| 摘要 |
This invention relates to process stream heaters. These heaters comprise a furnace chamber through which a number of tubes carrying the process stream to be heated pass. These tubes must be free to expand along their length but should not distort away from position since such distortion might result in uneven and insufficient heating. According to the invention this distortion is prevented where there are adjacent pairs of rows of tubes by means of a tube guide system comprising a zig-zag lattice made up of a number of clamping bars. Adjacent bars are pivoted to one another near their ends and the tubes nest in and are trapped in the V-shaped openings of the zig-zag lattice. In this way, the tubes are left free to expand and more relatively to one another along their lengths but any attempted distortion of a tube away from its axial position tends to cause pivoting of the clamping bars retaining that tube in place so that the lattice tends to lock more tightly onto other tubes so restraining that tube attempting to distort.
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