Filling Machines - The Fill Cycle and Bottles Per Minute
When determining the speed of a filling machine, the amount of time spent dispensing liquid into the bottle is an obvious factor. However, the dispensing of liquid is only one component of what is known as the "fill cycle" used to determine how many bottles per minute an automated liquid filler can produce. So what else makes up the fill cycle for automated production?
First, part of the automation of filling machines includes moving bottles into and out of the fill area, without the assistance of manual labor. This is typically achieved using a power conveyor along with the bottle filler. The bottles must, however, be stopped under the fill heads to achieve a consistent and reliable fill. The amount of time it takes for bottles to move in and out of position in the fill area is known as indexing time, and this time, regardless of the type of indexing used, also makes up a part of the fill cycle.
Once bottles are in place, different filling machines may also use several delay and duration settings within the fill cycle. For instance, a filling machine with diving heads may use a head dive delay to offer a short amount of time between the bottles coming into the fill area and the fill heads starting their descent. The same may filler may also use a fill head release delay as well, meaning there will be a slight pause before diving heads retract to allow for pressure to release or to avoid drips. The type and number of delay and duration times may vary from machine to machine based on fill principle, product, nozzles and more, but each of these times are also included in determining the fill cycle time.
Putting the indexing time, the fill time and all of the delay and duration times together gives you the time for each fill cycle. Once this time is found, a simple equation will tell a packager how many bottles per minute they can expect to get from the machine.
As an example, let's imagine an automatic overflow filling machine with 10 fill heads and a pin indexing system. The start of the cycle begins when the entry gate (or pin) opens allowing bottles to enter the fill area. The first four seconds of the fill cycle is made up of bottles entering the fill area. Once in place, the heads will delay for 0.5 seconds and then the duration of the head dive is another 0.5 seconds. The product is then released into the bottle and the fill lasts for 5 seconds. Once complete, the retract delay is 0.5 seconds and the time to retract is also 0.5 seconds, at which time fill heads raise, the exit gate (pin) opens and bottles start to move out of the fill area. A slight delay of 1 second from the opening of the exit gate to the next opening of the entry gate allows separation of the filled bottles from the empty bottles entering the fill area for the next cycle.
Simply adding up all of these times gives the packager a fill cycle time of 12 seconds, or 5 cycles per minute. With ten heads and five cycles per minute, the packager knows they will be able to produce 50 bottles per minute on their Overflow Filling Machine. Factors such as bottle size, product viscosity and fill principle will all help to determine how fast a filling machine will work on any given project. For questions regarding machine speed or for other information on liquid fillers, contact Liquid Packaging Solutions to speak with a Packaging Specialist today.