nonflammable, but it will support combustion when
activities because the flame is easy to regulate, the
combined with other gases. This means that it aids in
gases may be produced inexpensively, and the
burning, and this burning gives off considerable heat
equipment can be transported easily and safely.
and light. In its free state, oxygen is one of the most
Oxyacetylene Welding Equipment
common elements. The atmosphere is made up of
approximately 21 parts of oxygen and 78 parts of
The equipment used for oxyacetylene welding
nitrogen, with the remainder being rare gases. It is the
consists of a source of oxygen and a source of acetylene
presence of oxygen in the air that causes rusting of
from a portable or stationary outfit. The portable outfit
ferrous metals, the discoloration of copper, and
consists of an oxygen cylinder and an acetylene
corrosion of aluminum. This action is known as
cylinder with attached valves, regulators, gauges, and
oxidation.
hoses (fig. 6-23). This equipment may be temporarily
Oxygen is obtained commercially either by the
secured on the floor or mounted on a two-wheel,
liquid air process or by the electrolytic process. In the
welded, steel truck equipped with a platform that will
liquid air process, air is compressed and cooled to a
support two large size cylinders. The cylinders are
point where the gases become a liquid. As the
secured by chains attached to the truck frame. A metal
temperature of the liquid air is raised, nitrogen in a
toolbox, welded to the frame, provides storage for
gaseous form is given off first, since its boiling point is
torches, tips, gloves, fluxes, goggles, and necessary
lower than that of liquid oxygen. These gases, having
wrenches.
been separated, are further purified and compressed
Stationary equipment is installed where welding
into cylinders for use.
operations are conducted in a fixed location. The
In the electrolytic process, water is broken down
acetylene and oxygen are piped to several welding
into hydrogen and oxygen by the passage of an electric
stations from a central supply. Master regulators are
current through it. The oxygen collects at the positive
used to control the flow of gas and maintain a constant
terminal and the hydrogen at the negative terminal.
pressure at each station.
Each of the gases is then collected and compressed into
OXYGEN.--Oxygen is a colorless, tasteless,
cylinders for use.
odorless gas that is slightly heavier than air. Oxygen is
OXYGEN CYLINDERS.--A typical oxygen
cylinder (fig. 6-24) is made of steel and has a capacity
Figure 6-23.--Portable oxyacetylene welding and cutting
Figure 6-24.--Typical oxygen cylinder.
equipment.
6-18
