ENGINE No. 38. 153 



Engine No. 38 is a horizontal cross compound. The cylin- 

 ders are steam-jacketed, and the intermediate receiver, which is 

 a chamber 30" in diameter and 8' high, is also jacketed. The 

 arrangement of the jacket-piping is such that the drain pipe of 

 the high-pressure jacket supplies the low-pressure jacket, and 

 the drain pipe of this supplies the receiver jacket, and ^their 

 sizes are so proportioned that there is a continual reduction of 

 pressure from one point to the next, and consequently a con- 

 tinuous circulation. The engine is fitted with a jet condenser 

 operated by a direct connected air-pump. Steam is furnished 

 by horizontal return tubular boilers located at a distance of 

 some 200 feet. The water of condensation which collects in 

 the steam pipe is carried back to a feed tank in the boiler-room, 

 and steam used by the feed pump exhausts into the same tank. 

 There was some leakage of joints in the steam piping which 

 has not been allowed for. The valves and pistons of the high- 

 pressure cylinder were practically tight. The valves of the 

 low-pressure cylinder were tight, but the piston contained a 

 loosely fitting packing ring and leaked very badly. The load 

 consisted of cordage machinery. 



The interest in this test centers upon the effect which was 

 produced by excessive leakage through the low-pressure piston. 

 In a well jacketed engine the steam accounted for by the indi- 

 cator is nearly as great in the low-pressure cylinder as in the 

 high pressure cylinder. In this case there is a reduction from 

 .675 to .435, or 24% of the total weight of steam consumed, 

 and this is evidently due to the leakage referred to. 



