Talk:Oxygen concentrator

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[edit] efficiency?

Most concentrators capable of delivering 5 litres per minute are rated at about 400 watts. But what about the new Sequal's that evidently require lower pressure. Unfortunately their specs do not include power consumption although they claim efficiency and fewer moving parts. I am tempted to purchase one just to put it on a power meter. 8-( Anyone have a better source of information? See [1]. --Poodleboy 20:10, 23 April 2006 (UTC)

Have you heard of the Inogen One? This page lists its specs: http://www.inogen.net/products/inogenone/specs.asp I'll see if I can find other manufacturers' specs. Cholerashot 21:23, 14 January 2007 (UTC)

The SeQual Integra 10 LPM EZ uses about 600 Watts to make 10 LPM. Compared to typical 5 LPM concentrators at 400 Watts / 5 liters = 80 Watts per liter, the Integra 10 is 600 W / 10 LPM = 60 Watts per liter. Some of the portables are actually less efficient in terms of power and weight than the larger 5 LPM concentrators. The pulse portable oxygen concentrators (those which have no continuous flow settings) typically make less than 1 liter per minute, but use demand or pulse flow to deliver oxygen only when the patient is inhaling and consume about 75 watts, which works out to 75W / 0.7 LPM = 107 Watts per liter. The SeQual Eclipse makes 3 LPM of continuous flow oxygen using about 150 W, which is 145 W / 3 LPM = 48 Watts per liter. The power efficiency affects a patient's power bill. See [2]

In terms of weight efficiency, the pulse portables are at about 10 pounds / 0.7 LPM = 14.3 pounds per liter compared to stationary 5 LPM concentrators at 50 pounds / 5 LPM = 10 pounds per liter, while the Eclipse is at 18 pounds / 3 LPM = 6 pounds per liter. Actually, since this weight is inclusive of the battery, which is something the other portables have, but the larger 5 LPM and 10 LPM stationary concentrators do not have, the weight without battery may be a more appropriate comparison against stationary concentrators. The Eclipse is 14.7 pounds / 3 liters = 4.9 pounds per liter, about half the weight per liter of stationary concentrators. The weight efficiency reflects the weight of the equipment per liter it delivers. With both weight efficiency and power efficiency, portables might be compared to one another with just the onboard battery, with external batteries included in the weight, or with all carts and accessories considered in the calculation. When comparing portables to stationary concentrators, it is probably appropriate to compare the weight without battery, but with the AC adapter.

Because many of the portables do not have continuous flow capability, it can be difficult to choose the right number for liter flow when calculating either power or weight efficiency. Whenever possible, the continuous flow capability of the machine should be considered, as this relates how much oxygen it actually makes, and the stationary concentrators make continuous flow. The conserving features of the portables make it possible to claim higher liter flows by delivering oxygen only when the patient is inhaling, and the manufacturers may not provide information about the actual liter flow of the machine prior to conserving. See Long Term Oxygen Therapy: Getting Better All the Time

Note that most of the stationary 5 LPM and 10 LPM concentrators consume the same amount of power independent of the oxygen flow setting. If the flow is turned down, the machine uses the same amount of power as it does at the highest setting. The extra oxygen just goes out the purge, rather than to the patient. With the Eclipse, if the flow is turned down, the unit consumes less power. Similarly, if the pulse setting is used, the concentrator may consume less power. These features are used to extend battery life when away from a power source, but also have benefits in the car and at home. At the lower flow settings of 1 LPM continuous flow, for example, the Eclipse uses only 52 Watts, and at a pulse setting of 1, it uses only 44 Watts, about 1/3 of its power consumption at 3 LPM continuous flow. This is 1/8th of the 400 Watts a stationary 5 LPM concentrator uses no matter what oxygen flow it is producing. So, a patient with a concentrator that uses less power at lower flow settings and uses less Watts per liter will have dramatically lower power bill than a patient with a standard concentrator. See [3]

Manufacturers of PSA systems and chemical engineers measure efficiency in two terms, recovery and productivity. Recovery is how much oxygen is obtained from the amount of air pushed into the separation process by the compressor (unitless, expressed as a percent, and higher is better). Productivity is how much oxygen is obtained from the weight of the sieve material in the sieve beds (liters/pound of sieve). The higher the recovery, the smaller the compressor can be for a given system, which will lead to lower power consumption, noise, heat, and weight. The higher the productivity, the smaller the sieve beds can be, which will lead to lower weight. Typical recoveries in most concentrators are about 25%-35%. The Integra 10 is on the order of 42%. The Eclipse is above 60%.

However, users will likely not be as interested in recovery and productivity as they will in the things they can measure, which were discussed above. How many liters can the concentrator deliver divided by how much does it weigh? How many liters can the concentrator deliver divided by how much power does the concentrator consume to make that oxygen? Mscott0 07:05, 10 July 2007 (UTC)