. Railway mechanical engineer . Elasticity and Hardnessof Rubber completely ejected upon unlocking it by raising the knob. Theextent of its ejection is shown on the scale of the instrument inper cent of the total penetration. The extent of the recovery ofthe material thus indicated corresponds to the percentage of elas-ticity as measured by the older form of stretch test. The newtest has the advantage of being applicable to the plane surfacesof finished articles and leaves practically no visible mark. These instruments are principally for the use of manufacturersof rubber to aid in economic pr
. Railway mechanical engineer . Elasticity and Hardnessof Rubber completely ejected upon unlocking it by raising the knob. Theextent of its ejection is shown on the scale of the instrument inper cent of the total penetration. The extent of the recovery ofthe material thus indicated corresponds to the percentage of elas-ticity as measured by the older form of stretch test. The newtest has the advantage of being applicable to the plane surfacesof finished articles and leaves practically no visible mark. These instruments are principally for the use of manufacturersof rubber to aid in economic production and the buyers of rubbergoods in formulating purchase specifications and inspecting goods,as well as for research work. HIGH SPEED BLOWER AND CENTRIFUGALAIR COMPRESSOR .Among the obvious faults of the usual type i_>i paddle-wheelfan or blower is the shock with which the air is received by theimpeller blades, the abrupt turns and sudden changes in cross-section of the passages through -ivbicb the air flows. The sup-. Two Single Stage ■G Direct-Connected toStage Turbine De Laval Velocity- ports for the floats or vanes obstruct the flow of the air, and theamount of surface in contact with the air moving at high veloci-ties is large, resulting in considerable loss by skin friction. The hM. 101- R/MLWAY AGE GAZETTK, MIICI lANICAL IDITION 375 crtkicncy is luvv iiiid Ihc action iKiisy, and as ordinarily Ijiiilt, thefan is bulky, dnc to the slow speeds required because (jl struc-tnral weakness and lack of balance. The so-called multi-bladefans, which to some extent have replaced the paddle-wlieel fan,run at slill slower speeds for the same pressures and type of fan is suited f(]r direct connection to the modernlii,i,ii-s|Ked rotative prime movers, such as the steam turbine and
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectrailroadengineering
