Standard procedure to accomplish a diluent flush ?

[tarpio]

Hi All,

I would like to have your feedback about the way you learned or practice a Air Diluent Flush on MEG.

Which one did you learned or practice :
Open dump valve on the exhale counter lung, Activating the ADV compressing the counter lungs and purging the gas :

1/from the mouth
or
2/ through the dump valve on the exhale counter lung (with trim 0° )
​

What is the ISC's standard way to do a diluent flush on MEG APECS ( with Air diluant to start)

Regards,

 

[cardysnr]

DIL flush on Meg

Activating the ADV compressing the counter lungs and purging the gas through the dump valve on the exhale counter lung.

Dump valve closed on surface but fully open once submerged.

David.

 

[divingabe]

Activating the ADV compressing the counter lungs and purging the gas through the dump valve on the exhale counter lung.

Dump valve closed on surface but fully open once submerged.

David.

Would this then only dump the dill out of the OP valve and not circulate it through the can and over the cells.
Just a thought!!!!
Gabe

 

[PeterN]

Activating the ADV compressing the counter lungs and purging the gas through the dump valve on the exhale counter lung.

Dump valve closed on surface but fully open once submerged.

David.

Not what I do. This will only flush the exhale counter lung.

If you go a bit heads up and open the adv slider and press in the adv while keeping the lungs held in AND venting from your lips, you will truly flush your loop in short order.

Peter

 

[trimixdiver]

Not what I do. This will only flush the exhale counter lung.

If you go a bit heads up and open the adv slider and press in the adv while keeping the lungs held in AND venting from your lips, you will truly flush your loop in short order.

Peter

+1 exactly how I remember on the Mod1 course.

 

[Philippe GERIN]

If you go a bit heads up and open the adv slider and press in the adv while keeping the lungs held in AND venting from your lips, you will truly flush your loop in short order.
Peter

To add to your excellent comment: cross your harms over your chest. You reach the ADV with your right hand and your right shoulder CL T with your left hand so your elbows will press and hold down your CLs. Do it twice and you're sure to fully flush the loop.
Best
Philipe

 

[cardysnr]

In my 1st post I only directly addressed items 1 & 2 so ........

Full DIL flush proceedure taught on MOD1 with lung OPV fully open.....

Head up orientation, pull down on ADV slider to activate, crush both counter lungs, depress the ADV, take deep breaths and deep exhales, vent via nose to move fresh DIL around closed loop as you can have significant residual gas in your lungs.

Thoughts....

* For an effective DIL Flush to perform a cell check I would inhibit O2
injection (Setpoint to Manual or shut O2)

Must however remember to open O2 or change setpoint back on handset
before continuing dive.

* DIL Flush at depth will comsume valuable Diluent vs Sanity breaths from
ADV / BOV & go OC.

David.

 

[Megangel1]

In my 1st post I only directly addressed items 1 & 2 so ........

Full DIL flush proceedure taught on MOD1 with lung OPV fully open.....

Head up orientation, pull down on ADV slider to activate, crush both counter lungs, depress the ADV, take deep breaths and deep exhales, vent via nose to move fresh DIL around closed loop as you can have significant residual gas in your lungs.

+1 but if loop o2 is outside safe limits, vent via mouth rather than breath.

 

[tarpio]

Hi All,

Thanks for all your inputs

But do you have any idea about the ISC Standard procedure?

Regards

 

[cardysnr]

Hi,

Send a PM to AndyMumford here on CCRexplorers (UK ISC Meg Instructor) he should be able to advise on the current ISC standard.

Regards,

David

Hi All,

Thanks for all your inputs

But do you have any idea about the ISC Standard procedure?

Regards

 

[Michael Thornton]

If you pinch the hose just to the side of the BOV/DSV it will block the flow and force the newly injected dil back the other way around the loop and into the can and past the cells. One technique.

 

[PeterN]

If you pinch the hose just to the side of the BOV/DSV it will block the flow and force the newly injected dil back the other way around the loop and into the can and past the cells. One technique.

Hard to do on the Meg as the hoses are very stiff compaired to others. This taught, but IMHO rairly pulled off well on this rig.

I struggled with this for awhile, it may be easier fo warm water divers with no heavy gloves, but to me it seems much slower than what I earlier describe.

Peter

 

[Michael Thornton]

Hard to do on the Meg as the hoses are very stiff compaired to others. This taught, but IMHO rairly pulled off well on this rig.

I struggled with this for awhile, it may be easier fo warm water divers with no heavy gloves, but to me it seems much slower than what I earlier describe.

Peter

From your picture it looks like you dive a Golem Shrimp BOV. With this BOV there is no need to pinch a hose because closing it will actually stop flow of gas. Accomplishing the same thing. This is the procedure I use. I have tried the other method on lots of different rebreathers but not on the meg. I have done it with HH rubber hoses, PRism2 hoses, Cooper hoses and inspo hoses.

 

[Megangel1]

If you pinch the hose just to the side of the BOV/DSV it will block the flow and force the newly injected dil back the other way around the loop and into the can and past the cells. One technique.

eh?

Is it just me?

Might work for an 02 flush, IF you can crush the hose effectively but A GG shrimp BOV turned to OC works even better! But I really can not see how this can ever work for a DIL flush, even with the GG Shrimp BOV on OC. Think about it, the OPV and ADV are both on the exhale lung! Hoses have nothing to do with it.
The only way to get DIL through the can is for gas to be vented from the mouth/nose or be breathed through the BOV/DSV.

However, if you have swapped DIL and O2 MAV injection points, then yes.

PLEASE DO NOT START THE SWAP OVER DEBATE HERE TOO!

 

[PeterN]

From your picture it looks like you dive a Golem Shrimp BOV. With this BOV there is no need to pinch a hose because closing it will actually stop flow of gas. Accomplishing the same thing. This is the procedure I use. I have tried the other method on lots of different rebreathers but not on the meg. I have done it with HH rubber hoses, PRism2 hoses, Cooper hoses and inspo hoses.

You have a good eye for spotting the Shrimp.

However I still feel that a bettter flush will result from spilling from the mouth as the gas flow will be through the entire loop.

Peter

 

[Garth]

You have a good eye for spotting the Shrimp.

However I still feel that a bettter flush will result from spilling from the mouth as the gas flow will be through the entire loop.

Peter

I may be rather green but if it is spilling through your mouth it's not traveling through the whole loop. If it is spilling from the OPV which is the farthest point from the manual add diluent button when the shrimp is closed it is traveling the entire loop.

At least that's what the schematic in my head is saying.


... and when you breath from it you instantly feel better about life. [The Hammerhead]

 

[Dave Sutton]

If it is spilling from the OPV which is the farthest point from the manual add diluent button when the shrimp is closed it is traveling the entire loop.

Uhh... no.

On the Meg, which is what we are discussing, the diluent manual add (ADV which is manually depressed to function) and the OPV are about, oh... six inches apart in the same lung. You can press the ADV all you like with the OPV open and all you're gonna do is to flush the exhale CL.


Dave


.

 

[Megangel1]

Uhh... no.

On the Meg, which is what we are discussing, the diluent manual add (ADV which is manually depressed to function) and the OPV are about, oh... six inches apart in the same lung. You can press the ADV all you like with the OPV open and all you're gonna do is to flush the exhale CL.

Not just me then :thumbsup:

For the most efficient usage of gas, why don't we fully close the OPV rather than open it and just vent past the mouth, crushing the lungs with our arms?

For a while I dived with an exhale lung on the inhale side (rather than an inhale lung) using it to hold the 4th cell unit. DIL flush was easy and efficient, close the OPV on the exhale lung, open the one on the inhale lung, crush lungs with arms and hit the ADV.

To be honest, didn't see much benefit so went back to 'stock' config and DIL flush by gas venting around mouth.

 

[Michael Thornton]

eh?

Is it just me?

Might work for an 02 flush, IF you can crush the hose effectively but A GG shrimp BOV turned to OC works even better! But I really can not see how this can ever work for a DIL flush, even with the GG Shrimp BOV on OC. Think about it, the OPV and ADV are both on the exhale lung! Hoses have nothing to do with it.
The only way to get DIL through the can is for gas to be vented from the mouth/nose or be breathed through the BOV/DSV.

However, if you have swapped DIL and O2 MAV injection points, then yes.

PLEASE DO NOT START THE SWAP OVER DEBATE HERE TOO!

Your right I was thinking of a meg with the MAVs swapped. And don't worry I have 0 interest in starting that debate.

 

[Garth]

Uhh... no.

On the Meg, which is what we are discussing, the diluent manual add (ADV which is manually depressed to function) and the OPV are about, oh... six inches apart in the same lung. You can press the ADV all you like with the OPV open and all you're gonna do is to flush the exhale CL.


Dave


.

right i forgot the Meg has a different direction of gas flow than the Hammerhead. I suppose it made sense in my head for my machine which also has a shrimp on it.

sorry