48 ANNUAL OF SCIENTIFIC DISCOVERY. 



ON THE EMPLOYMENT OF SAL AMMONIAC TO PREVENT INCRUS- 

 TATIONS IN STEAB1-BOILERS. 



The employment of sal ammoniac to prevent incrustations in steam- 

 boilers, to remove them when formed, has formed the subject of a series 

 of experiments undertaken by M. Conrad, Director of the corps of 

 engineers, Holland. In his report, he says : The experiments which have 

 been tried on locomotives on the Holland railways, have demonstrated 

 that it is an excellent means to detach and dissolve the calcareous incrus- 

 tations of boilers, and dispose of them so far that the boilers may be com- 

 pletely rid of them. To prove this, there was introduced 60 grammes (a 

 Trench gramme is the one-thousandth part of a kilogramme, or 2.2 

 pounds) of sal ammoniac in powder into a boiler, immediately after being 

 filled with water. This was left until the evening of the next day, after 

 the locomotive had done its service. Tfhe boiler being found not dirty, it 

 was run still another day, at the end of which it was emptied, and the 

 boiler appeared perfectly clean. The water taken out was generally, in 

 proportion to the calcareous matters containe-d in the boiler, a solution 

 more or less saturated with sal ammoniac and lime, which amounted to 

 one eight-hundredth the weight of the solution. Later, there were formed 

 paillettes of lime, which easily passed off by the discharge-cocks. After- 

 the boiler had thus been, during fifteen days or a month, purged of incrus- 

 tations, it sufficed to introduce once or twice per week, 60 grammes of the 

 salt, to keep it entirely clean. A more attentive examination showed that 

 the water, after one or two days of service, did not give a single trace of 

 iron or copper in solution. 



It is certain, then, that the quantity of salt indicated cannot in the 

 least shorten the duration of the boiler ; but, on the contrary, may aug- 

 ment that of the fire-box and tubes, by preventing destructive incrusta- 

 tions ; and it also decreases the quantity of combustion, as the incrusta- 

 tions are very bad conductors of heat. Again, the decreased quantity of 

 fuel used tends of course to make the boiler last longer. It is probable 

 that the sal ammoniac, in combining with the lime, forms chlorhydrate of 

 lime, and that by this combination the ammonia is set free ; at least, this 

 is what is conjectured by the odor of the steam. 



Rejjort of If. C. Scheffer. " At the commencement of the year 1847, 

 experiments were undertaken on the steam-boiler at the royal saw-manu- 

 factory of Rotterdam with sal ammoniac, to ascertain to what point they 

 could succeed by this means to prevent the injurious effects of incrusta- 

 tions on the sides of this boiler. This boiler is low-pressure, the tension 

 of the steam being scarcely one-tenth of an atmosphere above the ordinary 

 atmospheric pressure, and puts in movement a machine of sixteen-horse 

 power, of Maudslay's. The water employed is that of the Meuse, which 

 according to the analysis of M. Muller, contains much calcareous matter. 

 From the 26th March there were introduced, three times a week, 100 



