Transactions . ubject. Moreover,its employment is so general in mining operations that noapology is needed for the presentation to the Institute of sucha paper as the present. The admirable articles of Mr. E. , published in Compressed Air, show a wide range in the me-chanical efficiency of air-compressors, varying, under differentconditions, from 15 to 60 per cent.; and it is evident that any * Trans., vii., 308. in i: DAURIA AIR-00MPRB880R. I L8 improvements increasing the efficiency of these machines mastinterest mining engineers. The present paper calls attention to a nrw form of air-c
Transactions . ubject. Moreover,its employment is so general in mining operations that noapology is needed for the presentation to the Institute of sucha paper as the present. The admirable articles of Mr. E. , published in Compressed Air, show a wide range in the me-chanical efficiency of air-compressors, varying, under differentconditions, from 15 to 60 per cent.; and it is evident that any * Trans., vii., 308. in i: DAURIA AIR-00MPRB880R. I L8 improvements increasing the efficiency of these machines mastinterest mining engineers. The present paper calls attention to a nrw form of air-com-pressor, bo extraordinary in character that, had I nt bniltseveral of them and seen them work satisfactorily, I wouldhardly dare to bring it forward as an accomplished mechanicalfact: namely, the dAnria air-compressor, bnilt on the Bameprinciple as the dAnria pumping-engine. This is, as Fig. 1 shows, a non-rotative compressor of the duplex type. So tar as Bteam-economy is concerned, it may be Fio. The DAnria Air-Compressor. said to have less limitations than even a crank and fly-wheelcompressor, for the simple reason that, while in the latter thehigh degree of steam-expansion calls for heavier fly-wheels,heavier crank-shafts, etc., the moving parts in the dAnriacompressor are not in the least affected by the degree of steam-expansion, and the machine works as well with a high as witha low expansion. Figs. 2 and 3 explain themselves. Since there is no mechanism of levers, etc., employed toequalize the propelling force and the resistance at every pointof the stroke (such as is used, for instance, in a Worthingtonhigh-duty pumping-engine), the question arises, how perfectly VOL. XXXI.—8 11 \ THE D AURIA AIR-COMPRESSOR. smooth action is attained in the dAuria compressor, startingat the beginning of the stroke with a high initial pressure ofsteam against no resistance, and ending the stroke with a pro-pel Ling force practically nil, ami resistance at a maximum. This result
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Keywords: ., bo, bookcentury1800, bookdecade1870, booksubjectmineralindustries
