An oxygen concentrator is fundamentally different from an oxygen tank, though both devices deliver supplemental oxygen for medical therapy. Oxygen therapy is prescribed when a person’s blood oxygen levels are low due to a respiratory condition, such as COPD or pulmonary fibrosis. The key difference lies in their mechanism of action: one stores a finite supply of pre-made oxygen, while the other manufactures a continuous supply from the surrounding air. Understanding this distinction is necessary for effective therapy management.
How Oxygen Tanks Deliver Oxygen
An oxygen tank, also called an oxygen cylinder, is a sturdy metal container designed to hold a finite volume of highly pressurized oxygen gas or liquid oxygen. The stored oxygen is of very high purity, typically at least 99%, achieved through processes like cryogenic distillation before bottling. Because the pressure inside the cylinder is extremely high, the tank requires a regulator and a flow meter to control the gas release. Once the oxygen supply is used up, the tank must be physically exchanged for a full one or refilled by a specialized provider. The user’s therapy is limited by this fixed capacity, requiring regular logistical planning.
Liquid oxygen systems, a variation of the tank concept, store oxygen cooled to a cryogenic temperature of -297°F (-183°C). Storing oxygen as a liquid allows a much larger volume of gas to be contained in a smaller space; one liter of liquid oxygen expands to approximately 860 liters of gaseous oxygen. This liquid oxygen still represents a finite supply that must be replenished from a stationary reservoir or supplier.
How Oxygen Concentrators Produce Oxygen
An oxygen concentrator does not store oxygen but produces it on demand by filtering the surrounding ambient air, which is composed of 78% nitrogen and 21% oxygen. The concentrator draws in this air and uses Pressure Swing Adsorption (PSA) technology to separate the gases. A compressor forces air into cylinders filled with zeolite, a molecular sieve that preferentially traps nitrogen molecules under high pressure. The remaining gas, now highly concentrated oxygen (typically 87% to 95%), is collected and delivered to the user. The process repeats in a second cylinder to ensure continuous flow, making the supply essentially unlimited as long as the machine has an operating power source.
Practical Differences in Operation and Logistics
The operational differences between the two devices create distinct logistical considerations for the user. An oxygen tank is a passive system that requires no electrical power, making it useful during power outages or when electricity is unavailable. Conversely, an oxygen concentrator is an active device that relies completely on an electrical outlet or charged battery to run its compressor. The pre-filled tank provides higher purity (99%), while the concentrator delivers medical-grade purity ranging from 87% to 95%.
The supply mechanism also dictates maintenance needs. Oxygen tanks require the recurring expense of refilling or exchanging cylinders when exhausted. Concentrators eliminate the need for refills but require regular maintenance, such as cleaning air filters and eventually replacing the internal sieve beds.
Portability varies significantly between the two options. Tanks are generally heavier for equivalent oxygen duration, and the high-pressure gas poses a greater fire risk if a leak occurs. Portable oxygen concentrators, while requiring a battery, are often preferred for travel because they are lighter and can produce oxygen indefinitely with access to charging.
Determining Which Device Is Appropriate
The decision between an oxygen tank and a concentrator is guided by clinical needs and the patient’s lifestyle. A patient’s prescribed oxygen flow rate is a primary consideration, as high-flow requirements may be better met by the immediate, high-purity supply of a tank. If the patient requires oxygen only intermittently or for short bursts of activity, a small, lightweight tank may be the most straightforward solution. Concentrators are typically the preferred choice for long-term, continuous oxygen therapy, especially for homebound patients.
The continuous supply of a concentrator eliminates the concern of running out of oxygen, which is a major advantage for patients requiring oxygen around the clock. For active individuals who travel frequently, a portable concentrator with battery power is often more practical, provided the user has access to charging.
Planning for contingencies is important, as the reliance of concentrators on power means a backup plan is necessary. Many patients who use a concentrator at home keep a small oxygen tank on hand to ensure a supply during electrical outages. Consulting with a healthcare provider is necessary to match the device’s capabilities with the patient’s medical prescription and daily living needs.