Vacuum Transducers in Tetra Pak & F&B Processing: Measurement Principles, Types, and Uptime Benefits in Hygienic Systems
A vacuum transducer (or vacuum pressure sensor/gauge) measures pressures below atmospheric (gauge vacuum) or relative to a near-vacuum reference (absolute vacuum). It does not require a perfect vacuum—true absolute vacuum is unattainable on Earth (or even in space, where trace matter exists)—but provides precise readings for low-pressure environments.
In food & beverage processing, vacuum transducers ensure product safety, quality, and efficiency:
- Monitoring vacuum levels during packaging to remove oxygen, prevent oxidation/bacterial growth, and extend shelf life.
- Detecting leaks or maintaining negative pressure in aseptic chambers/lines for sterility.
- Level control in tanks or hoppers via differential pressure in closed systems.
Principles & Measurement
Vacuum transducers compare process pressure to a reference (often atmospheric or near-vacuum). Common outputs: 4-20 mA, 0-10 V, or digital (for PLC/SCADA integration). Hygienic designs feature stainless steel wetted parts, flush diaphragms, and IP68/69K ratings for CIP/SIP washdowns.
Vacuum transducers compare process pressure to a reference (often atmospheric or near-vacuum). Common outputs: 4-20 mA, 0-10 V, or digital (for PLC/SCADA integration). Hygienic designs feature stainless steel wetted parts, flush diaphragms, and IP68/69K ratings for CIP/SIP washdowns.
Common Types in Industrial Use
- Pirani Gauge — Thermal conductivity-based: A heated filament loses heat proportional to gas pressure (effective ~10⁻⁴ to 1000 mbar). Widely used in vacuum packaging and low-pressure monitoring; modern MEMS versions offer compact, wide-range accuracy.
- Ionization Gauge — Hot/cold cathode: Ionizes residual gas to measure ion current (high vacuum ~10⁻⁵ to 10⁻³ mbar). Suitable for ultra-low pressures in specialized aseptic or drying processes.
- Gas Drag / Spinning Rotor Gauge — Measures molecular drag on a levitated spinning ball (high accuracy in medium vacuum). Less common in F&B but useful for calibration/reference.
Applications in Tetra Pak & F&B
- Aseptic Packaging Integrity — Vacuum leak testing on cartons/pouches ensures hermetic seals, preserving sterility and shelf life without refrigeration.
- Vacuum Packaging & Degassing — Removes air from liquids (e.g., juices, sauces) to prevent spoilage and maintain flavor.
- Tank & Process Monitoring — Differential vacuum/pressure in balance tanks or fillers for accurate level/dosing control.
- CIP/SIP Validation — Confirms negative pressure during cleaning to verify system hygiene.
- Select hygienic models (EHEDG/3-A compliant) for F&B.
- Prioritize wide range, fast response, and digital outputs for automation.
- Regular calibration prevents drift; overload protection avoids damage.