Troubleshooting Leaks on Overflow Filling Machines


As we have mentioned before, automatic filling machines can use a number of different filling principles, each with unique characteristics and advantages.  The overflow filler is unique in that the fill heads create a seal over bottle openings and recirculate excess liquid back to the supply tank.  This process results in consistent and level fills on each and every bottle, an ideal solution for products that are packaged in clear bottles or containers.  Of course, the completion of the seal on the bottle during each fill cycle is an integral part of this process and a majority of the troubleshooting we perform for our customers revolves around leaking bottles during the fill.  Luckily, the fix is usually fairly simple.
On many occasions, a leak on an overflow filler at the bottle opening can be fixed by simply adjusting the starting height of the fill bar.  If the fill heads start too high, the nozzles will not dive far enough to create the necessary seal over the bottle openings.  With some plastic bottles, nozzles may even start too low and dive too deep, crushing the bottle itself.  In either case, the result is likely to be a compromised seal that causes leaking product around the bottle opening.  As a general rule, a packager using an overflow filler can use the manual toggle screens and the height adjustment on the machine to find the correct starting height for fill heads.  With bottles lined up under each nozzle the manual toggle screen can be used to fully dive the heads to the down position.  The height adjustment can then be used to lower the heads until the seals are over bottle openings. Continue to lower the heads until the  springs are compressed to the point that a dime, or a fingernail, can be squeezed in between the coils, though some slight adjustment may be necessary based on bottle material or other factors.  Once this adjustment is made, a manual fill cycle can be run to confirm that the leaking has been stopped.
If the leaking persists, the operator of the filling machine should then check the pump speed settings on the operator interface of the overflow filler.  LPS overflow fillers use multi-speed pumps that will allow the pump to change speeds during the actual fill.  Running the pumps at a single high speed during the entire duration of the fill can, with some projects, lead to a build up of pressure that compromises the seal on the bottle opening, leading to leaking product.  By slowing the pump speed at the end of the fill, the seal remains intact and the fill remains level and consistent, absent the leak.
Should a leak remain after the height and pump speed are adjusted, the time has probably come to replace nozzle seals and/or washers.  Nozzle seals will normally consist of foam or rubber circles that cover the bottle opening.  The nozzle washers will normally be steel or plastic washers immediately behind the seals.  The seals themselves are considered a wear part on the overflow filling machine.  Over time, the normal functions of the overflow filler will cause these seals to erode or break down.  Sometimes, a chemical based product may cause both the seals and the washers to break down.  At a certain point, these wear parts will erode to the point that they can no longer create a secure seal over the bottle opening.  This break down will also be evidenced by leaking at the point of the seal and the simple solution is to replace the seals and/or washers.
As a packager, leaking bottles during production runs can be a frustrating experience.  However, knowing how to troubleshoot the issue can relieve the frustration while saving both time and money.  If you are experiencing problems with your overflow filler or any of your packaging machinery, contact an LPS representative to walk you through the steps to the solution.