Bellows counterlung schematics

divingtoors · 28th June 2007, 06:51

HI There

We are in process of designing and building our own version of a PASCR, and the only real "problem" we have encountered this far, is finding a suitable inner and outer Bellows counterlung.

I have sourced a company that can cut bellows CL's from Teflon, but they need diagrams and sketches.

Does anybody have such schetces or diagrams. We are looking for something similar to the CL's of the Rebreather-80 and its "clones".

Any ideas on substitutes?

Thanx and regards

Johan

**jmurba** · 23rd November 2007, 20:05

Quote: (Originally Posted by divingtoors)

HI There

We are in process of designing and building our own version of a PASCR, and the only real "problem" we have encountered this far, is finding a suitable inner and outer Bellows counterlung.

I have sourced a company that can cut bellows CL's from Teflon, but they need diagrams and sketches.

Does anybody have such schetces or diagrams. We are looking for something similar to the CL's of the Rebreather-80 and its "clones".

Any ideas on substitutes?

Thanx and regards

Johan

Hello,

have a look at mac master carr in the usa,

McMaster-Carr

Counterlung / Metered Discharge:
McMaster-Carr sells a range of neoprene-coated nylon bellows ranging from 1 3/4" O.D. to 12" O.D. If I could find a suitable tube for the main housing (approximately 7" I.D.), I'd use the 6 3/4" O.D. X 5" I.D. bellows for the outer bellows. This would need to be about 9" long to give a maximum counterlung volume » my vital capacity » 4 liters. An inner bellows measuring 3" O.D. X 2" I.D. would give a discharge ratio of about 17%. An 8" X 6" outer bellows would allow a shorter counterlung (at about 6 1/2") and would give a choice of 3 1/2" X 2 1/2" or 3" X 2" inner bellows for a discharge ratio of 18% or 12%.

I read this there you probably also read it:

PASCR

otherwise I have ideas,
you make the belows form in wood
then you buy RTV silicon resin ,
you take a painbrush and paint many lyers of rtv resie on the wooden bellow...it coud take you a week end to complete it layer after layers, at the end you get the bellow rtv resin is really resistant elastic fantastic I've used it many time .
it is worth to try IMHO
regards
jean mi

Marvintpa · 23rd November 2007, 21:11

I could be wrong but I was under the impression the RB80-clones use a bellows from a hospital respirator. Sure looks like one. Not sure I'd go trusting that to someone willing to build a one-off over something that's been in use in life-critical applications for many years.

**jmurba** · 24th November 2007, 14:08

Quote: (Originally Posted by Marvintpa)

I could be wrong but I was under the impression the RB80-clones use a bellows from a hospital respirator. Sure looks like one. Not sure I'd go trusting that to someone willing to build a one-off over something that's been in use in life-critical applications for many years.

I am not sure I have understood what you exactly meant.
if you mean thata medical respirator bellow is better then an home buit bellow you are certainely rigth, except if the bellow is properly built.
sometimes diy parts are good you know.
it depends on the builder (((-:
I've alway dived my gauges and so far survived.
the real reason to make bellow yourself is to get the size you exactly need.
buying bellows from medical industry has to bad consequencies
the first is that they are longer then wide and that it makes it impossible to locate the bellow at the top of the diver back as a real french dc55 that is easy to breathe in all positions unlike the R80 and clones.
the second problem is that if you can decide the elimination ratio you want and not simply get the one you can get buying industry bellows.
you also can chose the sickness of you bellows, ther rigidity.
regards
jean mi

divingtoors · 25th November 2007, 05:56

Hi There

I have been thinking about this a while and a possible solluion might be as follows:

Two stainless Steel coil springs, one of large diameter and a second of a smaller (1/10th) diameter.
It must be a spring that is easily collapasable in the legnth, but with a strong rigidity.

The idea would be to use a food grade very thin PVC material or similar, and build 2 x tubes (a lare tube and a smaller (1/10th volume) inner tube, which fits tightly over the springs.
The spring then becomes the "ribs" of the bellows, allowing compresion lengthwise and stability over the width.

The end flanges of the PVC material can then be tailored to fit over any circumfrence ending of the bellows.

Do you think it can work?

Regards

Johan

DepthCharge · 25th November 2007, 12:10

Quote: (Originally Posted by divingtoors)

Hi There

I have been thinking about this a while and a possible solluion might be as follows:

Two stainless Steel coil springs, one of large diameter and a second of a smaller (1/10th) diameter.
It must be a spring that is easily collapasable in the legnth, but with a strong rigidity.

The idea would be to use a food grade very thin PVC material or similar, and build 2 x tubes (a lare tube and a smaller (1/10th volume) inner tube, which fits tightly over the springs.
The spring then becomes the "ribs" of the bellows, allowing compresion lengthwise and stability over the width.

The end flanges of the PVC material can then be tailored to fit over any circumfrence ending of the bellows.

Do you think it can work?

Regards

Johan

On the DC 55 they have thin plastic (teflon?) rings that fit inside each loop of the CL to maintain the sidewall rigidity. It doesn't effect the collapsibility.

**jmurba** · 25th November 2007, 14:20

hello,
it would be like a chinese Lamp,
good idea to explore,
IMHO it is something to try out
regards
jean mi

Quote: (Originally Posted by divingtoors)

Hi There

I have been thinking about this a while and a possible solluion might be as follows:

Two stainless Steel coil springs, one of large diameter and a second of a smaller (1/10th) diameter.
It must be a spring that is easily collapasable in the legnth, but with a strong rigidity.

The idea would be to use a food grade very thin PVC material or similar, and build 2 x tubes (a lare tube and a smaller (1/10th volume) inner tube, which fits tightly over the springs.
The spring then becomes the "ribs" of the bellows, allowing compresion lengthwise and stability over the width.

The end flanges of the PVC material can then be tailored to fit over any circumfrence ending of the bellows.

Do you think it can work?

Regards

Johan

28th June 2007, 06:51	#1 (permalink)
divingtoors RBW Member Current Rebreather/s: Home Build Other Rebreather/s: Not Bought Yet Home Build Join Date: Mar 2006 Location: Cape Town Posts: 103	Bellows counterlung schematics HI There We are in process of designing and building our own version of a PASCR, and the only real "problem" we have encountered this far, is finding a suitable inner and outer Bellows counterlung. I have sourced a company that can cut bellows CL's from Teflon, but they need diagrams and sketches. Does anybody have such schetces or diagrams. We are looking for something similar to the CL's of the Rebreather-80 and its "clones". Any ideas on substitutes? Thanx and regards Johan
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23rd November 2007, 20:05	#2 (permalink)
jmurba wet bear Current Rebreather/s: Home Build Other Rebreather/s: Home Build Join Date: May 2006 Location: cannes france Posts: 920	Re: Bellows counterlung schematics Quote: (Originally Posted by divingtoors) HI There We are in process of designing and building our own version of a PASCR, and the only real "problem" we have encountered this far, is finding a suitable inner and outer Bellows counterlung. I have sourced a company that can cut bellows CL's from Teflon, but they need diagrams and sketches. Does anybody have such schetces or diagrams. We are looking for something similar to the CL's of the Rebreather-80 and its "clones". Any ideas on substitutes? Thanx and regards Johan Hello, have a look at mac master carr in the usa, McMaster-Carr Counterlung / Metered Discharge: McMaster-Carr sells a range of neoprene-coated nylon bellows ranging from 1 3/4" O.D. to 12" O.D. If I could find a suitable tube for the main housing (approximately 7" I.D.), I'd use the 6 3/4" O.D. X 5" I.D. bellows for the outer bellows. This would need to be about 9" long to give a maximum counterlung volume » my vital capacity » 4 liters. An inner bellows measuring 3" O.D. X 2" I.D. would give a discharge ratio of about 17%. An 8" X 6" outer bellows would allow a shorter counterlung (at about 6 1/2") and would give a choice of 3 1/2" X 2 1/2" or 3" X 2" inner bellows for a discharge ratio of 18% or 12%. I read this there you probably also read it: PASCR otherwise I have ideas, you make the belows form in wood then you buy RTV silicon resin , you take a painbrush and paint many lyers of rtv resie on the wooden bellow...it coud take you a week end to complete it layer after layers, at the end you get the bellow rtv resin is really resistant elastic fantastic I've used it many time . it is worth to try IMHO regards jean mi __________________ when will I be able to think about something else then spending hours underwater, when will I be normal ? http://web.mac.com/jmurba/Site_2/home.html http://web.mac.com/jmurba/Site_3/home.html
(Offline)

23rd November 2007, 21:11	#3 (permalink)
Marvintpa Bad knees, matching brain Current Rebreather/s: Classic Kiss Other Rebreather/s: Join Date: Mar 2005 Location: Ontario, Canada Posts: 284	Re: Bellows counterlung schematics I could be wrong but I was under the impression the RB80-clones use a bellows from a hospital respirator. Sure looks like one. Not sure I'd go trusting that to someone willing to build a one-off over something that's been in use in life-critical applications for many years. Last edited by Marvintpa : 23rd November 2007 at 21:13.
(Online)

24th November 2007, 14:08	#4 (permalink)
jmurba wet bear Current Rebreather/s: Home Build Other Rebreather/s: Home Build Join Date: May 2006 Location: cannes france Posts: 920	Re: Bellows counterlung schematics Quote: (Originally Posted by Marvintpa) I could be wrong but I was under the impression the RB80-clones use a bellows from a hospital respirator. Sure looks like one. Not sure I'd go trusting that to someone willing to build a one-off over something that's been in use in life-critical applications for many years. I am not sure I have understood what you exactly meant. if you mean thata medical respirator bellow is better then an home buit bellow you are certainely rigth, except if the bellow is properly built. sometimes diy parts are good you know. it depends on the builder (((-: I've alway dived my gauges and so far survived. the real reason to make bellow yourself is to get the size you exactly need. buying bellows from medical industry has to bad consequencies the first is that they are longer then wide and that it makes it impossible to locate the bellow at the top of the diver back as a real french dc55 that is easy to breathe in all positions unlike the R80 and clones. the second problem is that if you can decide the elimination ratio you want and not simply get the one you can get buying industry bellows. you also can chose the sickness of you bellows, ther rigidity. regards jean mi __________________ when will I be able to think about something else then spending hours underwater, when will I be normal ? http://web.mac.com/jmurba/Site_2/home.html http://web.mac.com/jmurba/Site_3/home.html
(Offline)

25th November 2007, 05:56	#5 (permalink)
divingtoors RBW Member Current Rebreather/s: Home Build Other Rebreather/s: Not Bought Yet Home Build Join Date: Mar 2006 Location: Cape Town Posts: 103	Re: Bellows counterlung schematics Hi There I have been thinking about this a while and a possible solluion might be as follows: Two stainless Steel coil springs, one of large diameter and a second of a smaller (1/10th) diameter. It must be a spring that is easily collapasable in the legnth, but with a strong rigidity. The idea would be to use a food grade very thin PVC material or similar, and build 2 x tubes (a lare tube and a smaller (1/10th volume) inner tube, which fits tightly over the springs. The spring then becomes the "ribs" of the bellows, allowing compresion lengthwise and stability over the width. The end flanges of the PVC material can then be tailored to fit over any circumfrence ending of the bellows. Do you think it can work? Regards Johan __________________ "..Recreational scuba training has developed the denial of risk into an art form...." ( Larry "Harris" Taylor, Ph.D.) "The closer you are to danger, the further you are from harm" - Pippin Took (Hobbit)
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25th November 2007, 12:10	#6 (permalink)
DepthCharge New Member Current Rebreather/s: Inspiration Classic Home Build Other Rebreather/s: Home Build Join Date: Mar 2005 Location: upstate NY Posts: 234	Re: Bellows counterlung schematics Quote: (Originally Posted by divingtoors) Hi There I have been thinking about this a while and a possible solluion might be as follows: Two stainless Steel coil springs, one of large diameter and a second of a smaller (1/10th) diameter. It must be a spring that is easily collapasable in the legnth, but with a strong rigidity. The idea would be to use a food grade very thin PVC material or similar, and build 2 x tubes (a lare tube and a smaller (1/10th volume) inner tube, which fits tightly over the springs. The spring then becomes the "ribs" of the bellows, allowing compresion lengthwise and stability over the width. The end flanges of the PVC material can then be tailored to fit over any circumfrence ending of the bellows. Do you think it can work? Regards Johan On the DC 55 they have thin plastic (teflon?) rings that fit inside each loop of the CL to maintain the sidewall rigidity. It doesn't effect the collapsibility. __________________ Later, John It's better to beg forgiveness than ask permission
(Offline)

25th November 2007, 14:20	#7 (permalink)
jmurba wet bear Current Rebreather/s: Home Build Other Rebreather/s: Home Build Join Date: May 2006 Location: cannes france Posts: 920	Re: Bellows counterlung schematics hello, it would be like a chinese Lamp, good idea to explore, IMHO it is something to try out regards jean mi Quote: (Originally Posted by divingtoors) Hi There I have been thinking about this a while and a possible solluion might be as follows: Two stainless Steel coil springs, one of large diameter and a second of a smaller (1/10th) diameter. It must be a spring that is easily collapasable in the legnth, but with a strong rigidity. The idea would be to use a food grade very thin PVC material or similar, and build 2 x tubes (a lare tube and a smaller (1/10th volume) inner tube, which fits tightly over the springs. The spring then becomes the "ribs" of the bellows, allowing compresion lengthwise and stability over the width. The end flanges of the PVC material can then be tailored to fit over any circumfrence ending of the bellows. Do you think it can work? Regards Johan __________________ when will I be able to think about something else then spending hours underwater, when will I be normal ? http://web.mac.com/jmurba/Site_2/home.html http://web.mac.com/jmurba/Site_3/home.html
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