Abstract:
A method of supplying hypoxic gas includes supplying a hypoxic gas with a hypoxic gas supply at a continuous flow rate; and delivering the hypoxic gas intermittently with a conserving mechanism so that an effective hypoxic gas flow rate at least twice the flow rate from the hypoxic gas supply is realized.

Description:
FIELD OF THE INVENTION  
       [0001]     The field of this invention relates to hypoxic gas stream systems and methods.  
       BACKGROUND OF THE INVENTION  
       [0002]     When a person is exposed to a higher altitude or reduced oxygen environment for longer periods, the person acclimatizes to the higher altitude or reduced oxygen environment. The physiological effects of altitude acclimatization produce an increase in the oxygen carrying capacity of the blood and the body&#39;s ability to use the oxygen transported resulting in a major difference in the body&#39;s ability to perform work both at altitude and at sea level. The net result of such changes is an improvement in athletic performance.  
         [0003]     There have been various attempts at providing systems for simulating a different altitude from the altitude that a person resides in order to presumably address the debilitating effects of increased altitude, and/or to obtain some of the advantages of purposely simulating different altitudes for, e.g., athletic training or treatment of a medical condition.  
         [0004]     For example, hypoxic rooms or tents have been provided at low altitudes to provide benefits, e.g., the training of athletes, the treating or preventing of altitude sickness as well as other altitude or altitude change related conditions or for the purposes of inducing weight loss. In such systems, a hypoxic gas stream including an oxygen concentration less than atmospheric air is provided to a person in the hypoxic room or tent. As a result, the person is exposed to an atmosphere that simulates an altitude different than the altitude that a person resides in order to obtain some advantage or address some potential problem related to a change in altitude.  
         [0005]     A problem recognized by the inventor for hypoxic room or tent systems is that they use a continuous flow of hypoxic gas. As a result the hypoxic gas stream supply is large and heavy, making it difficult and cumbersome for portable and widespread use. The inventor has recognized that by combining a conserving mechanism with an efficient hypoxic gas stream supply the advantages of hypoxic gas use can be more readily achieved by more individuals.  
       SUMMARY OF THE INVENTION  
       [0006]     To solve these problems and others, an aspect of present invention relates to use of a conserving system for hypoxic gas streams. A conserving system multiplies the apparent gas flow from the hypoxic gas stream source by delivering the hypoxic gas in intervals. The conserving system detects the onset of inhalation and delivers the hypoxic gas when a triggering condition is met. By delivering a flow of gas to the user only during the time when it is useful, i.e., during or near the time the user is inhaling, the apparent flow of hypoxic gas mixtures can be multiplied. This enables the use of a smaller hypoxic gas system.  
         [0007]     Another aspect of the invention involves a method of supplying hypoxic gas. The method includes supplying a hypoxic gas with a hypoxic gas supply at a continuous flow rate; and delivering the hypoxic gas intermittently with a conserving mechanism so that an effective hypoxic gas flow rate at least twice the flow rate from the hypoxic gas supply is realized.  
         [0008]     Further implementations of the aspect of the invention described immediately above include one or more of the following: The hypoxic gas supply is a hypoxic separator. The hypoxic gas supply is a pressure swing adsorption (“PSA”) system, and supplying includes supplying purged hypoxic gas from the PSA system to the conserving mechanism. The hypoxic gas supply is a vacuum pressure swing adsorption (“VPSA”) system, and supplying includes transferring purged hypoxic gas from the VPSA system to the conserving mechanism under vacuum pressure. The hypoxic gas supply is a ceramic hypoxic gas source. The hypoxic gas supply is a membrane hypoxic gas source. The hypoxic gas supply is a container of compressed hypoxic gas. The conserving mechanism includes a booster compressor and a storage tank, and the method further includes increasing the pressure of the hypoxic gas with the booster, and storing the hypoxic gas in the storage tank for intermittent use of hypoxic gas. The conserving mechanism includes a blower. The conserving mechanism includes an accumulator. The conserving mechanism includes a conserving mask. The conserving mechanism includes a mask. The conserving mechanism includes a cannula. The conserving mechanism provides pulse flow. The conserving mechanism provides demand flow. The conserving mechanism includes means for detecting the inhalation of the user. The means for detecting inhalation is an electronic pressure sensor. The means for detecting inhalation is a mechanical pressure sensor. Delivering includes delivering the hypoxic gas intermittently with a conserving mechanism so that an effective hypoxic gas flow rate at least two times the flow rate from the hypoxic gas supply is realized. The hypoxic gas supply supplies hypoxic gas at less than 15% oxygen by volume. The hypoxic gas supply supplies hypoxic gas at less than 13% oxygen by volume. The hypoxic gas supply supplies hypoxic gas at less than 11% oxygen by volume.  
         [0009]     Further objects and advantages will be apparent to those skilled in the art after a review of the drawings and the detailed description of the preferred embodiments set forth below. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]      FIG. 1  is a simple schematic of an embodiment of a hypoxic gas stream conserving system.  
         [0011]      FIG. 2  is a simple schematic of another embodiment of a hypoxic gas stream conserving system.  
         [0012]      FIG. 3  is a simple schematic of an additional embodiment of a hypoxic gas stream conserving system.  
         [0013]      FIG. 4  is a simple schematic of further embodiment of a hypoxic gas stream conserving system.  
         [0014]      FIG. 5  is a simple schematic of a still further embodiment of a hypoxic gas stream conserving system.  
         [0015]      FIG. 6  is a simple schematic of another embodiment of a hypoxic gas stream conserving system.  
         [0016]      FIG. 7  is graph of pressure versus time of a breathing cycle of a user of a hypoxic gas stream conserving system, and shows various conditions or trigger points for triggering the delivery of a pulse of oxygen. 
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0017]     With reference to  FIG. 1 , an embodiment of a hypoxic gas stream conserving system  10  will be described. The hypoxic gas stream conserving system (“system”)  10  includes a hypoxic gas supply  20  coupled with a conserving mechanism  30 .  
         [0018]     The hypoxic gas supply  20  supplies a continuous hypoxic gas stream to the conserving mechanism  30 . As used herein, a hypoxic gas or gas stream, is gas having an oxygen concentration less than ambient air. The hypoxic gas supply  20  may be one or more of, but not by way of limitation, a hypoxic separator, a concentrator, an oxygen concentrator, a pressure swing adsorption (“PSA”) system, a vacuum pressure swing adsorption (“VPSA”) system, a ceramic hypoxic gas source, a membrane hypoxic gas source, and a container of compressed hypoxic gas. For example, in an embodiment of the system  10  where the hypoxic gas supply  20  is a PSA system, ambient air may be drawn into a compressor and delivered under high pressure to a PSA module. The PSA module separates oxygen from the air, and produces concentrated oxygen as a product gas. Purging of the beds in the PSA module causes a hypoxic gas to be exhausted from the PSA module. This exhausted hypoxic gas is supplied to the conserving mechanism  30 , and delivered to the user or application. In an embodiment of the invention, the PSA module is a rotary valve PSA system or rotary valve VPSA system. Example rotary valve PSA and VPSA systems are shown and described in one or more of U.S. Pat. Nos. 6,651,658; 6,691,702; 6,629,525; 5,114,441; 6,311,719; 6,712,087; 6,457,485; 6,471,744; 5,366,541; Re. 35,099; 5,268,021; 5,593,478; 5,730,778, which are incorporated by reference as though set forth in full.  
         [0019]     The inventor has determined the following: Newer technologies are leading to higher recovery oxygen concentrators. Similarly, other parallel non-PSA/VPSA techniques such as membrane or ceramics have the advantage of possible less air into a separating process for a corresponding oxygen product. As a result, there is a lower flow rate in the hypoxic purge/exhaust in the newer oxygen separator technologies. The lower flow rate of hypoxic gas creates problems for free-flow hypoxic applications, but the decreased oxygen concentrations resulting from the newer, higher recovery oxygen concentrators improves the hypoxic qualities of the gas stream.  
         [0020]     In an embodiment of the invention, the hypoxic gas supply  20  supplies hypoxic gas at less than 11% oxygen by volume. In another embodiment of the invention, the hypoxic gas supply  20  supplies hypoxic gas at 11-13% oxygen by volume. In a further embodiment of the invention, the hypoxic gas supply  20  supplies hypoxic gas at 13-15% oxygen by volume.  
         [0021]     Hypoxic gas supplies  20  delivering hypoxic gas in these ranges have relatively low flow rates (e.g., in the low tens of liters per minute). The present inventor has recognized that combining a conserving mechanism  30  with such low flow rate, high recovery oxygen concentrators multiplies the effective flow at least two times, for breathing, and more for other intermittent applications. Combining the conserving mechanism  30  with the low flow rate, high recovery oxygen concentrators is especially helpful for traveling athletes with portable concentrators and other intermittent demand applications for which size, power consumption, noise, weight, and/or portability are important.  
         [0022]     The conserving mechanism  30  supplies hypoxic gas flow to the hypoxic application (e.g., hypoxic training tent) or user (e.g. via mask) intermittently, when the application/user needs hypoxic gas, for example, during inhalation. During exhalation, or when there is little or no gas movement, the exhaust gas is stored for delivery during the next demand period. The conserving mechanism  30  may include one or more of, but not by way of limitation, a booster compressor, a blower, a storage tank, a mask, a cannula, pulse flow, demand flow, and a conserving mask. In the embodiment of the system  10  where the hypoxic gas supply  20  is a PSA system, it is important not to obstruct the exhaust/purge. This is the way the PSA system regenerates and renders the process reversible. According, in this embodiment of the system  10 , purge is not limited and gas is stored for intermittent flow. For example, exhaust/purge gas may pass into a booster pump, then into a storage tank, then be delivered either in demand or in pulse flow. Example conserving mechanisms, which are for smaller flow rates, high-purity oxygen, and not for hypoxic applications, are described in U.S. Pat. Nos. 6,651,658; 6,691,702; and 6,629,525, which are incorporated by reference as though set forth in full.  
         [0023]     With reference to  FIG. 2 , another embodiment of a hypoxic gas stream conserving system  100  will be described. The system  100  includes a hypoxic separator  110  (e.g., PSA system, VPSA system) as a hypoxic supply and a conserving mask  120  as a conserving mechanism. Ambient air is received by the hypoxic separator  110 . A concentrated oxygen gas stream is produced as a product gas and a hypoxic gas stream is produced as an exhaust/purge gas. The hypoxic gas stream is supplied to the conserving mask  120 , where hypoxic gas is supplied to the user during inhalation, but not during exhalation.  
         [0024]     With reference to  FIG. 3 , an additional embodiment of a hypoxic gas stream conserving system  200  will be described. The system  200  includes a hypoxic separator  210  as a hypoxic supply and a booster  220 , a storage tank  230 , and a mask or conserving mask  240  as a conserving mechanism. The hypoxic separator  210  produces a hypoxic exhaust/purge gas stream. The booster  220  supplies the hypoxic gas stream to the storage tank  230  at an elevated pressure. With the booster  220  and storage tank  230 , purge is not limited and gas is stored for intermittent flow. The hypoxic gas stream is supplied by the storage tank  230  to the conserving mask  240 , where hypoxic gas is delivered in demand mode to the user during inhalation, but not during exhalation. The conserving system  200  multiplies the apparent flow of hypoxic gas to the user compared to free flow.  
         [0025]     With reference to  FIG. 4 , a further embodiment of a hypoxic gas stream conserving system  300  will be described. The system  300  includes a hypoxic separator  310  as a hypoxic supply and a booster  320 , a storage tank  330 , a pressure regulator or instrument  340 , and a mask or conserving mask  350  as a conserving mechanism. The hypoxic separator  310  produces a hypoxic exhaust/purge gas stream. The booster  320  supplies the hypoxic gas stream to the storage tank  330  at an elevated pressure. The regulator  340  drops the pressure of the hypoxic gas from the storage tank  330  to a usable level, and the hypoxic gas stream is supplied to the conserving mask  350 , where hypoxic gas is delivered in demand mode to the user during inhalation, but not during exhalation.  
         [0026]     With reference to  FIG. 5 , a still further embodiment of a hypoxic gas stream conserving system  400  will be described. The system  400  includes a hypoxic separator  410  as a hypoxic supply and an accumulator  420 , demand/pulse sensor  430 , and a mask or conserving mask  440  as a conserving mechanism. The hypoxic separator  410  produces a hypoxic exhaust/purge gas stream that may temporarily be stored in the accumulator  420 . With the demand/pulse sensor  430  and mask/conserving mask  440 , hypoxic gas is delivered in demand or pulse flow. In an implementation of the system  400 , the hypoxic separator  410  may be a VPSA system, where a vacuum mechanism is used to vacuum purge gas off a vent. During the vacuum process, the hypoxic gas is stepped up in pressure above ambient and goes into the accumulator  420 . Thus, with the VPSA system, a booster is not required.  
         [0027]     With further reference to  FIG. 6 , another embodiment of a hypoxic gas stream conserving system  500  will be described. The system  500  includes a hypoxic separator  510  as a hypoxic supply and an accumulator  520 , demand/pulse sensor  530 , and a mask or conserving mask  540  as a conserving mechanism. The hypoxic separator  510  produces a hypoxic exhaust/purge gas stream that may temporarily be stored in the accumulator  520 . The demand/pulse sensor  530  is a mechanical pressure sensor or an electronic pressure sensor. In an implementation of this embodiment, the mask or conserving mask  540  is connected to the demand/pulse sensor  530  by a length of tubing other than the length of tubing used for delivering hypoxic gas from the conserving mechanism to the user. Such an independent connection reduces the pressure transients experienced by the demand/pulse sensor  530  during the delivery of a pulse of hypoxic gas.  
         [0028]     With reference to  FIG. 7 , in alternative embodiments, various conditions or trigger points are used to trigger the delivery of a pulse of oxygen. For example, in one embodiment, the demand/pulse sensor  530  detects a start of inhalation condition (See point A) by the user. In another embodiment, the demand/pulse sensor  530  detects a peak of exhalation condition (See point B) by the user. In a further embodiment, the demand/pulse sensor  530  detects a decay of exhalation condition (See point C) by the user.  
         [0029]     As the gas volumes required for hypoxic demand/pulse operation are quite high, in further embodiments, various means are used to reduce the disturbance caused by the high rate of flow of hypoxic gas delivered to the user. For example, but not by way of limitation, a large flow of gas can be initiated without the disturbance of a square wave pulse by ramping flow rate of the hypoxic gas flow.  
         [0030]     With the hypoxic gas stream conserving systems and methods described above, hypoxic gas is supplied in an efficient manner by the hypoxic gas supply  20  and the hypoxic gas is consumed in an efficient manner with the conserving mechanism  30 . The apparent gas flow is multiplied from the hypoxic gas stream source by delivering the hypoxic gas intermittently or in intervals. Using demand flow or pulse flow, gas storage, and/or pressure boosting, the apparent flow of hypoxic gas mixtures can be multiplied also. Combining the conserving mechanism with the higher recovery hypoxic separator multiplies the effective flow at least two times, for breathing, and more for other intermittent applications. Combining the conserving mechanism with the higher recovery hypoxic separator is especially helpful for traveling athletes with portable concentrators and other intermittent demand applications for which size, power consumption, noise, weight, and/or portability are important.  
         [0031]     It will be readily apparent to those skilled in the art that still further changes and modifications in the actual concepts described herein can readily be made without departing from the spirit and scope of the invention as defined by the following claims.