Overflow filling machines ensure consistent liquid levels during filling and are indispensable in the pharmaceutical industry. In this article, you will get comprehensive information about their operating principles, technical advantages, and selection criteria to help you make more optimal decisions for your production line configuration.
Advantages of Overflow Filling Machines
Precise Liquid Level Filling
These machines adopt a constant liquid level control system to achieve consistent filling height no matter what kind of container volume or shape is. Liquid level accuracy reaches ±0.3mm and this meets stringent visual consistency requirements for pharmaceuticals, health supplements, and similar products.
Minimized Material Waste
Excess liquid is automatically recovered through a recirculation system, achieving over 98% material recovery. This reduces production costs and enhances cleanliness and batch-to-batch consistency as well, suitable for filling your high-value pharmaceutical solutions.
High-Efficiency Production
The equipment integrates seamlessly with bottle sorting machines, bottle capping machines, and labeling machines to form automated production lines. This significantly reduces manual intervention and substantially boosts your production efficiency.
Adaptable to Multiple Container
The equipment flexibly accommodates bottles of varying specifications and shapes without frequent mold changes or complex adjustments. It enables rapid production line switching to meet your needs for multi-variety, small-batch production.
Handles Diverse Liquids
The overflow filler can fill low-viscosity, free-flowing liquids and medium-viscosity pharmaceutical solutions. It also achieves smooth filling for liquids containing solid particles up to 1/16 inch in size, suitable for syrups, oral solutions, topical liquids, and other pharmaceuticals.
Easy to Clean
The machines feature a streamlined structure and standardized interfaces. Some models support CIP/SIP online cleaning and sterilization, complying with pharmaceutical GMP standards and minimizing cross-contamination risks.
Optimized for Foam-Prone Products
The overflow filling principle effectively eliminates foam interference and avoids underfilling or bottle mouth contamination caused by bubbles. This ensures accurate product volume and a clean appearance.
Working Principle of Overflow Filling Machines
Container Positioning
The containers move along the conveyor belt into the filling zone. And under the photoelectric sensors and gripping devices working together, the containers are precisely secured beneath the filling nozzle.
Filling
- After the nozzle automatically descends and inserts into the bottle opening, the metering pump or time-controlled valve begins dispensing liquid.
- When the liquid level reaches the preset height, the overflow port automatically opens, returning excess liquid to the storage tank to maintain a constant liquid level.
- While the nozzle is immersed in the bottle, the filling nozzle can seal the bottle opening to prevent leakage or spillage. At the same time, the nozzle height automatically adjusts according to the bottle type to ensure consistent liquid level height regardless of the container being filled.
Reset
Once the liquid reaches the target level and overflow ceases, the nozzle automatically closes the inlet channel and slowly retracts.
The entire process is controlled in real-time by the PLC system, you can precisely set filling time, flow rate, and return speed.
Special Design
Sterile Design
- To meet the sterile production requirements of the pharmaceutical and high-end health supplement industries, all contact components are manufactured from 316L medical-grade stainless steel and undergo mirror polishing (Ra ≤ 0.4μm). This can prevent material residue and microbial growth.
- And the machines are paired with an aseptic air barrier and an online cleaning and sterilization system. This effectively isolates external non-aseptic air from entering the filling zone while enabling efficient and reliable cleaning between batches for you.
Anti-Foaming Design
- For products easy to foaming, the filling nozzle used a beveled cut and multi-hole diverter design which reduces the impact force of falling liquid. It prevents foam generation during filling.
- It is optional to be paired with non-contact sensors, such as photoelectric liquid level sensors. The non-contact sensors replace traditional mechanical probe detection,and completely eliminates false triggers or cross-contamination caused by contact to ensure your filling accuracy and product purity.
Quick Changeover Design
- On one hand, the equipment employs a modular structure with highly adjustable nozzles. It can rapidly adapt to different bottle shapes or liquid level requirements.
- On the other hand, the control system supports storing multiple sets of formula parameters and one-touch recall, allowing you to resume production within minutes during batch changeovers without complex debugging, significantly reducing downtime.
Suction Recovery System
- The machines are equipped with a high-precision suction recovery system that instantly creates negative pressure at the end of filling. This precisely cuts off liquid droplets and achieves a material recovery rate of ≥98%, which effectively reduces raw material waste and also keeps bottle openings clean, preventing drips from contaminating the filling area.
- It is particularly suitable for production lines handling high-value pharmaceutical liquids or solutions containing active ingredients.
Components of Overflow Filling Machines
Storage Tank
The storage tank holds the liquid to be filled and also serves as a temporary holding unit for refluxed material.
If your material is prone to sedimentation or solidification, it is recommended selecting a tank equipped with insulation and agitation functions.
Transfer Pump
The transfer pump is responsible for steadily conveying liquid from the storage tank to the filling head. Common types include centrifugal pumps and rotary lobe pumps.
When the liquids are easy to foaming or contain surfactants like syrups, chlorhexidine solutions, low-shear rotary pumps are recommended to minimize bubble formation and ensure uniform flow rates.
Filling Head
The filling head performs precise volumetric filling. Quantity is typically configured based on production capacity (usually in even numbers).
For products prone to foaming, you should choose slow-flow nozzles or submerged filling structures that can further enhance filling accuracy and surface finish.
Liquid Level Sensor
The liquid level sensor continuously monitors the fill height in each container to ensure consistent filling. Photoelectric reflective sensors are commonly used to achieve accuracy within ±1 mm.
Overflow Recirculation System
This system recovers liquid exceeding the set level back to the storage tank. A typical design allocates 10% of the tank’s total capacity to balance recirculation rate and pressure fluctuations.
We recommend selecting models with a buffer tank, which effectively absorbs recirculation impacts and prevents secondary bubbles or component stratification caused by liquid collisions.
PLC Control System
The entire machine is centrally controlled by a PLC system, paired with a Human-Machine Interface (HMI) for parameter setting, status monitoring, and alarm notifications.
You can easily configure key parameters such as filling speed, liquid level height, reflux ratio, and nozzle lifting rhythm via the interface.
Types of Overflow Filling Machines
Semi-Automatic Overflow Filling Machine
The semi-automatic overflow filling machine needs manual container loading and unloading by an operator, with foot pedal or pneumatic control operation. A single unit can fill approximately 100 bottles per hour. And it shows a simple structure, easy maintenance, and a compact footprint.
Due to its low investment costs and flexible production changeovers, it is ideal for intermittent production, small-batch trials, or facilities requiring frequent formula switching.
Automatic Overflow Filling Machine
The automatic overflow filling machine automates feeding, positioning, filling, and backflow processes. And it reaches high-efficiency production exceeding 1,000 bottles per hour, meeting your large-scale production demands.
Linear Overflow Filling Machine
Its filling heads are arranged in a straight line, typically equipped with 2 to 12 heads. Featuring a simple structure and easy maintenance, it achieves stable filling of 500 to 3000 bottles per hour.
Its high flexibility allows rapid switching between different bottle types and capacities and make it ideal for you to produce multi-specification or customized products.
Rotary Overflow Filling Machine
Filling nozzles are evenly distributed around a circular turntable, typically featuring 12 or more nozzles. Containers rotate synchronously with the turntable during filling, maintaining liquid level accuracy within ±0.5mm. The whole process is continuous, high-speed, and stable.
This model is particularly suited for high-volume continuous production lines, capable of filling over 6,000 bottles per hour.
Consideration When Selecting an Overflow Filling Machine
Production Capacity
Before selecting a model, you must clearly know your target production capacity. Different models offer varying capacities. For large-scale batch production, we recommend choosing a fully automatic overflow filling machine. In addition, please share your production plan with us, and we will provide you with a suitable overflow filling machine.
Material Properties
The state, viscosity, and chemical characteristics of your material directly affect equipment configuration. If you need to fill alcohol-based or volatile solvent-containing products, explosion-proof overflow filling machines are a good choice. We can provide tailored solutions for pump types, nozzles, and reflux methods based on your product formulation.
Container Dimensions and Shape
The height, neck diameter, and shape of the bottle determine the nozzle stroke and positioning methods. Our equipment displays quick-adjustment structures compatible with various containers—from small-capacity reagent bottles to large plastic bottles—supporting flexible production across multiple product lines.
Why Choose Our Overflow Filling Machines
Customized Solutions
We specialize in providing customized filling systems according to your actual production scenarios. Regardless of the material you fill, we design matching overflow filling solutions based on your material properties, production volume planning, and cleanliness requirements.
Durable Equipment
Our machine is constructed from stainless steel, demonstrating excellent corrosion resistance and wear resistance. Each unit undergoes rigorous durability and precision testing to satisfy your long-term stable operation.
Turnkey Solutions
We deliver integrated packaging lines encompassing filling, capping, labeling, inspection, conveying, and packaging. Unified design and control systems help achieve higher automation levels while reducing operational and maintenance costs.
Expert Support
Our experienced technical team provides end-to-end services—from preliminary design and workshop layout to process validation and installation commissioning. Besides, we also provide on-site maintenance training to ensure your production line remains in optimal operating condition at all times.
Conclusion
Overflow filling machines have become indispensable core equipment in the liquid filling process for the pharmaceutical and health supplement industries, thanks to their stable liquid level control, excellent cleaning performance, and adaptability to multiple bottle types and formulations.
Whether you’re conducting small-batch trials, process validation, or preparing to scale up with automated production lines, we can provide GMP-compliant, high-precision liquid filling solutions. Get in touch with us today!
FAQ
How to Maintain an Overflow Filling Machine?
- Please regularly inspect critical components such as sensors, pipe connections, seals, and filling head valve cores to ensure long-term stable operation.
- After each production run, promptly clean the inner walls of the filling head, pipes, and overflow ports to avoid residual liquid buildup that could affect filling accuracy or cause cross-contamination.
- Replace worn or aged seals, filling head valve cores, and other vulnerable parts in a timely manner to maintain equipment performance and filling precision.
How to Calibrate an Overflow Filling Machine?
- First, fill the equipment to the set liquid level.
- Place the container on an electronic balance to weigh it, converting the weight to actual liquid volume.
- use a laser distance meter to measure the liquid level height inside the bottle.
- If the liquid level error exceeds ±0.1 mm, fine-tune the liquid level sensor threshold.
- Repeat the calibration three times until the liquid level height error is controlled within ±0.1 mm to ensure filling consistency.
Can the equipment support future capacity upgrades?
Yes. Some models support modular upgrades like increasing the number of filling heads, boosting pump power, or upgrading the control system to meet future production growth needs.
Clearly communicating your future expansion plans” during initial model selection so that we can recommend models conducive to future upgrades to ensure your production line maintains long-term scalability.
