P OL YTECHNIC A SSOCIA TION Pr CEEDINGS. 7 1 9 



trifling expeuse of time or money; and such want of care, which is 

 the cause in other boilers of so many explosions, with loss of life 

 and property, in this boiler cannot cause the least damage. 



The strong circulation prevents sediment from adhering to the 

 inside of the tubes, unless allowed to accumulate from carelessness, 

 ■while the inclination at which they are set causes all sediment to 

 descend into the water cross-pipe, or mud-di*um, where the water 

 is at rest, and beyond the contact of the fire, and to remain there 

 until blown out as du'ccted. 



If the blowing ofl" is attended to as often as the impurity of the 

 water demands, the operation of this boiler, as far as sediment is 

 concerned, is perfect. 



If, through inattention, there should be an accumulation of scale, 

 by the use of solvents, in the form of molasses, sugar, petroleum, 

 or other forms, it can be loosened or blown off; or by removing 

 the return bends at each end of the tubes, access is given to the 

 inside of each tube for the removal of any deposit it may contain. 



The water cross-pipe, or mud-drum, is easily detached, or can be 

 cleaned through the ends by removing the heads. 



If any tube should be damaged, it can be taken out and replaced 

 by another, in an hour, without disturbing any other part. 



It is well known that neglect of proper cleaning, in boilers with 

 large shells, is the cause, in many cases, of disastrous explosions. 

 On the Mississippi river, where the safest form of the old style 

 boiler are used (cylinder and flue), the explosions have been fear- 

 fully frequent, and are well known to be caused, almost entirely, by 

 the great amount of mud and sediment contained in the water, and 

 deposited in the boilers, preventing the water from contact with 

 the plates, and causing them to burn out. This damage occurs, to 

 a greater or less extent, in all cases where sediment is allowed to 

 accumulate. 



I claim that in the safety boiler all danger of explosion in such 

 cases is avoided, for the reason that it is impossible to explode a 

 tube such as used, owing to the small volume of steam or water 

 that it contains, in proportion to its strength. It may get red hot, 

 or burn out so that it will leak and require replacing, but it will 

 not explode. 



In a large shell, say four feet in diameter, which is a common 

 size, if it becomes weakened by burning out, or other causes, in 

 any part, the internal surface upon which the pressure of the steam 

 or water is exerted is so great that it is immediately burst open at 



