Capability of regulators ?

[Externet]

Hello.
Regulators have a fixed capability manufacturers have to comply with, or they decide the litres per minute/cubic feet per minute they can supply at 150 psi ? I believe the regulated pressure delivery is standard, right ?

 

[tbone1004]

intermediate pressure is not a standard, it goes anywhere from 123psi ish to 165psi ish and everywhere in between. All depends on the manufacturer and individual regulator design. Most second stages stem from one of two designs and as such the 135ish psi spec that most regulators are set to. It is a range as the springs are not perfect and the second stages don't really care whether it is 130 or 140psi.

Manufacturers outside of Europe have no government spec they have to comply with, though if they want to sell to Europe they have to pass the CE tests. These are much more about work of breathing specifications which will obviously have a minimum flow rate, but the reality is the vast majority of first stages can flow more gas than the valve on the scuba tank itself, so while the MK25 has all this marketing nonsense about how much flow it has but a normal tank valve has like 30cfm flow rate if I remember correctly which seems right based on how long it takes to drain a tank.

 

[lowwall]

Hello.
Regulators have a fixed capability manufacturers have to comply with, or they decide the litres per minute/cubic feet per minute they can supply at 150 psi ? I believe the regulated pressure delivery is standard, right ?

@tbone1004 has correctly answered the question you asked. But I suspect there is an underlying reason for the question. If you let us know what it is, I'm pretty sure we can help with that too.

FWIW, the US Navy standard is for a given maximum work of breathing at 62.5 liters/minute at 60m (198'). The European EN250 standard uses 62.5 liters/minute at 50m (165'). That's on a breathing cycle, if you just hold down the second stage purge, the actual flow will be much higher. For example Poseidon claims its Xstream Deep Mk 3 can flow "76 Standard Cubic Feet per Minute (SCFM) Flow of Gas (2,150 liters per minute)". Which as tbone pointed out is silly since tank valves aren't capable of supplying that much gas.

 

[p_kos]

intermediate pressure is not a standard, it goes anywhere from 123psi ish to 165psi ish and everywhere in between. All depends on the manufacturer and individual regulator design. Most second stages stem from one of two designs and as such the 135ish psi spec that most regulators are set to. It is a range as the springs are not perfect and the second stages don't really care whether it is 130 or 140psi.

Manufacturers outside of Europe have no government spec they have to comply with, though if they want to sell to Europe they have to pass the CE tests. These are much more about work of breathing specifications which will obviously have a minimum flow rate, but the reality is the vast majority of first stages can flow more gas than the valve on the scuba tank itself, so while the MK25 has all this marketing nonsense about how much flow it has but a normal tank valve has like 30cfm flow rate if I remember correctly which seems right based on how long it takes to drain a tank.

Takes forever to drain a tank with just an open valve. But put a reg on it and purge it and it takes a fraction of the time.

 

[tbone1004]

Takes forever to drain a tank with just an open valve. But put a reg on it and purge it and it takes a fraction of the time.

This is true, but that's a weird phenomenon in the valve outlet, if you put the proper tank drainers on there you can drain an AL80 in about 3mins give or take from memory and it's certainly no faster than that from a single LP port.

 

[lowwall]

This is true, but that's a weird phenomenon in the valve outlet, if you put the proper tank drainers on there...

Tank drainer? [googles]

Cool. I learned something today

Divesoft Tank Silencer

The Divesoft Silencer allows for fast and quiet draining of diving cylinders.

www.divegearexpress.com

 

[axxel57]

My tank drainers took almost 15 minutes to drain the tank, but at least with little noise.
If it`s true that you can empty a tank faster with a reg connected, it should have to do with the Venturi Assist of the 2nd stage, which might help to suck the air faster from the tank than the presure release itself, everythng else wouldn`t make sense.
But I never tried to empty a full tank like that......

 

[p_kos]

My tank drainers took almost 15 minutes to drain the tank, but at least with little noise.
If it`s true that you can empty a tank faster with a reg connected, it should have to do with the Venturi Assist of the 2nd stage, which might help to suck the air faster from the tank than the presure release itself, everythng else wouldn`t make sense.
But I never tried to empty a full tank like that......

I reckon it would take around 3 minutes or less to drain a full tank with a purged reg. I’ve always done it on partially full tanks and never timed it but I know it was way faster then just leaving the valve open. It has to do with the uninterrupted flow to a larger outlet vs the sudden drastic constriction on the tank valve opening. Kinda like it’s quicker for a room full of people to leave in a controlled manner rather than everyone running for the door at once and bottle-necking. That’s my very unscientific guess at it.

 

[halocline]

I reckon it would take around 3 minutes or less to drain a full tank with a purged reg.

I think it's more than that on land, but at depth it is faster. The pressure differential is less the deeper you go.

It's definitely less with a regulator than just opening the valve, the fastest way would probably be a first stage with all the LP ports out and no hoses. There would be quite bubble show if you did that in the water, and maybe an ice show if you did it on land.

I think you are right about the aerodynamics of the tank valve vs the regulator. The tank valve merely has to flow enough to keep the HP part of the reg above IP, so there's no huge pressure drop at the tank valve. That's probably what makes it faster, better aerodynamics in the regulator.

 

[wetb4igetinthewater]

Takes forever to drain a tank with just an open valve. But put a reg on it and purge it and it takes a fraction of the time.

Not if you knock the valve off with a 8 kilo sledgehammer.

FORE! <insert golf emoji here>