Abstract:
A breathing gas dispenser with selectable output flow rates. The dispenser includes a vessel containing a supply of breathable gas at storage pressure. The vessel is in fluid communication with a regulator assembly capable of reducing the pressure of the gas to a delivery pressure in a chamber. A plate is disposed in the chamber. The plate has a plurality of openings defined therein. The openings are disposed in pairs including a first opening and a second opening. The first or second opening or both may contain an orifice housing with a precision metering orifice defined therein. A flow selector is capable of causing the plate to rotate such that each of the pairs of openings are sequentially brought into registry with the outlet such that a user can select an output flow rate.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims the benefit of U.S. Provisional Patent Application Nos. 60/550,247 filed Mar. 4, 2004, and 60/564,511 filed Apr. 22, 2004. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention relates to a breathing gas system or a “walk around bottle” system, for use in aircraft.  
       BACKGROUND OF THE INVENTION  
       [0003]     The use of breathing gas systems on aircraft is known. It has been known to provide breathing gas systems with fixed output flow rates. Many of the systems are supplied with multiple outlets, each outlet being preset to deliver a different flow rate.  
         [0004]     There is a need for a breathing gas dispenser with selectable output flow rates that relies on flow control by calibrated orifice.  
       SUMMARY OF THE INVENTION  
       [0005]     The present invention meets the above-described need by providing a breathing gas dispenser with selectable output flow rates. The dispenser includes a vessel containing a supply of breathable gas at storage pressure. The vessel is in fluid communication with a regulator assembly. The regulator assembly is capable of reducing the pressure of the gas to a delivery pressure in a chamber. The chamber has an outlet. A plate is disposed in the chamber. The plate has a plurality of openings defined therein. The openings are disposed in pairs comprising a first opening and a second opening. The first or second opening or both may contain an orifice housing with a precision metering orifice defined therein. A flow selector is capable of causing the plate to rotate such that each of the pairs of openings are sequentially brought into registry with the outlet such that a user can select an output flow rate. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0006]     The invention is illustrated in the drawings in which like reference characters designate the same or similar parts throughout the figures of which:  
         [0007]      FIG. 1  is a block diagram of the present invention;  
         [0008]      FIG. 2  is a front elevational view of the selectable flow regulator assembly of the present invention with the cover removed for clarity;  
         [0009]      FIG. 3  is a side elevational view of the selectable flow regulator assembly of the present invention with the cover removed for clarity;  
         [0010]      FIG. 4  is a cross-sectional view taken along lines  4 - 4  of  FIG. 3 ;  
         [0011]      FIG. 5  is a cross-sectional view taken along lines  5 - 5  of  FIG. 4 ;  
         [0012]      FIG. 6  is an elevational view of the indexer of the present invention;  
         [0013]      FIG. 7  is a top plan view of the indexer with the orifice plate installed therein;  
         [0014]      FIG. 8  is a cross-sectional view taken along lines  8 - 8  of  FIG. 7 ;  
         [0015]      FIG. 9  is a top perspective view showing the low pressure chamber;  
         [0016]      FIG. 10  is a top plan view of the selectable flow regulator assembly; and,  
         [0017]      FIG. 11  is a cross-sectional view taken along lines  11 - 11  of  FIG. 10 ;  
         [0018]      FIG. 12  is a block diagram of an alternate embodiment of the present invention;  
         [0019]      FIG. 13  is a cross-sectional view of the flow selector of the breathing gas dispenser of  FIG. 12 ; and,  
         [0020]      FIG. 14  is an exploded view of the flow selector of the breathing gas dispenser of  FIG. 12 . 
     
    
     DETAILED DESCRIPTION  
       [0021]     Referring to  FIG. 1 , a breathing gas supply system provides supplemental breathing gas for persons that may require supplemental breathing gas for medical or therapeutic use or for use at higher altitudes. The breathing gas supply system may be made lightweight and small enough to be carried on the person of the user and therefore may be easily transported by an adult in a crowded environment.  
         [0022]     The pressure vessel  10  may be manufactured of a composite material such as an aluminum liner with a carbon fiber over-wrap and an epoxy resin finish as will be evident to those of ordinary skill in the art. The vessel  10  may have a nominal volume up to 140 cubic inches and may store breathing gas at pressures up to 1850 p.s.i.g. (hereinafter referred to as “storage pressure”).  
         [0023]     As will also be evident to those of ordinary skill in the art based on this disclosure, the pressure vessel  10  is typically provided with a high pressure relief valve  13 , a high pressure fill valve  16 , an indicating gauge  19  and a filter  22 . The high pressure relief valve  13  may be of a frangible disc type. The high pressure fill valve  16  is a normally closed check valve. Application of a pressure higher than the storage pressure will cause the check valve to open and the storage pressure can be replenished. The indicating gauge  19  may be of a direct drive type. The filter  22  captures particles that may be generated by the mechanical interaction of the upstream components prior to reaching the regulator inlet.  
         [0024]     When an on-off valve  25  is opened, gas flow is allowed to pass to the inlet passage  26  ( FIG. 4 ) of a balanced-type regulator assembly  28 . Other types of fluid controlling regulators may also be suitable. The regulator assembly  28  accepts storage pressure between 150 and 1850 p.s.i.g. and reduces it to approximately 70 p.s.i.g. at the flow selector  33 . A resetting low pressure relief valve  31  is connected to the regulator. The low pressure relief valve  31  opens between 90 and 135 p.s.i.g. to vent pressure in the event of a regulator malfunction such as leakage past the regulating seat of regulator assembly  28  in a no flow condition or other condition causing excess pressure. This valve  31  protects low pressure components from being over pressurized. The low pressure relief valve  31  will reset automatically when the regulated pressure returns to normal levels.  
         [0025]     A flow selector  33  provides for switching between precise metering rates and is coupled to the control knob  50  for the on/off valve  25  as indicated by dashed lines  36 .  
         [0026]     Turning to  FIG. 2 , the indicating gauge  19  is disposed on the front of the selectable flow regulator assembly  39 . The fill valve  16  is shown at the left of the figure. A drain tube  34  is provided to prevent water condensation from inside the cylinder from entering the valve. A visual indicator  37  of the status of the selectable flow assembly  39  is also provided.  
         [0027]     A control knob  50  ( FIG. 4 ) allows the user to manually open the on/off valve  25  and select the desired flow setting. The knob  50  synchronizes the position of the on/off valve  25  with an indexer  43  as will be described in greater detail below. The on/off valve  25  may be made of VESPEL® material which is commercially available (VESPEL® is a registered trademark of E.I. duPont Nemours and Company), and the high pressure seal is made by impressing the VESPEL® valve onto a brass seat  44  ( FIG. 4 ). Other materials may also be suitable.  
         [0028]     In  FIG. 3 , the cover and knob  50  (best shown in  FIGS. 4, 10  and  11 ) have been removed to show a face gear  53  at the base of the on/off knob  50  that mates with a pinion  56  on the bottom of the indexer  43 . The indexer  43  is a cylindrical housing that retains the orifice plate  70  ( FIG. 4 ). Although the knob  50  is coupled to the indexer  43  by a face gear and pinion arrangement it will be evident to those of ordinary skill in the art that other arrangements for coupling the knob  50  to the indexer  43  may also be suitable.  
         [0029]     Turning to  FIGS. 4-5 , a central passage  63  communicates storage pressure to the high pressure relief valve  13 , fill valve  16 , storage pressure gauge  19  and on/off valve  25 . Passage  63  is formed in high pressure valve body  14 . Relief valve  13  includes a rupture disc  15 . The first three-quarters of a turn of knob  50  opens the on/off valve  25  by means of a shaft  60  that rotates a threaded member carrying the VESPEL® valve off of its brass seat  44 . Upon opening the on/off valve  25  by rotating the knob  50 , storage pressure is applied to a balanced-type pressure regulator  28  which reduces it to a lower pressure. The regulator  28  has a stem  29 . Regulator  28  may also include a diaphragm  30 , a regulator opening spring  32 , and an adjusting screw  35  as will be evident to those of ordinary skill in the art. The regulated pressure travels through inlet passage  26  into low pressure chamber  110 . As described in greater detail below, this lower regulated pressure is applied to the interface between the low pressure body  69  and the indexer  43 .  
         [0030]     Turning of the knob  50  opens the on/off valve  25  through rotation of shaft  60 . As described above, the knob  50  is also coupled to the indexer  43  by means of the engagement of the face gears  53  attached to the knob  50  with pinion  56  attached to or formed integrally with the indexer  43 . Accordingly, turning of the knob  50  also causes an orifice plate  70  retained by the indexer  43  to rotate. Rotation of the orifice plate  70  causes the flow setting to switch. When the indexer  43  rotates, it repositions the orifice plate  70  to allow multiple flow rates. The visual indicator  37  located on the outside surface of the indexer  43  indicates the flow setting (i.e., in the example shown, there are three positions: off, “2” or “4” liters per minute). The visual indicator  37  aligns with a window (not shown) in the protective cover  75 .  
         [0031]     In  FIGS. 6-8 , the indexer  43  and orifice plate  70  are shown in greater detail. The assembly includes the indexer  43 , the orifice plate  70 , and a number of seals. The orifice plate  70  may be constructed of suitable materials and may be approximately 0.1″ thick. An orifice housing  80  containing a precisely drilled orifice may be pressed into an opening in the orifice plate  70 . The orifice  83  may be constructed of ruby or other suitable materials. The precisely calibrated orifice  83  in the orifice housing  80  meters the flow to the desired value based upon its diameter and the upstream pressure. In addition to the calibrated metering orifices, the orifice plate  70  also has holes drilled into it that pass completely through the orifice plate. These through holes  86  are on a different diameter than the pressed orifices, and are disposed in pairs with the openings for receiving the orifice housing  80 . The indexer  43  has a bottom wall  89 . Cavities  92  are defined within orifice plate  70 . In the example shown there are three such cavities, however other numbers are also suitable. The cavities  92  on the orifice plate  70  are formed in registry with the through holes  86  and calibrated orifices  83 . The indexer  43  and orifice plate  70  are sealed around the cavities by seals  95  ( FIG. 8 ).  
         [0032]     As shown in  FIG. 8 , the interface between passageway  100  through the low pressure body  69  and the orifice plate  70  may be sealed by quad ring seals  106 .  
         [0033]     When the passageway  100  is pressurized with a fixed regulated pressure, flow passes along the flow path indicated by arrows  87  down the passageway  100  and into the through hole  86  in the orifice plate  70 . Next, the flow enters the cavity  92  in the plate  70  and then exits the cavity  92  through the precisely calibrated orifice  83  back up through a second passageway  111  where it is communicated to the outlet  120  for the user.  
         [0034]     The passageway  100  through the low pressure body  69  is fixed such that rotation of the indexer  43  successively brings each pair of openings in the orifice plate  70  into registry with the passageways. The quad ring seals  106  provide the necessary seals at the interface between the passageway  100  and the through hole  86  in the orifice plate and between the calibrated orifice  83  and the second passageway  111 .  
         [0035]     Turning to  FIG. 9 , the low pressure chamber  110  is located above the low pressure body  69  as shown. A first opening  113  at the bottom of the chamber  110  provides the entry point for regulated pressure that has been reduced from storage pressure by the balanced type pressure regulator  28 . A passageway  116  leading to the low pressure relief valve  31  is shown in the side wall. In the alternative, the low pressure relief valve  31  may be located at other positions along the flow path as will be evident to those of ordinary skill in the art. The passageway  100  leading to the orifice plate  70  is also shown in  FIG. 9 . The position of the passageway  100  is fixed and the indexer  43  moves each successive pair of openings into registry with the passageways  100  and  111 .  
         [0036]     In  FIGS. 10 and 11 , the flow path through the low pressure body  69 , orifice plate  70  and indexer  43  is shown in greater detail. As described the regulated pressure passes through passageway  100  into the through hole  86  in the orifice plate  70 . The low pressure body  69  and orifice plate  70  are sealed by the quad ring seals  106 . The flow passes into the cavity  92  in the plate  70  where it is sealed by kidney shaped seals  95 . The flow then passes through the precisely calibrated opening  83 , back through a second passageway  111  in the low pressure body and into the outlet  120  for communication with the user.  
         [0037]     Referring to  FIG. 12 , an alternate embodiment of the present invention is shown in a block diagram. The pressure vessel  210  may be manufactured of a composite material such as an aluminum liner with a carbon fiber over-wrap and an epoxy resin finish as will be evident to those of ordinary skill in the art. The vessel  210  may have a nominal volume up to 140 cubic inches and may store breathing gas at pressures up to 1850 p.s.i.g. (hereinafter referred to as “storage pressure”).  
         [0038]     As will also be evident to those of ordinary skill in the art based on this disclosure, the pressure vessel  210  is typically provided with a high pressure relief valve  213 , a high pressure fill valve  216 , an indicating gauge  219  and a filter  222 . The high pressure relief valve  213  may be of a frangible disc type. The high pressure fill valve  216  is a normally closed check valve. Application of a pressure higher than the storage pressure will cause the check valve to open and the storage pressure can be replenished. The indicating gauge  219  may be of a direct drive type. The filter  222  captures particles that may be generated by the mechanical interaction of the upstream components prior to reaching the regulator inlet.  
         [0039]     When an on-off valve  225  is opened, gas flow is allowed to pass to the inlet passage of a regulator  228 . The regulator  228  accepts any pressure between 150 and 1850 p.s.i.g. and reduces it to approximately 55 p.s.i.g. A resetting low pressure relief valve  131  is connected to the regulator. The low pressure relief valve  231  opens between 90 and 135 p.s.i.g. to vent pressure in the event of a regulator malfunction such as leakage past the regulating seat (not shown) of regulator  228  in a no flow condition or other condition causing excess pressure. This valve  231  protects low pressure components from being over pressurized. The low pressure relief valve  231  will reset automatically when the regulated pressure returns to normal levels.  
         [0040]     As shown in the diagram, the regulator  228  is provided with an outlet position (“Port  1 ”) capable of receiving a flow selector  234  of the present invention. Accordingly, Port  1  designates a fitting on the regulator  228  that is capable of receiving the flow selector  234  of the present invention. As will be described in greater detail below, the flow selector  234  receives regulated pressure from the pressure regulator  228 , meters it to a user selected flow rate and allows it to pass into one or more outlets for user connected devices such as breathing masks (not shown).  
         [0041]     Turning to  FIG. 13 , the path of breathing gas flow is depicted by the heavy line  237 . Pressure from the output of the regulator  228  is applied to the passageway  240  disposed through the center of the flow selector  234 . The flow selector  234  includes three main components a selector body  243 , a cylinder  246  and a seal nut  249 , which will be described in greater detail herein. The flow selector  234  is received in a first outlet Port  1  of the regulator  228  which is specially designed to engage with the flow selector  234 . An O-ring  252  seals the opening where the passageway  240  interfaces with regulator  228 . The O-ring  252  is retained by a washer  255  and a spring  258 , and the O-ring  252  seals the regulated pressure from escaping into a cavity  261  in Port  1 .  
         [0042]     The regulated pressure travels through the passageway  240  through the flow selector  234  until it pressurizes the cavity  264  of the selector body  243  containing the cylinder  246 . The cylinder  246  has multiple chambers  267  disposed around its circumference. When the chambers  267  are rotated about an axis of rotation  270 , each chamber  267  rotates sequentially into alignment with a passageway  273  defined in the selector body  243  at an offset from the longitudinal axis  274  of the selector body  243 . The chambers  267  are capable of receiving calibrated orifices  276  of specific flow rate. The metering orifices  276  are precisely machined parts that are pre-calibrated such that they will provide specific flow rates at predetermined pressure differentials. Accordingly, the system of the present invention does not have to be calibrated for flow when the calibrated orifices  276  are installed or changed.  
         [0043]     By way of example only, the embodiment shown has six chambers  267  with two chambers containing metering orifices  276  (best shown in  FIG. 14 ). In  FIG. 13 , a metering orifice  276  is present in the chamber  267  on the right hand side of the figure and the chamber  267  on the left hand side of the figure is empty.  
         [0044]     The seal nut  249  attaches the cylinder  246  to the selector body  243 . O-ring  268  between the cylinder  246  and the seal nut  249  and O-ring  269  between the seal nut  249  and the selector body  243  prevent the regulated pressure from escaping to atmosphere.  
         [0045]     A quad ring  270  seals the interface between the metered orifice  276  and passageway  273  inside the selector body  243  to prevent the regulated pressure from leaking into the passageway  280  formed by intersecting drills  283  and  286  in selector body  243 .  
         [0046]     The pressure above or upstream of the metering orifice  276  is the regulated pressure, and the pressure below or downstream of the orifice  276  is communicated to the cavity  261  inside Port  1 . When Port  1  of the regulator  228  is configured with the flow selector  234  of the present invention, the output of the flow selector is directed to Port  2  as shown in  FIG. 13 . There may be other ports provided and interconnected with Port  2 .  
         [0047]     Port  3  may be connected to breathing masks (not shown) or other devices. Port  3  may be provided with a check valve  288 . When the check valve  288  of the outlet in Port  3  is opened, all the ports are exposed to ambient pressure. Therefore, the pressure below the metering orifice  276  is atmospheric pressure. The pressure differential above and below the metering orifice  276  will cause the gas to flow through the orifice  276 . The metering orifice  276  is sized so that the differential pressure provides a specific user requested flow rate. The gas flow follows the path  237  indicated by the heavy line  237  into cavity  261  in Port  1 , to Port  2 , and out to the user through Port  3 .  
         [0048]     Turning to  FIG. 14 , the cylinder  246  has multiple chambers  267  formed within it. Each chamber  267  is capable of receiving a calibrated orifice  276  of specific flow rate. Since the flow path allowing gas to pass to the user is offset from the center of the selector body  243 , only one of the orifices  276  can be aligned to allow gas to flow to the user. The cylinder  246  and knob  290  are fixedly attached such that as the knob  290  is rotated the cylinder  246  rotates with it. The knob  290  may be rotated in either direction or it may be ratcheted to rotate in a single direction as will be evident to those of ordinary skill in the art.  
         [0049]     The user rotates the knob  290  to align different orifices  276  within the cylinder  246  with the flow path to the user. Accordingly, the user can select from multiple different flow rates (up to six different flow rates in this example). One of the positions in cylinder  246  may be configured to provide a no-flow position by means of a closed chamber  267  (as shown on the left side of  FIG. 13 ) or by plugging one of the orifices  276 .  
         [0050]     The specific flow rates associated with the orifices  276  loaded into the cylinder  246  may be printed on the cylindrical surface  299  of the knob  290 . The flow rate of the orifice  276  that is aligned to flow gas to the user can be seen on the surface of knob  290  through a window  291  on the seal nut  249 . This indicator notifies the user of and allows him to select the desired flow rate. The knob  290  and cylinder  246  may be detented in various ways as will be evident to those of ordinary skill in the art to provide an indication when a specific orifice is aligned for a specific flow rate. For example, a spring (i.e., ball and spring arrangement) may be used to provide a torque threshold that must be exceeded in order to rotate the cylinder  146  to another orifice  276 . Also, a positive locking mechanism with a release button could also be used.  
         [0051]     The flow selector  234  of the present invention may be disposed in fluid communication with a single outlet leading to a breathing mask as described above. The flow selector  234  of the present invention may also be disposed in fluid communication with more than one outlet connected in parallel. As a result the flow selector  234  of the present invention can be used to simultaneously feed multiple outlets. If the outlets are connected to masks or other devices having similar resistance, then the gas flow will divide substantially equally between the outlets.  
         [0052]     While the invention has been described in connection with certain embodiments, it is not intended to limit the scope of the invention to the particular forms set forth, but, on the contrary, it is intended to cover such alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention. Also, the shapes of some of the components may vary due to weight reduction considerations. For instance, depending on the number of different calibrated orifices required, the indexer and orifice plate could be oval-shaped, or clover-shaped or the like.