The following table gives the draught area and heating surface of the various sized boiler tubes and flues:
----------+---------------+-------------+----------------+-------------+ | | | | No. of | | | |Heating surface | tubes in 1 | External |Draught area |Draught Area |in feet | sq. foot of | Diameter. |in sq. inches. |in sq. feet. |per ft. of tube | draught | | | |in length. | area. | ----------+---------------+-------------+----------------+-------------+ 5/8 | ...... | ...... | .1636 | ..... | ¾ | ...... | ...... | .1963 | ..... | 1 | .575 | .0040 | .2618 | 250.0 | 1¼ | .968 | .0067 | .3272 | 149.3 | 1½ | 1.389 | .00964 | .3927 | 103.7 | 1¾ | 1.911 | .0133 | .4581 | 75.2 | 2 | 2.573 | .0179 | .5236 | 55.9 | 2¼ | 3.333 | .0231 | .5891 | 43.3 | 2½ | 4.083 | .0284 | .6545 | 35.2 | 2¾ | 5.027 | .0349 | .7200 | 28.7 | 3 | 6.070 | .0422 | .7854 | 23.7 | 3¼ | 7.116 | .0494 | .8508 | 20.2 | 3½ | 8.347 | .0580 | .9163 | 17.2 | 3¾ | 9.676 | .0672 | .9818 | 14.9 | 4 | 10.93 | .0759 | 1.0472 | 13.2 | 4½ | 14.05 | .0996 | 1.1781 | 10.2 | 5 | 17.35 | .1205 | 1.3090 | 8.3 | 6 | 25.25 | .1753 | 1.5708 | 5.7 | 7 | 34.94 | .2426 | 1.8326 | 4.1 | 8 | 46.20 | .3208 | 2.0944 | 3.1 | 9 | 58.63 | .4072 | 2.3562 | 2.5 | 10 | 72.23 | .5016 | 2.6180 | 2.0 | ----------+---------------+-------------+----------------+-------------+
We give below two views of a ladle carriage which has been constructed from the designs of Mr. Thomas Wood, the chief engineer to the Ebbw Vale Steel, Iron, and Coal Company. These works cover a large extent of ground, the Victoria furnaces and the Ebbw Vale furnaces, both of which supply one steel plant, being over a mile apart. Although this gives a long distance over which the molten metal from the furnaces has to be carried, it is by no means unprecedented; the Barrow furnaces for instance being situated still further from the steel works they supply. Until a short time ago, however, the Ebbw Vale Company had their Sirhowy furnaces in blast. These are, or rather were, for now they are dismantled, situated six miles by rail from the converters they supplied at Ebbw Vale, consequently the ladle containing the 10 tons of molten metal had to be brought this distance each time the converters were charged. In order to meet the exigencies of such a service, the ladle carriage we now illustrate was designed by Mr. Wood.