Air bubbles in dosing lines

[AddictedtoSalt]

Maybe someone can help me with this.
I have a BM-01 dosing pump with 2 seaside aquatics containers setup to dose vodka and my 2 part alk solution.
The problem im having is 1 of the pumps keeps sucking air in so im not getting an accurate dose.
I thought it might be ciming from the outlet of the drip line so I installed one way check valves but im still getting air bubbles in the line. The bubbles are on both sides of the pump.
Any suggestions appreciated.

 

[Jhuneke]

I've read that check valves on the inlet works. Maybe do it on both inlet and outlet... Is it the manufacturers tubing? Also heard folks having issues using other lines.

 

[AddictedtoSalt]

Yes its the lines from the kit.

 

[Jhuneke]

Somehow it loses prime from the inlet side .. Idk how , but have been watching out on mine since I heard about it. You are getting air in the reservoir side.. Check that plastic tube is snug and check for bubbles inside the reservoir along the feed tube.

 

[AddictedtoSalt]

Will do. Thanks

 

[Jhuneke]

Sure hope it helps..

 

[AddictedtoSalt]

So I checked the input line and the airbubbles start after the lid on the container. So I pulled then line off the pump and removed the lid. Using my vacuum pump that I use for test vscuum advance systems on distributors I checked the line from the pump end through the lid to the end of the pickup tube. It held 10inhg of vacuum for a full 5 minutes. This means no leak. Im wondering if maybe the doser is mounted to high above the containers. But then where is the air coming from and why only one line. Hmmmm.
Maybe ill swap lids and see what happens just for S.A.G.

 

[Jhuneke]

My head unit is about a foot above and 6 in over from containers. Hmmm ..Could there be a hole in the head tubing?


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[AddictedtoSalt]

Hmmm Could there be a hole in the head tubing?


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I suppose but I cant see air bubbles traveling down the tubing toward the container as air tends to travel up.
Unless the fluid is traveling back into the container and pulling ai in as it goes.
Possiblilty.
Maybe ill swap lines over to the 3rd pump and see what happens

 

[watchguy123]

It is likely from the container itself. The hard tubing connecting to the cap very well has the air leak. May need to add superglue to seal where the hard tubing connects to the cap. Unless there is a hole in your soft tubing or it's not well connected, that is the most likely culprit. Can be on the internal of the cap or the external.

 

[Livinlocal]

I eliminated this issue by laying my dosing pump tubing sideways and not having too much of it perpendicular with the ground if you get what I mean, in my case; was my issue was because gravity would pull one single drop out of the line and then the air would find its way up through the tube replacing the volume of liquid that was in the tube.

 

[AddictedtoSalt]

It is likely from the container itself. The hard tubing connecting to the cap very well has the air leak. May need to add superglue to seal where the hard tubing connects to the cap. Unless there is a hole in your soft tubing or it's not well connected, that is the most likely culprit. Can be on the internal of the cap or the external.

I tested the lid and tubing from the inlet of the pickup to the pump with a vacuum pump. If there was a leak it wouldnt hold vacuum.

 

[AddictedtoSalt]

I eliminated this issue by laying my dosing pump tubing sideways and not having too much of it perpendicular with the ground if you get what I mean, in my case; was my issue was because gravity would pull one single drop out of the line and then the air would find its way up through the tube replacing the volume of liquid that was in the tube.

Yea I see what your saying.

Thanks for the replies guys im going to try several things and see if I can narrow it down

 

[Jhuneke]

I was meaning the soft tube wrapped around the pump head might have a pinhole or something?

I suppose but I cant see air bubbles traveling down the tubing toward the container as air tends to travel up.
Unless the fluid is traveling back into the container and pulling ai in as it goes.
Possiblilty.
Maybe ill swap lines over to the 3rd pump and see what happens

 

[AddictedtoSalt]

Possible. Im going to check it a minute
I swapped the lines over to the 3rd pump and am setting it up right now. We'll see how it goes

 

[AddictedtoSalt]

Ok do pump #3 just dosed 28ml. Of alk with now sign of air bubbles, so maybe the line in #2 has a pin hole in it. Im going to leave it as is and rest the time for an hour from now and recheck the lines
I'll post the results then thanks everyone

 

[Jhuneke]

Hey, when you says air bubbles.. How big? I have a bunch of tiny micro bubbles lining the inside of tubing. Not breaking the flow or fill of the line so it still holds prime . Not thinking it's enough to matter dosage wise , right?

 

[AddictedtoSalt]

I have micro bubbles also but they come together and form large bubbles that affect the dosage amount

 

[Jhuneke]

Oh ok, thanks.. Mine just stick to tubing so I guess it's not interfering w amounts.. Yet! Knock on wood! Lol

 

[AddictedtoSalt]

Still no air bubbles on pump 3
Looking like a possible pin hole on pump 2
Im gonna let it sit there until tomorrow and recheck