AU766344B2

AU766344B2 - Refuge chamber

Info

Publication number: AU766344B2
Application number: AU48720/00A
Authority: AU
Inventors: Geoffrey Allan Whittaker
Original assignee: Ness Gerald John
Current assignee: Ness Gerald John
Priority date: 1999-07-20
Filing date: 2000-07-20
Publication date: 2003-10-16
Anticipated expiration: 2020-07-20
Also published as: AU4872000A

Description

P/00/011 28/5/91 Regulation 3.2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Name of Applicants: GEOFFREY ALLAN WHITTAKER and GERALD JOHN

NESS

Actual Inventor Address for service is: go *22* WRAY ASSOCIATES 239 Adelaide Terrace Perth, WA 6000 Attorney code: WR Invention Title: "Refuge Chamber" Details of Associated Provisional Application No(s): PQ1732 The following statement is a full description of this invention, including the best method of performing it known to me:- Title "Refuge Chamber" Field of the Invention This invention relates to a refuge chamber.

Background Art Refuge chambers are used in underground mining operations and other environments where it may be necessary to have an area where personnel can take refuge in the event of a catastrophe or other circumstance in which the lives or welfare of the personnel are put into jeopardy.

10 Typically, a refuge chamber comprises a protective environment in which personnel can take refuge and which can be closed with respect to the outside environment in which the refuge chamber is situated. The refuge chamber incorporates a scrubbing system for removal of carbon dioxide from the closed environment. In this way, personnel taking refuge in the chamber can remain in 15 a life-sustaining environment for a period of time while a rescue operation is carried-out or the danger associated with the event subsides.

It has been a long held belief that carbon dioxide (C0 2 is the only gas usually present in the closed environment of a refuge chamber which is of such concern that it needs to be removed in order to prolong the life-sustaining environment within the refuge chamber.

It has now been found that carbon monoxide (CO) is released into the closed environment within the refuge chamber from the bodies of the inhabitants within the refuge chamber. Contrary to established beliefs, the inventors have recognised that the presence of CO can be harmful to the inhabitants within the closed environment in the refuge chamber.

-3- It is against this background that the present invention has been developed.

Disclosure of the Invention The present invention provides a refuge chamber having a temporary life-supporting closed environment and conversion means for converting at least some of the carbon monoxide released into air within the closed environment to carbon dioxide.

Further the present invention provides a refuge chamber having a temporary life-supporting closed environment, a conversion means and a removal means, S the conversion means for converting at least some of the carbon monoxide to i 10 carbon dioxide, and the removal means for removal of carbon dioxide present in the closed environment.

The present invention also provides a method for providing a temporary life-supporting closed environment in a refuge chamber characterized by the step of converting at least some of the carbon monoxide released into air of the 15 closed environment to carbon dioxide.

The method may comprise a further removal step for removal of carbon dioxide present in the closed atmosphere.

Any suitable arrangement may be employed to convert the carbon monoxide to carbon dioxide. A particularly suitable arrangement for conversion of carbon monoxide to carbon dioxide involves first passing a stream of air containing carbon monoxide to be removed through a moisture removal stage and then through a conversion stage where carbon monoxide is converted to carbon dioxide. The moisture removal stage may be achieved by passing the stream of air over a suitable moisture removal means such as mole sieve, silica gel or other suitable drying agent. The air stream is preferably passed over the moisture removal means at a rate of about 4.25 litre per second. Typically the moisture removal means is used to extract moisture in the air to -700 dewpoint.

-4- The conversion stage may be achieved using a catalyst filter in a Sofnocat 514 filter. Alternatively, catalyst filters such as Hoppercalite or Molecularlite may be used. The air stream is preferably passed through the Sofnocat filter at a rate of about 4.2 litres per second to create a residence time of between about 1 and 2.5 seconds, preferably the latter. The carbon monoxide is then converted to carbon dioxide which is returned to the atmosphere within the closed environment of the refuse chamber.

The arrangement for conversion of carbon monoxide to carbon dioxide may also comprise a blower to assist in effecting flow of the air stream through the catalyst filter.

The removal of carbon dioxide from the atmosphere within the closed **environment may be achieved in any suitable way. A particularly convenient way for removal of carbon dioxide from the atmosphere is by way of a scrubbing process which involves passing moisture laden air containing the carbon dioxide through a Sofno lime filter at a rate of 186 litres per second for a residence time of about 0.6 seconds. This results in carbonisation of the hydroxide absorbent, :°°°removing the carbon dioxide from the air stream.

Brief Description of the Drawings The invention will be better understood by reference to the following description of one specific embodiment thereof as shown in the accompanying drawings in which: Figure 1 is a schematic view of a process for converting carbon monoxide to carbon dioxide; and Figure 2 is a schematic view of a process for removing carbon dioxide from air within the refuge chamber; Figure 3 is a side elevation view of a carbon monoxide scrubber according to the invention; and Figure 4 is a perspective view of a unit housing a carbon monoxide scrubber and a carbon dioxide scrubber.

Best Mode(s) for Carrying out the Invention The embodiment is directed to a refuge chamber which is particularly suitable for use in underground mining environments.

The refuge chamber provides a protective environment which can be closed and sealed from the outside environment in which it is located.

The refuge chamber includes a carbon monoxide (CO) scrubber 11, and a carbon dioxide (CO2) scrubber 12.

10 The CO scrubber 11 'converts carbon monoxide (CO) to carbon dioxide (CO2).

At least some of the CO2 can then be removed from the closed atmosphere within the refuge chamber by the CO2 scrubber, along with other CO2 produced by the respiration process of inhabitants within the refuge chamber.

0 The CO scrubber 11 is shown schematically in Figure 1 of the drawings and includes an inlet 13 for intaking a stream of air containing CO and an outlet 15 for exhausting the air in which the CO has been converted to CO2. The CO scrubber 11 incorporates a first stage 17 for removing at least some of the moisture within the air stream. The air stream is drawn into the inlet at a rate of 4.25 litres per second. The first stage 17 incorporates a mole sieve or silica gel bed to remove the moisture. The second stage 21 incorporates a Sofnocat 514 filter in which CO contained within the air is converted to CO2. The air containing the CO is passed through the Sofnocat 514 filter at a rate of about 4.12 litres per second to create a residence time of 2.5 seconds. After passing through the second stage 21, the air is returned to the closed environment through the outlet 15. The outlet 15 may also comprise a blower to effect flow of the air stream through the CO scrubber.

-6- The air returning into the closed environment from the outlet 15 of the CO Sscrubber 11 returns to a moist environment within the closed atmosphere in the refuge chamber.

As shown in Figure 3, the CO scrubber 11 is conveniently in the form of a casing 18 having a first section A and a second section B. The first section A comprises the first stage 17 of the moisture removal means as well as the second stage 21 incorporating the Sofnocat 514 filter for CO removal. The second section B tapers inwardly to the outlet 15. The second section B is of greater longitudinal length than that of section A. The ratio of length of section A section B 10 350:375. The tapering of section B assists in ensuring an even flow of air through section A. Neoprene seals 35 which are resistant to attack by catalysts are conveniently positioned between the components of the CO scrubber 11.

e The CO2 scrubber 12 incorporates an inlet 23 for receiving a stream of air containing 002 and an outlet 25 for exhausting the scrubbed air. The air entering the inlet 23 passes through a first stage 27 where CO2 absorption occurs, the process being assisted by the presence of moisture in the air. The absorption process is achieved in this embodiment by use of a Sofno lime filter.

The air is passed through the first stage 27 at a rate of 186 litres per second for a residence time of 0.6 seconds. The scrubbed air is then discharged through 20 outlet 25. A blower system may be conveniently incorporated within the outlet The CO scrubber 11 and CO2 scrubber 12 also include charger systems 22 and 31 respectively and power packs 24 and 33 respectively.

As a further embodiment there may be provided a fibre filter between the first stage 17 and the second stage 21 which reduces the air speed prior to entry to the second stage 21 incorporating the Sofnocat 514 filter.

The CO scrubber 11 and CO2 scrubber 12 are conveniently provided in a single unit 37 for location in the refuge chamber. As will be seen additional features such as an oxygen candle cannister 39, charger systems 49 and 51, fans 25, a -7control panel 41, a charger unit 31 and a battery bank 51 are also included in the unit 37. The unit 37 may also include a discharge vent (not shown) for scrubber air covered by a cowling, the cowling assisting in deflecting the air. Other features (not shown) which may be included in the unit include an air conditioning system, a communications system, medical supplies, backup oxygen source and backup for power failure such as dry cell and lead acid batteries.

From the foregoing, it is evident that the present embodiment provides a simple, yet highly effective, arrangement for prolonging a sustainable environment within 10 a closed refuge chamber. Inhabitants in the chamber generate both CO2 and CO. The CO2 is generated by the respiration process of the inhabitants and CO previously accumulated in the bodies of the inhabitants is released into the :closed environment by cellular exchange. The refuge chamber addresses the problem of the CO released by the inhabitants as well as the CO2 produced by 15 the respiration process of the inhabitants.

It should be appreciated that the scope of the invention is not limited to the scope of the embodiments described. In particular, it should be appreciated that any suitable systems may be employed for converting CO to 002 and for removal of *CO2 from the closed atmosphere within the refuge chamber.

o Throughout the specification, unless the context requires otherwise, the word "comprise" or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

Claims

1. A refuge chamber having a temporary life-supporting closed environment and conversion means for converting at least some of the carbon monoxide released into air within the closed environment to carbon dioxide.

2. A refuge chamber according to claim 1 wherein the conversion means comprises a catalyst filter through which the air in the form of an air stream is passed to convert at least some of the carbon monoxide to carbon dioxide.

3. A refuge chamber according to claim 2 wherein the catalyst filter is a transition metal oxide catalyst filter.

4. A refuge chamber according to claim 3 wherein the transition metal oxide catalyst filter comprises a mixture of platinum and palladium on a tin oxide base.

5. A refuge chamber according to claim 3 or claim 4 wherein the transition metal oxide catalyst filter is a Sofnocat 514 filter. 15

6. A refuge chamber according to claim 2 wherein the catalyst filter is Hoppercalite or Molecularlite.

7. A refuge chamber according to any one of claims 2 to 6 wherein the air stream is passed through the catalyst filter at a rate of about 4.2 litres per second.

8. A refuge chamber according to any one of claims 2 to 7 wherein the air stream is passed through the catalyst filter at a rate to create a residence time of between about 1 and 2.5 seconds.

9. A refuge chamber according to any one of claims 1 to 8 wherein the conversion means further comprises a moisture removal means through which the air stream passes prior to entry into the catalyst filter to at least -9- partially remove moisture from the air stream to produce moisture reduced air.

A refuge chamber according to claim 9 wherein the moisture removal means comprises a mole sieve, a silica gel bed or other drying agent.

11. A refuge chamber according to claim 9 or claim 10 wherein the moisture removal means is used to extract moisture in the air to -700C dewpoint.

12. A refuge chamber according to any one of claims 9 to 11 wherein the air stream enters the moisture removal means at about 4.25 litre/second. ooo*

13. A refuge chamber according to any one of claims 9 to 12 wherein the 10 moisture reduced air is passed over a filter to reduce the air speed before entry into the catalyst filter. o*

"14. A refuge chamber according to claim 13 wherein the filter is a fibre filter.

15. A refuge chamber according to any one of claims 1 to 14 wherein the conversion means further comprises an outlet by means of which the air stream is exhausted from the conversion means.

16. A refuge chamber according to any one of claims 1 to 15 wherein the conversion means further comprises a blower.

17. A refuge chamber according to claim 16 wherein the blower effects flow of the air stream through the catalyst filter.

18. A refuge chamber according to claim 16 or claim 17 wherein the blower is located adjacent the outlet.

19. A refuge chamber according to any one of claims 15 to 18 wherein the outlet includes a tapered section.

A refuge chamber according to any one of claims 1 to 19 comprising a casing having a first section and a second section, the first section accommodating the catalyst filter, the moisture removal means and the filter, and the second section tapering inwardly to an outlet.

21. A refuge chamber according to claim 20 wherein the longitudinal length of the second section is greater than the longitudinal length of the first section.

22. A refuge chamber according to claim 20 or claim 21 wherein the casing further comprises a third section which defines the outlet.

23. A refuge chamber according to claim 22 wherein the blower is accommodated in the third section.

24. A method for providing a temporary life-supporting closed environment in a refuge chamber characterized by the step of converting at least some of the carbon monoxide released into air of the closed environment to carbon dioxide.

25. A method according to claim 24 further comprising the step of passing an air stream from the closed environment through a catalyst filter to convert the S. carbon monoxide to carbon dioxide and followed by the step of returning the carbon dioxide to the closed environment.

26. A method according to claim 25 wherein the catalyst filter is a transition metal oxide catalyst filter.

27. A method according to claim 26 wherein the transition metal oxide catalyst filter comprises a mixture of platinum and palladium on a tin oxide base.

28. A method according to any one of claims 25 to 27 wherein the catalyst filter is a Sofnocat 514 filter. -11

29. A method according to any one of claims 25 to 28 wherein the air stream is passed through the catalyst filter at a rate of about 4.2 litres per second.

A method according to any one of claims 25 to 28 wherein the air stream is passed through the catalyst filter at a rate to create a residence time of between about 1 and 2.5 seconds.

31. A method according to any one of claims 24 to 30 wherein the method further comprises the step of at least partially removing moisture from the air stream prior to passing the air stream through the catalyst filter to produce moisture reduced air.

32. A method according to claim 31 wherein the moisture removal step comprises passing the air stream through a mole sieve, silica gel bed or other drying agent.

.33. A method according to claim 31 or claim 32 wherein the air stream enters the moisture removal step at a rate of about 4.25 litres per second. oo**

34. A method according to any one of claims 31 to 33 wherein the method further comprises the step of passing the moisture reduced air over a filter to reduce the speed of the air before entering the conversion step.

A method according to claim 34 wherein the filter is a fibre filter.

36. A method according to any one of claims 24 to 35 wherein the method further comprises a removal step for removal of carbon dioxide present in the closed environment.

37. A refuge chamber having a temporary life-supporting closed environment, a conversion means and a removal means, the conversion means for converting at least some of the carbon monoxide to carbon dioxide, and the removal means for removal of carbon dioxide present in the closed environment. -12-

38. A refuge chamber according to claim 37 wherein the removal means comprises a carbon dioxide scrubber.

39. A refuge chamber according to claim 38 wherein the carbon dioxide scrubber comprises an inlet for receiving an air stream, an absorption means and an outlet, and whereby the air stream passes from the inlet to the absorption means for at least partial absorption of carbon dioxide to produce scrubbed air, the scrubbed air being discharged through the outlet.

A refuge chamber according to claim 39 wherein the absorption means comprises a lime filter. 10

41. A refuge chamber according to claim 39 or claim 40 wherein the air stream °passes through the absorption means for a residence time of about 0.6 seconds.

42. A refuge chamber substantially as herein described with reference to the accompanying drawings.

43. A method for providing a temporary life-supporting closed environment in a refuge chamber substantially as herein described. S. Dated this twentieth day of July 2000. GEOFFREY ALLAN WHITTAKER and GERALD JOHN NESS Applicants Wray Associates Perth, Western Australia Patent Attorneys for the Applicants