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108 BiG: 5. tachometer, and the vacuum adjusted to exactly 22.78 in. corrected to a_baro- metric pressure of 30 in. The. vacuum was purposely carried abnormally low by bleeding a small quantity of air into - the exhaust pipe. By means of a small valve in the air inlet pipe, the vacuum ! 2p l LD ! 2d dddDII DDD DD Lda ee ee JDIIIIIIIIIID Ulla Ae 1 1 ! N oN aN AN DdDIIIIIIII DD Lila CZZZ4 N NS La Dd A NY N ZZ DIIIIIIIIIIIIDID Dds CD 2 i . after each tri CLL TRE MarRINE REVIEW column 5, divided by the quantity stand- ing against it in column 6, gives the efficiency as it appears in column : TABLE II. Bos , eae = = = in ee Se ee mo og geo Biol Eee sestoane » pe SS, ee. Oe. ee Bee 33 as ails: 28 Boon D 29 On aR ho ae See 3 ae See Soo ee ese Sa 08 As. Be 8A. BH0 a 118. 2,900 388 2.912 3,212 93,771. 98:7 122.3 3,200 388 2,812 4,156 4,197 99.0 132.3. 3,480 388 3,092 4,576 4,623 98.9 142.3 3,791 388 3,403 5,036 5,108 -98.7 152.3 4,100 388 3,712 5,486 5,567 98.5 162.3 4,400 388 4,012 5,927 6,057 98.7 In spite of the fact that the greatest precautions were taken to insure ac- curacy, the readings being checked by several observers, and the gages and scales being standardized before and Hone Would" "feel some hesitation in vouching for these effici- encies if there were no way of checking them. Fortunately, a satisfactory check is available. The gear is lubricated by circulating a copious supply of oil under a head of. about 10 lIbs., through the bearings, and lL VVVIVVVVVVIVVVYY PA Gf bab DVVYVVIVIVVIVVVV VY Whe yyy A PVVVVVYVY ry y VAN Tea oN ee Y N NN REN Pie bad SPP. yy Q N ee 'yyy N NY NY» iS Hic: 6: could be quickly and accurately adjusted to the arbitrary standard without its be- ing necessary to make any change in the speed of the air pump or the quan- tity of the circulating water. The gear and pinion having respect- ively 176 and 35 teeth, the speed of the driven shaft would be 2983 R. P. M:. The horsepower constant of the dynamo- meter is, as stated above, 0.0049612. In Table II, column 1, are the ob- served absolute inlet pressures corres- ponding to the different loads transmit- ted through the gear as set down in colimn 5. In column 6 are given the horsepowers of the turbine alone cor- responding to the same inlet pressures, as determined from the calibration curve. Obviously, the quantities in col- umn 5 represent the power output of the gear, and those in column 6 rep- resent the power input, The quantity in through a spray which plays continuous- ly on the teeth of the wheels. The transmission loss in the gear therefore appears as heat in the oil. The heated oil coming from the gear is passed through a cooler which is very like a March, 1910. surface condenser with cold water cir- culating through the tubes. By measuring the quantity of oil cir. culated and noting the rise in tempera- ture in passing through the gear, a close approximation of the number of British Thermal Units lost per ae! in vai is obtainable. Atoa doad: ot 5088. -H. P: detiveteat by the gear, 591 lbs. of oil were circul- ated per minute, with an average rise in temperature of 9.86 degrees Fahr. The specific heat of this oil is 0.47, and con- sequently the total heat absorbed per hour is 591 X 0.47 X 60=.164,208 B. T. J, As 2045 "Be TI. "Ul per hour' is the equivalent of a horsepower, the total. heat accounted for in the oil is 164,208 = 64.17 B. H. P. 2,545 © The brake horsepower being 5,088, and 64.17 horsepower being accounted for by the heat in the oil, the efficiency by this method of calculation would be 5,088 5,088 + 64.17 This figure is probably a little too high, as there is an indeterminate small quantity of heat radiated from the gear casing and from the oil piping that has not been accounted for. Even if this were 20 per cent of that accounted for, which is most improbable, the efficiency indicated would still be 98.5 per cent. The gear having thus demonstrated the soundness of the judgment of its designers in all respects except as ex- perience is to be gained by more ex- tended actual service at sea, Mr. West- -- inghouse has designed a turbine especial- ly for marine use in connection with the Melville and Macalpine reduction gear, and a half-tone view of the com- plete unit is presented herewith. Fig. 10. The illustration shows a. design for a 600-H. P. unit which will weigh about YO000 ibs; or 15° Ibs. per H.*P. de larger units the weight will be reduced to approximately 12 lbs. per H. P. Mr. Westinghouse says in reference to» this design: = 98.75 per cent. SS -- Lyf it Y LW Lf SS Yy WN Y Yj SVK RQ X49 \---- pf Y J 4 Y yy, WM ffs "fp A Yep