GB2394281A - Carbon dioxide detector for life support systems - Google Patents
Carbon dioxide detector for life support systems Download PDFInfo
- Publication number
- GB2394281A GB2394281A GB0220379A GB0220379A GB2394281A GB 2394281 A GB2394281 A GB 2394281A GB 0220379 A GB0220379 A GB 0220379A GB 0220379 A GB0220379 A GB 0220379A GB 2394281 A GB2394281 A GB 2394281A
- Authority
- GB
- United Kingdom
- Prior art keywords
- carbon dioxide
- sensor
- dioxide gas
- gas
- partial pressure
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 title claims abstract description 112
- 229910002092 carbon dioxide Inorganic materials 0.000 title claims abstract description 56
- 239000001569 carbon dioxide Substances 0.000 title claims abstract description 56
- 239000007789 gas Substances 0.000 claims abstract description 53
- 230000029058 respiratory gaseous exchange Effects 0.000 claims abstract description 25
- 238000005259 measurement Methods 0.000 claims abstract description 9
- 230000000694 effects Effects 0.000 claims abstract description 4
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 11
- 238000012544 monitoring process Methods 0.000 claims description 11
- 239000001301 oxygen Substances 0.000 claims description 11
- 229910052760 oxygen Inorganic materials 0.000 claims description 11
- 238000010521 absorption reaction Methods 0.000 claims description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims 2
- 230000000007 visual effect Effects 0.000 claims 2
- 229910052786 argon Inorganic materials 0.000 claims 1
- 239000001307 helium Substances 0.000 claims 1
- 229910052734 helium Inorganic materials 0.000 claims 1
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 claims 1
- 239000000203 mixture Substances 0.000 claims 1
- 229910052754 neon Inorganic materials 0.000 claims 1
- GKAOGPIIYCISHV-UHFFFAOYSA-N neon atom Chemical compound [Ne] GKAOGPIIYCISHV-UHFFFAOYSA-N 0.000 claims 1
- 229910052757 nitrogen Inorganic materials 0.000 claims 1
- 230000001960 triggered effect Effects 0.000 claims 1
- 231100001261 hazardous Toxicity 0.000 abstract description 2
- 238000005201 scrubbing Methods 0.000 abstract description 2
- 238000009423 ventilation Methods 0.000 abstract 1
- 239000000126 substance Substances 0.000 description 6
- 230000009189 diving Effects 0.000 description 4
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 3
- 208000003443 Unconsciousness Diseases 0.000 description 3
- 230000001143 conditioned effect Effects 0.000 description 3
- 229910001882 dioxygen Inorganic materials 0.000 description 3
- 230000001360 synchronised effect Effects 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 230000002745 absorbent Effects 0.000 description 1
- 239000002250 absorbent Substances 0.000 description 1
- 239000006096 absorbing agent Substances 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 238000004590 computer program Methods 0.000 description 1
- 238000013500 data storage Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 230000000737 periodic effect Effects 0.000 description 1
- 231100000572 poisoning Toxicity 0.000 description 1
- 230000000607 poisoning effect Effects 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 239000002912 waste gas Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63C—LAUNCHING, HAULING-OUT, OR DRY-DOCKING OF VESSELS; LIFE-SAVING IN WATER; EQUIPMENT FOR DWELLING OR WORKING UNDER WATER; MEANS FOR SALVAGING OR SEARCHING FOR UNDERWATER OBJECTS
- B63C11/00—Equipment for dwelling or working underwater; Means for searching for underwater objects
- B63C11/02—Divers' equipment
- B63C11/18—Air supply
- B63C11/22—Air supply carried by diver
- B63C11/24—Air supply carried by diver in closed circulation
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
- G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
- G01N21/35—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light
- G01N21/3504—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light for analysing gases, e.g. multi-gas analysis
-
- G—PHYSICS
- G08—SIGNALLING
- G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
- G08B21/00—Alarms responsive to a single specified undesired or abnormal condition and not otherwise provided for
- G08B21/02—Alarms for ensuring the safety of persons
- G08B21/12—Alarms for ensuring the safety of persons responsive to undesired emission of substances, e.g. pollution alarms
- G08B21/14—Toxic gas alarms
-
- A—HUMAN NECESSITIES
- A62—LIFE-SAVING; FIRE-FIGHTING
- A62B—DEVICES, APPARATUS OR METHODS FOR LIFE-SAVING
- A62B9/00—Component parts for respiratory or breathing apparatus
- A62B9/006—Indicators or warning devices, e.g. of low pressure, contamination
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63C—LAUNCHING, HAULING-OUT, OR DRY-DOCKING OF VESSELS; LIFE-SAVING IN WATER; EQUIPMENT FOR DWELLING OR WORKING UNDER WATER; MEANS FOR SALVAGING OR SEARCHING FOR UNDERWATER OBJECTS
- B63C11/00—Equipment for dwelling or working underwater; Means for searching for underwater objects
- B63C11/02—Divers' equipment
- B63C2011/021—Diving computers, i.e. portable computers specially adapted for divers, e.g. wrist worn, watertight electronic devices for detecting or calculating scuba diving parameters
Landscapes
- General Health & Medical Sciences (AREA)
- Health & Medical Sciences (AREA)
- Physics & Mathematics (AREA)
- Spectroscopy & Molecular Physics (AREA)
- Engineering & Computer Science (AREA)
- Toxicology (AREA)
- General Physics & Mathematics (AREA)
- Pathology (AREA)
- Biochemistry (AREA)
- Immunology (AREA)
- Analytical Chemistry (AREA)
- Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Environmental & Geological Engineering (AREA)
- Business, Economics & Management (AREA)
- Emergency Management (AREA)
- Pulmonology (AREA)
- Mechanical Engineering (AREA)
- Ocean & Marine Engineering (AREA)
- Investigating Or Analysing Materials By Optical Means (AREA)
Abstract
A carbon dioxide detector for use in self-contained breathable atmospheres is used to detect an increase of carbon dioxide gas caused by inadequate ventilation or scrubbing. The electronic system consists of a sensor to detect carbon dioxide gas plus other sensors to compensate the measurement for the effects of pressure and temperature and the effects of other gases. The system can be used in breathable habitats or with self-contained breathing apparatus in wide variations of ambient pressures. The detector raises alarms in response to increasing levels of the gas and optionally can control and reduce the levels of carbon dioxide hazardous to health.
Description
239428 1
CARBON DIOXIDE GAS DETECTOR FOR DMNG AND UNDERSEA
APPLICATIONS
The present invention relates to gas measurement of breathing gases when used in high-pressure environments such as deep-sea diving and underwater submersibles and habitat's. In particular where the life-support equipment is a diving re-breather where the breathing gases are recycled and waste gas is absorbed. More particularly the breathing gases will contain Oxygen and Carbon Dioxide, if the level of Carbon Dioxide exhaled by breathing is not controlled in a suitable manner then the level can rise and lead to poisoning and subsequent unconsciousness and death.
In the situations referred to where gas is breathed the Carbon Dioxide level as usually controlled by passing the exhaled breathing gas through a scrubber system, normally chemical based which absorbs the Carbon Dioxide gas from the exhaled air. The remaining air is resumed to the breathing loop. However the chemical absorbent removes Carbon Dioxide only during a finite period, after which the chemical is exhausted and the Carbon Dioxide gas level increases to a level which is hazardous to health.
Also exercise and activity can temporary increase the level of Carbon Dioxide build-up such that the chemical absorption is overwhelmed.
It would be of considerable advantage to be able to measure the build up of Carbon Dioxide in the breathing loop and be able to indicate in some manner that the concentration of gas is within an acceptable level and to provide an alarm signal should the concentration of gas exceed a preset point. Similarly, it would be an advantage if the concentration of Oxygen were measured within the same system so an alarm could be raised should the Oxygen concentration be reduced or exceeded from the ideal value.
It would also be an advantage if the ambient pressure or depth was measured and used to calculate the safe concentrations of Carbon Dioxide and Oxygen, as these will vary depending on the local ambient pressure.
It would also be an advantage if all the above parameters could be logged together with time to provide a warning that the consumables e.g. oxygen gas and chemical scrubber may be due to expire as some time must be allowed for the diver to come safely to the surface.
It would be an advantage if the invention as described could be fitted to existing diving breather systems and integrated into new designs to provide an enhanced level of monitoring and protection.
It would also be an advantage for the unit to be fitted to all closed circuit breathing systems that make use of the fact that Carbon Dioxide is absorbed by a scrubbing device before the remaining gases is recycled for breathing.
A Carbon Dioxide detector and alarm system in accordance with invention is able to handle such requirements and has at least one or more of the following features.
It is able to measure the concentration of Carbon dioxide in the breathing loop of a closed-loop breathing apparatus. It is able to detect the ambient pressure and correct for variations in sensor performance and variations in the safe operating concentrations, which is dependent on the ambient pressure. It can measure the partial pressure of Carbon Dioxide gas under conditions of varying external pressures and it can measure the partial pressure of Oxygen gas under conditions of varying external pressures.
It is able to measure the concentration of Oxygen in the breathing loop and correct for the variations in safe gas concentration caused by changes in the ambient pressure. It is able to perform in conditions that vary from almost zero ambient pressure to conditions, which approximate those, experienced at twenty atmospheres of pressure (200 metros salt water). It is able to display the results of these measurements in a manner, which is meaningful to the operator, and it is able to alarm the operator by various means that the safe operating limits are about to or have been exceeded.
It is able to store the information in a log so that together with the duration of the dive and the data measured a profile of the working environment can be stored for later analysis should a situation develop.
The invention is able to be battery powered and operate continuously for the required duration of the dive and requires no periodic testing before use other that being subjected to the Carbon Dioxide from normal breathing in order to check functionality. The only consumables that the invention requires are new batteries and a replacement Oxygen sensor at regular intervals. These and other aspects of the invention will be apparent from the embodiment described in reference to Figure 1 of the accompanying drawing.
The Carbon Dioxide sensor and the Oxygen sensor are available commercially as off-the-shelf items, the use of these items together with the use of pressure and other sensors plus a computer program to calculate the interactions and outputs of the sensors are the essence of this invention.
The sensors are exposed to the ambient gas stream so that the breathing gas flows (1) past and covers all the sensors. Valves (2) and (3) ensure the breathing gases go round the breathing loop and pass through the absorber chemical (4) The Carbon Dioxide sensor (5) the Oxygen sensor (6) the Ambient pressure sensor (7) and the Temperature sensor (8) are all electrical sensors that are read and conditioned by electronic circuits.
The embodiment described in Figure 2 of the accompanying drawing is one way in which the invention may be realised.
The Carbon Dioxide sensor (9) is provided with a pulsed infrared emitter (10) which results in a output which contains a pulsed voltage signal(11) this signal is amplified and conditioned before being passed through a
synchronous detector(12) which results in a signal which being filtered is proportional to the level of Carbon Dioxide presented to the detector. A similar second output on the Carbon Detector (13) provides a reference signal, which allows variations in emitter output and detector themmal stability to be compensated for. This signal is also passed through a synchronous detector (14) The reference signal is used as the reference input to a analogue to digital decoder (ADC)(15) in such a manner that the output from the ADC is a ratio of the Carbon Dioxide signal divided by the reference signal. An Oxygen sensor (16) and a Pressure sensor (17) and a Temperature sensor (18) provide signals which are conditioned and amplified and passed to a separate (ADC) (19) A electronic computer or micro controller which uses software to (20) read the signals from the ADC elements and computes the level of Carbon Dioxide Gas and the level of Oxygen gas in the breathing loop. The computation is non-linear and the exact form of the computation depends on the nature of the Carbon Dioxide sensor type used, However the algorithm required is discovered by the reading of various concentrations of carbon dioxide gas in a pressure vessel with this equipment. By applying the information derived in a lookup table or a mathematical calculation which presents the gas partial pressure concentration in a linearform, the resulting information once computed can be displayed (21) or used to provide an alarm with could be acoustic signal or a light signal (22)
The software in the micro-controller also caused the data to be stored in memory, which could be battery, backed of non-volatile (23) for later use once a mission or dive had been completed. Extraction of the data is by connection to a local surface computer or other data storage device.
The partial pressure concentrations of Carbon Dioxide gas measured in this way ranges from zero to levels which would cause unconsciousness and death in a short time if exposure was under conditions of ambient pressure.
Additionally Oxygen levels are measured at concentrations from zero to above those which would result in unconsciousness and depth in a short time. It will be apparent that a Carbon Dioxide monitor in accordant with the invention is not limited in use to a diving or undersea vehicle application.
Separate units performing the same functions as those described in the embodiment may be substituted for those described. For example, omer types of Carbon dioxide gas sensor may be employed from that described.
Although the Carbon Dioxide monitor has been specifically described in relation to its use for monitoring Carbon Dioxide gas partial pressure concentrations that are a hazard to life. It will be appreciated that it may be used in other applications, both alone or as part of a system in association with other measuring instruments which monitor the ambient atmosphere from zero pressure to great pressure and also to provide a measurement of the quality of breathable atmosphere under those conditions.
In addition, the Carbon Dioxide monitor may be used in conditions where in conjunction with other equipment it would be use in pressurised or low pressure environments where the concentrations of venous gases need to be measured and monitored or transmitted to remote reading stations.
Additionally other gases may be measured and used to provide information as to the suitable nature of the surrounding atmosphere especially in conditions where the ambient pressure can vary depending on location or circumstance.
Claims (4)
1. A portable battery powered measuring and warning system intended to measure and record the partial pressure of carbon dioxide gas comprising an electronics assembly together with a sensor group comprising of an Infrared absorption carbon dioxide gas sensor, a pressure sensor, a temperature sensor, and a humidity sensor, the electronics comprise a measuring section and a computing section and an alarm section, the sensors are so placed as to be able to measure breathing gases or be in the breathing loop of a life support system, a display derived from the computing section can indicate the actual real time partial pressure of inhaled carbon dioxide gas and an alarm can be triggered by an increase in partial pressure of carbon dioxide gas caused by expired breathing and inadequate carbon dioxide gas removal, the system computes and compensates using a mathematical formulae for the pressure broadening effect of the carbon dioxide gas measurement using data derived from the basic carbon dioxide gas sensor and data from the pressure and temperature sensors to correct the errors the would arise from only using the carbon dioxide sensor data, the system allows, and compensates for, the operational changes in ambient pressure or depth and changes in temperature which result from normal operation in the intended environment and displays the actual partial pressure of carbon dioxide gas in the breathing loop plus alarm information to the operator in the form of audio or visual information.
2. The sensor as claimed in Claim I but reduced to use the sensor group of Infrared absorption carbon dioxide gas sensor, a pressure sensor, and temperature sensor, but including the complete electronics package to monitor and display the partial pressure of carbon dioxide gas.
3. A Gas monitoring package as claimed in Claim 1, or in Claim 2, which is used within or as part of another overall gas monitoring package used for control and monitoring of other gases where the partial pressure of carbon dioxide is a required measurement under conditions of elevated or changing ambient pressures
4. A Gas monitoring and control package as in Claim 3 where the results of the carbon dioxide gas measurement are transmitted via a umbilical or data link to a receiving station. r
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB0220379A GB2394281A (en) | 2002-09-03 | 2002-09-03 | Carbon dioxide detector for life support systems |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB0220379A GB2394281A (en) | 2002-09-03 | 2002-09-03 | Carbon dioxide detector for life support systems |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB0220379D0 GB0220379D0 (en) | 2002-10-09 |
| GB2394281A true GB2394281A (en) | 2004-04-21 |
Family
ID=9943361
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB0220379A Withdrawn GB2394281A (en) | 2002-09-03 | 2002-09-03 | Carbon dioxide detector for life support systems |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2394281A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2010005343A2 (en) * | 2008-07-08 | 2010-01-14 | Marat Vadimovich Evtukhov | Rebreather respiratory loop failure detector |
| GB2463308A (en) * | 2008-07-09 | 2010-03-17 | Alexander Roger Deas | Rebreather respiratory loop failure detector incorporating a carbon dioxide sensor |
| GB2479183A (en) * | 2010-04-01 | 2011-10-05 | Alexander Roger Deas | Rebreather apparatus having a sol-gel oxygen sensor |
| US20140014098A1 (en) * | 2012-07-11 | 2014-01-16 | Be Aerospace, Inc. | Aircraft crew member protective breathing apparatus |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2208203A (en) * | 1987-07-03 | 1989-03-15 | Carmellan Research Limited | Diving system |
| US5789660A (en) * | 1996-07-15 | 1998-08-04 | Novametrix Medical Systems, Inc. | Multiple function airway adapter |
| EP1145740A1 (en) * | 2000-04-10 | 2001-10-17 | John E. Lewis | System and method for air time remaining calculations in a self-contained breathing apparatus |
| WO2002036204A2 (en) * | 2000-10-31 | 2002-05-10 | Marat Vadimovich Evtukhov | Integral life support system |
-
2002
- 2002-09-03 GB GB0220379A patent/GB2394281A/en not_active Withdrawn
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2208203A (en) * | 1987-07-03 | 1989-03-15 | Carmellan Research Limited | Diving system |
| US5789660A (en) * | 1996-07-15 | 1998-08-04 | Novametrix Medical Systems, Inc. | Multiple function airway adapter |
| EP1145740A1 (en) * | 2000-04-10 | 2001-10-17 | John E. Lewis | System and method for air time remaining calculations in a self-contained breathing apparatus |
| WO2002036204A2 (en) * | 2000-10-31 | 2002-05-10 | Marat Vadimovich Evtukhov | Integral life support system |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2010005343A2 (en) * | 2008-07-08 | 2010-01-14 | Marat Vadimovich Evtukhov | Rebreather respiratory loop failure detector |
| WO2010005343A3 (en) * | 2008-07-08 | 2010-07-15 | Marat Vadimovich Evtukhov | Rebreather respiratory loop failure detector |
| GB2463308A (en) * | 2008-07-09 | 2010-03-17 | Alexander Roger Deas | Rebreather respiratory loop failure detector incorporating a carbon dioxide sensor |
| GB2479183A (en) * | 2010-04-01 | 2011-10-05 | Alexander Roger Deas | Rebreather apparatus having a sol-gel oxygen sensor |
| US20140014098A1 (en) * | 2012-07-11 | 2014-01-16 | Be Aerospace, Inc. | Aircraft crew member protective breathing apparatus |
| US9498656B2 (en) * | 2012-07-11 | 2016-11-22 | B/E Aerospace, Inc. | Aircraft crew member protective breathing apparatus |
| US10046184B2 (en) | 2012-07-11 | 2018-08-14 | B/E Aerospace, Inc. | Aircraft crew member protective breathing apparatus |
Also Published As
| Publication number | Publication date |
|---|---|
| GB0220379D0 (en) | 2002-10-09 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |