Operating Principles of a Gravity-Based Filling Machine
The supply tank or the filling bowl is on the top and in the machine’s center. This gravity-based filling machine has a stem connected to the bottom of the bowl for every container filling point. The vent tube then inserts into the filling bowl until it reaches a point above the liquid level.
The platform lifts the container till it hits the filling stem to begin filling. The container then raises until it touches the stem, which unlocks the filling valve. When the filling valve opens, liquid pours into the container. The container’s air travels through the vent tube and into the space above the liquid in the filling bowl. Even when the container is almost full, the liquid continues to flow. The excess water rises through the vent tube to the same level as the water in the bowl. No liquid from the container flows into the bowl because the vent tube is higher than the level of the liquid in the bowl.
In the vent tube, the foam will rise beyond the bowl liquid level if the product is frothy. If the foam is stable and won’t degrade, it will eventually overflow into the bowl. Gravity fillers are thus hardly adopted for foamy products.
After the container is full, it moves out of the filling position and closes the filling valve at a set time. There are several ways to get liquid out of the vent tube still in the filling stem.
It is typical for one container to fill and drain into the next. The vent tube usually extends further than the bowl’s side or top for thick liquids. The outer end may be connected to a machine that draws liquid out of the tube by applying pressure or a vacuum. Gravity head pressure produces the bowl’s overall differential pressure. Normally, 1-2 feet of head or one psi. With this, fillers cannot quickly fill viscous liquids without bigger filling stems. To fit the stem, the container’s neck must be big; otherwise, machines must undergo adjustments.
Electronics also apply in another form of gravity filler. It comprises an open-end filling stem and a fixed liquid storage or bowl. The containers move irregularly down the filling line, pausing under the filling stems. A ball check links to a long rod within each filling stem. A magnetic block in the form of a pencil connects to the top of the rod and goes through a magnetic coil.
Like a limit switch or electronic eye, a sensing device detects the container as it travels under the stem. It deactivates the conveyor and activates the magnetic coil. The electric force allows the magnetic blocks to rise, causing the rod and ball check to lift from their positions within the stem.
You can control how much the filling is by changing the size of the opening in the stem and turning on the time delay relay on the magnetic coil. For this gravity filler model, the hole in the filling stem must be smaller than the inside diameter of the container so that it doesn’t leak. When filling smaller containers, the bottle is put under the filling stem more surely. Along with fluid flow, manage the liquid level as well.
Gravity Filling Machine
In general, lifting filling machines adjust the fill height from the bottle bottom to the liquid level. The container rises positively, and differences in total container height are adjusted for by higher or lesser seal pressure.
Most rising container machines have a compression spring built into the part that lifts the tray. With this, the spring makes up for differences in the height of the container. The filling is then from above the neck of the bottle to the surface of the liquid. When filling a container with square shoulders, it’s sometimes essential to control the level of the liquid from above, so it doesn’t look like underfill.
Most of the plant’s vertical space in rising stem fillers comes from the stem itself. Typically, the fill level changes from the top of the bottle to where the liquid is. This is because gravity or a small amount of spring pressure pushes it down.
If the product has a liquid that evaporates quickly, like alcohol, it is crucial to control the height of the fill. In this case, the extra space could let dangerous gases build up, and if the container keeps in a warm warehouse, it could even blow up. So, the filling machine must be able to control the height of the fill. Most of the time, a fill height sensitivity of 1/32″ is reasonable.
Several pieces of equipment take control of the containers as they come into the filling area. Some of them are star wheels, worm or screw sorters, and lug chains. Depending on the container, filling device, and product, they may be used together or separately.
Most liquid filling machines work continuously. Many devices have a huge rotating filling head that must be fed containers. This is possible with a flat-top chain conveyor that continually feeds a star wheel or leads screw. From here, the containers are filled. Star wheels separate the containers, so they are all under the stem for filling. They can work with many different containers, but they may need to go toward the star wheel for the best separation. Worm sorters move containers into a star wheel. They can be short and only near the machine’s input, or they can be the whole primary conveyor.
How much control there is over the container determines how long the worm gets. Worm sorters often start small and grow to their full size, like a wood screw. At the point where the high crest of the thread meets the root, a continuous pocket is made. This pocket moves the container to where it needs to be on the filling machine by rotating. Most worm sorters specialize in a certain task.
In most cases, inclined conveyors and semiautomatic filling machines are the best candidates for installing lugged chains. Devices in this category may move continuously or occasionally. It is for the filling equipment’s nozzles or stems to fit tightly between the chain’s lugs. As an example, think about filling stems that are 4 inches apart. At the driving sprocket, you can change how the chain moves. Filling heads move around to change where they are. Proper management of containers, no matter what form it takes, is vital for the machine to work well.