Английский для сварщиков. Гричин С.В. - 73 стр.

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73
determine the amount of oxygen in a compressed gas cylinder by reading the
volume scale on the high-pressure gauge attached to the regulator.
Regulators
You must be able to reduce the high-pressure gas in a cylinder to a
working pressure before you can use it. This pressure reduction is done by a
regulator or reducing valve. The one basic job of all regulators is to take the
high-pressure gas from the cylinder and reduce it to a level that can be safely
used. Not only do they control the pressure but they also control the flow
(volume of gas per hour).
Regulators come in all sizes and types. Some are designed for high-
pressure oxygen cylinders (2,200 psig), while others are designed for low-
pressure gases, such as natural gas (5 psig). Some gases like nitrous oxide or
carbon dioxide freeze when their pressure is reduced so they require
electrically heated regulators.
Most regulators have two gauges: one indicates the cylinder pressure
when the valve is opened and the other indicates the pressure of the gas
coming out of the regulator. You must open the regulator before you get a
reading on the second gauge. This is the delivery pressure of the gas, and you
must set the pressure that you need for your particular job.
The pressures that you read on regulator gauges is called gauge
pressure. If you are using pounds per square inch, it should be written as psig
(this acronym means pounds per square inch gauge). When the gauge on a
cylinder reads zero, this does not mean that the cylinder is empty. In
actuality, the cylinder is still full of gas, but the pressure is equal to the
surrounding atmospheric pressure. Remember: no gas cylinder is empty
unless it has been pumped out by a vacuum pump.
There are two types of regulators that control the flow of gas from a
cylinder. These are either single-stage or double-stage regulators.
Single-Stage Regulators
Regulators are used on both high- and
low-pressure systems. Figure at left shows two
SINGLE-STAGE regulators: one for acetylene
and one for oxygen. The regulator mechanism
consists of a nozzle through which the gases
pass, a valve seat to close off the nozzle, a
diaphragm, and balancing springs. These
mechanisms are all enclosed in a suitable
housing. Fuel-gas regulators and oxygen
regulators are basically the same design. The
Single stage regulators

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