Modern Gasworks Practice

318 MODERN GASWORKS PRACTICE H.P. Eequired for Gravity-Bucket Conveyors Size of Buckets (inches). 12 < 12 24 15 3e x 20 Spacing of buckets (inches) .... 18 36 18 36 18 36 H.P. required for each 10 feet vertical lift 0-46 0-23 1-35 0-67 3-8 1-9 H.P. required for each 100 feet per hour (unloaded) ...... 1-20 0-90 1-70 1-30 2-4 1-6 H.P. required for each 100 feet per hour (loaded with coal) ...... 3-20 1-90 7-40 4-20 18 9-4 THE MECHANICAL HANDLING OF COKE The utilization of labour-saving machinery in connection with the handling of coke has always involved difficulties owing to tlie faet that in coke-manufacturing establishments the material lias, in the first instance, a temperature approaching 1,000° C. In metallurgical works the question is simpler owing to the heat factor being eliminated, but the physical characteristics of the material, with its hard, gritty, and abrasive nature, present many difficulties which are not common to most other materials håndled in bulk. Tt is, in fact, probably owing to considerations of wear and tear that machinery for the purpose is of comparatively recent introduction, for engineers in the past hesitated to employ moving parts constructed of iron and steel which, in addition to withstanding abrasion, were faced with rapid contraction and expansion owing to the comparatively sudden changes of temperature resulting from the process of quenching the hot material. Experience, however, though perhaps unfortunate in the early days, has brought its consolations, so much so that wlien machinery of the kind is contemplated to-day the factor of wear and tear is accorded only secondary con-sideration, and the main decision turns upon the saving in operating costs which is likely to be effected. This must not be taken to mean that the factor of maintenance can be altogether neglected, for it must obviously have an important effect on economy. The question, however, is one which relates rather to the different methods employed than to the problem as a whole. Before coming to a decision as to the installation of coke plant it is highly desirable to view those considerations which are not actually measurable in terms ■of money. For instance, efficiency of production might be sacrificed in order to effect an apparent economy, and machinery may possibly be followed by less effective working results. Moreover, the peace of mind of those in charge is a factor which deserves consideration, and when apparatus such as coke plant, which. has to meet exceptional demands, is in question it is as well to take heed as to whether it will give rise to anxieties, such as breakdown, from which man-handling may normally be said to be free. In considering coke-handling machinery as employed on gasworks it is necessary to bear in mind that the plant will have to effect one or all of the following operations :