Modern Gasworks Practice

THE HORIZONTAL RETORT BENCH 105 (9) The verticäl division walls supporting the retorts need not be of greater width than 4| inches, pro vided that 9-inch walls are put in where the retort joint comes. The walls forming the combustion chamber should not be less than 6 inches in width. (10) The gases should be throttled to a certain extent at the top of the setting. These get away too quickly if excessive room is permitted. The bottom retorts should be no more than 4 inches to inches from the side of the main arch wall. Specifications for Horizontal Benches It would not be possible, owing to the multitude of designs now adopted by individual engineers, to give here a general specification for a horizontal retort beuch. The foregoing pages should, liowever, prove of some assistance to the engi-neer contemplating extensions or renewals; and, with. their aid, there should be little difficulty in compiling specifications for benches of whatever type or capacity. The chief points requiring consideration have been fully dealt with, and in addition it is imperative to ensure that first-class material should be used throughout. Except in certain classes of silica work the joints should be thin, and two to one cement mortar used in all stock brickwork, with fireclay cement for all fireclay work. As regards the types of materials suitable for various portions of the setting, reference should be made to Chapter VI dealing with Refractory Materials. THE COST OF HORIZONTAL RETORT SETTINGS Costs of erection must necessarily vary to some considerable extent in accordance with the fluctuations in price of materials and labour, also the design or “ stifEness ” of the work put down. To attempt to give precise figures at the present time is an unenviable task, and the author suggests, therefore, that the following estimates should only be used as a guide for the purpose of obtaining an approximate idea of the outlay involved. Stage floors, whilst costing on an average about £6 10s. per mouthpiece, may rise to as much as £17 10s., in cases where exceptionally heavy charging macliinery, etc., is allowed for. Other factors affecting the ultimate cost are the distance and ease of access of the point of supply from the site on which the structure is to be erected, also the prevailing railway rates and water freightage. In most cases all the above considerations should not influence the following prices to a greater extent than 10 per cent, in either direction. Owing to competition. amongst contractors, a certain amount of “ cheeseparing ” is ine vitable in the pre-liminary tenders ; for this reason the figures given below lean, if anything, towards cxtravagance—that is to say, they exemplify expenditure where a few extra potmds have not been withheld.