How to avoid the acetic acid evaporation

[Charles Silva]

Hi all

I'm going to start dosing vinegar using a peristaltic pump (BRS 1 mL/min) controlled by an Apex.
I'm using a 500 mL water bottle as the vinegar reservoir.
I noticed in my room the vinegar smell and Im worried if the reservoir is loosing the acetic acid (evaporation) and the eficiency over the time during my dailly dosing.
Any idea how to prevent the evaporation ?
Can I install an air valve under the reservoir allowing the air entering only when the vinegar is pumped ?

Charles Silva
Rio de Janeiro - Brazil

 

[FranklinDattein]

Hi Charles,

A check valve on the container cap, is what I use.

 

[jason2459]

What did you do to make the hole for the tubing?

I just drilled a hole big enough in the top of my vinegar bottle to just barely shove in a 1/4" tube.

Then when its very near empty I remove the cap with the tube in it and place on the next vinegar bottle and put the new cap not drilled on the old almost used up vinegar and use it for something else.

I even did the same thing with my iron(II) citrate I'm dosing now.

Ran down and just shoved my nose up to it and smell 0 vinegar odor from it. Never have smelled it in that room.

 

[FranklinDattein]

What did you do to make the hole for the tubing?

I just drilled a hole big enough in the top of my vinegar bottle to just barely shove in a 1/4" tube.

Then when its very near empty I remove the cap with the tube in it and place on the next vinegar bottle and put the new cap not drilled on the old almost use

Jason,
If you allow air easily in, a bit of liquid will evaporate, specially vinegar. Perhaps the reason you can't smell vinegar is because it quickly lose its smell when exposed to air.(it most likely also lose some of its desirable properties)

If you don't allow air in, the bottle will deform and cause resistance against the pump, which will result in inaccurate doses and even burst the bottle, tubing or motor.

 

[Randy Holmes-Farley Verified Community Expert]

Jason,
If you allow air easily in, a bit of liquid will evaporate, specially vinegar. Perhaps the reason you can't smell vinegar is because it quickly lose its smell when exposed to air.(it most likely also lose some of its desirable properties)

If you don't allow air in, the bottle will deform and cause resistance against the pump, which will result in inaccurate doses and even burst the bottle, tubing or motor.

Vinegar is easily smelled, but actually evaporates more slowly than water (the boiling point of acetic acid is 118 deg C), so a small hole is no concern, even if you can smell it.

FWIW, vinegar will get more concentrated during evaporation, not less so (unless the humidity is very high around it).

 

[jason2459]

Why does the air have to easily get in? Are you dosing an entire bottle at once?

I assure you when I have little left on the bottom of the vinegar it is at or near full strength.

FYI, If you are concerned with exact precision the BRS 1.1ml/m is said to not be 1.1ml/m. You will have to test flow rate and retest again after the tube is broken in. Many say it is more then 1.1ml/m.

I have not tested my flow rate. I have not been concerned. I initially kept jumping up in dosage until I got excessive bacterial growth and then backed off a little.

I have been using the same cap, tube, and brs 1.1ml/m dosing pump since I think 2010. Has worked very well.

 

[Randy Holmes-Farley Verified Community Expert]

FWIW, i used a BRS 1.1 mL per min doser and used a jug exactly as Jason does, except it wasn't a hole, it was a small 1/8-1/4 pie slice taken from the lid.

 

[spicymikey]

Hi all

I'm going to start dosing vinegar using a peristaltic pump (BRS 1 mL/min) controlled by an Apex.
I'm using a 500 mL water bottle as the vinegar reservoir.
I noticed in my room the vinegar smell and Im worried if the reservoir is loosing the acetic acid (evaporation) and the eficiency over the time during my dailly dosing.
Any idea how to prevent the evaporation ?
Can I install an air valve under the reservoir allowing the air entering only when the vinegar is pumped ?

Charles Silva
Rio de Janeiro - Brazil

White Vinegar (5% acetic acid concentration) actually evaporates fairly slowly. It has a strong odor so it is noticeable but it is not considered a "fast evaporating" chemical such as alcohol (Ethanol). If you dose Vodka or straight Ethanol you have more to worry about regarding evaporation. Do some quick searching on "evaporation rate" for both chemicals and you'll learn more

 

[Randy Holmes-Farley Verified Community Expert]

To a first approximation, evaporation is correlated with the boiling point. Ethanol boils a much lower temps (78 deg C) than water (100 deg C), which in turn boils at a lower temp than acetic acid (118 deg C)