METHODS TO CYLINDRICAL RETURN TUBULAR BOILERS. 171 



Allowing a water space of 9 inches at the back of the combustion chamber 

 and 3 inches for the total thickness of heads, and combustion chamber back and 

 tube sheets, the length of the tubes between sheets will be 7 feet 3 inches. 



The weight of water obtained from Plate 64 will be 20.6 long tons. 



The above results may now be compared with the results actually obtained in 

 the design illustrated by Plate 67, which results were calculated. 



Estimated. Actual. 



Diameter 15' o" 15' o" 



Length 11' o" 11' o" 



Diameter of furnaces 311" 3' n" 



Number of tubes 320 327 



Eff . length of tubes 73" / 3 " 



Heating surface 2,220 2,288 



Grate surface 67.5 67.5 



Area through tubes 1,890 1,962 



Depth of combustion chamber 2' 9" 2' 9" 



Weight of boiler 102.500 lbs. 



Weight of water 23.2 tons 



It will be seen that the design in Plate 6"/ closely approximates the desired char- 

 acteristics and that specifications can be quickly prepared by this method. 



DISCUSSION. 



The President : — Mr. Meyer's paper, "The Application of Standardization and Graph- 

 ical Methods to the Design of Cylindrical Boilers," so ably presented by the author, is now 

 before you. Is there any discussion on the paper? 



Mr. E. a. Stevens, Jr., Member: — Mr. Meyer should be congratulated on devoting the 

 time and attention to turning out a series of charts such as he shows in this paper. More than 

 once the boilers of a ship have been ruined by trying to crowd in too much heating surface, 

 due to lack of proper information as to the size required, to obtain the required heating sur- 

 face. Many boilers would be in much better condition today if they had had less heating 

 surface. 



There is one question I would like to ask Mr. Meyer which I do not see stated in his 

 paper. What is the pitch of the tubes, and if the pitch is determined according to the diam- 

 eter or by the distance in between the tubes ? This is important not only for proper circula- 

 tion, but for cleaning as well. The curves showing the weight of water and the weight of 

 boilers would also be useful in getting out preliminary calculations for a vessel. 



