726
MODERN GASWORKS PRACTICE
the vessel is operated and maintained, whilst temperature is a factor of considerable importance. The main consideration to Tbear in mind is that the heat must be sufficient to crack up the oil into vapours which. will as far as possible be retained as permanent gases, but it must not be so great as to cause such degradation as gives rise to over-cracking and the deposition cf free carbon. Frequently, it.is stated that a desirable working temperature for both carburettor and superheater is 930 C., or thereabouts. The author finds, however, that for high results in the direction of “ candles per gallon. ” the American oil as now almost universally used is preferably decomposed at lower temperatures. Moreover, it will be found advantageous to work
Tig. 450.—Gbnebatok fitted with Automatic Clinkerimg Device.
the superheater at slightly higher temperatures than the carburettor. The temperatures suggested when. under normal working conditions are :—
Carburettor . • . • * . . • bctwccn /00 cind 760 C«,
Superheater »■ 760° and 800 C.
This, however, must not be considered as a hard-and-fast rule, for very inucli depends upon the quantity of oil being injected during the “ run.” For instan.ee, if a poorer quality gas is being manufactured, and only ab out lialf the normal quan-tity of oil is in use, the temperature must be regulated in accordance. Another