Coating Dilution with H+B Recirculator

[tmason]

We have a Harris and Bruno coating unit and recently had two instances where the coating in the drum has been diluted with water. We checked our timer settings and they seem fine for all the processes.
We closely watch the drain and wash cycles and everything seems to be working fine, we cannot duplicate the problem. Possibly a sticking valve???
Has anyone had this issue and if so, what did you do to fix it?

Thanks for your help,
Todd

[sburger6]

Ive used this system on a Mitsu and a Heidelberg and have never seen this , it may be during the wash or recovery cycle? its a pretty good coater set up but Id like to know whats causing that myself.....that watered down coating can be used to lower your viscosity on drums that are to high if that helps you.......good luck

Steve

[tmason]

We checked all of the timer settings and changed a few of them to try and get more water out of the lines during washes. I also thought maybe the air solenoid under the water tank was sticking open but after watching it, it seems fine and if it were stuck, we would see water traveling up the line to the drum. I think it's got to be in the wash cycle or in the return pump. I rebuilt the feed pump and am thinking the other pump may not be pumping the volume that it should. I'll keep you posted.

[cincyinkslinger]

There are is a valve inline in both the coating supply and return lines that should close during wash up. These lines are purged and rinsed during the wash-up cycle. If one or both of these valves do not close, then water would be introduced into your coating barrel.

[Freeman A.Gain]

Also, the air bladder at the top of the probes could have a split. This too could also lead to water getting in during the start up...after a AQ washup.