MARINE ENGINES.
4 2 7
Fig. 310.—Tape Packing for Tubes.a, Tube, b, Packing gland.
with a screw driver. Another mode of making the tube joints iswith a sheet of india rubber having holes suited to the pitch of the
tube. The holes are left smaller thanthe outside diameter, and when the tubesare all in position, being merely passedthrough plain holes drilled in the tubeplates, the india-rubber sheet is laid overthem, and an outside plate is bolted upagainst it, which plate is recessed for thereception of the tubes, and leaves anarrow edge round each tube; thus withthe pressure, and the holes in the indiarubber being much smaller than thediameter of the tube, a raised flange ofindia rubber is formed around each tube,and the tubes are gripped by an elasticmedium, while the pressure transmittedthrough the plate by the bolts to theflat surface of the india rubber keeps itin perfect contact with the plate, and agood joint is obtained. Some engineers, however, think that eachtube should be made air and water tight separately, so that if ajoint gets out of order it can be repaired without disturbing the
whole series; besides with suchthin tubes it is an object to havethe joint elastic, so that the tubescan expand and contract easily.With these objects in view theauthor has arranged a packing ringof a peculiar construction. Theholes in the tube plate are boredparallel, and then tapped; a glandor screwed nut having a recess fora ring of india rubber or any otherelastic medium is fitted to eachhole. The india rubber ring is agood fit in the recess, and is put in place by merely squeezingit together; its inside diameter is made smaller than that of thetube, according to the amount of grip required; and to facili-tate the Operation of tubing, a loose cone plug is inserted in