AUTO CALIBRATION / VALIDATION OF OXYGEN SENSOR IN BREATHING APPARATUS

• US 20110114094A1
• Filed: 10/29/2008
• Published: 05/19/2011
• Est. Priority Date: 10/29/2007
• Status: Active Grant

• Current Assignee: Poseidon Diving Systems AB
• Original Assignee: Poseidon Design Systems, Inc.
• Inventors: Stone, William C., Jones, Nigel
• Granted Patent: US 8,820,135 B2
• Time in Patent Office: Days
• US Class Current: 128/204.22
• CPC Class Codes: A61M 16/085 Gas sampling
• CPC Class Codes: A61M 16/12 by mixing different gases
• CPC Class Codes: A61M 16/122 with dilution
• CPC Class Codes: A61M 16/203 Proportional
• CPC Class Codes: A61M 16/22 Carbon dioxide-absorbing devices ; Other means for removing carbon dioxidecartridges with absorbing substances for respiratory apparatus A62B19/00
• CPC Class Codes: A61M 2016/1025 the O2 concentration
• CPC Class Codes: A61M 2202/0208 Oxygen
• CPC Class Codes: A61M 2205/17 with redundant control systems
• CPC Class Codes: A61M 2205/502 User interfaces, e.g. screens or keyboards
• CPC Class Codes: A61M 2205/702 automatically during use
• CPC Class Codes: A61M 2205/8206 battery-operated
• CPC Class Codes: A61M 2230/435 partial O2 pressure (P-O2)
• CPC Class Codes: A62B 9/006 Indicators or warning devices, e.g. of low pressure, contamination
• CPC Class Codes: B63C 11/12 Diving masks
• CPC Class Codes: B63C 11/24 in closed circulation

Abstract

The Invention is directed to an oxygen sensor arrangement (8) and a method for operating such an arrangement for sensing the oxygen in a breathing loop (29) of a breathing apparatus. The sensor arrangement comprises: at least one primary oxygen sensor (30) arranged to operatively measure the oxygen in the breathing loop (29), at least a secondary oxygen sensor (31) arranged to operatively measure the oxygen in the breathing loop (29), and a control arrangement (40) for obtaining measures from said oxygen sensors. A test channel arrangement (15, 48) is adapted to operatively provide a first gas having a first fraction of oxygen from a first gas supply (16) to said primary oxygen sensor (30) at a position (267) adjacent to said primary oxygen sensor (30). At least a first test valve arrangement (41, 42) is arranged to operatively open and close the flow of said first gas through said test channel arrangement (15, 48). Said control arrangement (40) is arranged to operatively actuate said first test valve arrangement (41, 42) so as to provide an amount of said first gas to said primary oxygen sensor (30) via said test channel arrangement (15, 48). Said control arrangement is arranged to operatively obtain measures from said primary (30) and secondary (31) oxygen sensors.

Claims

1. -34. (canceled)

35. An oxygen sensor arrangement (8) for sensing the oxygen in a breathing loop (29) of a breathing apparatus (100), which oxygen sensor arrangement (8) comprises:

at least one primary oxygen sensor (30, 31) arranged to operatively measure the oxygen in the breathing loop (29),

at least a secondary oxygen sensor (31, 32) arranged to operatively measure the oxygen in the breathing loop (29), and

a control arrangement (40) for obtaining measures from said oxygen sensor, wherein;

a test channel arrangement (15, 362) is adapted to operatively provide a first gas having a first known fraction of oxygen from a first gas supply (20) to said primary oxygen sensor (30, 31) at a position (267, 267′

) adjacent to or directly adjacent to said primary oxygen sensor, and

at least a first test valve arrangement (41) is arranged to operatively open and close the flow of said first gas through said test channel arrangement (15, 362),

said control arrangement (40) is arranged to operatively actuate said first test valve arrangement (41) so as to provide an amount of said first gas to said primary oxygen sensor (30, 31) via said test channel arrangement (15, 362), and

said control arrangement (40) is arranged to operatively obtain measures from said primary and secondary oxygen sensors (30, 31, 32).

36. The oxygen sensor arrangement (8) according to claim 35,

wherein:

the test channel arrangement (15, 362) is adapted to provide a second gas having

a second known fraction of oxygen from a second gas supply (16) to said primary oxygen sensor (30, 31) at a position (267, 267′

) adjacent to or directly adjacent to said primary oxygen sensor (30, 31), and

at least a second test valve arrangement (46) is arranged to operatively open and

close the flow of said second gas through said test channel arrangement (15, 362), and

said control arrangement (40) is arranged to operatively actuate said second test valve arrangement (46) so as to provide an amount of said second gas to said primary oxygen sensor via said test channel arrangement (15, 362).

37. The oxygen sensor arrangement (8) according to claim 35,

wherein:

said control arrangement (40) is arranged to operatively obtain at least one first test measure from said primary oxygen sensor (30, 31) when it is provided with an amount of said first gas.

38. The oxygen sensor arrangement (8) according to claim 36,

wherein:

said control arrangement (40) is arranged to operatively obtain at least one second test measure from said primary oxygen sensor (30, 31) when it is provided with an amount of said second gas.

39. The oxygen sensor arrangement (8) according to claim 38,

wherein said control arrangement (40) is arranged to operatively:

calculate a at least first calibration point using said first test measure and at least using the known fraction of oxygen in the first gas,

calculate a at least second calibration point using said second test measure and at least using the known fraction of oxygen in the second gas, and

generate a calibration curve for said primary oxygen sensor (30, 31) at least based on said first calibration point and said second calibration point.

40. The oxygen sensor arrangement (8) according to claim 37,

wherein said control arrangement (40) is arranged to operatively:

obtain a validation point value using said first test measure or said second test measure,

obtain an expected value for the validation point value, at least using the known fraction of oxygen in the first gas or the known fraction of oxygen in the second gas, and

determine if the validation point value deviates from the expected value more than a predetermined amount.

41. The oxygen sensor arrangement (8) according to claim 39,

wherein said control arrangement (40) is arranged to operatively:

obtain the expected value for the validation point value by using the calibration curve so as to compensate for possible deviations in said primary oxygen sensor (30, 31).

42. The oxygen sensor arrangement (8) according to claim 35

wherein:

said primary oxygen sensor (30, 31) is arranged in a cavity (33, 34, 35) that is in fluid communication with the breathing loop (29, 29′

) and that is provided with at least one output orifice (267, 267′

) for said test channel arrangement (15, 362), which output orifice is arranged at a position adjacent to or directly adjacent to said primary oxygen sensor (30, 31) so that at least on of said first gas or said second gas can be operatively injected at an oblique angle with respect to the surface of the primary oxygen sensor (30, 31).

43. The oxygen sensor arrangement (8) according to claim 35, wherein:

said control arrangement (40) is arranged to operatively obtain measures from the secondary oxygen sensor (31, 32) and the primary sensor (30, 31) when no test valve arrangements (41, 46) are actuated to provide any of the first gas or the second gas onto the secondary oxygen sensor (31, 32) or the primary sensor (30, 31).

44. The oxygen sensor arrangement (8) according to claim 35, wherein:

said control arrangement (40) is arranged to operatively obtain a fitted calibration curve for said secondary oxygen sensor (31, 32) using measures operatively assembled from the secondary oxygen sensor (31, 32) and the primary sensor (30, 31).

45. The oxygen sensor arrangement (8) according to claim 44, wherein:

said control arrangement (40) is arranged to operatively obtain statistical correlation representation indicative of the correlation of the assembled measures with respect to the obtained fitted calibration curve.

46. The oxygen sensor arrangement (8) according to claim 45, wherein:

said control arrangement (40) is arranged to operatively issue an alert to the user if the statistical correlation representation is outside an allowable tolerance.

47. The oxygen sensor arrangement (8) according to claim 43, wherein:

said control arrangement (40) is arranged to operatively actuate at least one of said first test valve arrangement (41) or said second test valve arrangement (46) if the primary sensor (30, 31) measures deviates from the secondary oxygen sensor (31, 32) measures more than a predetermined amount.

48. The oxygen sensor arrangement (8) according to claim 43, wherein:

said secondary oxygen sensor is arranged at a distance from the gas output of at least one of said first test valve arrangement (41) or said second test valve arrangement (46), such that a gas leakage from at least one of said first test valve arrangement (41) or said second test valve arrangement (46) will cause the secondary sensor (31, 32) to operatively provide a different measure compared to the measure provided by the primary oxygen sensor (30, 31).

49. Method for sensing the oxygen in a breathing loop (29) of a breathing apparatus (100) wherein the method in an oxygen sensor arrangement (8) comprises the steps of;

actuating a first test valve arrangement (41) so as to provide an amount of a first gas having a first known fraction of oxygen via a test channel arrangement (15, 362) to a primary oxygen sensor (30, 31) at a position (267, 267′

) adjacent to or directly adjacent to said primary oxygen sensor.

50. The method according to claim 49,

wherein the method comprises the steps of:

actuating a second test valve arrangement (46) so as to provide an amount of a second gas having a second known fraction of oxygen via said test channel arrangement (15, 362) to said primary oxygen sensor (30, 31) at a position (267, 267′

) adjacent to or directly adjacent to said primary oxygen sensor.

51. The method according to claim 49,

wherein the method comprises the steps of:

obtaining at least one first test measure from said primary oxygen sensor (30, 31) when it is provided with an amount of said first gas.

52. The method according to claim 50,

wherein the method comprises the steps of:

obtaining at least one second test measure from said primary oxygen sensor (30, 31) when it is provided with an amount of said second gas.

53. The method according to claim 52,

wherein the method comprises the steps of:

calculating at least a first calibration point using said first test measure and at least using the known fraction of oxygen in the first gas,

calculating at least a second calibration point using said second test measure and

at least using the known fraction of oxygen in the second gas, and

generating a calibration curve for said primary oxygen sensor (30, 31) at least based on said first calibration point and said second calibration point.

54. The method according to claim 52,

wherein the method comprises the steps of:

obtaining a validation point value using said first test measure or said second test measure,

obtaining an expected value for the validation point value, at least using the known fraction of oxygen in the first gas or the known fraction of oxygen in the second gas, and

determining if the validation point value deviates from the expected value more than a predetermined amount.

55. The method according to claim 53,

wherein the method comprises the steps of:

obtaining the expected value for the validation point value by using the calibration curve so as to compensate for possible deviations in said primary oxygen sensor (30, 31).

56. The method according to claim 49,

wherein the method comprises the steps of:

obtaining measures from a secondary oxygen sensor (31, 32) and the primary sensor (30, 31) when no test valve arrangements (41, 46) are actuated to provide any of the first gas or the second gas onto the secondary oxygen sensor (31, 32) or the primary sensor (30, 31).

57. The method according to claim 56,

wherein the method comprises the steps of:

obtaining a fitted calibration curve for said secondary oxygen sensor (31, 32) using measures operatively assembled from the secondary oxygen sensor (31, 32) and the primary sensor (30, 31).

58. The method according to claim 57,

wherein the method comprises the steps of:

obtaining statistical correlation representation indicative of the correlation of the assembled measures with respect to the obtained fitted calibration curve.

59. The method according to claim 58

wherein the method comprises the steps of:

issuing an alert to the user if the statistical correlation representation is outside an allowable tolerance.

60. The method according to claim 56,

wherein the method comprises the steps of:

actuating at least one of said first test valve arrangement (41) or said second test valve arrangement (46) if the primary sensor (30, 31) measures deviates from the secondary oxygen sensor (31, 32) measures more than a predetermined amount.

61. The method according to claim 56,

wherein the method comprises the steps of:

arranging the secondary oxygen sensor at a distance from the gas output of at least one of said first test valve arrangement (41) or said second test valve arrangement (46), such that a gas leakage from at least one of said first test valve arrangement (41) or said second test valve arrangement (46) will cause the secondary sensor (31, 32) to operatively provide a different measure compared to the measure provided by the primary oxygen sensor (30, 31).