SUPERHEATED STEAM IN MARINE PRACTICE. 197 



In order to ascertain as far as possible the actual saving due to superheat on a moderate 

 scale, we are building at the New York Shipbuilding Company's works, Camden, New 

 Jersey, a collier which is being equipped with two Scotch boilers fitted with my superheat- 

 ing arrangement, which, however, is not in accordance with the author's illustration in the 

 preliminary paper of my superheater, but is in accordance with Plate 93. It is our inten- 

 tion to run a series of tests with the superheater in use, recording all the necessary 

 data, and then to run a series of tests without the superheater in use and record 

 the same data. This will enable us to form an exact comparison that will be indisputable 

 on account of the conditions being the same. In my early type of superheater, as shown by 

 Mr. Oatley, the superheater tubes in the upper part of the boiler were in free connection 

 with the steam space in the upper part of the boiler, and, realizing that this would not prove 

 effective, I designed the superheater referred to previously, and, as shown on my latest plan, 

 in order to overcome this possible defect. It will be noticed that my last form of super- 

 heater utilizes the two outer rows of tubes as drying tubes, in order to absorb any moisture 

 that might exist in the steam prior to entering the superheater tubes proper. Any moisture 

 that has collected in the drying tube chamber finds its way through a pipe down to the water 

 spaces below, and the dry steam then passes over the superheating tubes in counter current 

 to the flow of the gases over and under the baffles shown in the central group of tubes only. 



I have not attempted to obtain a high degree of superheat on the boilers we are build- 

 ing, and it has been a very difficult matter to interest the average engineer in any degree of 

 superheat up to the present time, and, while I strongly favor a high degree of superheat, I 

 have designed the present boilers with a view to giving absolutely dry or a slight degree of 

 superheat, not more than 50°. I have endeavored to make the apparatus as nearly fool- 

 proof as it possibly could be, and therefore have made the tubes from the combustion cham- 

 ber into the uptake about the same size as the stay bolts. They have holes of y& inch in 

 diameter, in order to reduce the temperature of the gases from about 2,500 down to 1,000°, 

 with the damper full open. It would have been possible to have kept the same sized tubes in 

 the back of the combustion chamber as the regular tubes and then to have operated the 

 damper when regulating the temperature of the gases, but, of course, there would have been 

 the possibility of having the damper open too far and therefore the temperature too high. 

 In the upper part of the boiler I have used tubes of ^ inch thickness and expanded the ends 

 into recesses in the heads of % inch wide by 1/16 inch deep and beaded the same over at 

 the ends, thus forming a very good head stay. I had also considered using spirally corrugated 

 steel tubes for this purpose, together with the usual head stays, in order to avoid any adverse 

 comment in regard to the possible trouble due to the difference in expansion between these 

 tubes and the shell, but, after considering the expansion and contraction of the regular 

 tubes in all boilers, I felt convinced that the work on the tubes of my superheater would be 

 no more severe than is encountered in every-day practice with said regular boiler tubes. 



Mr. Ernest H. B. Anderson, Member: — Mr. Chairman and gentlemen, it has not 

 been generally recognized in this country that the regular impulse reaction Parsons turbine 

 is suitable for superheat. The impression has been that the drum construction of turbine 

 does not permit of the use of a very high superheat. This is not so, provided that the turbine 

 is designed to use superheated steam. The reason it has not been adopted more than it has in 

 marine work has been largely due to the superheaters. One never knew whether the degree 

 of superheat would be limited — it might be 100 degrees or it might be 200 degrees, and that 



