METHOD AND DEVICE FOR DETECTING THE COMPOSITION OF GAS MIXTURES

• US 20100300180A1
• Filed: 11/26/2008
• Published: 12/02/2010
• Est. Priority Date: 11/29/2007
• Status: Active Grant

• Current Assignee: Sacmi Cooperativa Meccanici Imola Soc. Coop.
• Original Assignee: Sacmi Cooperativa Meccanici Imola Soc. Coop.
• Inventors: Ricco', Ibanez, Bosi, Gildo, Remondini, Marco
• Granted Patent: US 8,256,264 B2
• Time in Patent Office: Days
• US Class Current: 73/29.02
• CPC Class Codes: G01N 33/0006 Calibrating gas analysers
• CPC Class Codes: G01N 33/0031 comprising two or more sensors, e.g. a sensor array

Abstract

A method for detecting the composition of an unknown gas mixture (M_inc) through an electronic nose (2) equipped with a measuring chamber (3) that houses at least one sensor comprises the steps of: calibrating a sensor by feeding a known gas mixture (M_n) into the measuring chamber (3); feeding the unknown gas mixture (M_inc) into the chamber (3), while keeping the unknown gas mixture (Mine) in a predetermined desired state; and detecting the composition of the unknown gas mixture (M_inc) by means of the sensor.

Claims

1-27. -27. (canceled)

28. A method for detecting the composition of an unknown gas mixture (M_inc) through an electronic nose (2) equipped with a measuring chamber (3) that houses at least one sensor, comprising the steps of:

calibrating the at least one sensor by feeding a known gas mixture (M_n) into the measuring chamber (3);

feeding the unknown gas mixture (M_inc) into the chamber (3), while keeping the unknown gas mixture (M_inc) in a predetermined desired state;

detecting the composition of the unknown gas mixture (M_inc) by means of the at least one sensor,

wherein it further comprises steps of

mixing the unknown gas mixture (M_inc) with a cleaning gas mixture (M_p) to form a sample gas mixture (M_camp) and

regulating the state of the cleaning gas mixture (M_p) in order to keep the sample gas mixture (M_camp) and hence the unknown gas mixture (M_inc) in the predetermined desired state, in such a way as to keep the humidity of the sample gas mixture M_camp, and hence of the unknown gas mixture M_inc constant.

29. The method according to claim 28, wherein a humidity and temperature sensor (8) measures the humidity and temperature of the sample gas mixture M_camp before the latter enters the measuring chamber (3) and a conditioning system (18) varies the humidity of the cleaning gas mixture M_p in such a way as to keep the humidity of the sample gas mixture M_camp and hence of the unknown gas mixture M_inc constant.

30. The method according to claim 28, wherein the step, of calibrating the at least one sensor by feeding a known gas mixture (M_n) into the chamber (3) comprises the further step of keeping the known gas mixture (M_n) in the predetermined desired state.

31. The method according to claim 28, wherein it further comprises the step of mixing a fraction of a standard gas (G_S) and a fraction of the cleaning gas mixture (M_r) to form the known gas mixture (M_n).

32. The method according to claim 31, wherein the step of calibrating the at least one sensor with the known gas mixture (M_n) comprises the step of regulating the state of the cleaning gas mixture (M_p) in such a way as to keep the known gas mixture (M_n) in the desired state.

33. The method according to claim 28, wherein the state of the cleaning gas mixture (M_p) is regulated by a conditioning system (18).

34. The method according to claim 28, wherein the step of regulating the state of the cleaning gas mixture (M_p) comprises the step of delivering the cleaning gas mixture (M_p) into an evaporating chamber (28) on the bottom of which there is water heated by a heater (32, 33), the water evaporating and thus increasing the degree of humidity of the cleaning gas mixture (M_p).

35. The method according to claim 34, wherein the step of regulating the state of the cleaning gas mixture (M_p) comprises the step of delivering the cleaning gas mixture (M_p) leaving the evaporating chamber (28) into a condenser device (30) in such a way as to lower the degree of humidity of the cleaning gas mixture (M_p) to a preset value.

36. The method according to claim 28, wherein it comprises the step of making the cleaning gas mixture (M_p) flow through a catalyser (16) before mixing the cleaning gas mixture (M_p) with the unknown gas mixture (M_inc).

37. The method according to claim 28, wherein it comprises the step of making the cleaning gas mixture (M_p) flow through a catalyser (16) before mixing the cleaning gas mixture (M_p) with the standard gas (G_S) to form the known gas mixture (M_n).

38. The method according to claim 28, wherein it comprises the step of making the cleaning gas mixture (M_p) flow through an active carbon filter (17) before mixing the cleaning gas mixture (M_p) with the unknown gas mixture (M_inc) and with the standard gas (G_S).

39. The method according to claim 28, wherein the step of detecting the composition of the unknown gas mixture (M_inc) comprises the step of detecting the odoriferous compound in the unknown gas mixture (M_inc).

40. The method according to claim 28, where the unknown gas mixture (M_inc) is sample air (A_c) with unknown odour and the known gas mixture (M_n) is reference air (A_r), characterized in that it comprises the steps of:

calibrating the sensor with the reference air (A_r);

delivering a fraction of the sample air (A_c) into the chamber (3);

detecting the odour in the sample air (A_c);

regulating the state of one of either the reference air (A_r) or the sample air (A_c) before both the sample air (A_c) and the reference air (A_r) flow into the chamber (3).

41. The method according to claim 40, wherein during the regulating step the state of the reference air (A_r) is regulated.

42. The method according to claim 41, wherein the step of regulating the state of the reference air (A_r) comprises the step of regulating the temperature and humidity of the reference air (A_r).

43. The method according to claim 41, wherein the step of regulating the state of the reference air (A_r) comprises the step of delivering the reference air (A_r) into an evaporating chamber (28) on the bottom of which there is water heated by a heater (32, 33), the water evaporating and thus increasing the degree of humidity of the reference air (A_r).

44. The method according to claim 43, wherein the step of regulating the reference air (A_r) comprises the step of delivering the reference air (A_r) leaving the evaporating chamber (28) into a condenser device (30) in such a way as to lower the degree of humidity of the reference air (A_r) to a preset value.

45. The method according to claim 44, wherein it comprises the step of measuring the temperature and percentage of humidity of the sample air (A_c) before the air (A_c) flows into the measuring chamber (3).

46. The method according to claim 45, wherein the step of regulating the state of the reference air (A_r) is a function of the step of measuring the temperature and humidity of the sample air (A_c).

47. The method according to claim 45, wherein the step of regulating the degree of condensation of the reference air (A_r) inside the condenser device (30) is a function of the measured temperature and relative humidity of the sample air (A_c) so that the absolute humidity of the reference air (A_r) is substantially the same as the absolute humidity of the sample air (A_c).

48. The method according to claim 40, characterized in that it comprises the step of making the temperature of the reference air (A_r) and that of the sample air (A_c) equal before the two types of air flow into the measuring chamber (3).

49. A device for detecting the composition of at least one compound in an unknown gas mixture (M_inc) comprising:

an electronic nose (2) equipped with a measuring chamber (3) that houses at least one sensor for detecting the composition of the unknown gas mixture;

a system (18) for conditioning a cleaning gas mixture (M_p) that can be mixed with the unknown gas mixture (M_inc) and designed to regulate the state of the cleaning gas mixture (M_p) in such a way that the latter reaches desired predetermined conditions;

a junction (22) for mixing the unknown gas mixture (M_inc) with the cleaning gas mixture (M_p), located upstream of the measuring chamber (3),

the system (18) for conditioning the cleaning gas mixture (M_p) being designed to keep the humidity of the sample gas mixture M_camp and hence of the unknown gas mixture M_inc constant, to regulate the state of the cleaning gas mixture (M_p) in such a way as to keep the state of the unknown gas mixture (M_inc) in desired predetermined conditions.

50. The device according to claim 49, comprising

a humidity and temperature sensor (8) for measuring the humidity and temperature of the sample gas mixture M_camp before the latter enters the measuring chamber (3) and

a conditioning system (18) for varying the humidity of the cleaning gas mixture M_p in such a way as to keep the humidity of the sample gas mixture M_camp and hence of the unknown gas mixture M_inc constant.

51. The device according to claim 49, wherein the conditioning system (18) comprises an evaporating chamber (28) designed to increase the degree of humidity of the cleaning gas mixture (M_p) to a preset value.

52. The device according to claim 49, wherein the conditioning system (18) comprises a condenser (30) in fluid communication with the evaporating chamber (28) and designed to lower the degree of humidity of the cleaning gas mixture (M_p) to a preset value.

53. The device according to claim 49, wherein it comprises a sensor (8) for measuring the temperature and humidity of the unknown gas mixture (M_inc).

54. The device according to claim 53, characterized in that it comprises means (37) which, in response to a signal from the sensor (8), regulate the degree of condensation of the cleaning gas mixture (M_p) inside the condenser (30).