An oxygen concentrator is a medical device that takes in room air and delivers oxygen-rich gas to a patient through tubing and a nasal cannula or mask. It matters because many patients with lung or heart conditions need extra oxygen to keep blood oxygen levels in a safe range. Unlike an oxygen tank, a concentrator does not store a large supply of oxygen under high pressure.
It continuously separates oxygen from the surrounding air while plugged into power.
Key Facts
- Room air is about 78% nitrogen, 21% oxygen, and 1% other gases.
- Oxygen concentrators commonly deliver gas that is about 90% to 95% oxygen at the outlet.
- Pressure swing adsorption uses zeolite sieve beds to trap nitrogen at high pressure and release it at low pressure.
- Flow rate is often measured in liters per minute, written as L/min.
- Volume delivered = flow rate × time, so V = Q × t.
- Oxygen purity can drop if the flow setting is higher than the device is designed to provide.
Vocabulary
- Oxygen concentrator
- A medical device that separates oxygen from room air and delivers oxygen-rich gas to a patient.
- Molecular sieve
- A material with tiny pores that can selectively hold certain gas molecules, such as nitrogen.
- Zeolite
- A porous mineral commonly used in oxygen concentrators because it adsorbs nitrogen under pressure.
- Pressure swing adsorption
- A gas separation method that traps nitrogen at high pressure and releases it when pressure is lowered.
- Flow meter
- A gauge or control that shows and adjusts how many liters of gas leave the concentrator each minute.
Common Mistakes to Avoid
- Thinking the device creates oxygen atoms, which is wrong because it separates existing oxygen molecules from air rather than producing oxygen chemically.
- Setting the flow rate higher than prescribed, which is wrong because the patient may not receive the intended oxygen concentration and the device may alarm or work poorly.
- Blocking or skipping the intake filter, which is wrong because dust can reduce airflow, damage the compressor, and lower performance.
- Assuming concentrators work without electricity like oxygen cylinders, which is wrong because the compressor, valves, and sensors need power to separate gases.
Practice Questions
- 1 A concentrator is set to 2 L/min. How many liters of oxygen-rich gas are delivered in 45 minutes?
- 2 A device takes in room air that is 21% oxygen. If it processes 100 L of room air, about how many liters of oxygen are present in that air before separation?
- 3 Explain why an oxygen concentrator uses two molecular sieve beds instead of one continuous bed.