2814. Bennis, A. W. Feb. 22. Grates.-The links or bars of a travelling chain grate are perforated transversely so that, when they are placed side by side and linked up in the usual manner, transverse air conduits are formed, to which air is supplied under pressure and from which air escapes to the fire through passages formed in the. links. The link shown in Figs. 1 and 2 is perforated by a hole 2 of round, oval, or irregular shape, and Preferably provided with fingers 10 to give as large a. heatconducting surface as practicable. The links abut on the surfaces 4 and are provided with passages 3, which may have corrugated surfaces for admitting air to the fire. These passages 3 are longer and narrower at the top than at the bottom, and may be formed by cutting recesses on both sides of the link or by casting a slot through the body of the link. To minimize leakage of air, flanges and recesses may be provided on opposite sides of a link to engage with corresponding recesses and flanges on adjacent links. These flanges and recesses also prevent a link from dropping out in the event of breakage. Similar advantages may be obtained by providing projections 8 and depressions 9 on each side of the links. Instead of, or in addition to, flanges or projections and recesses or depressions, one or more plate; 29, Fig. 10, which may engage with recesses 30 or be secured by set-screws, may be arranged at the lower portion of the air conduit. By supporting the upper run of the grate upon a plate 15, as shown in Fig. 9, air boxes 27 are formed beneath the joints of the links, and by supplying air to these boxes and providing air passages between the ears of the links, the ain passages between adjacent links are made continuous. The plate 15 may be secured to the side frame and one or more air boxes may be formed by plates 16, 17. Figs. 4 and 5 show a form of side link which may be employed, as shown in Fig. 8, for leading the air from the conduit 26 to the conduits 2 by way of apertures 25 in the plate 15. The rib 14 and curved wall 13 of these side links form a continuous wall. which prevents the escape of air except to the boxes 27 and conduits 2. -The apertures 25 may he varied by suitable louver plates or dampers. and the air boxes formed beneath the plate 15 may have separately-controlled air supplies. Certain of the links may be provided with orifices through the bottom edges adapted to coincide with orifices in the plate 15 to supply air to any desired point of the transverse air conduits in the grate. Such links are provided with a. vertical diaphragm situated over the orifice to deflect the air to the right or left. or both. The orifices in the plate 15 may be varied in size or be formed as a tapered slot. Figs. 14 and 15 show two arrangements for supplying air to the links. The side links may have tapered orifices 62, Fig. 14, or the orifices may be of uniform bore, and the air may be supplied by a tapered duct 64. The air-supply ducts may be also provided with pivoted or spring-pressed plates adapted to engage with the side links. In the modification shown in Fig. 13, the bars 47 are mounted on chains 48. The side bars may be attached to the chains by lugs 49 and pins or rods 50, or flanges may be formed on the chains and the bars 47 attached thereto. The pins or rods 50 may pass through lugs on all the bars, or the intermediate bars may be held to the side bars by bolts passing through holes .51. or by means of dowels or projections and recesses. Supplementary air conduits are formed by rounding the lower corners of the bars, such conduits being closed at the ends by flanges 52. The air ducts at the sides of the grate may communicate with the interior of the rear drum, over which the chain runs, suitable holes being provided in the drum to allow for the circulation of air for cooling purposes.