Chemical oxygen generator with bimetal reaction control

Abstract

The invention relates to a regulation device for a source of breathable gas, comprising a reaction medium adapted to perform an exothermic reaction for the production of breathable gas, the reaction medium surrounding an interior reaction volume having a breathable gas outlet. The invention further relates to a chemical oxygen generator system for the provision of breathable gas in an aircraft as well as to a method for regulating a source of breathable gas comprising the step of initiating an exothermic reaction of a reaction medium for the production of breathable gas, the reaction medium surrounding an interior reaction volume having a breathable gas outlet, wherein the breathable gas is flowing through the breathable gas outlet.

Claims

1. A regulation device for a source of breathable gas, comprising: a reaction medium comprising sodium chlorate having iron fillings, the reaction medium adapted to perform an exothermic reaction for production of oxygen, the reaction medium having an annular shape and surrounding an interior reaction volume having a reaction gas inlet and a first breathable gas outlet; a flow regulator arranged at the first breathable gas outlet and adapted to regulate a flow of oxygen through the first breathable gas outlet depending at least on a temperature of the regulation device and to throttle the flow of oxygen through the first breathable gas outlet if the temperature of the regulation device is increased; a rigid housing comprising a substantially tubular shape and comprising a second breathable gas outlet; and an exterior volume arranged radially outwardly between the reaction medium and an annular wall of the housing, the exterior volume surrounding the reaction medium radially, wherein the regulation device is adapted to direct a flow of reaction gas through the exterior volume towards the reaction gas inlet of the interior reaction volume.

2. A regulation device according to claim 1, wherein the flow regulator comprises a valve body actuated by a bimetal element.

3. A regulation device according to claim 1, comprising: a pressure relief valve adapted to release the oxygen from the housing if a predetermined pressure value is exceeded.

4. A regulation device according to claim 1, wherein the flow regulator is adapted to regulate the flow of the oxygen through the first breathable gas outlet depending on an ambient temperature of an aircraft.

5. A regulation device according to claim 4, wherein the flow regulator is adapted to throttle the flow of the oxygen through the first breathable gas outlet if the ambient temperature of the aircraft is increased.

6. Method for regulating a source of breathable gas, comprising the steps of: a) initiating an exothermic reaction of a reaction medium comprising sodium chlorate having iron fillings for production of oxygen, the reaction medium having an annular shape and surrounding an interior reaction volume having a reaction gas inlet and a first breathable gas outlet, wherein the oxygen is flowing in a first direction through an exterior volume formed circumferentially around the reaction medium, from the exterior volume through the reaction gas inlet into the interior reaction volume, through the interior reaction volume in a second direction opposite the first direction and through the first breathable gas outlet, and b) regulating a flow of the oxygen, which is flowing through the first breathable gas outlet, by a regulation device depending at least on a temperature of the regulation device.

7. Method according to claim 6, wherein the regulating is achieved by a flow regulator comprising a valve body actuated by a bimetal.

8. Method according to claim 6, comprising the step of: directing a flow of reaction gas, which is flowing to a reaction gas inlet of the interior volume, through the exterior volume, the exterior volume being arranged between the reaction medium and a wall of a housing having a second breathable gas outlet.

9. Method according to claim 6, comprising the step of: regulating the flow of the oxygen through the first breathable gas outlet depending on an ambient temperature of an aircraft.

10. Method according to claim 9, comprising the step of: throttling the flow of the oxygen through the first breathable gas outlet if the temperature of the regulation device and/or the ambient temperature of the aircraft increases.

11. A regulation device according to claim 1, wherein the flow regulator consists of a valve body actuated by a bimetal element.

12. A regulation device according to claim 2, wherein the bimetal element is a bimetallic arm.

13. A regulation device according to claim 11, wherein the bimetal element is a bimetallic arm.

14. A regulation device according to claim 3, wherein the pressure relief valve is connected to a conduit adapted to direct the oxygen released by the pressure relief valve to an aircraft cabin.

15. A regulation device for a source of breathable gas, comprising: a rigid housing comprising a substantially tubular shape that includes an exterior sidewall defining an inner cavity and a gas outlet in fluid communication with the inner cavity; a reaction medium positioned within the inner cavity, the reaction medium defining an interior reaction volume having an inlet and an outlet, the reaction medium and housing defining an exterior reaction volume between the reaction medium and the exterior sidewall and in fluid communication with the interior reaction volume; a flow regulator arranged between the outlet of the inner reaction volume and the gas outlet of the housing, the flow regulator adapted to selectively throttle a flow of the breathable gas from the outlet of the reaction medium to the gas outlet of the housing based on a temperature of the regulation device; and an ignitor adapted to activate the reaction medium, wherein an activation of the reaction medium produces the breathable gas.

16. A regulation device according to claim 15, wherein the housing further comprises an interior wall within the inner cavity, wherein the interior wall defines a first chamber and a second chamber within the inner cavity, wherein the reaction medium is positioned within the first chamber, and wherein the flow regulator is positioned within the second chamber.

17. A regulation device according to claim 16, wherein the housing further comprises a support within the inner cavity, wherein the reaction medium is supported by the support within the inner cavity.

18. A regulation device according to claim 17, wherein the interior wall defines an aperture in fluid communication with the outlet of the interior reaction volume, and wherein the flow regulator comprises: a valve seat extending from the interior wall; a valve body selectively movable through the valve seat; and a bimetallic arm connected to the valve body, the bimetallic arm elastically deformable between a first state and a second state.

19. A regulation device according to claim 15, wherein the housing further comprises an isolation layer at the exterior sidewall within the inner cavity.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) A preferred embodiment of the invention is described in connection with the FIGURE which illustrates an embodiment of the regulation device according to the present invention.

DETAILED DESCRIPTION OF THE DRAWING

(2) The FIGURE shows an embodiment of a regulation device 1 according to the present invention in a cross-sectional side view. The regulation device 1 operates according to an embodiment of the method according to the present invention. The regulation device 1 is seated within a housing 3 having a first chamber 5 and a second chamber 7. A reaction medium 9 is seated within the first chamber 5. The reaction medium 9 has annular shape surrounding an interior reaction volume 10 having a reaction gas inlet 11 and a breathable gas outlet 13. A wall 15 separates the first chamber 5 and second chamber 7, the wall 13 having an aperture 17 for flow 18 of breathable gas from the reaction gas outlet 13 to a flow regulator 19. The reaction medium 9 abuts the wall 15 at the breathable gas outlet 13 and is seated partially within a support 21.

(3) The reaction medium 9 consists of sodium chlorate (NaClO.sub.3) having iron fillings. When the reaction for the production of oxygen is initiated, the sodium chlorate reacts with the iron to sodium chloride, iron(II) oxide (FeO) and oxygen.

(4) An exterior volume 23 is formed between the reaction medium 9 and an annular wall 25 of the housing 3. The support 21 has an aperture 27 for allowing a flow 29 of reaction gas to pass when flowing through the exterior volume 23 on its way to the interior reaction volume 10.

(5) The flow regulator 19 is arranged within the second chamber 7 of the housing 3 and consists of a valve seat 31, a valve body 33 and a bimetallic arm 35. The valve seat 31 extends from the wall 15 having a substantially conical shape. The valve body 33 consists of a rod 37 and a head portion 39 having a substantially conical surface 41 corresponding to a conical surface 43 of the valve seat 31.

(6) The regulation device 1 has an ignitor 45 for triggering an exothermic reaction of the reaction medium 9 for the production of breathable oxygen, in a method step a). The ignition is started when a passenger pulls an oxygen supply mask from a passenger service unit. The exothermic reaction produces the flow 18 of breathable gas to the breathable gas outlet 13. The housing 3 has a breathable gas outlet 47 for directing the breathable gas to a passenger in an aircraft (not shown in the FIGURE).

(7) In a method step b), when the temperature in the first chamber 5 and second chamber 7 increases, the bimetallic arm 35 changes its form, i.e. the bimetallic arm bends to the left (as seen in viewing direction of the FIGURE). Thereby, valve body 33 moves horizontally to the left (as see in viewing direction) and the head portion 39 moves closer to the valve seat 31. Thereby, the flow of breathable gas through the flow regulator 19 is throttled and, at the same time, the pressure within the first chamber 5, in particular the interior reaction volume 10 increases. An increase of the pressure in the first chamber 5 leads to a negative shift of the exothermic reaction, i.e. the exothermic reaction is slowed down.

(8) The first chamber 5 further has a pressure relief valve 49 arranged at the housing 3. The pressure relief valve 49 releases breathable gas from the housing 3 if a predetermined pressure value is exceeded. The pressure relief valve 49 is connected to a conduct 51 for directing the breathable gas released by means of the pressure relief valve 49 to the oxygen supply mask arranged in an aircraft cabin where the passengers are seated. Furthermore, an annular isolation layer 53 is formed at the annular wall 25 for preventing high temperatures within the housing 3 to be transferred to the environment of the housing 3.

REFERENCE NUMERALS

(9) 1 regulation device 3 housing 5 first chamber 7 second chamber 9 reaction medium 10 interior reaction volume 11 reaction gas inlet 13 breathable gas outlet 15 wall 17 aperture 18 flow 19 flow regulator 21 support 23 exterior volume 25 annular wall 27 aperture 29 flow 31 valve seat 33 valve body 35 bimetallic arm 37 rod 39 head portion 41 conical surface 43 conical surface 45 ignitor 47 breathable gas outlet 49 pressure relief valve 51 conduct 53 isolation layer