132 THE SCIENTIFIC PAPERS OP 



In the discussion of the Paper 



"ON RECENT IMPROVEMENTS IN REGENERATIVE 

 HOT BLAST STOVES FOR BLAST FURNACES," 



By EDWARD ALFRED COWPER, M. Inst. C.E., 



MR. C. W. SIEMENS* said, the apparatus described by Mr. 

 Cowper for heating the blast differed from the ordinary hot blast 

 stove in this essential respect, that the same surface of refractory 

 material that absorbed the heat from the products of combustion 

 served also to impart heat to the incoming blast. It was neces- 

 sary, under these circumstances, that there should be two stoves, 

 or air-tight receivers, filled with the refractory materials : the one 

 to give off its heat to the incoming blast on its way to the furnace, 

 and the other to be heated up for continuing the operation when 

 the heat of the first-named stove was exhausted, valves being pro- 

 vided for reversing the currents from time to time, as described 

 in the paper. By these means the same surface of refractory 

 materials was made to take up the heat from the burning gas and 

 to impart it to the blast ; and as a consequence it followed, that 

 the degree of heat that might be imparted to the blast was not 

 limited by the point of safety of the iron tubes composing the 

 ordinary stoves, but was limited only by the point of fusion of the 

 refractory material's composing the regenerator of the new stoves. 

 For heating blast to a moderate degree only, this stove possessed 

 some advantages over the ordinary tube-stove, as the use of re- 

 generators was always attended with a saving of fuel : but when- 

 ever a high degree of heat was desired exceeding 1,000 Fahr., then 

 the tubular stove altogether failed, and the regenerative stove 

 must be used. 



The question of importance connected with this subject was, 

 whether it was desirable to use blast of such very high tempera- 

 ture. Some years ago it was the opinion of practical ironmasters, 

 that the quality of the pig metal produced was deteriorated when 



* Excerpt Minutes of Proceedings of the Institution of Civil Engineers, Vol. 

 XXX. Session 1869-70, pp. 315-317. 



