Help with doser

[slfcaptain]

I bought a Jabeo doser and I am having problems with the lines draining back into the reservoir. This is the second unit that I have received, the first one was sent back for the same reason. Before I send this one back I want to make sure that I have done everything that I can to make it work. I am using tubing that I bought from BRS and I am pretty sure that I am making a tight connection to the pump. I heated the ends of the tubing and pushed them on real hard. I have calibrated and 'primed' the pump. When I prime the lines the solution stays in the line fine but when the pump is finished dosing the lines start draining back into the reservoir as if the rollers are not pinching the tubing enough. First, this shouldn't happen right? I am only dosing 5ml of solution at a time, this shouldn't be a problem right? Is there anything else I can try or should I throw in the towel?

Thanks

 

[Ratpack]

You are correct, there should not be any draining based on what you are doing. I had the same thing happen on one head of my doser. I would call the place you got it from and explain it to them and how it is doing the same thing as the one just returned. The doser itself sounds fine, just the heads are bad. I got some replacement heads and things seem to be OK now.

 

[DaveK]

I have not used this specific dosing system, but have used similar units.

When you deal with a peristaltic pump the tubing used inside the pump head itself is critical. Too small or too large, and you will have problems. The tubing must also be soft so that it will seal tight. You have a new unit so the tubing should be OK.

I would contact the manufacturer first, as peristaltic pumps should not get any back flow and they should not need priming.

As a quick fix, you can use an airline check valve to prevent backflow. Install it after the pumphead. Make sure you get ones that are all plastic with no metal parts or springs inside.