Portable electronic spirometer

• US 20030216659A1
• Filed: 07/15/2002
• Published: 11/20/2003
• Est. Priority Date: 05/16/2002
• Status: Active Grant

• Current Assignee: Dynamic Mt AG
• Original Assignee: Dynamic Mt AG
• Inventors: Hegarty, Christopher, Brawner, David
• Granted Patent: US 7,063,669 B2
• Time in Patent Office: Days
• US Class Current: 600/532
• CPC Class Codes: A61B 2560/0242 adapted to measure environmental factors, e.g. temperature, pollution
• CPC Class Codes: A61B 5/0871 Peak expiratory flowmeters

Abstract

A spirometer having a housing with an elongated flow chamber open at one end, a pressure sensing end opposite the open end and an outlet passageway intercepting the flow chamber at an angle α and proximate the pressure sensing end. A differential pressure sensor is coupled to the pressure sensing end from a port at an angle β to an axis of the flow chamber. The angle α is substantially greater than 0° but substantially less than 180° while the angle β may range from 90° to 180°, such that a significantly increased measured air pressure results over that measured when α=180° and β=90°.

Claims

1. A spirometer, comprising:

a. a housing having an elongated flow chamber open at one end, a pressure sensing end opposite said one end and an outlet passageway intercepting said flow chamber at an angle α and

proximate said pressure sensing end;

b. a differential pressure sensor coupled to said pressure sensing end from a port at an angle β

to an axis of said flow chamber;

wherein said angle α

is substantially greater than 0°

but substantially less than 180° and

wherein said angle β

is equal to or greater than 90° and

less than or equal to 180°

such that a significantly increased measured air pressure results over that measured when α

=180° and

β

=90°

.

2. A spirometer according to claim 1, wherein said differential pressure sensor is coupled to said flow chamber by a meander passageway through which only diffusion of air takes place and whose length divided by the speed of sound is less than the measuring rate of said differential pressure sensor.

3. A spirometer according to claim 2, wherein said meander passageway is bent to inhibit contaminants from said flow chamber from reaching said differential pressure sensor.

4. A spirometer according to claim 1, wherein said spirometer is portable.

5. A spirometer according to claim 1, wherein α

is 90° and

β

is 180°

.

6. A spirometer according to claim 1, wherein said flow chamber has an elliptical cross-section.

7. A spirometer according to claim 1, wherein said differential pressure sensor is detachable from said spirometer housing to permit sterilization of said spirometer housing.

8. A spirometer according to claim 1, wherein a rate of measurement by said pressure sensor is sufficiently high to obtain a complete flow rate versus time curve.

9. A spirometer according to claim 1, wherein a width of the flow chamber is greater than a width of said outlet chamber.

10. A spirometer according to claim 1, having data acquisition and processing electronics coupled to said differential pressure sensor.

11. A spirometer according to claim 1, wherein said electronics includes a EEPROM memory for storing an operating program, flow rate data and time stamp values corresponding to said flow rate data.

12. A spirometer according to claim 1, including a computer interface port for coupling to an external computer to provide access by said external computer to flow rate data and time stamp values stored in said EEPROM memory.

13. A spirometer according to claim 1, including an absolute pressure sensor and temperature sensor coupled to said data acquisition and processing electronics.

15. A spirometer according to claim 1, including a computer interface port coupled to said microcontroller operative to provide external access to the flow rate data and time stamp values stored in said EEPROM memory.

14. A spirometer of a type having an inlet tube, an outlet tube, a differential pressure sensor in said inlet tube proximate an end thereof, comprising:

a. a microcontroller coupled to an output of said pressure sensor; and

b. EEPROM memory coupled to said microcontroller operative to store a program for operating said microcontroller, flow rate data and time stamp values corresponding to said flow rate data.

c. an absolute pressure and temperature sensor to enable the automatic correction of flow results according to the local atmospheric pressure and temperature at the time of the measurement.