Twentieth century hand-book for steam engineers and electricians with questions and answers; a practical non-technical treatise .. (1913)
Swingle, Calvin Franklin, 1846- [from old catalog] · Chicago, F. J. Drake & company · leaf 265
back,about 3 thick, made of hard iron. These wearing backswill last from 10 to 18 months, and are quickly replacedwhen worn out, and can be replaced without interfering 252 Steam Engineering with theworking of the convej^or, and at trifling cost.Patented fittings with interchangeable wearing back… … Fig. 100exhauster set driven by direct current motor can be readily seen on looking into a conveyor pipe inoperation. This fact prevents serious wear on the pipe^, and fromobservation of plants in use up to two and one-half years,shows that an ordinary steel pipe, handling ashes, will lastfor…
