GENERATOR CONSTRUCTION

The water for generating purposes is carried in the large tank-like
compartment directly below the carbide chamber. See Figure 11. This water
compartment is filled through a pipe of such a height that the water level
cannot be brought above the proper point or else the water compartment is
provided with a drain connection which accomplishes this same result by
allowing an excess to flow away.

The quantity of water depends on the capacity of the generator inasmuch as
there must be one gallon for each pound of carbide required. The generator
should be of sufficient capacity to furnish gas under working conditions
from one charge of carbide to all torches installed for at least five hours
continuous use.

After calculating the withdrawal of the whole number of torches according
to the work they are to do for this period of five hours the proper
generator capacity may be found on the basis of one cubic foot of gas per
hour for each pound of carbide. Thus if the torches were to use sixty cubic
feet of gas per hour, five hours would call for three hundred cubic feet
and a three hundred pound generator should be installed. Generators are
rated according to their carbide capacity in pounds.

_Charging._--The carbide capacity of the generator should be great
enough to furnish a continuous supply of gas for the maximum operating
time, basing the quantity of gas generated on four and one-half cubic feet
from each pound of lump carbide and on four cubic feet from each pound of
quarter, intermediate sizes being in proportion.