Storage
Pure oxygen is stored in high-pressure, alloy steel cylinders. The gas is compressed under pressures as high as 2,200 pounds per square inch (psi). Oxygen cylinders are needed for operating certain medical equipment when a centralized hospital oxygen supply is not available, and for portable oxy-acetylene welding systems.
Regulating the Pressure
Inside a regulator, attached to the outlet of a high-pressure oxygen cylinder, the outflow passage is covered by a spring-loaded diaphragm which presses against the outlet with a force that balances the gas pressure. This prevents gas from escaping the system.
Regulating the Escape
A hand-screw can be turned to apply pressure against the spring-loaded diaphragm so that it is pushed away from the gas outlet of the cylinder. This allows oxygen to escape from the cylinder.
Fine-Tuning the Flow
The threads of the hand-screw are very fine, so a slight turn of the screw causes a very small movement of the diaphragm. This fine control allows small and precise regulation in the flow rate of escaping oxygen.
Two-stage Regulators
When the pressure in a cylinder falls as the gas is used, the lower pressure produces lower flows. Adding a second regulator downstream from the first maintains a consistent flow from the lower pressure source.
Applications
Patients using oxygen must receive precise doses of as little as 1/2 to 1 liter per minute (LPM) to meet very specific physiological needs.
Welders need a closely regulated flow of oxygen to mix with acetylene so they can control temperatures between 4,000 and 6,000 degrees F. Raising the oxygen content of the welding gas raises the temperature.
Safety
The North American Compressed Gas Association, a non-governmental authority, establishes safe practices for all compressed gases and their uses, creating consistency, predictability and reliability for oxygen regulators, as well as regulators for all other compressed gases.
