COPD Oxygen Therapy Systems: Container/Storage & Delivery Systems
Stationary Systems continued...
These units must be placed in an open, ventilated area. They must be kept away from heat and flames. Concentrators need routine maintenance. They need inspections, filter changes and oxygen analysis. Some of the newer models provide an oxygen concentration gauge. This measures the oxygen level delivered by the concentrator. It sounds an alarm if the reading falls below a certain level.
Another stationary system is a reservoir for liquid oxygen. Liquid oxygen is gas condensed into a liquid state by extreme cold. Liquid systems have a large reservoir tank. This tank is filled by the oxygen supplier once or twice a month. These systems require no electricity. They have very few moving parts. They require little maintenance or repair. When dealing with liquid oxygen, caution must be exercised to prevent spills. Liquid oxygen is very cold. It can injure the skin instantly upon contact.
A typical liquid oxygen reservoir weighs 124 pounds when filled. It contains 31 liters, or 73 pounds, of liquid. This amount of liquid oxygen is the same as 24,950 liters of oxygen in the gas form. At a flow rate of two liters per minute, this amount of oxygen would last 208 hours, or eight days. Liquid systems constantly lose oxygen through evaporation, even when not in use. So they are suitable for regular use at home, or for filling up portable units. They are not suitable as an emergency back-up system. Newer units are now available that reduce the amount of oxygen lost into the air. These new systems also have improvements in size and stability. Many of these systems have built-in pulsed delivery or conserving devices.
Compressed gas oxygen in large tanks or cylinders is another example of a stationary system.
Large steel or aluminum tanks are heavy. They cannot be moved easily. They must be safely secured to prevent them from falling over. They are not appropriate for someone who requires continuous flow oxygen. This is because of the volume required to meet a continuous need and the high cost.
This system is better suited as a back-up system for a concentrator.