Oxygen supply device and method for supplying a passenger cabin of an aircraft with oxygen

Abstract

Oxygen supply device (10) for an aircraft (100), comprising a reaction tank (11) for chemical oxygen production; a pressure tank (12) filled with oxygen; an energy converter (13) for converting thermal energy into electrical energy; a control unit (14) for adjusting an amount of oxygen supplied from the pressure tank (12) to a consumer unit (15); wherein the energy converter (13) is designed to convert heat energy generated by the chemical oxygen generation in the reaction tank (11) into electrical energy and to provide the electrical energy; and wherein the control unit (14) is designed to adjust the amount of oxygen supplied by the pressure tank (12) to the consumer unit (15) using the electrical energy supplied by the energy converter (13); wherein the pressure tank (12) is connected to the consumer unit (15) exclusively via an electrical ignition device (19a), a second line (22), a control valve (19) and a third line (23).

Description

Field of the InventionThe present invention relates to the supply of oxygen for aerospace systems. In particular, the invention relates to an oxygen supply device for an aircraft and to a method for supplying an aircraft passenger cabin with oxygen.BACKGROUND OF THE INVENTIONDifferent possibilities are suitable for supplying a passenger cabin of an aircraft with oxygen depending on the operating state of the aircraft. The primary source for supplying air to the passenger cabin of an aircraft is generally located in the engines of the aircraft. However, other oxygen supply systems are also possible, such as, for example, the supply by compressed air from oxygen tanks or by chemically generated oxygen. A chemical oxygen supply uses a chemical reaction that generates heat and oxygen without requiring electrical energy. This type of oxygen generation is, however, less suitable for longer supply times of more than 30 min due to the weight.In the case of the gaseous oxygen supply, pure, gaseous oxygen is stored in a closed high-pressure cylinder. It is necessary to reduce the pressure of the oxygen gas before it is fed into the passenger cabin and to regulate the oxygen flow to the required quantity depending on the ambient pressure of the cabin. This requires electronic measuring and regulating devices and an electropneumatic flow restriction. This allows longer supply times of up to 60 min to be achieved.US 2010 / 0 051 113 A1 describes a redundant gas supply or oxygen supply for an aircraft with two main lines and a group supply line which is connected to a consumer or to a plurality of consumers. In each case one connecting line connects the respective one main line to the group supply line. Flow restrictors and check valves can be provided in the connecting lines.US 2005 / 0 061 915 A1 describes a controller for connecting a therapeutic oxygen supply to an emergency oxygen distribution system of an aircraft, wherein the oxygen source is used either partially for therapeutic purposes or completely for emergency purposes.EP 2 127 699 B1 describes an oxygen breathing apparatus, in particular for oxygen supply to passengers or crew members of an aircraft, comprising a chemical oxygen source in which oxygen is stored in chemically bound form, a first oxygen flow path for connecting the chemical oxygen source to a flow control valve and a second oxygen flow path connecting the flow control valve to at least one oxygen outflow opening, wherein the flow control valve is adapted to control an oxygen pressure at the oxygen outflow opening and wherein the oxygen breathing apparatus has an oxygen buffer connected to the first oxygen flow path.WO 2009 / 100 900 A1 describes an oxygen breathing apparatus, in particular for oxygen supply to passengers or crew of an aircraft, wherein the apparatus comprises an oxygen source in which oxygen is stored, in particular in chemically bound or compressed form, an oxygen guide device for guiding oxygen from the oxygen source to a person, and a control unit for controlling the pressure and / or the flow rate of the oxygen which flows through the guide device. An energy conversion device is also described which is configured to convert energy stored or generated within the oxygen respirator into an energy required by the control unit and to provide this required energy to the control unit.EP 3 235 545 A1 describes an oxygen supply system and a method for testing an oxygen supply system, in particular for use in a passenger aircraft.WO 2013 / 176 996 A1 describes a system and a method for providing a controlled oxygen flow, including for a pilot or a member of the cockpit crew on board an aircraft.SUMMARY OF THE INVENTIONIt is an object of the present invention to reduce the power consumption in an aircraft.This object is achieved by the subject matters of the independent claims. Exemplary embodiments are evident from the dependent claims and the following description.According to one aspect of the invention, an oxygen supply device for an aircraft is specified. The oxygen supply device has a reaction tank for chemical oxygen generation and a pressure tank filled with oxygen. Furthermore, the oxygen supply device has an energy converter for converting thermal energy into electrical energy. The oxygen supply device has a control unit for adjusting an amount of oxygen provided from the pressure tank to a consumer unit. For example, the control unit is designed to set a first oxygen quantity provided from the reaction tank to the consumer unit and the second oxygen quantity provided from the pressure tank to the consumer unit. The energy converter is designed to convert a thermal energy generated by the chemical oxygen generation in the reaction tank into electrical energy and to provide the electrical energy. The control unit is designed to adjust or regulate the amount of oxygen provided from the pressure tank to the consumer unit using the electrical energy provided by the energy converter. In particular, the control unit is designed to set or regulate the second oxygen quantity provided by the pressure tank to the consumer unit using the electrical energy provided by the energy converter. The pressure tank is connected to the consumer unit exclusively via an electrical ignition device, a second line, a regulating valve and a third line.The first oxygen quantity can also describe a first oxygen flow coming from the reaction tank, i.e. a first oxygen quantity per unit time. Likewise, the second oxygen quantity can describe a second oxygen flow coming from the pressure tank, i.e. a second oxygen quantity per unit time. The terms oxygen quantity and oxygen flow can have the same or a similar meaning content in the following.With such an oxygen supply device, two techniques for supplying oxygen can be advantageously combined with one another, namely the combination of a chemical oxygen supply with a compressed gas oxygen supply. In particular, the electrical energy consumption for the oxygen supply by the oxygen supply device according to the invention can be reduced or even avoided during longer operating times, so that the oxygen supply device does not require an external power supply. For this purpose, chemically generated oxygen is provided for an initial short-term operation by a relatively small chemical generator, i.e. the reaction tank. The thermal energy of the chemical reaction generated in this case can be converted into electrical energy by an energy generation method in the energy converter. During the operating time of the reaction tank, the electrical energy is stored in an energy store, for example a capacitor. After the end of the reaction, i.e. after chemical oxygen generation in the reaction tank, the compressed gas oxygen supply through the pressure tank is activated for the remaining supply time. The electrical energy for operating the oxygen flow regulation from the pressure tank can now be provided by the provided electrical energy or via the electrical energy stored in the energy store.The reaction tank may be a chemical oxygen generator equipped with a mechanical igniter. The chemical reaction in the reaction tank may be an exothermic reaction, by which oxygen is generated. For example, during the chemical reaction, sodium chlorate and iron may react with each other, thereby producing chemically generated oxygen with heat release. The chemical reaction takes place within the reaction tank. The oxygen generated in this way can be used to provide the first amount of oxygen, which is provided, for example, as emergency oxygen to the consumer unit. The consumer unit can be a passenger cabin of a vehicle, in particular of an aircraft. It is possible that the consumer unit is an emergency oxygen mask for a passenger of the passenger cabin. In this case, the first oxygen quantity is conducted via a first oxygen line to the consumer unit.The heat can be emitted to the energy converter via the walls of the reaction tank, wherein a wide variety of possibilities are possible for converting the generated thermal energy into electrical energy. The energy converter may be a thermal-electrical energy converter which generates an electrical voltage from the operating temperature of the reaction tank in operation. The energy converter can have a piezoelectric current generator, for example. It is also possible for the energy converter for converting the thermal energy into electrical energy to have one or more Peltier elements in order to generate the electrical energy from the thermal energy released by the exothermic reaction in the reaction tank. The electrical energy is then preferably present in the form of electrical current.The generated electrical energy is then supplied to the control unit via power lines. It is possible for the generated electrical energy to be initially supplied to a voltage converter and / or an energy store before the electrical energy reaches the control unit. The voltage converter can provide a constant voltage, for example of 3 V or more, on the basis of the generated electrical energy, in particular the generated electrical current, which voltage converter is subsequently used for operating the control unit in order to set the second oxygen quantity emitted from the pressure tank to the load unit using the electrical energy provided by the energy converter. In this case, the pressure tank can be activated by means of the control unit, in particular a regulating valve can be opened, so that an oxygen flow from the pressure tank is initiated in order to provide the second oxygen demand to the consumer unit.The pressure tank may be, for example, a gas cylinder filled with pressurized gas, i.e., pressurized oxygen gas, or the like. In particular, the pressure tank can be a permanently sealed or sealed oxygen cylinder tank with an electrical ignition device. The pressure tank has a connection to a second oxygen line, so that the second oxygen quantity provided by the pressure tank can be provided to the consumer unit via the second oxygen line.According to one embodiment of the invention, the oxygen supply device has a detection unit for detecting a measured value, wherein the detected measured value corresponds to an oxygen flow from the reaction tank and / or wherein the detected measured value corresponds to an ambient pressure in or outside the aircraft and / or wherein the detected measured value corresponds to an operating time of the control unit.The detection unit may include a sensor for detecting the oxygen flow conducted through the first oxygen line. This means that the oxygen flow coming from the reaction tank is detectable by the detection unit and is provided as a measurement value to the control unit.The detection unit may also comprise a pressure sensor for measuring a cabin pressure in the passenger cabin of the aircraft in order to measure the pressure in the cabin and to provide the measured pressure measurement value from the cabin to the control unit.The detection unit can also determine the operating time of the control unit, wherein the operating time of the control unit can be predefined by the start of the power supply by the electrical energy provided by the energy converter and / or by the stored electrical energy provided by the energy store.According to a further embodiment of the invention, the control unit is designed to set the second oxygen quantity provided by the pressure tank to the consumer unit as a function of the recorded measured value.The control unit can have, for example, a computing unit or a computer for processing the captured measured values and for generating control signals based on these measured values. The control unit preferably has a microcontroller on which a software or a program for evaluating the captured measured value and for generating corresponding control signals is stored. The microcontroller is supplied by the electrical energy from the energy converter, in particular from the energy storage unit. The generated control signals drive a control valve to control the oxygen flow from the pressure tank. Further, the control signals drive the electrical igniter of the pressure tank to initiate the second oxygen flow from the pressure tank.The measurement value or a combination of the above-explained measurement values can now be used by the control unit as a basis for the regulation of the oxygen flow through the first oxygen line coming from the reaction tank and / or for the regulation of the oxygen flow through the second oxygen line coming from the pressure tank. For example, the oxygen flow from the pressure tank can be activated if the oxygen flow from the reaction tank through the first oxygen line falls below a limit value.According to a further embodiment of the invention, the oxygen supply device has an energy storage unit which is designed to store the electrical energy provided by the energy converter and to provide it to the control unit.Thus, the energy provided by the energy converter may be stored first before being used by the control unit for regulating the oxygen flow or the amount of oxygen from the pressure tank. For this purpose, the energy storage unit can have a capacitor, in particular a supercapacitor, for example. The energy store is preferably charged by the electrical energy provided via the voltage converter and maintains this state of charge during the entire supply period during which oxygen is emitted to the load unit by the oxygen supply device.According to a further embodiment of the invention, the control unit is activated only when a predefined state of charge of the energy storage unit is reached.Thus, sufficient energy can be stored in the energy storage unit so that the stored energy alone is sufficient to subsequently supply the control unit and the control circuit connected thereto with electric current for adjusting the oxygen flows without recourse to an external power supply. As a result, the power consumption when supplying oxygen to a passenger cabin of an aircraft can be significantly reduced.According to a further embodiment of the invention, the control unit is designed to provide a minimum oxygen flow from the reaction tank and / or from the pressure tank to the consumer unit of the aircraft during a predefined period of time.Thus, an adequate oxygen supply to the consumer unit, in particular in the case of an emergency oxygen supply, can always be ensured. In this case, for example, the second oxygen flow provided by the pressure tank can be initiated or increased if the first oxygen flow becomes lower, in particular if the second oxygen flow falls below a limit value.According to a further embodiment of the invention, the control unit is designed to continuously adjust the second oxygen quantity provided from the pressure tank to the consumer unit by means of a control valve, so that the second oxygen quantity provided increases as the first oxygen quantity is provided in a decreasing manner.Thus, a desired oxygen flow to the consumer unit can always be kept constant, so that any legal regulations available for an oxygen provision at the consumer unit are complied with. The control valve can be continuously opened or closed, so that a continuous adjustment of the oxygen flow provided by the pressure tank is made possible.According to a further embodiment of the invention, the reaction tank is designed to provide the first amount of oxygen to the consumer unit over a period of at least 10 min. Furthermore, the pressure tank is designed to provide the second amount of oxygen to the consumer unit over a period of at least 50 min.This means that the minimum oxygen flow to be delivered to the consumer unit is not fallen below during a total period of 60 min. After 10 min, the oxygen flow provided by the pressure tank can thus be activated, since the oxygen flow from the reaction tank is no longer sufficient, for example, to ensure the minimum oxygen flow to be provided to the consumer unit. The pressure tank is then switched on in a quasi-way, so that a sufficient oxygen flow is ensured for the remaining 50 min. These times can correspond to legal framework conditions, in particular for the case of an emergency oxygen supply in a passenger cabin of an aircraft.According to one aspect of the invention, an aircraft having the above-described oxygen supply device for supplying a passenger cabin of the aircraft with oxygen, in particular emergency oxygen, is specified.Furthermore, a use of the above-described oxygen supply device for supplying a passenger cabin of the aircraft with emergency oxygen is also specified.According to a further aspect of the invention, a method for supplying a passenger cabin of an aircraft with oxygen is specified. In one step of the method, a first amount of oxygen obtained from a chemical reaction in a reaction tank is provided. In a further step, a second amount of oxygen stored in a pressure tank is provided. In a further step, a thermal energy generated by the chemical reaction is converted into electrical energy. Finally, in a further step, this electrical energy is used to adjust the second amount of oxygen provided by the pressure tank to a consumer unit. The pressure tank is connected to the consumer unit exclusively via an electrical ignition device, a second line, a regulating valve and a third line.In this case, it is possible for only the first oxygen quantity to be provided first and for the second oxygen quantity to be provided only when a specific time has elapsed and / or when a measured value is recorded.A typical cycle of operation of the oxygen supply device according to the invention could appear as follows in the order given:First, the oxygen supply device is activated, for example automatically in the event of a pressure drop in the passenger cabin of the aircraft or by pilot decision. Then, flaps in the passenger cabin are opened and the passengers are provided with oxygen or breathing masks, respectively. By pulling on the breathing masks, the chemical generator, i.e. the reaction tank, is started and oxygen is conducted to the breathing masks and provided to the passengers for at least 10 min by the exothermic reaction in the reaction tank. The heat generated by the chemical reaction is converted into an electric voltage and then stored. After the electrical storage has reached a specific state of charge, the microcontroller is activated and monitors the sensors for the acquisition of the measured values. Based on the sensing of the sensor inputs, in particular the sensing of the measurement (e.g., the measured oxygen flow from the chemical generator, the measured flight altitude, and / or the determined microcontroller operating time), the microcontroller software determines when to open the sealed pressure tank. Due to the thermal mass of the chemical generator, thermal energy can still be provided even when the reaction in the generator has already ended. The oxygen is now supplied from the pressure tank for at least 50 minutes.Brief Description of the FiguresFIG. 1 shows an oxygen supply device according to an embodiment of the invention. FIG. 2 shows an aircraft with an oxygen supply device according to an exemplary embodiment of the invention. FIG. 3 shows a flow chart for a method for supplying a passenger cabin of an aircraft with oxygen.DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTSThe representations in the figures are schematic and not to scale.If the same reference numerals are used in the following description of the figures in different figures, these denote the same or similar elements. Identical or similar elements can, however, also be denoted by different reference numerals.FIG. 1 shows a circuit diagram of an oxygen supply device 10. The oxygen supply device 10 has a reaction tank 11 for chemical oxygen generation and a pressure tank 12 filled with oxygen. The oxygen supply device 10 further comprises an energy converter 13 for converting thermal energy into electrical energy, in particular into electrical current. A voltage converter 18 of the oxygen supply device 10 is designed to set a specific voltage on the basis of the electric current generated by the energy converter 13. The electrical energy provided by the voltage converter 18 and / or the electrical energy provided by the energy converter 13 can be stored in an energy store 17 and subsequently supplied to a control unit of the oxygen supply device 10 or directly supplied to the control unit 14.The control unit 14 can adjust or regulate a first oxygen quantity provided from the reaction tank 11 to a consumer unit 15 and / or a second oxygen quantity provided from the pressure tank 12 to the consumer unit 15. In particular, a first oxygen flow 21 afrom the reaction tank 11 to the consumer unit 15 and / or a second oxygen flow 22 afrom the pressure tank 12 to the consumer unit 15 can be adjusted by the control unit 14. For this adjustment, which is carried out by means of the control unit 14, the electrical energy provided by the energy converter 13 is used. It is possible that the control unit 14 adjusts the second oxygen quantity provided by the pressure tank 12 to the consumer unit 15 using only the electrical energy provided by the energy converter 13 and thus does not require an external energy source.The oxygen supply device 10 has a detection unit 16 for detecting a measured value, wherein the detection unit 16 itself can also be supplied by the electrical energy provided by the energy converter 13. The detection unit 16 has a sensor 16 afor measuring the oxygen flow 21 athrough a first line 21. The first line 21 connects the reaction tank 11 to the consumer unit 15. Furthermore, a pressure sensor 16 bmay be provided for measuring a current pressure within a passenger cabin of the aircraft.The sensors 16 a, 16 bmay be connected to the control unit 14 via data lines 30 in order to supply the control unit 14 with data, in particular with the measurement values measured by the sensors 16 a, 16 b.Further signal or data lines 30 connect the control unit 14 to a regulating valve 19, so that the regulating valve 19 can be controlled by the control signals provided by the control unit 14 in such a way that the second oxygen flow 22 acan be adjusted from the pressure tank 12 to the consumer unit 15. In this case, an electrical ignition device 19 acan likewise trigger activation of the pressure tank 12 by control signals, that is to say start or initiate the second oxygen flow 22 a. A second line 22 connects the pressure tank 12 to the consumer unit 15. The control unit 14 adjusts the second oxygen quantity provided from the pressure tank 12 to the consumer unit 15, i.e. the second oxygen flow 22 athrough the second line 22, as a function of the measured values acquired by the acquisition unit 16.The first line 21 and the second line 22 merge into a third line 23 before the third line 23 finally ends in the consumer unit 15.The control unit 14 is designed to provide a minimum oxygen flow from the reaction tank 11 and / or from the pressure tank 12 to the consumer unit 15 of the aircraft during a predefined period of time, in that the first oxygen flow 21 athrough the first line 21 and / or the second oxygen flow 22 athrough the second line 22 are regulated such that the oxygen flow through the third line 23 does not fall below a minimum limit value.The control unit 14 is also designed to continuously adjust the second oxygen quantity provided by the pressure tank 12 to the consumer unit 15 by means of the regulating valve 19 in such a way that the second oxygen flow 22 ais increased with a decreasing first oxygen flow 21 a. However, it can also be provided that the control valve 19 for providing the second oxygen flow 22 ais only opened when the first oxygen flow 21 aexceeds a limit value, which is determined by the sensor 16 a.FIG. 2 shows an aircraft 100 having an oxygen supply device 10 for supplying a passenger cabin 110 of the aircraft 100 with oxygen, in particular with emergency oxygen, via the load unit 15, not shown. In this case, it can be provided that the emergency oxygen is provided to the passengers of the aircraft 100 via breathing masks, wherein the consumer unit 15 can have a multiplicity of breathing masks.FIG. 3 shows a flow diagram of a method for supplying a passenger cabin 110 of an aircraft 100 with oxygen. In a step S 1 of the method, a first amount of oxygen obtained from a chemical reaction in a reaction tank 11 is provided. In a further step S 2, a second amount of oxygen stored in a pressure tank 12 is provided. In a further step S 3, a thermal energy generated by the chemical reaction is converted into electrical energy. This electrical energy is then used in a further step S 4 for adjusting the second oxygen quantity provided by the pressure tank 12 to a consumer unit 15.Additionally, it should be noted that "comprising" does not exclude other elements or steps and "a" or "an" does not exclude a plurality. It should also be noted that features or steps that have been described with reference to one of the above exemplary embodiments can also be used in combination with other features or steps of other exemplary embodiments described above. Reference signs in the claims should not be regarded as limiting.

Claims

Oxygen supply device (10) for an aircraft (100), comprising: a reaction tank (11) for chemical oxygen generation; a pressure tank (12) filled with oxygen; an energy converter (13) for converting thermal energy into electrical energy; a control unit (14) for adjusting an amount of oxygen provided by the pressure tank (12) to a consumer unit (15); wherein the energy converter (13) is designed to convert a thermal energy generated by the chemical oxygen generation in the reaction tank (11) into electrical energy and to provide the electrical energy; and wherein the control unit (14) is designed to adjust the amount of oxygen provided by the pressure tank (12) to the consumer unit (15) using the electrical energy provided by the energy converter (13); wherein the pressure tank (12) is connected to the consumer unit (15) exclusively via an electrical ignition device (19a), a second line (22), a control valve (19) and a third line (23).The oxygen supply device (10) according to claim 1, comprising: a detection unit (16) for detecting a measurement value, wherein the detected measurement value corresponds to an oxygen flow (21a) from the reaction tank (11); and / or wherein the detected measurement value corresponds to an ambient pressure in the aircraft (100); and / or wherein the detected measurement value corresponds to an operating time of the control unit (14).Oxygen supply device (10) according to Claim 2, wherein the control unit (14) is designed to set the second oxygen quantity provided by the pressure tank (12) to the consumer unit (15) as a function of the recorded measured value.Oxygen supply device (10) according to one of the preceding claims, comprising: an energy storage unit (17) which is designed to store the electrical energy provided by the energy converter (13) and to provide it to the control unit (14).Oxygen supply device (10) according to Claim 4, wherein the control unit (14) is activated only when a predefined state of charge of the energy storage unit (17) is reached.The oxygen supply device (10) according to any one of the preceding claims, wherein the control unit (14) is configured to provide a minimum oxygen flow from the reaction tank (11) and / or from the pressure tank (12) to the consumer unit (15) of the aircraft (100) during a predetermined period of time.Oxygen supply device (10) according to one of the preceding claims, wherein the control unit (14) is designed to continuously adjust the second oxygen quantity provided by the pressure tank (12) to the consumer unit (15) by means of a control valve (19), such that the second oxygen quantity provided increases as the first oxygen quantity is provided in a decreasing manner.The oxygen supply device (10) according to any one of the preceding claims, wherein the reaction tank (11) is configured to provide the first amount of oxygen to the consumer unit (15) over a period of at least 10 min; and / or wherein the pressure tank (12) is configured to provide the second amount of oxygen to the consumer unit (15) over a period of at least 50 min.Aircraft (100) having an oxygen supply device (10) according to one of the preceding claims for supplying a passenger cabin (110) of the aircraft (100) with oxygen.Method for supplying a passenger cabin (110) of an aircraft (100) with oxygen, comprising the steps of: providing a first amount of oxygen (S1) obtained from a chemical reaction in a reaction tank (11); providing a second amount of oxygen (S2) stored in a pressure tank (12); converting a thermal energy generated by the chemical reaction into electrical energy (S3); using the electrical energy for adjusting the second amount of oxygen provided by the pressure tank (12) to a consumer unit (15, S4); wherein the pressure tank (12) is connected to the consumer unit (15) exclusively via an electrical ignition device (19a), a second line (22), a control valve (19) and a third line (23).

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