Exit bag - How tight

[itsme777]

I haven't found any clear info about how tight the exit bag should be. Does anyone have a good understanding of that part?

 

[Olisop21.]

Interested

 

[Pikmin]

The PPeH suggests letting the exit bag fill up while it's on your ears - think of a chef's hat, and pulling it down after it's inflated in 2 minutes or so. I don't believe it's supposed to be significantly tighter than that.

 

[itsme777]

Okay, so basically the same tighness as when placed tighly around the head?
Thanks for your reply

Comment 2:
I am also using an argon regulator for a nitrogen tank. Since that was the only thing easily available. From what I understand, the LPM should be set to 21 LPM to be equal to 15 liter per minute of nitrogen (due to different densities). Some have stated 12 lpm, but that seems to be for something different from what I understan

 

[Kapsyl]

Okay, so basically the same tighness as when placed tighly around the head?
Thanks for your reply

Comment 2:
I am also using an argon regulator for a nitrogen tank. Since that was the only thing easily available. From what I understand, the LPM should be set to 21 LPM to be equal to 15 liter per minute of nitrogen (due to different densities). Some have stated 12 lpm, but that seems to be for something different from what I understan

Here is conversion sheet to use.

- 12.5LPM on argon flowmeter gives ~15litres LPM nitrogen flow
- 15LPM on argon flowmeter gives ~ 18LPM nitrogen flow
- 20 LPM on argon flowmeter gives ~ 24 LPM nitrogen flow

If you're using an exit bag and have enough nitrogen to spare I would recommend a higher lpm then 15/lpm. Some have been experiencing co2 build up due to low gas flow.

 

[Ironborn]

It's not supposed to be super tight, think of it like trousers with an elasticated waist.
Enough to keep it in place but it isn't meant to be airtight, the helium or whichever gas you are using, the pressure is meant to force out the oxygen and co2 from the bag.

 

[itsme777]

Thanks very much for your helpful info from both of you

Although, I emailed two welding firms in Sweden about the conversion rate using argon meter for Nitrogen. Neither of them were sure what to use to get 15 lpm.

I think the best way is probably to see what the pressure is inside the bottle and then adjust the reducer until 2 bars pressure is lost per minute. Either that or waiting for the bag to fill up in 1-2 minutes time.

 

[thewalkingdread]

It should be tight enough to restrict air from flowing freely in or out, but not tight to the point no air flow is present so that it would eventually blow up the bag.

 

[Kapsyl]

Thanks very much for your helpful info from both of you

Although, I emailed two welding firms in Sweden about the conversion rate using argon meter for Nitrogen. Neither of them were sure what to use to get 15 lpm.

I think the best way is probably to see what the pressure is inside the bottle and then adjust the reducer until 2 bars pressure is lost per minute. Either that or waiting for the bag to fill up in 1-2 minutes time.

Here is a resource that you can calculate the conversion rate yourself. I would personally set the flowmeter on 15/lpm, since nitrogen is lighter then argon it will deliver slightly more then 15/lpm ensuring enough gas being delivered.

Can you accurately flow a different gas through a flow control device not calibrated for the same gas?

www.harrisproductsgroup.com

Do you live in Sweden? I can pm you the source I got, filled nitrogen cylinder with built in regulator. If you still haven't resourced the nitrogen.

 

[itsme777]

Ah thanks for that link. I found similar info, but they never mentioned that it could be used for a flow gauge regulator. Just flowmeters.
But seems like that should work too.

Thanks, but I already got a cylinder

 

[Kapsyl]

Ah thanks for that link. I found similar info, but they never mentioned that it could be used for a flow gauge regulator. Just flowmeters.
But seems like that should work too.

Thanks, but I already got a cylinder

A gauge regulator should work the same way as a flowmeter, but there is nothing wrong with testing it with a balloon to be sure.

I'm happy to help answer any other questions you have, especially to a fellow Swede.

 

[itsme777]

Thank you. Are you going to test your cylinder by opening it a little without a regulator? I saw a video doing that to blow out dust etc

 

[Kapsyl]

Thank you. Are you going to test your cylinder by opening it a little without a regulator? I saw a video doing that to blow out dust etc

I'm using one with a built in regulator but I have tested mine with the flow meter. I would suggest not opening the main valve without the regulator since it would be a safety hazard and potentially wasting precious gas. Most videos I have seen only recommend wiping the connection down beforehand if you're thorough.