PROCESS FOR LEAK TESTING, DEVICE AND RESPIRATOR

• US 20120022390A1
• Filed: 05/05/2011
• Published: 01/26/2012
• Est. Priority Date: 07/22/2010
• Status: Active Grant

• Current Assignee: Draeger Safety Incorporated (Dragerwerk AG)
• Original Assignee: Draeger Safety Incorporated (Dragerwerk AG)
• Inventors: UNGER, Jürgen
• Granted Patent: US 8,986,216 B2
• Time in Patent Office: Days
• US Class Current: 600/538
• CPC Class Codes: A62B 27/00 Methods or devices for testing respiratory or breathing apparatus for high altitudesapparatus for testing gastightness in general G01M
• CPC Class Codes: G01M 3/26 by measuring rate of loss or gain of fluid, e.g. by pressure-responsive devices, by flow detectors

Abstract

A process is provided for leak testing in a respirator (10) with overpressure operation. An indicator of a breathing gas consumption is compared with an indicator of an expiration volume and a leak is detected in case of a deviation of the result of the comparison (58) from a desired value. A device is also provided for carrying out the process as well as to a respirator (10) with overpressure operation with such a device.

Claims

1. A process for leak testing in a respirator with overpressure operation, the process comprising the steps of:

providing an indicator of a breathing gas consumption;

providing an indicator of an expiration volume;

comparing the indicator of the breathing gas consumption with the indicator of the expiration volume to produce a comparison value result;

providing a desired value for the comparison of the indicator of the breathing gas consumption with the indicator of the expiration volume;

detecting a leak in a case of a deviation of the comparison value result from the desired value.

2. A process in accordance with claim 1, wherein a correlation factor of the indicator of the breathing gas consumption and of the indicator of the expiration volume is determined and the leak is detected in case of a deviation of the correlation factor from the desired value.

3. A process in accordance with claim 1, wherein the leak is detected when the deviation exceeds or drops below a threshold value.

4. A process in accordance with claim 2, wherein:

the step of providing the indicator of the breathing gas consumption includes providing a breathing gas consumption characteristic as the indicator of the breathing gas consumption; and

the step of providing the indicator of the expiration volume includes providing an expiration volume characteristic as the indicator of the expiration volume.

5. A process in accordance with claim 4, wherein a first correlation factor of the breathing gas consumption characteristic and of the expiration volume characteristic is determined as the desired value and this is compared with a second correlation factor of the breathing gas consumption characteristic and the expiration volume characteristic.

6. A process in accordance with claim 5, wherein the first correlation factor indicates a ratio of a slope of the breathing gas consumption characteristic to a slope of the expiration volume characteristic relative to a first time period and the second correlation factor indicates the ratio of the slope of the breathing gas consumption characteristic to the slope of the expiration volume characteristic relative to a second time period.

7. A process in accordance with claim 5, wherein the leak is detected if the second correlation factor is lower than the first correlation factor.

8. A process in accordance with claim 1, wherein the indicator of the expiration volume is compared with an indicator of the desired value of stress and a stress signal is generated in case of a deviation.

9. A device for leak testing in a respirator with overpressure operation, the device comprising:

a first determination device for determining a first indicator of a breathing gas consumption;

a second determination device for determining a second indicator of an expiration volume; and

a comparator which receives the indicators as input signals and compares the indicator of the breathing gas consumption with the indicator of the expiration volume to produce a comparison value result, which has a desired value for the comparison of the indicator of the breathing gas consumption with the indicator of the expiration volume and detects a leak in a case of a deviation of the comparison value result from the desired value.

10. A device in accordance with claim 9, wherein the first determination device comprises a value from a high pressure sensor for determining a pressure of an oxygen reserve and/or the second determination device comprises a flow sensor arranged in an expiration branch.

11. A device in accordance with claim 9, wherein the comparator is part of a microcontroller that determines a correlation factor of the indicator of the breathing gas consumption and of the indicator of the expiration volume and the leak is detected in case of a deviation of the correlation factor from the desired value.

12. A device in accordance with claim 11, wherein the leak is detected when the deviation exceeds or drops below a threshold value.

13. A respirator with overpressure operation, the respirator comprising:

a closed breathing circuit with an inspiration branch and an expiration branch;

a first determination device for determining a first indicator of a breathing gas consumption;

a second determination device for determining a second indicator of an expiration volume; and

a comparator which receives the indicators as input signals and compares the indicator of the breathing gas consumption with the indicator of the expiration volume to produce a comparison value result, which has a desired value for the comparison of the indicator of the breathing gas consumption with the indicator of the expiration volume and detects a leak in a case of a deviation of the comparison value result from the desired value.

14. A respirator in accordance with claim 13, wherein:

the first determination device comprises a value from a high pressure sensor for determining a pressure of an oxygen reserve; and

the second determination device comprises a flow sensor arranged in the expiration branch.

15. A respirator in accordance with claim 14, wherein the comparator is part of a microcontroller that determines a correlation factor of the indicator of the breathing gas consumption and of the indicator of the expiration volume and the leak is detected in case of a deviation of the correlation factor from the desired value.

16. A respirator in accordance with claim 14, wherein the leak is detected when the deviation exceeds or drops below a threshold value.

17. A respirator in accordance with claim 14, wherein:

the indicator of the breathing gas consumption includes a breathing gas consumption characteristic as the indicator of the breathing gas consumption; and

the indicator of the expiration volume includes an expiration volume characteristic as the indicator of the expiration volume.

18. A respirator in accordance with claim 17, wherein a first correlation factor of the breathing gas consumption characteristic and of the expiration volume characteristic is determined as a desired value and this is compared with a second correlation factor of the breathing gas consumption characteristic and the expiration volume characteristic.

19. A respirator in accordance with claim 18, wherein the first correlation factor indicates a ratio of a slope of the breathing gas consumption characteristic to a slope of the expiration volume characteristic relative to a first time period and the second correlation factor indicates the ratio of the slope of the breathing gas consumption characteristic to the slope of the expiration volume characteristic relative to a second time period.

20. A respirator in accordance with claim 19, wherein the leak is detected if the second correlation factor is lower than the first correlation factor.