PRODUCTION OF SULPHURIC ACID. yi 
Blau * proposed to cool the gases in the first chamber by injecting a 
spray of cold sulphuric acid, and in order to 8Sbtain the optimum 
yield of acid from the gases in the subsequent chamber their tempera- 
ture is raised by injecting sprays of warm sulphuric acid. 
Falding’s process? has for its object the segregating of the active 
gases In a system. To accomplish this he employs a chamber the 
height of which is approximately one and one-half times greater 
than its horizontal dimensions. The burned gases after passing 
through the Glover tower in the usual way are introduced either 
near the top or lower down on the chamber’s side. Since the fresh 
gases are hot, not only because they have recently issued from the 
pyrites burners but because of the reactions taking place between 
some of the constituents, they collect in the upper part of the chamber 
in a relatively active layer. 
As the reactions subside the spent gases gradually cool and settle 
to the bottom of the chamber, where they are withdrawn. Falding 
claims that by using the high chamber a zone of great chemical 
activity is always maintained in the upper part of the chamber, 
and that the spent or inactive gases, which in ordinary chamber 
systems acf as diluents, are continually bemg removed from the 
active zone. It is also claimed that much less chamber space is 
required to complete the reactions by this process, so that even 
where large volumes of gases are handled each chamber is a unit in 
itself, bemg connected directly with the Glover tower instead of in 
series as in ordinary chamber systems. 
A number of plants in this country are equipped with chambers 
of this type and it is reported that. the process is commercially suc- 
cessful. | 
The main objections to the Falding system, in the opinion of the 
writer, are, first, that no provision is made for obtaining an intimate 
mixture of the gases other than the prelimimary mixing brought 
about in the Glover tower, and, second, that no adequate means is 
provided for the condensation of the acid mist formed by the re- 
actions. 
The most widely used method of mixing and cooling the reacting 
gases 1s by means of intermediate towers containing plates, tubes, or 
baffles of some acid-resisting material cooled either by water, air, 
or dilute sulphuric acid. A number of different types of towers 
have been designed, but mention is here made of only a few of the 
better-known designs. 
Lunge’s plate tower * consists of a shell of lead either cylindrical 
or angular in form and filled with a series of perforated plates laid 
1 German patent No. 95083. 
2U.S. patent 932771 (1909). 
3 Treatise on Sulphuric Acid, vol. 1, Pt.I, pp. 478-498. 
