It
should be observed that in the diagrams B^1 and B^3, the amount of
pressure, and the consequent alteration in level, is grossly exaggerated
to gain clearness; one inch or less in both cases may be sufficient to
start or retard evolution of acetylene. Fig. B^3 is somewhat ideal, but
indicates the principle of opposing gas pressure to a supply of water
depending upon gravitation; a method often adopted in the construction of
portable acetylene apparatus. The arrangement consists of an upper tank
containing water open to the air, and a lower vessel holding carbide
closed everywhere except at the pipe P, which leads to the burners, and
at the pipe S, which introduces water from the store-tank. If the cock at
T is closed, pressure begins to rise in the carbide holder until it is
sufficient to counterbalance the weight of the column of water in the
pipe S, when a further supply is prevented until the pressure sinks
again. This idea is simply an application of the displacement-holder
principle, and as such is defective (except for vehicular lamps) by
reason of lack of uniformity in pressure.
[Illustration: FIG. 2.--TYPICAL METHODS OF AUTOMATIC GENERATION
CONTROLLED BY INTERNAL GAS PRESSURE.
Pages:
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187