Vacuum?

[Alien Traveler]

Again in one of the threads I found “vacuum” in a tank mentioned. But what vacuum? Where in a tank? (and strictly speaking we should not mention word “vacuum” at all, since it refer to significant pressure drop)

OK, juice is delivered to a coil by capillary action (you can see how it works here )

According to Mr. Bernoulli, when speed of gas flow in some confinement increase, it’s pressure decrease. So, we should have some pressure drop in a chamber during draw. It should help a bit to capillary action to get juice to a coil. And as juice is going out of a tank, pressure in a tank slightly drops. After the draw pressure in a chamber restore to right atmospheric pressure, but pressure in a tank is still a bit low. Now it works against capillary action and draw juice back into a tank. But capillary action is stronger and it will dominate all these small changes in pressure.

Now again my question: why “vacuum” is mentioned in vaping so often? Where it occurs? What it is doing?

 

[Baditude]

Again in one of the threads I found “vacuum” in a tank mentioned. But what vacuum? Where in a tank? (and strictly speaking we should not mention word “vacuum” at all, since it refer to significant pressure drop)

OK, juice is delivered to a coil by capillary action.
Now again my question: why “vacuum” is mentioned in vaping so often? Where it occurs? What it is doing?

I would argue that negative pressure has a greater effect on e-liquid flow than does capillary action inside of a tank. Your video demonstration shows capillary action quite well, but as the tops of the glasses are open to air there is no containment of air to the glasses. This does not represent what goes on in a cartotank or clearomizer which are primarily based on vacuum or negative pressure.

When we suck on our mouthpiece, air is drawn from the coil area. This creates negative pressure (vacuum) in the air chamber, in the coil, and within the holding area of the tank. Our e-liquid is physically drawn into the wick in the process by this vacuum. The negative pressure within the tank then attempts to balance back to normal -- we can often see evidence of this inside the tank reservoir with tiny air bubbles coming up from the coil (wick) area after a draw.

The consumed liquid inside the tank is replaced by air from the air chamber of the atomizer. After this occurs, the pressure in the tank is back to normal. The vacuum or negative pressure is only present when we take a draw.

The main reason we suggest doing a "primer puff" right after filling a tank, or when the wick appears to be dry, is to force liquid from the tank into the coil and wick area by taking a draw, but without the fire button being pressed. This creates a mild vacuum inside the tank. If we relied solely on capillary action, this would not occur. Or, at least it wouldn't occur as quickly nor as effectively.



Having said that, I'll agree that capillary action is important when considering the wick material used. The old clearomizer tanks used silica string as a wick, which had poor capillary action. Once clearomizers began using cotton as the wick, they performed much better because cotton has better capillary action than does silica.

People who used cartomizers or cartotanks are familiar with "bad batches" of cartos. If the polyfill (wick material) in cartos was of inferior quality, they wouldn't wick because of poor capillary action and the cartos would taste burnt right from the start.

 

[HauntedMyst]

and strictly speaking we should not mention word “vacuum” at all

Agreed. I've been vaping in my office for 3 years and it hasn't gotten any cleaner.

 

[Maestro]

Of course it's not a complete vacuum. It's just a lower pressure. In this case, vacuum would be a relative term. It's between the liquid and the top of the tank. Remove the top of a full tank and it will empty out without any capillary help at all. And if you fill a tank completely with no air gap, capillary action can't compensate for the actual vacuum you're trying to induce.

Put a full water bottle in the tub and turn it upside down and lift it partway out. All the suction in the world won't pull the water out without collapsing the bottle, so capillary action sure isn't going to do it.

 

[Alien Traveler]

I would argue that negative pressure has a greater effect on e-liquid flow than does capillary action inside of a tank. Your video shows capillary action quite well, but as the tops of the glasses are open to air there is no containment of air to the glasses. This does not represent what goes on in a cartotank or clearomizer which are primarily based on vacuum or negative pressure.

When we suck on our mouthpiece, air is drawn from the coil area. This creates negative pressure (vacuum) in the air chamber, in the coil, and within the holding area of the tank. Our e-liquid is physically drawn into the wick in the process by this vacuum. The negative pressure within the tank then attempts to balance back to normal -- we can often see evidence of this inside the tank with tiny air bubbles coming up from the coil (wick) area after a draw.

The consumed liquid inside the tank is replaced by air from the air chamber of the atomizer. After this occurs, the pressure in the tank is back to normal. The vacuum or negative pressure is only present when we take a draw.

The main reason we suggest doing a "primer puff" right after filling a tank, or when the wick appears to be dry, is to force liquid from the tank into the coil and wick area by taking a draw, but without the fire button being pressed. This creates a vacuum inside the tank. If we relied solely on capillary action, this would not occur. Or, at least it wouldn't occur as quickly nor as effectively.



Having said that, I'll agree that capillary action is important when considering the wick material used. The old clearomizer tanks used silica string as a wick, which had poor capillary action. Once clearomizers began using cotton as the wick, they performed much better because cotton has better capillary action than does silica.

People who used cartomizers or cartotanks are familiar with "bad batches" of cartos. If the polyfill (wick material) in cartos was of inferior quality, they wouldn't wick because of poor capillary action and the cartos would taste burnt right from the start.

Actually, we are mostly saying the same thing. You believe pressure is more important for juice delivery, I believe capillary action is. But without proper experiments/equipment we cannot prove our points. The main thing - they are working in the same direction.
And what about top coil atomizers, like iClear 16? It was capillary action that fed them, not pressure.

 

[Alien Traveler]

Of course it's not a complete vacuum. It's just a lower pressure. In this case, vacuum would be a relative term. It's between the liquid and the top of the tank. Remove the top of a full tank and it will empty out without any capillary help at all. And if you fill a tank completely with no air gap, capillary action can't compensate for the actual vacuum you're trying to induce.

OK. I have two tanks (Kayfuns 4 and 5) with me and made an experiment. I unscred tops without closing flow contorl and left them for 15 minutes. Kayfun 5 - one drop, Kayfun 4 - no leak at all. And as I remember, Serpent Mini and Subtank are not leaking when refilling (have not used them for a while). I would not argue - a closed tank is much more leak proof than an open one, but with proper wicking leaks are not a problem.
Anyway, I do not see what is your point. Is it leak prevention? Then I mostly agree with you.

 

[Baditude]

And what about top coil atomizers, like iClear 16? It was capillary action that fed them, not pressure.

I beg to differ. Doesn't matter if its top or bottom coil design, they still depended upon negative pressure to work.

If you removed the tank's top and tried to vape that way for an extended period of time, you'd begin to get dry hits as the capillary action would not be able to keep up with you without the vacuum created with the top on.

 

[Alien Traveler]

I beg to differ. Doesn't matter if its top or bottom coil design, they still depended upon negative pressure to work.

If you removed the tank's top and tried to vape that way for an extended period of time, you'd begin to get dry hits as the capillary action would not be able to keep up with you without the vacuum created with the top on.

Unfortunately it is impossible to remove top of top coil clearo and vape.
Also, what about alcohol burner? It keeps going without any help of negative pressure.

 

[Baditude]

Also, what about alcohol burner? It keeps going without any help of negative pressure.

That's comparing apples to oranges.

An alcohol burner is burning fuel at a slow, consistant rate. A vaporizer setup is vaporizing e-liquid at a faster, inconsistant rate comparatively. If you only take a single hit once every five minutes, capillary action might be able to keep up with you. However, most vapers take several hits at one time. A vacuum-style tank is needed to force more liquid into the wick with each hit for a more efficient and satisfying vape.

 

[Alien Traveler]

That's comparing apples to oranges.

Nope. Exactly the same thing - feeding by capillary action.

EDIT: wick of burner just evaporates alcohol, flame is above the wick, exactly as a coil in a tank.

 

[Baditude]

Nope. Exactly the same thing - feeding by capillary action.

EDIT: wick of burner just evaporates alcohol, flame is above the wick, exactly as a coil in a tank.

Then we agree to disagree.

If the vacuum is disturbed in a tank, for example if the glass develops a crack allowing air into the tank, the tank will be unable to hold a vacuum and stop working efficiently. The wick hasn't been disturbed, so capillary action should still work. But since the tank can no longer hold an air-tight seal, it will develop problems.

 

[SteveS45]

I would say that there is no vacuum created in a tank because the air holes will not allow a vacuum to be created. The air moving does create a lower pressure area in the coil much like how a carburetor functions. Yes a running engine creates vacuum in the intake manifold but the transfer of fuel is done by lower air pressure. To create a vacuum the tank would require being sealed completely.

 

[BackDoc]

I think we are confusing"pressure" if you will , with " Vacuum"

 

[Maestro]

OK. I have two tanks (Kayfuns 4 and 5) with me and made an experiment. I unscred tops without closing flow contorl and left them for 15 minutes. Kayfun 5 - one drop, Kayfun 4 - no leak at all. And as I remember, Serpent Mini and Subtank are not leaking when refilling (have not used them for a while). I would not argue - a closed tank is much more leak proof than an open one, but with proper wicking leaks are not a problem.
Anyway, I do not see what is your point. Is it leak prevention? Then I mostly agree with you.

I have several kayfun v3 minis and if I forget to close the juice control before I start to fill, it all runs out the air holes. I've learned from hard (messy) experience how important the vacuum is.

 

[SteveS45]

You cannot have a vacuum if the top of the tank is open.

 

[Maestro]

You cannot have a vacuum if the top of the tank is open.

Yes, that's why you have to close the juice control when filling.

 

[Eskie]

I think we are confusing"pressure" if you will , with " Vacuum"

You cannot have a vacuum if the top of the tank is open.

Or, to keep it simple, you cannot have a pressure differential if the top is open, or your o rings are improperly set, or any other such condition.

 

[Maestro]

OK. I have two tanks (Kayfuns 4 and 5) with me and made an experiment. I unscred tops without closing flow contorl and left them for 15 minutes. Kayfun 5 - one drop, Kayfun 4 - no leak at all. And as I remember, Serpent Mini and Subtank are not leaking when refilling (have not used them for a while). I would not argue - a closed tank is much more leak proof than an open one, but with proper wicking leaks are not a problem.
Anyway, I do not see what is your point. Is it leak prevention? Then I mostly agree with you.

If you're plugging the juice holes like a washcloth in a drain, then it will probably prevent leaking. However, as I understand it, the wicks are supposed to barely touch the deck and NOT plug the juice holes. If you're wicking it that way, dry hits would be a bigger problem than leaking. When people have leaking problems, it's almost always the o-rings (loss of vacuum), not the way they're wicking it.

 

[beckdg]

Actually, we are mostly saying the same thing. You believe pressure is more important for juice delivery, I believe capillary action is. But without proper experiments/equipment we cannot prove our points. The main thing - they are working in the same direction.
And what about top coil atomizers, like iClear 16? It was capillary action that fed them, not pressure.

Go in and out between hot and cold environments...

Or up and down in altitude...

With a carto, clearo or other tank...

And it will be immediately and PAINFULLY obvious which is more important in a tank.

In a dripper, vacuum is completely useless and likely non-existant.

Tapatyped

 

[beckdg]

Also, what about alcohol burner? It keeps going without any help of negative pressure.

Heat rises.

Creating a very subtle vacuum.

Tapatyped