REBREATHER RESPIRATORY LOOP FAILURE DETECTOR

• US 20100012124A1
• Filed: 07/08/2009
• Published: 01/21/2010
• Est. Priority Date: 07/08/2008
• Status: Abandoned Application

• Current Assignee: Alexander Roger Deas
• Original Assignee: Alexander Roger Deas
• Inventors: Deas, Alexander Roger
• Application Number:
  US12/499,225
• Publication Number:
  US 20100012124A1
• Time in Patent Office: Days
• US Class Current: 128/204.220
• 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: A62B 9/006 Indicators or warning devices, e.g. of low pressure, contamination
• CPC Class Codes: B63C 11/24 in closed circulation

Abstract

A rebreather safety monitoring device comprising a carbon dioxide sensor provided with a gas sampler adapted for sampling a gas in a rebreather breathing loop from a location between an inhale one-way valve on a rebreather mouthpiece and a carbon dioxide scrubber and providing the obtained gas sample to the carbon dioxide sensor, and a means to provide alarms or warnings based on the level of the expired carbon dioxide. The present invention detects a wide range of failures of a rebreather by measurement of the expired carbon dioxide level and application of that level to trigger alarms, provide loop shut-off or provide safety warnings.

Claims

1. A rebreather safety monitoring device comprising:

a carbon dioxide sensor provided with a gas sampler, wherein the gas sampler is adapted for sampling a gas in a rebreather breathing loop from a location between an inhale one-way valve on a rebreather mouthpiece and a carbon dioxide scrubber and providing an obtained gas sample to the carbon dioxide sensor; and

an interface to one selected from the group consisting of an alarm and a warning, wherein the interface is based on a carbon dioxide reading.

2. A monitor according to claim 1, wherein the carbon dioxide sensor is calibrated using a carbon dioxide level in human expired gas.

3. A monitor according to claim 1, wherein the carbon dioxide sensor is fitted with a hydrophobic membrane.

4. A monitor according to claim 1, wherein the carbon dioxide sensor comprises a dual channel infra-red absorption sensor.

5. A monitor according to claim 1 wherein the carbon dioxide sensor is powered up with a low periodic duty cycle, but where an alarm system is powered even when the carbon dioxide sensor is powered down.

6. A monitor according to claim 1 wherein the carbon dioxide reading is powered up and a reading taken when a change in a user'"'"'s respiratory rate is detected.

7. A monitor according to claim 1 further comprising a pressure sensor that is applied to compensate the carbon dioxide reading for changes in ambient pressure.

8. A monitor according to claim 1 further comprising a helium sensor that is applied to compensate the carbon dioxide reading for changes in the partial pressure of helium.

9. A monitor according to claim 1, wherein the carbon dioxide sensor is a dual channel infra-red absorption sensor with a circuit to drive an infra-red light source with greater power when under ambient pressure or in a presence of gases having a high thermal capacity, than in air at one atmosphere pressure, thus stabilising a spectrum of an emitted light under a range of pressures or in the presence of helium.

10. A monitor according to claim 1, wherein the carbon dioxide sensor comprises a dual channel infra-red absorption sensor with an infra-red emitter isolated from the effects of pressure and helium such that the emitted spectrum does not change by more than 50% under a range of operating pressures or helium the monitor covers.

11. A monitor according to claim 1, wherein an alarm level is used to drive shut a valve that closes the breathing loop.

12. A monitor according to claim 1, wherein an alarm level is used to drive shut a valve that closes the breathing loop at the mouthpiece and switches a user to an alternative gas source.

13. A monitor according to claim 1, wherein an absence of carbon dioxide, or a presence of carbon dioxide at a partial pressure lower than that normally expired by a human, is applied to trigger one selected from the group consisting of a warning or an alarm level.

14. A monitor according to claim 1, wherein a presence of carbon dioxide at a partial pressure higher than that normally expired by a human is applied to trigger one selected from the group consisting of a warning or an alarm level.

15. A monitor according to claim 1, wherein the device is integrated with one selected from the group consisting of a partial pressure of oxygen monitor, a measurement device, and a controller.

16. A monitor according to claim 1, wherein the carbon dioxide sensor is coupled thermally to a scrubber such that it operates at more than 3 degrees Celsius above an ambient temperature.

17. A monitor according to claim 1, that is calibrated automatically when a scrubber canister is opened and a scrubber removed, as indicated by a the presence of light on a light sensor, with a human interface that allows a background level of carbon dioxide to be indicated to a calibration system.