Gas sensor

• US 5,351,522 A
• Filed: 11/02/1993
• Issued: 10/04/1994
• Est. Priority Date: 11/02/1993
• Status: Expired due to Term

• Current Assignee: Nellcor Puritan Bennett Incorporated (Medtronic Plc)
• Original Assignee: Aequitron Medical, Inc. (Medtronic Plc)
• Inventors: Lura, David B.
• Primary Examiner(s): Williams, Hezron E.
• Assistant Examiner(s): ROSKOS, JOSEPH
• Application Number:
  US08/147,326
• Time in Patent Office: 336 Days
• Field of Search: 73/24.01, 73/64.53, 73/61.75, 73/61.79, 73/597, 73/861.18, 73/861.27, 73/861.28, 73/61.49
• US Class Current: 73/24.01
• CPC Class Codes: G01N 2291/0212 Binary gases
• CPC Class Codes: G01N 2291/02881 Temperature
• CPC Class Codes: G01N 2291/102 one emitter, one receiver
• CPC Class Codes: G01N 29/024 by measuring propagation velocity or propagation time of acoustic waves
• CPC Class Codes: G01N 29/2481 Wireless probes, e.g. with transponders or radio links
• CPC Class Codes: G01N 29/326 compensating for temperature variations

Abstract

The invention relates to an oxygen sensor which measures the concentration of oxygen based upon ultrasonic sound waves traveling through a binary gas. The measured sound-wave delay through the gases determines the concentration level for oxygen within the transducer chamber. The invention includes an L-shaped housing where a transmitter/transducer is attached to one end of the housing and the receiver/transponder is positioned at the junction between the two substantially straight portions of the L-shaped housing. A straight transducer chamber is thereby provided, while simultaneously provided a housing design which minimizes reflected standing waves for detection by the receiver/transponder. The invention includes a sonic baffle positioned at the opposite end of the L-shaped housing from the transmitter/transducer which minimizes standing waves thereby improving the performance of the gas detection device. The invention also includes a sound buffer affixed to the interior of the L-shaped housing which further reduces the existence and reflection of standing waves for detection by the receiver/transponder. Temperature is monitored within the transducer chamber by an angularly offset temperature sensor.

Claims

1. A gas-sensor device for detection of the presence and concentration of a gas, said gas-sensor device comprising:

(a) an L-shaped housing having a first transmitter end, a second gas outflow end, a junction receiver end, and a gas inlet port through said L-shaped housing proximal to said first transmitter end, said gas inlet port permitting flow-through access of said gas to be detected;

(b) a transmitter assembly having a transmitter/transducer and a temperature sensor positioned in said first transmitter end, said transmitter/transducer having means for generating sound waves for passing through said gas within said L-shaped housing;

(c) a gas outflow end cap assembly having a sonic baffle and a gas outlet port positioned in said second gas outflow end, said sonic baffle having means for reducing reflection of said sound waves within the said L-shaped housing;

(d) a receiver assembly having a receiver/transponder for receipt of said sound waves positioned in said junction receiver end; and

(e) a sound buffer means for reduction of reflected sound waves, said sound buffer means engaged to said L-shaped housing, said first transmitter end, said second gas outflow end, and to said receiver assembly.

2. The gas-sensor device according to claim 1, wherein said L-shaped housing is tubular in shape.

3. The gas-sensor device according to claim 1, wherein said L-shaped housing has a first grooved surface proximal to said first transmitter end.

4. The gas-sensor device according to claim 3, wherein said L-shaped housing has a second grooved surface of smaller diameter than said first grooved surface, said second grooved surface being positioned proximal to said first grooved surface within said first transmitter end of said L-shaped housing.

5. The gas-sensor device according to claim 4, wherein said first transmitter end has a first interior surface of smaller diameter than said second grooved surface, said first interior surface being positioned proximal to said second grooved surface within said first transmitter end of said L-shaped housing.

6. The gas-sensor device according to claim 5, wherein said second gas outflow end has a first channel surface.

7. The gas-sensor device according to claim 6, wherein said second gas outflow end has a second interior surface of smaller diameter than said first channel surface, said second interior surface being positioned proximal to said first channel surface within said second gas outflow end of said L-shaped housing.

8. The gas-sensor device according to claim 1, wherein said junction receiver end has a stop ledge.

9. The gas-sensor device according to claim 1, wherein said transmitter assembly has a transmitter end cap, and input electrical connections affixed to said transmitter/transducer which pass through said transmitter end cap.

10. The gas-sensor device according to claim 9, wherein said temperature sensor further comprises a diode having anode and cathode electrical connections which pass through said transmitter end cap.

11. The gas-sensor device according to claim 1, wherein said temperature sensor is angularly offset with respect to said L-shaped housing and is positioned adjacent to said sound buffer means.

12. The gas-sensor device according to claim 1, wherein said temperature sensor is responsive to the temperature within said L-shaped housing.

13. The gas-sensor device according to claim 1, wherein said transmitter/transducer includes means for generating ultrasonic sound waves.

14. The gas-sensor device according to claim 1, wherein said sonic baffle is conical in shape extending within said L-shaped housing toward said junction receiver end.

15. The gas-sensor device according to claim 1, wherein said gas outlet port has a circular base having a centrally-positioned aperture therethrough and a cylindrical-shaped barbed extension aligned to said aperture.

16. A gas-sensor device according to claim 15, wherein said sonic baffle is affixed to, and extends inwardly from, said circular base of said gas outlet port.

17. The gas-sensor device according to claim 1, wherein said sonic baffle has a plurality of longitudinal slots.

18. The gas-sensor device according to claim 1, wherein said receiver assembly has a receiver end cap, and output electrical connections affixed to said receiver/transponder which traverse said receiver end cap.

19. The gas-sensor device according to claim 1, wherein said receiver assembly is angularly offset with respect to said L-shaped housing.

20. The gas-sensor device according to claim 19, wherein said receiver/transponder is angularly offset with respect to said L-shaped housing at an angle of 45°

.

21. The gas-sensor device according to claim 1, wherein said transmitter/transducer and said receiver/transponder are aligned to one another within said L-shaped housing.

22. The gas-sensor device according to claim 1, wherein said sound buffer means comprises at least one felt insert.

23. The gas-sensor device according to claim 7, wherein said sound buffer means engages said first interior surface of said first transmitter end and said second interior surface of said second gas outflow end.

24. A gas-sensor device for detection of the presence and concentration of a gas, said gas-sensor device comprising:

(a) an L-shaped housing having a first transmitter end, a second gas outflow end, a junction receiver end, and a gas inlet port through said L-shaped housing proximal to said first transmitter end, said gas inlet port permitting flow-through access of said gas to be detected;

(b) a transmitter assembly having a transmitter/transducer and a temperature sensor positioned in said first transmitter end, said transmitter/transducer having means for generating sound waves for passing through said gas within said L-shaped housing;

(c) a gas outflow end cap assembly having a sonic baffle and a gas outlet port positioned in said second gas outflow end, said sonic baffle having means for reducing reflection of said sound waves within said L-shaped housing;

(d) a receiver assembly having a receiver/transponder means for receipt of said sound waves, positioned in said junction receiver end; and

(e) a fabric insert for reduction of reflected sound waves, said fabric insert being positioned within said L-shaped housing and being further engaged to said first transmitter end, said transmitter assembly, said second gas outflow end, said gas outflow end cap assembly, and to said receiver assembly.

25. The gas-sensor device according to claim 24, wherein said L-shaped housing is tubular in shape.

26. The gas-sensor device according to claim 24, wherein said L-shaped housing has a first grooved surface proximal to said first transmitter end.

27. The gas-sensor device according to claim 26, wherein said L-shaped housing has a second grooved surface of smaller diameter than said first grooved surface, said second grooved surface being positioned proximal to said first grooved surface within said first transmitter end of said L-shaped housing.

28. The gas-sensor device according to claim 27, wherein said first transmitter end has a first interior surface of smaller diameter than said second grooved surface, said first interior surface being positioned proximal to said second grooved surface within said first transmitter end of said L-shaped housing.

29. The gas-sensor device according to claim 28, wherein said second gas outflow end has a first channel surface.

30. The gas-sensor device according to claim 29, wherein said second gas outflow end has a second interior surface of smaller diameter than said first channel surface, said second interior surface being positioned proximal to said first channel surface within said second gas outflow end of said L-shaped housing.

31. The gas-sensor device according to claim 24, wherein said junction receiver end has a stop ledge.

32. The gas-sensor device according to claim 24, wherein said transmitter assembly has a transmitter end cap, and input electrical connections affixed to said transmitter/transducer which pass through said transmitter end cap.

33. The gas-sensor device according to claim 32, wherein said temperature sensor further comprises a diode having anode and cathode electrical connections which pass through said transmitter end cap.

34. The gas-sensor device according to claim 24, wherein said temperature sensor is angularly offset with respect to said L-shaped housing and is positioned adjacent to said sound buffer means.

35. The gas-sensor device according to claim 24, wherein said temperature sensor includes means for measuring the temperature within said L-shaped housing.

36. The gas-sensor device according to claim 24, wherein said transmitter/transducer includes means for generating ultrasonic sound waves.

37. The gas-sensor device according to claim 36, wherein said sonic baffle is conical in shape extending within said L-shaped housing toward said junction receiver end.

38. The gas-sensor device according to claim 24, wherein said gas outlet port has a circular base having a centrally-positioned aperture therethrough and a cylindrical-shaped barbed extension aligned to said aperture.

39. A gas-sensor device according to claim 38, wherein said sonic baffle is affixed to, and extends inwardly from, said circular base of said gas outlet port.

40. The gas-sensor device according to claim 24, wherein said sonic baffle has a plurality of longitudinal slots.

41. The gas-sensor device according to claim 24, wherein said receiver assembly has a receiver end cap, and output electrical connections affixed to said receiver/transponder which traverse said receiver end cap.

42. The gas-sensor device according to claim 24, wherein said receiver assembly is angularly offset with respect to said L-shaped housing.

43. The gas-sensor device according to claim 42, wherein said receiver/transponder is angularly offset with respect to said L-shaped housing at an angle of 45°

.

44. The gas-sensor device according to claim 24, wherein said transmitter/transducer and said receiver/transponder are aligned to one another within said L-shaped housing.

45. The gas-sensor device according to claim 24, wherein said fabric insert is comprised of felt.

46. The gas-sensor device according to claim 30, wherein said fabric insert is engaged to said first interior surface of said first transmitter end and said second interior surface of said second gas outflow end.