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Its not leaking from the pump, it just may be that the pump head rollers don’t seal tightly against the tubing enough to prime the line. So you get a few bubbles from the beginning of the line that gets caught in the tubing going around the pump head and never gets worked out.I wasn’t aware the pump could leak air into the system. I too thought it was a closed system.
For what it's worth, you would need to dose 3 inches of air (in a 4mm ID pipe), to reduce actual Alk dosing by 1 ml. Assuming that's not happening?Maybe I should keep the lid off the reservoir to let it degas?
Looks like them. Amazon.Are these your containers
I have two. I have the same issue. Ive primed many times and I’ve replaced all the air line. I’ve also added check valves. I’m not sure what’s going on. I’m dosing sodium bicarbonate mixLooks like them. Amazon.
I actually bypassed the nipple and have the tubes directly in and still the same issue.I have two. I have the same issue. Ive primed many times and I’ve replaced all the air line. I’ve also added check valves. I’m not sure what’s going on. I’m dosing sodium bicarbonate mix
I suspect crappy nipple connection on the container. Read reviews and people mention replacing /sealing the fittings
No. Just no. There is no as exchange through silicone via suction. End of story. I work with these pumps in the pharmaceutical industry and platinum cured silicone is the gold standard for fluid transfers. It is considered an impermeable sterile barrier. There is no gas exchange.If you are using common silicone tubing, it is likely the high permeability of silicone is allowing gas exchange
Fair enough, I certainly yield to your expertise. I can only speak from a point of experience when I had a similar issue, and suspected the permeability of the tubing. A Google search returned that silicon has high relative permeability. Example:No. Just no. There is no as exchange through silicone via suction. End of story. I work with these pumps in the pharmaceutical industry and platinum cured silicone is the gold standard for fluid transfers. It is considered an impermeable sterile barrier. There is no gas exchange.
Fair enough, I certainly yield to your expertise. I can only speak from a point of experience when I had a similar issue, and suspected the permeability of the tubing. A Google search returned that silicon has high relative permeability. Example:
“Silicone rubber has many characteristics which have enabled it to achieve wide use. Its vapour permeability, however is extremely high which leads to both specific benefits and considerable drawbacks in many applications. It is an excellent barrier against liquids, but many vapours – such as oxygen, water vapour and hydrogen can pass through most types of silicone almost as if it was not there. This makes it highly suitable for use in some applications, and totally unsuitable for others”
When I changed the tubing to FEP, the problem went away. But I’m pretty sure I was not using pharmaceutical grade platinum cured silicone tubing.
If the mechanism is not gas exchange, then I do not know the reason why the bubbles disappeared. Could it be that I simply had poor quality silicone or it was somewhat porous tubing?
Interesting. Glad this solved your problem. Since rigid tubing seems to help, folks may also like to know that you can use 1/4 inch RODI tubing with the standard airline connectors on most dosing pumps. You just have to heat up the tubing to slip it over the barb. I made a video a while back:Changing the tubing resolved the issue. I went from a very flexible style tubing to a more rigid tubing and it’s been 48 hours and no air in the lines, where prior bubbles would form within a few hours.
Hopefully this helps any others out there that are experiencing similar issues.
Interesting. Glad this solved your problem. Since rigid tubing seems to help, folks may also like to know that you can use 1/4 inch RODI tubing with the standard airline connectors on most dosing pumps. You just have to heat up the tubing to slip it over the barb. I made a video a while back:
I used this method to connect RODI tubing to my DOS pump instead of the flexible tubing it comes with. I did it to prevent kinks and for aesthetic reasons, but maybe it can help with trapped air issues too.