Figuring Out Bottles Per Minute on A Liquid Filler
One recurring question that always seems to arise when discussing liquid filling equipment is how many bottles per minute will the filling machine handle. At first glance, one may be tempted to simply multiple the fill time by the number of fill heads on the machine. Figuring out the production capacity of a liquid filler will entail a little more than just fill time however. Below we look at other factors that can have an effect on the bottles per minute produced by the equipment.
First a few caveats to keep in mind regarding the bottles per minute capabilities of the machine. It is important to realize that the number of bottles filled each minute by the filler may or may not be equal to number of bottles produced by the complete packaging system per minute. The filling machine can only work as fast as the slowest machine on the complete line. So, for instance, if the a packaging line fills 80 bottles per minute, but only labels 40 bottles per minute, the efficiency of the filling machine will be reduced to the same speed as the labeler. Second, one must realize that the bottle size will, obviously, affect the amount of time required for a fill. So when speaking of bottles per minute, a packager must remember that the number will change based on the bottle being used. Finally, the same is true of the product being run. Some products are thin and free-flowing, while others are of a thicker quality and may also increase fill times. So the packager must also realize that different products may result in different fill times and, therefore, a different number of bottles per minute.
With the caveats out of the way, we must then look to the fill cycle to determine how many bottles per minute a filling machine can produce. The actual fill time will be only one component of the fill cycle. Imagine a ten head filling machine, whether using an overflow, gravity, pump or other filling principle. With bottles under the fill heads, it may take six (6) seconds to fill the containers. However, the bottles also take time to move into and out of the fill area. This is known as bottle indexing. If our filler is using pin indexing, the exit pin, or exit gate, will open after the fill is complete to allow the bottles to exit the fill area. Once bottles are moving out of the fill area, the entrance gate will open to allow new, empty bottles to slide in to place under the nozzles. The indexing time will also be a part of the fill cycle. For our example, we will assume that indexing of bottles takes four (4) seconds total. Our fill cycle is not at a total of ten (10) seconds.
Different filling machines will also take advantage of different delay and duration times. The two described above, the indexing and fill times, are examples of duration times. Delay times may include things such as a slight pause before diving fill heads begin to ascend again to protect against drips and spills or a slight pause before the pump begins to ensure bottles are precisely in place. If we assume that our filling machine used these two delay times as well, at one (1) second each, we have a total fill cycle time of twelve (12) seconds. This is now the entire time it takes for one set of bottles to index into the fill area, receive product and move out of the fill area. Doing the math shows us that we will be able to complete five cycles in a minute, at ten bottles in each cycle, meaning that the filling machine will produce fifty bottles per minute!
Again, a larger or smaller bottle, or a different product, introduced to our fictional filling machine above can change the equation, increasing or decreasing the bottles per minute. If you have additional questions or concerns regarding fill times, bottles per minute or filling machinery in general, feel free to call an NPACK Packaging Specialist for more information.