a test gas path from said gas inlet through said injector tubes;at least one pressure sensor in fluid communication with at least one of said injector tubes for measuring the back pressure in said one injector tube;wherein said wand body and said injector tubes are rigidly mounted together to form a single unit which is sufficiently rigid that said plurality of injector tubes can be inserted simultaneously into their respective reactor tubes by moving said wand body. 2. A device for measuring back pressure in open-ended chemical reactor tubes as recited in claim 1, and further comprising inflatable seals on said injector tubes and inflation gas paths from said gas inlet to said inflatable seals. 3. A device for measuring back pressure in open-ended chemical reactor tubes as recited in claim 2, and further comprising an interlock means for ensuring that said injector tubes are inserted into their respective reactor tubes before inflating said inflatable seals. 4. A device for measuring back pressure in open-ended chemical reactor tubes as recited in claim 1, and further comprising slidable mounting means which mount said injector tubes on said wand body. 5. A device for measuring back pressure in open-ended chemical reactor tubes as recited in claim 4, wherein said slidable mounting means include a frame portion having a bottom surface; wherein said injector tubes project downwardly from said bottom surface; and further comprising seals on said injector tubes below the bottom surface of said frame portion. 6. A device for measuring back pressure in open-ended chemical reactor tubes as recited in claim 5, and further comprising an interlock means for ensuring that said injector tubes are inserted into their respective reactor tubes before inflating said seals. 7. A device for measuring back pressure in open-ended chemical reactor tubes as recited in claim 1, and further comprising an umbilical wand body including an umbilical handle and an umbilical injector tube, and a flexible tube connecting said umbilical wand body to said wand body so the umbilical wand body can move independently of the wand body. 8. A device for measuring back pressure in open-ended chemical reactor tubes as recited in claim 1, and further comprising:a plurality of measurement paths between said at least one pressure sensor and said injector tubes; anda multiplexing valve in fluid communication with said measurement paths, including means for selectively putting said at least one pressure sensor in fluid communication with each of said injector tubes. 9. A device for measuring back pressure in open-ended chemical reactor tubes as recited in claim 1, and further comprising:a laser measuring means on said wand body for automatically measuring the distance from said wand body to a reflecting surface. 10. A device for measuring back pressure in open-ended chemical reactor tubes as recited in claim 9, and further comprising means for automatically determining which reactor tube is being measured based on the distance measured by said laser measuring means; means for automatically associating the pressure measurement with the reactor tube being measured; and means for electronically transmitting the pressure measurement together with an identifier for the chemical reactor tube being measured to a remote location. 11. A device for measuring back pressure in open-ended chemical reactor tubes as recited in claim 10, and further comprising a slidable mounting means which mounts said injector tubes on said wand body. 12. A device for measuring back pressure in open-ended chemical reactor tubes as recited in claim 11, wherein said at least one pressure sensor is mounted on said wand body. 13. A device for measuring back pressure in open-ended chemical reactor tubes, comprising:a wand body having upper and lower ends;a plurality of injector tubes mounted adjacent said lower end;a gas inlet on said wand body;a test gas path from said gas inlet through said injector tubes;at least one pressure sensor;at least one measurement path from one of said injector tubes to said at least one pressure sensor for measuring the back pressure in said one injector tube; an inflatable seal on each of said injector tubes;inflation gas paths from said gas inlet to said inflatable seals; andan interlock means for ensuring that said injector tubes are properly inserted into their respective chemical reactor tubes before inflating the inflatable seals. 14. A device for measuring back pressure in open-ended chemical reactor tubes as recited in claim 13, and further comprising:a plurality of measurement paths between said pressure sensor and said injector tubes; anda multiplexing valve in fluid communication with said measurement paths, including means for selectively putting said pressure sensor in fluid communication with each of said injector tubes. 15. A device for measuring back pressure in open-ended chemical reactor tubes as recited in claim 14, and further comprising:a laser measuring means on said wand body for automatically measuring the distance from said wand body to a reflecting surface. 16. A device for measuring back pressure in open-ended chemical reactor tubes as recited in claim 15, and further comprising means for automatically determining which reactor tube is being measured based on the distance measured by said laser measuring means; means for automatically associating the pressure measurement with the reactor tube being measured; and means for electronically transmitting the pressure measurement together with an identifier for the chemical reactor tube being measured to a remote location. 17. A device for measuring back pressure in open-ended chemical reactor tubes as recited in claim 16, and further comprising means for receiving the pressure measurements at the remote location; anddisplay means, in communication with said receiving means, for graphically displaying the layout of the tubes and the pressure data. 18. A device for measuring back pressure in open-ended chemical reactor tubes as recited in claim 13, and further comprising a slidable mounting means which mounts said injector tubes on said wand body.