Once adjusted, the production of flat and round spring wire by
the mile is an exceedingly simple matter. It is quite possible to obtain
absolute precision in temperature by a proper adjustment of the gas
pressure, and as this is, for tempering steel articles and some other
purposes, a matter of great importance, it is worth some consideration.
No pressure regulator alone will give an absolutely steady supply; but
if we put on first a regulator, adjusted to the minimum pressure of
supply, say one inch of water, and then fix another on the same pipe,
adjusted to a slightly lower pressure, say 9/10 of an inch, the first
regulator does the rough adjustment, and the second one will then give
an absolutely steady supply, provided always that the regulators are
both capable of passing more gas than is likely to be ever required. No
regulator can be relied on for absolute precision, if worked up to its
maximum possible capacity.
[Illustration: Fig. 5. ARRANGEMENT FOR HEATING BLANKS FOR STAMPING OR
HARDENING.
Pages:
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157