1. Raw Fruit Pressing and Treatment System
2. Juice Mixing and Hot Water System
4. CIP (Clean-in-Place) System
5. System Integration and Control
Design and Process Overview of a 0.5 Ton per Hour Fruit Juice Pre-Treatment Line
The production of high-quality fruit juice requires a well-designed pre-treatment process to ensure product stability, safety, and sensory attributes. A 0.5-ton-per-hour (0.5 T/H) juice pre-treatment line is ideal for small-to-medium-scale production facilities, pilot plants, or craft juice manufacturers. This system integrates four main subsystems: raw fruit pressing and treatment, juice mixing and hot water supply, UHT sterilization, and CIP cleaning. Below is a detailed description of each component and its role in the 0.5 T/H juice pre-treatment process.
Raw Fruit Pressing and Treatment System
This subsystem converts fresh fruit into clarified or pulpy juice. Key equipment includes:
|
Fruit Sorter (Roller Sorting Conveyor )
The fruit sorter is the first critical control point in the raw fruit treatment system, ensuring that only sound, mature fruits enter the juice production line. For this 0.5 T/H system, a roller sorting conveyor is employed. Unlike flat belt sorters or manual sorting tables, the roller bar design allows fruits to rotate as they travel, exposing all surfaces to the operator’s view. This is particularly beneficial for fruits with subtle defects (e.g., bruises, insect damage, or early-stage rot) that may be hidden on the underside. The rolling action also helps dislodge loose dirt or debris remaining after washing. |
|
 |
|
|
|
Fruit Washer and Elevator (Bubble Washing with Integrated Inclined Elevator)
This combined unit integrates bubble washing and inclined lifting into a single machine, saving floor space and reducing fruit handling damage.
Working Principle:
Fruits enter the water-filled stainless steel tank where multiple rows of air nozzles release compressed air from a blower. The rising bubbles create vigorous turbulence, causing fruits to tumble and rub against each other, effectively scrubbing away dirt, surface microbes, and pesticide residues without bruising. After washing, a perforated inclined belt (30°–45°) lifts fruits out of the water. As the belt rises, water drains back into the tank through the perforations. A final rinse spray bar removes residual debris, and clean fruits are discharged directly to the crusher. |
Crushing and Juicing Machine
Breaks fruit cell walls and extracts juice. For hard fruits like apples, a hammer mill reduces fruit to 5–10 mm pomace, followed by a screw press at 5–15 bar. Yield is 65–85% by weight. For citrus, a rotary juicer controls peel oil below 0.03% to avoid bitterness.
Juice Storage Tank
Temporarily holds raw extracted juice (capacity 500–1000 L) with a cooling jacket maintaining 4–7°C to slow enzymatic browning. A level sensor regulates upstream and downstream flow.
Screw Pump
Gently transfers viscous or pulpy juice without shearing. A progressive cavity pump with VFD delivers 0.6–1.0 m³/h at 2–3 bar. The elastomer stator is food-grade and acid-resistant.
Vibrating Screen
Removes large solids, seeds, and coarse pulp (greater than 0.5–1.0 mm) using one or two layers of stainless steel mesh (e.g., 20 and 40 mesh) vibrated at 1400–1500 rpm.
Twin-Filter (Duplex Filter)
Provides fine filtration (20–500 µm depending on product type) with two parallel housings. When pressure differential reaches 1.5–2.0 bar, flow switches to the clean housing.
Juice Buffer Tank
Balances flow fluctuations (capacity 300–500 L) with low-level and high-level switches to prevent pump cavitation or overflow.
Centrifugal Pump & Self-Priming Pump
Centrifugal pump (0.75–1.5 kW, 15–25 m head) transfers juice from buffer tank. Self-priming pump lifts juice from lower-level tanks up to 5–6 meters.
Pasteurizer (Plate Type)
Applies low-temperature pasteurization at 85–95°C for 15–30 seconds using a three-section plate heat exchanger with 85–90% heat regeneration. Hot water (90–95°C) from the hot water tank serves as heating medium. A diversion valve returns under-temperature juice.
Homogenizer
Reduces particle size to below 10–20 µm at 100–200 bar (or 50–100 bar for citrus to avoid gelation), preventing sedimentation and improving mouthfeel. Flow rate matches 0.5 T/H.
Juice Mixing and Hot Water System
This section adjusts juice formulation and provides thermal utility:
Hot Water Tank
Stores heated water (80–95°C) in a 500–1000 L insulated tank with electric heaters (6–12 kW) or steam exchanger. PID control maintains setpoint within ±2°C. Softened water is recommended.
Plate Heat Exchanger (PHE)
A small PHE (1–2 m² area) optionally tempers juice before blending or pre-heats water using waste heat from pasteurization.
Mixer (Inline or Static)
Blends juice with sugar syrup, acidulants, or water. A static mixer with 6–8 helical elements provides continuous mixing without moving parts.
High-Speed Circular Emulsifying Tank
Dissolves stabilizers (xanthan gum, CMC) or pectin using a rotor-stator head at 2800–3600 rpm (tip speed 15–25 m/s). Capacity 200–500 L, complete hydration in 5–15 minutes.
Agitated Tank (Blending Tank)
Holds mixed juice (500–1000 L) with an anchor or turbine agitator at 30–60 rpm to maintain homogeneity. A nitrogen blanketing option is available for oxygen-sensitive juices.
Twin-Filter (Duplex) – Second Stage
A second duplex filter (50–150 µm rating) captures undissolved particles or agglomerated stabilizers before UHT treatment.
Self-Priming Pump & Centrifugal Pump
Circulates hot water from the tank to the PHE and transfers mixed juice to the UHT system. Both are hygienic, CIP-capable, and VFD-equipped.
UHT Sterilization System
UHT (Ultra-High Temperature) treatment ensures commercial sterility without refrigerated storage:
High-Pressure Homogenizer (Second Unit): Operates at 200–300 bar (0.5–0.6 m³/h) to further disrupt microbial clumps and fat globules, enhancing thermal sensitivity. Two-stage design with ceramic plungers is recommended.
UHT Sterilization Tube (Indirect Heating): Holds juice at 135–140°C for 4–10 seconds using a multi-layer tube-in-tube configuration (inner tube AISI 316L, 6–12 mm diameter, Ra < 0.8 µm). Hot water (130–140°C) or steam (150–160°C) circulates in the annulus. Holding tube length is 10–25 meters depending on flow velocity.
Vacuum Deaerator: Removes dissolved oxygen (from 8–10 ppm to < 1 ppm) and volatile off-flavors under absolute pressure of 0.02–0.05 MPa at 20–40°C. Oxygen removal prevents oxidative browning and vitamin loss.
After UHT treatment, juice is aseptically cooled to 20–30°C before filling. An aseptic buffer tank can be added to smooth downstream packaging interruptions.
CIP (Clean-in-Place) System
The CIP system ensures all process surfaces are cleaned without disassembly:
CIP Cleaning Machine: A central unit with three or four tanks (200–300 L each) for water, alkali (1–3% NaOH at 70–80°C), acid (0.5–2% HNO₃ at 60–70°C), and optional sanitizer (0.2–0.5% peracetic acid). Includes a recirculation pump (2–5 bar, 2–5 m³/h), heaters, conductivity sensors, and pneumatic divert valves.
Operation Cycle: Pre-rinse (water, 2–3 min) → hot alkali circulation (75°C, 15–25 min) → intermediate rinse (2–3 min) → acid circulation (65°C, 10–15 min) → final rinse (2–3 min, conductivity < 10 µS/cm) → optional sanitizer rinse (5–10 min for aseptic zones).
Automation: For a 0.5 T/H line, a PLC with a small HMI controls the sequence, logging temperatures, flow rates, conductivities, and times for validation. Cleanliness is verified by ATP swab testing before production.
System Integration and Control
Piping and Valves: All product-contact surfaces are AISI 304 or 316L stainless steel with Ra ≤ 0.8 µm finish. Sanitary tri-clamp fittings (1.5 or 2 inch) are used throughout. Pneumatic butterfly valves enable automatic flow diversion.
Instrumentation: Magnetic flowmeters (±0.5% accuracy), Pt100 RTD sensors, pressure transmitters (0–10 bar), and radar or capacitance level sensors are installed at key points.
Control Panel: A central PLC (e.g., Siemens S7-1200) and HMI touch screen (7–10 inches) display real-time data, allow recipe selection, and provide alarms for temperature, flow, filter clogging, or CIP failure. Data logging ensures traceability.
Conclusion
A 0.5 T/H fruit juice pre-treatment line combines robust mechanical extraction, precise mixing, high-temperature UHT sterilization, and automated CIP cleaning to produce safe, stable, and flavorful juice. This configuration is scalable, energy-efficient, and suitable for a variety of fruits (e.g., apple, orange, pear, tropical blends, stone fruits). With proper maintenance and hygiene practices, the line achieves consistent product quality and extended shelf life (typically 6–12 months ambient storage in aseptic packaging). As consumer demand for high-quality, minimally processed juices grows, a well-engineered 0.5 T/H line offers both operational flexibility and economic viability for small-to-medium producers.