Un-level Fills on an Overflow Filler - Troubleshooting

Un-level Fills On an Overflow Filler - Troubleshooting

Anyone familiar with the overflow principle of filling bottles knows that the ability to fill bottles to the same level regardless of small differences in interior volume is a key benefit of the machines.  But what happens if the equipment suddenly stops achieving level fills?  Below are some common issues that can lead to inconsistent levels when dealing with an overflow filler.
1.  Filler Set Up
Overflow nozzles dive into a bottle and seal over the opening, using a compression spring to open up the nozzles.  Each head consists of a fill port and a return port, with both of these ports important to the level fill.  Bottles are filled through the fill port and, when the liquid reaches a certain level, it returns to the holding tank through the return port, creating the level fill (while also helping with issues such as foaming).  For this reason, initial set up for each and every bottle run is important.  During set up, with bottles lined up under the fill heads, the height adjustment can be used to lower heads until the springs compress rather tightly, generally until a dime or a fingernail can be fitted between coils.  Less compression can mean the return port does not open completely, leading to inconsistent fills.  While this is an unlikely culprit should the inconsistency begin in the middle of a production run, the packager should always ensure that the fill heads are set up correctly.
2.  Spacers
Overflow nozzles use also use spacers on each head to control dive depth and help set the actual level of the fill.  When changing from one bottle to another during the production day, the spacers on each fill head may need to be adjusted.  If un-level fills occur at the beginning of the production run, the packager should verify that all nozzles are using the same spacers, whether an individual spacer or some combination of sizes.  Different spacers on different heads can lead to fills that are not level across all heads.  Again, this will normally not be the solution when inconsistent fills begin after production has been running correctly on a certain bottle, but verifying the spacers is a quick and easy check.
3.  O-rings and Nozzle Seals
Liquid filling machines, like most packaging machines, include wear parts that will need to be replaced over time.  On overflow fill heads, O-rings and nozzle seals are examples of these wear parts.  Worn O-rings can lead to leaking in the nozzle itself.  Worn nozzle seals may allow air into the bottle or allow product to leak out as well as flow back through the return port.  Each of these items is simple to replace, and extra O-rings and seals should always be kept on hand.  If the packager can identify a leak on or near the filler head, the likely solution for the un-level fill is to replace these components of the fill head.  Unlike those above, O-ring or nozzle seal wear may begin after the equipment has been online and running production.
4.  Hose Clamps on Tubing
Another possible cause for inconsistent level, and one that is often overlooked, is air entering the lines somewhere along the product pathway.  Many overflow filling machines will use simple hose clamps to connect tubes to both the manifold and the nozzles themselves.  If these clamps loosen over time for any reason, or are not tightened properly to begin with, a small amount of air may work its way into the product pathway.  The existence of air in the line can lead to one or more fill heads that do not consistently hit the same level.  This can be a frustrating issue as the fix is not obvious, but when inconsistent fills are experienced, a packager should tighten hose clamps and check for possible points where air may be entering the product pathway.  Removing the air entering the pathway will correct the inconsistency and return production to normal.
Of course, sometimes the unexpected or unexplained can occur.  While the above are the most common explanation for the rare instances of inconsistent fills, there may be other sources.  For additional troubleshooting help on filling equipment or any of the packaging machinery manufactured or sold by LPS, contact Liquid Packaging Solutions directly, and toll free, at 1-888-393-3693.