referring to fig2 , a conserver of the present invention is shown . the conserver receives pressurized oxygen - rich air from a supply 1 , which could either be a finite capacity supply such as compressed gas bottles , or a limited rate supply such as an oxygen concentrator or other oxygen generating system . both supply types could be available either simultaneously or in rotation . by allowing dual source inputs to the conserver , the invention provides an automated means for backup oxygen based on flow demand from passengers or to automatically switch from a depleted or faulted primary oxygen source to a backup source without interrupting the delivery of oxygen to the pilot and passengers . a concentrator is the preferred approach of the inventors , as electrical power is typically available , and therefore a concentrator needs very little service compared to refilling gas bottles . the utilization of an oxygen conservation system in conjunction with an oxygen concentrator also removes time constraints from the flight duration that might otherwise be present using gas bottles or chemical oxygen generators . an exemplary suitable concentrator is described in referenced u . s . application ser . no . 10 / 192 , 194 . if needed , such a concentrator could be supplemented by gas bottles for circumstances where the rate required exceeds the capacity of the concentrator . in any case , the projected increase in time before re - fill for gas bottles , using the novel conserver , is a factor of six , so the invention provides significant improvement even for the case where bottles only are used . at least two independent ports are advantageous for most general aviation applications , as the pilot &# 39 ; s needs are greater than passengers &# 39 ;, both by law and for safety reasons . thus the conserver will preferably have at least two distribution ports serviced by valves 3 . each valve will preferably have an associated breath sensor 4 . in the example shown , four passenger ports and one pilot port are shown , each with its own valve and sensor . also , by way of example , one controller ( cpu ) 2 is shown which controls valve timing for each valve independently and manages the oxygen supply and distribution for the whole plane . of course , multiple controllers could also be employed . the control of the valve timing determines the bolus volume , and therefore gas usage rate for each port . the oxygen source pressure sensor 5 allows the source of oxygen to be monitored for safety purposes and also for the bolus delivery timing to be adjusted to maintain proper oxygen volume delivery even as the source pressure varies with altitude or as a finite oxygen source is depleted beyond the regulator &# 39 ; s set - point . rate limited oxygen concentrators generally produce oxygen based on a pressure ratio between a high pressure , ph , and a low pressure , pl where , the backpressure in the system changes with altitude , which would make current conserver technologies give unreliable bolus volume doses . the ambient pressure sensor 6 allows adjustment and response to the changing ambient pressure conditions without manual intervention by the flight crew . the ambient pressure sensor may also be used as a trigger for activating the oxygen supply when altitude is reached . alternatively , ambient pressure could be acauired from the aircraft &# 39 ; s instrumentation . a variety of user inputs or pre - programmed modes allow for significant flexibility in how gas is used by each passenger and pilot , thereby allowing for a variety of ways to reduce gas utilization while maintaining safety . the user interface panel ( uip ) 7 enables the conserver to be adapted to suit the number of passengers in a plane and to adjust the amount of oxygen delivered to each patient independently . the uip also functions to notify the flight crew of any errors or alarm conditions detected in the oxygen supply and delivery system . the backup oxygen input system 7 allows the conserver system and cpu to switch over to a backup supply in situations where the primary source is depleted or when the demanded delivery rate exceeds the capacity of the primary oxygen source . in cases of emergency or unexpected changes in altitude this backup system can ensure proper oxygen delivery without flight crew intervention . a . each distribution port on the conserver would enable users to select the appropriate flow setting for their physical condition and flying altitude b . the pilot would select the amount of oxygen required based on flying altitude and physical condition . c . the conserver would then distribute the remaining oxygen to the passengers evenly based on total minute - volume delivery ( assuming a fixed - rate oxygen generating system as the oxygen source ). d . the conserver could deliver the entire production capacity of the supply to the passengers and pilot based solely on the number of active ports . this would ensure maximum delivery of oxygen up to the capacity of the source . e . each position could have a simple ± switch that would refine the delivery amount at a given port to allow for some individualization of oxygen delivery . f . the conserver &# 39 ; s ambient pressure sensor would adjust the dosage rate to the pilot based on the flying altitude . dosing could commence at 12 , 500 feet during daytime hours and 5 , 000 feet during nighttime hours and proportionally increase with altitude to the maximum rate of delivery based on the oxygen source . g . the conserver could alternately have an altitude adjustment setting where the pilot would select the approximate flying altitude and the conserver would deliver a fixed amount based on that setting up to the maximum delivery rate of the oxygen source . h . to ensure oxygen delivery to the pilot and passengers at all times , the oxygen ports could be equipped with adaptive auto - pulse ( see references ) to deliver the correct minute volume of oxygen in the absence of breath detection . the oxygen conserver could alter the delivery of oxygen to maintain delivery to the pilot in preference over the passengers if the conserver &# 39 ; s source pressure sensor detected a drop in the source pressure other modes of operation may suggest themselves to one skilled in the art given the flexibility of the novel conserver . a visual confirmation that oxygen is being delivered such as an led indicator is advantageous as well . another embodiment of the distributed conserver design could include a number of satellite conservers in communication with a main control unit at the oxygen source . this concept is similar in principle to the communication concepts identified in referenced patent application ser . no . 11 / 274 , 755 however , in an aircraft environment , each seat could have an integrated conserving device with a common supply . with a rate limited supply , each seat conserver would communicate via hardwire or rf communication to the source controller to balance the oxygen demand to the oxygen supply , in order to achieve modes of operation such as described above . in this embodiment , the source unit would provide the cpu functions described above .
the invention is multi - port oxygen conserver design , particularly suited for general aviation applications . the novel conserver provides separate bolus control capability for multiple users from a common oxygen supply . thus a mix of gas usage reduction modes can be employed depending on whether the user is a pilot or passenger , operating altitude , and availability of oxygen , while maintaining safe operation .