2 Stromeyer, Explosions of Steam Pipes. 



would now be raised in the disused boiler, and, before 

 opening its valve, the attendant would open the drain 

 cock of the pipe to let out the condensed water. Then, 

 as soon as the water-level had sunk below the top of the 

 horizontal pipe, the steam in the vertical pipe would rush 

 into the small channel thus formed, and, having access to 

 the portion of cold water near the valve, condensation 

 would produce a powerful inrush of steam, which would 

 sweep up waves of water as shewn in Fig. i. According 

 to most accounts of such accidents, this commotion is so 

 intense as to shake the steam pipes violently, and in a few 

 seconds they or their valves are shattered. We have here 

 three very complicated problems to consider, the rate of 

 condensation of steam, the wave-making power of the in- 

 rushing steam, and the intensity of the resultant water- 

 hammer. It is only with the last of these problems that 

 I can deal in the present paper, though it is represented 

 by only a small number of steam pipe explosions. 



I magine a single boiler connected to a pipe, as in Fig. 2, 

 leading to an engine (in this case a steam hammer) ; 

 imagine water to be collected in the steam pipe near the 

 boiler, and that the engine valve is partially open ; then, 

 on opening the boiler stop-valve, the plug of water in the 

 pipe near the boiler will be shot along the pipe to the 

 engine, and either smash the valve or close it and smash 

 the pipe or valve chest. This action would also take 

 place if all the valves and pipe joints were so tight that a 

 vacuum existed above the water pocket. Then, again. 



