Complete guide to industrial liquid filling

How to use this guide

• Understanding liquid behaviour
• Identifying the right dosing technology
• Choosing the right filling nozzle
• Understanding constraints and specific requirements
• Validating choices through trials

 

Technical guides by liquid type

• Filling foaming products
• Filling viscous products
• Filling liquid chlorinated products
• Filling detergents

 

1. Understanding liquid behaviour

The different characteristics of liquids

Before looking at dosing technologies, it is essential to characterize the product — that is, to understand how the liquid behaves:

• Fluid / free-flowing liquid: flows freely under gravity. Requires a precise anti-drip nozzle to prevent contamination at the end of the filling cycle (e.g. water, solvents, light oils, liquid pharmaceutical products, etc.)
• Foaming liquid: generates foam during filling, particularly when falling into the packaging. Managing foam is critical for dosing cleanliness and dose accuracy (e.g. detergents, dishwashing liquids, certain food products, etc.)
• Semi-viscous liquid: flows but with noticeable resistance. Can form threads at the end of the filling cycle if the nozzle is not appropriate (e.g. syrups, certain food oils, fluid cosmetics, etc.)
• Viscous / pasty liquid: does not flow under gravity alone. Requires a mechanical push system. Cutting the thread at the end of dosing is a key challenge (e.g. honey, creams, adhesives, gels, etc.)
• Liquid with particles: contains suspended particles or solid fragments. Volumetric dosing may be affected; weight-based dosing is often preferred to maintain accuracy (e.g. sauces with pieces, cosmetics with beads, etc.)
• Corrosive / chlorinated liquid: attacks materials in contact with the product — stainless steel in particular. Material selection and vapour management are critical (e.g. chlorinated products, acids, bases, etc.)

Each of these characteristics plays a role in selecting the right technology and tooling. That is why MOM places such importance on understanding the physical and chemical properties of the liquid before defining any equipment.

Key parameters for characterizing a liquid

• Dynamic viscosity (in Pa.s, and its variation with temperature)
• Filling temperature (viscosity varies significantly with temperature)
• Physical characteristics (e.g. foaming tendency, particle content) and chemical characteristics (e.g. corrosiveness, pH)
• Batch-to-batch variability

These parameters already strongly guide the technology, nozzle type, and product feed design for industrial liquid filling.

2. The appropriate dosing technologies

Main dosing technologies

There are several major families of solutions for liquid dosing, each with its own advantages and limitations: gravity, volumetric, weight-based, constant-level and piston dosing (mechanical or pneumatic). In practice, the difference lies as much in the technology as in the nozzle design and the product feed configuration.

Technology	Suitable liquid type	Accuracy	Typical application	Key considerations
Gravity	Fluid, free-flowing	Moderate	Water, light solvents	Sensitive to pressure variations in the tank
Volumetric	Fluid to semi-viscous, foaming	Good	Cosmetics, detergents, syrups	Less suitable for liquids with particles
Weight-based (ponderal)	Fluid to semi-viscous, liquids with particles	Very good	Food, chemical, pharmaceutical industries	Throughput more limited at very high speeds
Constant-level	Fluid to semi-viscous	Good (visual)	Transparent bottles, perfumery	Less accurate by weight if density varies
Pneumatic piston	Semi-viscous to viscous	Moderate	Low added-value products	Dependent on compressed air quality; higher maintenance
Mechanical piston (cam)	Viscous to pasty	Excellent	Honey, creams, adhesives, gels	Higher initial investment than pneumatic

How to choose the right technology?

In industrial liquid filling, the choice of dosing technology depends first on product characteristics, production objectives and the packaging. The recommended approach is:

1. Characterize your liquid (viscosity, foaming tendency, corrosiveness, particles, batch-to-batch variability)
2. Define your objectives: dose, throughput, accuracy, cleanliness level, cleaning / product changeover requirements
3. Select the technology and define the appropriate nozzle
4. Validate through trials on your real products, in your real packaging

The product’s characteristics and the expected performance drive the solution. MOM’s team is available to analyse your specifications.

3. Choosing the right filling nozzle

The nozzle is the element in direct contact with both the product and the packaging. It determines dosing cleanliness: no drips, no threads, no overflowing foam. There is no universal nozzle: each product family requires an adapted nozzle.

Fluid to semi-viscous liquids

• Simple flap nozzle: metal-to-metal seal, no gasket. Easy to clean, autoclavable without disassembly. Requires a perfect surface finish to ensure sealing.
• Gasket flap nozzle: for semi-viscous liquids where viscosity prevents the simple flap from returning to its seat. Compatible with liquids containing small particles.

Foaming liquids

• Diving nozzle (bottom-up filling): the nozzle descends into the packaging and rises during filling. Effective against foam, but reduces throughput, increases changeover time, and carries a risk of cross-contamination.
• Screen nozzle: converts turbulent flow into laminar flow. Prevents dripping by capillary action. Effective in 75% of cases. Not suitable for viscous products (risk of threads).
• Spout nozzle: the most advanced solution. The spout (constriction) maximises the effect of the screens for a diffuse, laminar flow. No diving = no cross-contamination risk. Less expensive than the diving nozzle. Plug & play. No drip at end of dosing. More information: filling foaming products.

Viscous and pasty liquids

• Ball valve nozzle: the rotation of the ball mechanically cuts the thread. Particularly effective for highly viscous products. Mechanical actuation is preferred over pneumatic to ensure a clean cut. Slaved to the dosing system, it does not affect throughput. Key consideration: longer disassembly time and gaskets required (not autoclavable as-is). More information: filling viscous products.

Nozzle type	Suitable liquid	Anti-drip	Anti-foam	Cleaning	Throughput
Simple flap	Fluid	Yes	—	Autoclave without disassembly	High
Gasket flap	Semi-viscous	Yes	—	Simple disassembly	High
Diving nozzle	Foaming	Partial	Yes	Complex changeover adjustments	Reduced
Screen nozzle	Foaming (fluid)	Yes	Yes (75% of cases)	Simple	Standard
Spout nozzle	Foaming (all types)	Yes	Yes	Plug & play	Standard to high
Ball valve	Viscous to pasty	Yes	—	Longer disassembly	Standard

4. Environments and constraints

Beyond the product itself, an industrial liquid filling project also depends on specific requirements: the operating environment, regulatory compliance, and cleanability.

Legal metrology

Legal metrology covers the requirements and control procedures to ensure production quality and traceability.
The term “ponderal filler” is a protected designation. It refers to automatic weighing instruments (AWI).
To manufacture ponderal fillers, a machine builder must hold an EC type-approval certificate.

IQ/OQ/DQ/PQ qualification and data integrity

In the pharmaceutical sector, Quality teams often require IQ/OQ/DQ/PQ qualifications.
21 CFR Part 11 is increasingly required. It governs the management of electronic records and signatures (related to traceability and data integrity requirements).
Other industries, including cosmetics and food, are also increasingly requesting these qualifications and CFR 21 Part 11 compliance.

Cleanrooms and ultra-clean environments

Ease of cleaning, material and surface selection, and the addition of complementary equipment (e.g. laminar flow hoods) enable filling in cleanroom conditions (ISO 14644-1).

ATEX zones

In areas subject to explosion risk (ATEX zones), both electrical and non-electrical equipment must comply with the applicable technical prescriptions. MOM manufactures equipment suitable for these environments.

Corrosive and chlorinated products

Chlorine is one of the main enemies of stainless steel. For corrosive products, MOM offers machines built in PVC or with metal parts treated with epoxy paint. Fasteners are protected with plastic caps or replaced with inert material screws (e.g. PEEK). A drip tray is mandatory to protect operators and the surrounding environment. Cone-bottom tanks eliminate product retention zones.

Clean-in-place (CIP)

Clean-in-place (CIP) is available on MOM automatic equipment, regardless of the piston technology selected. On automatic machines, a recovery tray significantly reduces cleaning time in the event of a line incident.

Machinery Directive / Machinery Regulation (CE)

In Europe, placing a machine on the market requires the manufacturer to apply safety requirements, document the risk analysis and apply the CE marking. Regulations are evolving: the Machinery Directive is being replaced by Machinery Regulation (EU) 2023/1230, which applies more uniformly across the EU. In practice, this increases the importance of a clear specification and complete technical documentation from the start of the project.

Filling a liquid is an expertise: each product has its constraints, each environment its requirements, and the nozzle often makes the difference.

5. Industrial validation and trials

To commit to accuracy, throughput, dosing cleanliness, and cleanability, a machine builder must carry out trials.

MOM organizes trials on your liquid and your packaging formats to validate the technology, the nozzle, dosing cleanliness (no drips, no threads, no foam) and cleaning times. Let’s discuss your specification and production constraints.

 

Conclusion

Industrial liquid filling relies on three decisions: understand the product’s behaviour and viscosity, select the appropriate dosing technology and nozzle, and validate the solution under conditions close to real production. This guide gathers the fundamental technical principles to structure that decision and guide machine selection. For specific applications, dedicated guides (foaming products, viscous products, chlorinated products, detergents…) allow each concrete case to be explored in depth with MOM Packaging’s expertise.

MOM Packaging supports manufacturers in more than 60 countries across Europe, Africa, the Middle East, Oceania, the Americas and East Asia.

 

FAQ – Liquid filling