The aseptic buffer tanks are mainly used for storage and buffering liquid food and beverage(milk and dairy, plant-based drinks, NFC juice, prepared food) to maintain the sterilized products under condition of total sterility, waiting for the aseptic filling. The tanks system can be integrated into a full aseptic line or used in a separate unit for receiving all ultra-high temperature sterilized liquid aseptic products to keep the product of high quality and reduce the loss of nutrients.

The tank is suitable for storing the products with high or low viscosity, with or without fibers, with smaller or bigger particles, and it can also be equipped with a special agitator(with aseptic barriers) to make sure the material is in homogeneity after a long time storage.

Aseptic tank systems offer several advantages for liquid food and beverage products, including:

1. Preservation of product quality: it is designed to sterilize and maintain the quality of the product. This helps to extend the shelf life of the product, without the need for refrigeration or other preservatives.
2. Reduced risk of contamination: It uses a sterilization process that kills all bacteria and other microorganisms in the tank to ensure the products and tank are in an aseptic state. This reduces the risk of contamination and ensures that the product is safe for filling and consumption.
3. Flexibility in production: Aseptic tank systems can be used for a wide range of liquid food and beverage products, including dairy products, juices, soups, sauces, and more. The system allows for precise control of processing conditions, such as temperature, pressure, and time, which can be adjusted to meet the specific needs of each product.
4. Cost savings: It can help to reduce production costs by eliminating the need for refrigeration and other preservatives, as well as reducing the risk of product spoilage and waste. This can lead to significant savings in storage, transportation, and production costs.

• Pre-assembled and factory tested for easy and quick installation based on standardized designs.
• Can be integrated with a UHT control system or filling machine to meet the needs of UHT by connecting multiple filling machines.
• Uninterrupted production during product change or equipment cleaning to avoid secondary sterilization caused by product backflow.
• The system is configured with a remote module, which can perform system maintenance in real-time;
• Failure to maintain the front and rear sections without downtime.
• Intelligent operation, simple operation and high safety.
• The aseptic tank can be equipped with an optional stirrer, which can stir products that are prone to sedimentation such as chocolate and juice fibers evenly, and can also balance the temperature of the product.
• Tank bodies, pipelines and valves can be designed with SUS316L material for high-acid juice or liquid food.
• Product cooling and insulation functions can be achieved on the shell and bottom.
• Use steam sterilization and condensed water to prevent recontamination during production
• An alternative agitator can be installed on the top of the tank and with the steam barrier.
• Integrated CIP and SIP system to make sure the tank is in high hygiene condition and aseptic state.
• The design pressure of the inner tank is 0.1 ~ 0.4MPa.
• Tank capacity is from 5,000L-40,000L/H, and material incoming flowrate is from 2,000L-20,000L/H.
• The aseptic tank has a hollow jacket with high-efficiency cooling and heat exchanging.

The aseptic tank system is most commonly used when the following three situations occur in an aseptic processing line:

• Product buffering: If one of the packaging machines stops unexpectedly, the tank is used for buffer storage of product during the shutdown.
• Product replacement: Two products are packed at the same time. First, one product is filled into aseptic tanks, which is enough to ensure the whole batch of packaging. Then, the UHT equipment switches to produce another product and packs it directly into the aseptic filling machine.
• Product reflow: The UHT system has a product balance tank between 300-500 liters, and the product reflow cycle can keep the filling pressure stable through the balance tank. But sensitive or over-handling products cannot use this return flow, and the flow pressure requirements of the filling machine must be provided by the tank.

The aseptic tank system is composed of tank body, electronic control cabinet, sterile air pipeline system, clean steam pipeline system, tank instrumentation(angle seat valves, mix proof valves, sensors), agitators, etc.

The tank is sterilized by steam at a minimum temperature of 125°C for 30 minutes. It is then cooled by water circulating through the cooling jacket. During cooling, sterile air is fed into the tank to prevent vacuum formation. After sterilization, the aseptic tank is kept in aseptic conditions with an overpressure of sterile air and with steam barriers (110°C). During production, sterile air fills the tank space above the level of the product. The pressure is automatically controlled to maintain the feed pressure required by the filling machine in operation.

An aseptic tank is a sterile storage tank used to store and buffer liquid food products after sterilization and before aseptic filling. It maintains product sterility and prevents secondary contamination during production.

It maintains sterility through:

• Steam sterilization (SIP)
• Sterile air or nitrogen protection
• Hygienic valve design
• Sanitary piping connections
• High-quality surface finishing
• Proper CIP cleaning procedures

These features prevent microbial contamination after sterilization.

It is used for the sterile storage and buffering of liquid food products after sterilization and before aseptic filling. It maintains product sterility, prevents secondary contamination, and ensures stable continuous production.

Aseptic tanks are widely used in:

1. Dairy Processing

• UHT milk
• ESL milk
• Flavored milk
• Infant formula
• Cream and dairy beverages

2. Juice and Beverage Processing

• Aseptic fruit juice
• Juice concentrates
• Tea beverages
• Plant-based drinks (oat milk, almond milk, soy milk)

3. Food Processing

• Tomato products
• Sauces
• Liquid egg products
• Nutritional beverages

Main functions:

• Provide sterile buffer storage between sterilization and filling
• Maintain product quality during production interruptions
• Reduce the risk of microbial contamination
• Ensure continuous operation of aseptic filling machines

 The mixing system is designed to maintain product uniformity while minimizing contamination risks after sterilization. The main difference between a mechanical agitator and a magnetic mixer is the driving method:

• Mechanical agitator: The motor drives an impeller through a shaft and mechanical seal installed on the tank, which is suitable for yogurt, sauces, and high-viscosity products.
• Magnetic mixer: The motor transfers torque through a magnetic coupling, allowing the internal impeller to rotate without a shaft penetrating the tank wall, which is suitable for UHT milk, ESL milk, and aseptic beverages.

Mechanical Agitator vs Magnetic Mixer Comparison Table

The product holding time depends on:

• Product type
• Tank design
• Sterility level
• Production capacity

Under proper aseptic conditions, including effective SIP sterilization, sterile air protection, and hygienic design, UHT milk can typically be stored in the tank for 48–72 hours after sterilization.

However, in commercial production, the holding time is usually determined according to the complete process design, production schedule, and quality requirements. A shorter buffer time is often preferred to maintain product freshness and ensure stable continuous operation.

The capacity of a sterile tank depends on several factors, including:

• Sterilizer capacity
• Filling machine speed
• Required buffer time
• Production schedule

In general, the aseptic tank capacity is usually selected at 2–4 times the capacity of the sterilizer or filling machine to ensure continuous and stable production.

For example, for a 10,000 L/h UHT milk processing line, the UHT sterilizer capacity is 10,000 L/h. A suitable sterile tank capacity would typically be around 30,000 L.

The reason is that when the UHT system stops, it requires a complete SIP (Sterilization In Place) and CIP (Cleaning In Place) procedure before restarting. This process may take approximately 2–3 hours.

A properly sized tank provides sufficient buffer storage, allowing the filling machine to continue operation during sterilizer cleaning and sterilization cycles, improving production efficiency and reducing downtime.

A: A commercial sterility test is conducted to verify that the UHT sterilization system, aseptic transfer pipeline, and aseptic tank can maintain the microbiological stability of the product without contamination.

The typical test procedure is:

1. UHT Sterilization
   Process the products through the UHT system (for example, 137℃ for 3–5 seconds with milk sterilization) to achieve commercial sterility.
2. Aseptic Transfer to Tank
   Transfer the sterilized milk into the aseptic tank under aseptic conditions to avoid secondary contamination.
3. Incubation Test
   Hold the sterilized milk sample at an elevated temperature (for example, 37℃ for 72 hours) to accelerate potential microbial growth.
4. Microbiological Analysis
   After incubation, take samples from the aseptic tank and test the microbial count. If the bacterial count remains very low and no spoilage signs are observed, it indicates that the UHT system and aseptic tank are operating properly.

This verification method helps identify whether potential contamination comes from the sterilization and aseptic storage process or from the filling and packaging stage.

Note: A commercial sterility test verifies microbiological stability under controlled conditions. It does not mean the product is absolutely sterile, but confirms that the system can achieve and maintain a commercially sterile condition.