The Filling Machine Working Principle Explained

In this article, we take a closer look at the filling machine working principle.

Are you wondering how a filling machine works? The filling machine working principle varies from the simple to more complex but all have certain things in common: products move into containers. However there exist variations on how products are dispensed; this article goes over those different mechanisms so you can choose which works best for your needs.

Filling Machine Working Principle

The different kinds of filling machines employ a variety in techniques to fill containers with product. Some use a pump mechanism, while other machines use an auger screw to move the product from the supply container into the desired container. Let’s look at the different forms of filling machine working principle, whether manual or automatic.

Gravity Filling Machine

A gravity filling machine is one the filling mechanisms that you’ll often come across. It relies on a simple principle for its operation: the container to be filled is placed beneath a hopper or reservoir that contains the product. The filling head will usually have a special nozzle that can be opened and closed to regulate product flow.

When the filling cycle begins, the product is released from the hopper/reservoir and falls under gravity into the container below. This filler uses different methods to control product amount. Common types include time gravity filling machine, volumetric, and weight gravity filling machine.

Gravity fillers are popular, mostly owing to their simplicity and low cost. They are also ideal for freely flowing liquids, powders, and granules. Although a number of automated systems use gravity fillers, the gravity filling machine principle is mostly found in manual models that do not use powered drive systems.

Overflow Filling Machine

The overflow filling machine is another common type of filling principle, which as the name implies, uses overflow method to dispense the product. The container has the filling nozzle placed into it and a valve is opened to allow liquid to flow.

Unlike in other types of fillers, the liquid continues to flow until it reaches the required level and overflows out of the dispensing nozzle. This overflow can be caught and re-circulated or simply discarded. The method ensures every container is filled to identical levels regardless of container shape or volume variation.

This type of filling machine working principle, as you can guess, is mostly used with clear bottles or other containers whose product levels are visible to the buyer. With these containers, a variation in the fill level is easily detectable and can cause product rejection or returns. The overflow method ensures that does not happen.

Piston Filling Machine

A piston filling machine is a type of filler that uses a plunger-style apparatus (piston) to move the product from the hopper or reservoir and into the container. The plunger is mechanically driven, moving back to pull the product into a cylinder. During the forward motion, product moves from the cylinder into the intended container.

Piston fillers are usually electronically controlled and, therefore, high in accuracy. They can handle a wide range of products and are popular for their ability to fill containers with a variety of shapes and sizes. The piston filling method is also ideal for viscous and sticky products, as well as foamy products or those with air pockets.

Because of its high precision, this filling machine method is mostly used for expensive products such as those in the pharmaceutical industry. The machine is also commonly available as a bench top piston filling machine for viscous liquids but low runs.

Pump Filling Machine

This filling machine working principle relies on a special pump to move the product from a reservoir into the container. The pump is electrically or pneumatically powered. It’s also one of these types: magnetic pump filling machine, positive displacement pump filler, gear pump filling machine, or peristaltic pump filling machine.

Pump fillers are considered to be among the most accurate type of filling machines and can be used with a wide variety of products, including those with high viscosity. They also excel at handling containers with various shapes and sizes.

Net Weight Filling Machine

A net weight filling machine is a type of filling device that uses scales to measure the weight of the product as it is being filled into the container. The scale sends a signal to a controller, which in turn sends a signal to the dispensing section of the machine, telling it when to stop.

Net weight machines are mostly used to fill large containers, or products that are sold by weight. Application examples for this machine principle include filling large bags with powders or granules, large pails with all sorts of products, and so on.

Vacuum Filling Machine

This filling machine working principle is called so for using a vacuum to fill containers. Essentially, a vacuum pump draws air to produce a region of low pressure. This causes product to rush into the container, thereby filling it to the desired level.

The vacuum filling machine is often used for products that require a high degree of accuracy when it comes to filling (such as perfume), and can be fitted with various types of nozzles to accommodate different container sizes and shapes. Vacuum fillers can also be operated manually or automatically.


Several different mechanisms are used to fill containers with products. In most instances, the filling machine working principle depends on the type of product being filled as well as the desired accuracy and speed of the filling process.

Gravity, overflow, piston, pump, and net weight fillers are all types of filling machines that use different mechanisms to move the product from the hopper or reservoir into the container. Each type of filler has its own advantages and disadvantages that should be considered before making a purchase.

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