242 ENGINE TESTS. 



Engine No. 60 is a vertical triple expansion pumping-engine 

 with jacketed cylinders and two reheaters. Only the barrels 

 of the cylinders are jacketed, the heads being unjacketed, ex- 

 cept so far as the valve chests, which are located in the heads, 

 furnish a substitute. The jacket of the low-pressure cylinder 

 is supplied with steam at a reduced pressure. The remaining 

 jackets and the reheaters are supplied with boiler steam. The 

 engine is furnished with steam from horizontal return tubular 

 boilers, and at a point near the throttle valve the percentage of 

 moisture was found to be .3 r / . There was no undue leakage 

 of the valves and pistons, but they were not in a perfectly tight 

 condition. The load of each cylinder is that of a direct-acting 

 pump, the diameter of each plunger being 36, " and the total 

 head, expressed in pounds, 53.4 Ibs. per square inch. The 

 jackets consumed 955 Ibs. of steam per hour, which is 12.7 % of 

 total used by the engine ; and this is included in the quantities 

 given in the tables. When the engine was at rest, the jackets 

 consumed 163.5 Ibs. per hour, being the loss due to radiation. 



The analysis of the diagrams in this test shows a remarkably 

 close agreement between the steam accounted for by the indi- 

 cator in the various cylinders. There is a variation of less than 

 1 % between the quantities shown at the cut-off in the three 

 cylinders, and a similarly close agreement in the three quanti- 

 ties shown at the release. 



