Abstract:
An oxygen supply device, preferably a pilot oxygen supply device, has an oxygen source and at least one oxygen mask. A breathing regulator is arranged between the oxygen source and the oxygen mask. An oxygen sensor is arranged downstream of this breathing regulator.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of priority under 35 U.S.C. §119 of German Patent Application DE 10 2007 031 043.0 filed Jul. 4, 2007, the entire contents of which are incorporated herein by reference. 
     FIELD OF THE INVENTION 
     The invention relates to an oxygen supply device, particularly an oxygen supply device for an aircraft pilot. 
     BACKGROUND OF THE INVENTION 
     In aircraft, it is usual to provide oxygen supply devices with which the cockpit crew can be supplied with the requisite oxygen, for example in the event of decompression of the cockpit. These oxygen supply devices typically have an oxygen mask connected by a line to an oxygen reservoir. In the event of faulty behaviour or failure of these oxygen supply devices, replacement devices are normally also carried in aircraft, the use of which ensures the supply of oxygen to the pilot even in the event of failure of the actual oxygen supply device. 
     In the past, however, it has often been shown that such a failure of the oxygen supply device was not even noticed, which led to the pilots not using the replacement device also carried, despite there being a deficiency of oxygen. At high flight altitudes, this normally leads to a loss of consciousness of the pilot within a short time and, associated with this, often to the aircraft crashing. 
     SUMMARY OF THE INVENTION 
     Against this background, it is an object of the invention to devise an oxygen supply device which permits improved functional monitoring of the device and a clear indication of faults. 
     The oxygen supply device according to the invention, which is preferably a pilot oxygen supply device, has an oxygen source for providing the oxygen and at least one oxygen mask for dispensing the oxygen. Arranged between the oxygen source and the oxygen mask is a breathing regulator. An oxygen sensor is arranged downstream of this breathing regulator. 
     As will be explained in more detail in the further course, the oxygen sensor arranged downstream of the breathing regulator advantageously permits the serviceability of all the important components of the oxygen supply device to be monitored, from the oxygen source up to and including the breathing regulator. 
     The oxygen mask can be constructed both as a full mask, covering the entire face of the user, and also as a half mask covering only the mouth and nose of the user. The type of oxygen source is any desired, provided that it can ensure an adequate supply of oxygen. For example, chemical oxygen generators or oxygen bottles can be used as the oxygen source. 
     Between the oxygen source and the oxygen mask there can be arranged one or more pressure reducers, which reduce the oxygen pressure prevailing at the outlet of the oxygen source, step-by-step if necessary, to a desired breathing value. In principle, the oxygen supply device according to the invention has at least one pressure reducer, which is formed by the breathing regulator. The breathing regulator is used to expand the oxygen to the mask pressure required in the oxygen mask. If a plurality of pressure reducers or pressure regulating devices are provided in the line connection between oxygen source and oxygen mask, the breathing regulator always forms the last pressure regulating device in the flow direction, that is to say the pressure regulating device which is arranged closest to the oxygen mask. 
     The breathing regulator can be operated pneumatically or electrically. It can be constructed as such a regulator which provides the user of the oxygen mask with a constant oxygen flow. In addition, the breathing regulator can be what is known as an impulse breathing regulator. Such an impulse breathing regulator provides the user of the oxygen mask with a limited bolus volume of oxygen only in an initial inhalation phase, in which the oxygen diffuses into the arterial blood via the lung system, whereupon the mask user subsequently breathes in the oxygen-poor ambient air. 
     The oxygen sensor of the oxygen supply device according to the invention is designed to determine an oxygen pressure or oxygen partial pressure. The arrangement of the oxygen sensor on the outlet or downstream side of the breathing regulator, for example in the immediate vicinity of the mask body or else inside the mask body of the oxygen mask, advantageously permits malfunctions in substantially all the components arranged in the flow path from the oxygen source to the oxygen mask, for example valves and pressure regulating devices arranged there, including the breathing regulator, and also an inadequate or missing discharge of oxygen from the oxygen source itself, to be determined with only one sensor element, the oxygen sensor. Furthermore, by using the oxygen sensor, leaks occurring within the line connection can also be detected because of the pressure loss associated therewith. 
     The determination of possible malfunctions and leaks is in this case possible via a comparison of the values of the oxygen pressure or oxygen partial pressure prevailing on the outlet side of the pressure regulator, as determined by the oxygen sensor, with predefined desired pressure values. This desired/actual value comparison is performed by a control device, which expediently has a signal connection to the oxygen sensor. If the pressure values registered by the oxygen sensor lie below the pressure values predefined for the outlet side of the breathing regulator, this indicates the risk of an inadequate oxygen supply to the user of the oxygen supply device. This defective supply or inadequate supply with oxygen can be attributed to a malfunction of any component or possibly a plurality of components arranged between oxygen sensor and oxygen source or to a leak between oxygen sensor and oxygen source. 
     In order to be able to warn the user of the oxygen supply device according to the invention about a possible inadequate oxygen supply, the oxygen sensor expediently has a signal connection to a control device having a display function. This control device is preferably the control device with which the evaluation of the oxygen pressure or oxygen partial pressure values determined by the oxygen sensor is performed. The control device can have an optical and/or acoustic display, which reports any possible malfunction of the oxygen supply device. This display can be an integral constituent part of the control device or arranged separately from the latter. The display function of the control device is advantageously performed by a monitor which is preferably arranged in the immediate vicinity of the user of the oxygen supply device and, particularly advantageously, is arranged in his/her direct field of view and thus can particularly easily be perceived by the user of the oxygen supply device according to the invention. 
     In particular when the breathing regulator is constructed as an impulse breathing regulator, an inhalation valve is advantageously arranged between breathing regulator and oxygen mask, i.e. downstream of the breathing regulator. The inhalation valve closes the line connection from the oxygen source to the oxygen mask and opens a flow path into the mask body only during inhalation. To this end, the inhalation valve can preferably be designed to be controllable by the breathing activity itself, i.e. by the negative pressure produced within the mask body during inhalation. The inhalation valve can be arranged at a distance from the oxygen mask in the line connection between the breathing regulator and the oxygen mask. However, the inhalation valve is preferably arranged directly on the mask body of the oxygen mask. 
     Although the oxygen sensor can also be arranged within the mask body of the oxygen mask, it is preferably arranged in the line connection between the breathing regulator and the inhalation valve. As compared with that arrangement within the mask body, this arrangement of the oxygen sensor has the advantage that the moisture getting into the mask body with the exhaled air during exhalation cannot come into contact with the oxygen sensor because of the inhalation valve which is closed during exhalation, which moisture could otherwise distort the measured results from said oxygen sensor. 
     In a further advantageous embodiment of the oxygen supply device according to the invention, an air mixing valve is provided in the line connection between breathing regulator and inhalation valve. In this case, the oxygen sensor is then preferably arranged downstream of the air mixing valve. The air mixing valve is a valve communicating with the ambient air or cockpit air. The air mixing valve is expedient in particular when the breathing regulator is designed as an impulse breathing regulator and ambient air also has to be supplied to the user of an oxygen mask. The ambient air can then be provided via the air mixing valve. 
     The breathing regulator and the oxygen sensor are advantageously arranged in an integral component. It is further preferred for this integral component to have an inhalation valve and an air mixing valve as well. The breathing regulator, the air mixing valve, the oxygen sensor and finally the inhalation valve are then arranged in this component, preferably one after the other in the direction of flow through the component. In addition, a substantially unoccupied internal space, which forms a mixing chamber, is preferably provided in the component. This mixing chamber is bounded on the inlet side by the breathing regulator and on the outlet side by the inhalation valve. The inlet of the air mixing valve opens out into the mixing chamber. Furthermore, the oxygen sensor is arranged in the mixing chamber, preferably downstream of the air mixing valve, and, in this arrangement, registers at least the oxygen partial pressure of the mixed air. 
     The component preferably forms part of the oxygen mask. Thus, the component can be arranged on the outside of the mask body, it being possible for the outlet of the inhalation valve to open into the interior of the mask body, facing the face of the user of the oxygen mask. 
     A further advantageous embodiment of the oxygen supply device according to the invention provides means downstream of the breathing regulator for registering the breathing activity of a mask user. In this way, with the oxygen supply device according to the invention, it is possible to monitor not only the serviceability of the entire device but also the breathing of the user and to make him/her or other persons aware of possible breathing problems, so that countermeasures can be taken in good time. 
     The means for registering the breathing activity are advantageously formed by a sensor for registering an air mass flow. The sensor for registering an air mass flow expediently has a signal connection to a control device, by means of which it is possible to check whether the air mass flow values measured by the sensor for each breath are located in a predefined measured value window. 
     Particularly advantageously, the means for registering the breathing activity form an integral constituent part of the oxygen sensor. This means that the oxygen sensor provided is a sensor element which is constructed in such a way that, by using it on the outlet side of the breathing regulator or possibly of the air mixing valve, it is possible to register not only an oxygen partial pressure but also air mass flows present there. 
     In order to be able to match the quantity of oxygen discharged by the breathing regulator or the oxygen pressure in the mask body to the flight altitude or to the cockpit pressure, the control device preferably has a signal connection to an ambient pressure sensor. In this embodiment, based on the cockpit pressure determined by the ambient pressure sensor and based on the actual oxygen pressure registered by the oxygen sensor, the contro device is able to determine the opening times of the breathing regulator which are needed to provide the user of the oxygen mask with an adequate quantity of oxygen with regard to the flight altitude. 
     If the breathing regulator, as preferably provided, is constructed as an electronic controller, the control device preferably also serves as a regulating unit for the breathing regulator. In this case, the regulating unit is expediently connected to a pressure sensor arranged in the oxygen mask. With the aid of the pressure sensor, by using the preferably continuously determined internal mask pressure, it is possible to determine whether the user of the oxygen mask is currently in an inhalation or exhalation phase. By means of the control device, the actuation of the breathing regulator can then be coordinated with the breathing rhythm of the user of the oxygen supply device. In this way, it is ensured that the user is provided with an adequate quantity of oxygen when inhaling. 
     In the following text, the invention is explained by using an exemplary embodiment illustrated in a drawing figure. The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which a preferred embodiment of the invention is illustrated. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings: 
       The only FIGURE is a schematic view showing the principles of an oxygen supply device according to the invention. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to the drawing in particular, an oxygen supply device, in which an oxygen mask  2  is connected by a line to an oxygen bottle  4 , is shown schematically. On an oxygen outlet  6  of the oxygen bottle  4 , a shut-off valve  8  and a pressure reducer  10  are arranged directly one after the other in a manner known per se in the flow direction. The shut-off valve  8  is used to open and close the oxygen bottle  4 . By using the pressure reducer  10 , the oxygen pressure prevailing in the oxygen bottle  4 , which can be more than 100 bar, is reduced to an average pressure of about 2 to 3 bar. On the outlet side, the pressure reducer  10  has a line connection to the oxygen mask  2 . 
     The oxygen mask  2  is constructed as a half mask and has a mask body  12  covering mouth and nose. On the outside of the mask body  12  there is arranged a component  14 , which contains an electronic breathing regulator  16 , an air mixing valve  18  and an inhalation valve  20 . The component  14  has a hollow cylindrical base body  22 , in the interior of which the breathing regulator  16  is arranged at an end facing away from the mask body  12 . Via a supply line  24  led through the base body  22 , the oxygen inlet of the breathing regulator  16  is connected by a line to the oxygen outlet of the pressure reducer  10 . On the outlet side of the breathing regulator  16 , that is to say downstream of an oxygen outlet, not illustrated in the figure, of the breathing regulator  16 , the base body  22  of the component  14  forms an unoccupied internal space or mixing chamber  26 . 
     In the exemplary embodiment illustrated in the figure, the air mixing valve  18  is arranged on the outside of the base body  22 , in the region of the internal space  26 . Via an aperture  28  provided downstream of the breathing regulator  16  on the circumferential wall of the base body  22 , the air mixing valve  18  has a flow connection to the internal space  26  of the base body  22 . 
     The air mixing valve  18  has a flow inlet  30  communicating with the surroundings of the oxygen mask  2 . The flow inlet  30  of the air mixing valve  18  is closed by a valve body  32  in the form of a diaphragm. In this case, the valve body  32  is forced by a helical spring  34  into a position closing the flow inlet  30 . 
     The inhalation valve  20  is likewise arranged outside the base body  22  of the component  14  in the exemplary embodiment illustrated. The inhalation valve  20  has a flow connection to the internal space  26  of the base body  22  via a flow duct  36 . The flow duct  36  is arranged at the end of the base body  22  that is at a distance from the breathing regulator  16  in the longitudinal direction of the base body  22 . 
     The inhalation valve  20  has a flow outlet  37 , which opens in the interior of the body  12  of the oxygen mask  2 . The outlet on the downstream side of the flow duct  36  is closed by a valve body  38  arranged in the inhalation valve  20 . In this case, the valve body  38  is prestressed by means of a helical spring  40  in the direction of the narrow section  36 . 
     In the interior of the mask body  12  there is arranged an exhalation valve  42 . The valve housing of the exhalation valve  42  is divided by a diaphragm  44  into two valve parts  46  and  52  that are separated fluidically from each other. In this case, a first valve part  46  forms a flow path from an inlet opening  48  in the internal space of the mask body  12  to a large number of outlet openings  50 , which are arranged on the outside of the mask body  12 . A second valve part  52  communicates via a bypass duct  54  with the flow duct  36 , the flow duct  36  and the bypass duct  54  connecting the internal space  26  of the component  14  in a fluidically conductive manner to the second valve part  52  of the exhalation valve  42 . Arranged in the second valve part  52  of the exhalation valve  42  is a spring component  56 . In interaction with a positive pressure prevailing in the internal space  26  of the component  14  with respect to the internal mask pressure, the diaphragm  44  having the spring component  56  is prestressed into the closed position of the exhalation valve  42 . 
     In the internal space or mixing chamber  26  of the base body  22 , an oxygen sensor  58  is arranged downstream of the air mixing valve  18  and downstream of the aperture  28 . The oxygen sensor  58  has a signal connection to a control device  62  via an electric line  60 . The means for registering the breathing activity is advantageously formed by a sensor  59  for registering an air mass flow. The sensor  59  for registering an air mass flow expediently has a signal connection  61  to a control device  62 , by means of which it is possible to check whether the air mass flow values measured by the sensor  59  for each breath are located in a predefined measured value window. The control device  62  has a display function by means of a monitor  64 , which is connected to the control device  62  by an electric line  66 . Furthermore, an ambient pressure sensor  68  has a signal connection to the control device  62  via a line  70 , and a pressure sensor  72  arranged in the interior of the mask body  12  has a signal connection to the control device  62  via a line  74 . The pressure sensor  72  is used to register the internal mask pressure, which changes cyclically because of the successive inhalation and exhalation phases. On the basis of the pressure values provided by the pressure sensor  72 , the control device  62  is able to drive the breathing regulator  16  in a timed manner in such a way that the requisite quantity of oxygen is available to the user of the oxygen supply device at the start of inhalation. 
     In the following text, the functional monitoring of the oxygen supply device according to the invention will be described by using the drawing figure. 
     By means of the ambient pressure sensor  68 , the flight-altitude-dependent air pressure prevailing in the cockpit of an aircraft is measured. On the basis of the pressure values determined by the ambient pressure sensor  68 , the control device  62  determines the oxygen demand of the user of the oxygen supply device and sets the opening times of the breathing regulator  16  appropriately. As a result, desired values for the oxygen partial pressure that are proportional to the opening times result in the internal space  26  of the component  14 . The real or actual values of the oxygen partial pressure are registered by the oxygen sensor  58  and compared with the desired values by the control device  62 . 
     If the desired and actual values of the oxygen partial pressure agree, this indicates a satisfactory operating behaviour of the oxygen supply device. If the pressure values determined by the oxygen sensor  58  lie below the desired values predefined by the control device  62 , this means an inadequate oxygen supply to the user of the oxygen supply device. This deficient supply can be attributed to a malfunction of one or more of the components connected upstream of the oxygen sensor  58  in the flow direction. In detail, this can mean that the oxygen bottle  4  can be empty, shut-off valve  8 , pressure reducer  10 , breathing regulator  16  or air mixing valve  18  have a defect or there is a leak along the flow path from the oxygen bottle  4  to the oxygen sensor  58 . 
     If an excessively low actual value of the oxygen partial pressure has been determined by the control device  62  with the aid of the oxygen sensor  58 , this is displayed on the monitor  64  by the control device so that it is easily visible by the user of the oxygen supply device. The latter can then immediately use a replacement device for the oxygen supply. 
     While a specific embodiment of the invention has been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles. 
     
       
         
               
             
               
               
             
           
               
                 APPENDIX 
               
               
                   
               
               
                 LIST OF REFERENCE CHARACTERS 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 2 
                 Oxygen mask 
               
               
                 4 
                 Oxygen bottle 
               
               
                 6 
                 Oxygen outlet 
               
               
                 8 
                 Shut-off valve 
               
               
                 10 
                 Pressure reducer 
               
               
                 12 
                 Mask body 
               
               
                 14 
                 Component 
               
               
                 16 
                 Breathing regulator 
               
               
                 18 
                 Air mixing valve 
               
               
                 20 
                 Inhalation valve 
               
               
                 22 
                 Base body 
               
               
                 24 
                 Supply line 
               
               
                 26 
                 Internal space, mixing chamber 
               
               
                 28 
                 Aperture 
               
               
                 30 
                 Flow inlet 
               
               
                 32 
                 Valve body 
               
               
                 34 
                 Helical spring 
               
               
                 36 
                 Flow duct 
               
               
                 38 
                 Valve body 
               
               
                 40 
                 Helical spring 
               
               
                 42 
                 Exhalation valve 
               
               
                 44 
                 Diaphragm 
               
               
                 46 
                 Valve part 
               
               
                 48 
                 Inlet opening 
               
               
                 50 
                 Outlet openings 
               
               
                 52 
                 Valve part 
               
               
                 54 
                 Bypass duct 
               
               
                 56 
                 Spring component 
               
               
                 58 
                 Oxygen sensor 
               
               
                 60 
                 Line 
               
               
                 62 
                 Control device 
               
               
                 64 
                 Monitor 
               
               
                 66 
                 Line 
               
               
                 68 
                 Ambient pressure sensor 
               
               
                 70 
                 Line 
               
               
                 72 
                 Pressure sensor 
               
               
                 74 
                 Line