Inline Conductivity Measurement and CIP Systems for Food and Pharmaceutical Industry
CIP eliminates mechanical disassembly and reduces downtime, but requires precise control of sequence, detergent concentration, temperature and contact times. Inline measurement allows verifying that each phase was completed correctly and documenting the process to meet quality and food safety audits.
1. Typical phases of a CIP cycle
- Pre-rinse with water: removes coarse product residues.
- Caustic cleaning: soda or detergent solution that removes fats and proteins; recirculated at controlled temperature.
- Intermediate rinse: water to flush the detergent.
- Acid cleaning (optional): for mineral scaling or in processes with milk/mineralization.
- Final rinse and sanitization: water or sanitizer; in some industries the final rinse must leave conductivity values below a threshold.
2. Key instrumentation in CIP
- Conductivity sensor: Detects detergent concentration by its conductivity and allows segmenting the CIP phases (interface detection between water and solution). It enables redirecting rinse water that still contains product or chemical to drain and only sending clean water to recovery.
- Temperature sensor: Verifies the solution reached the required cleaning temperature during contact time.
- Flow meter: Ensures adequate recirculation and solution flow through lines and equipment.
- Sequence control (PLC/Batch): Orchestrates phases, times and validations following the configured recipe.
Interface detection between water and detergent using conductivity is the most used technique to optimize water and chemical consumption and to reduce effluent to treat.
3. Conductivity sensor selection criteria
- Technology: Inductive sensors (electrodeless contact) are ideal for dirty solutions, with particles or very conductive; conductive (electrode) sensors are suitable for water and low/medium conductivities.
- Sanitary material: Tri-clamp connections, stainless steel with sanitary polish and FDA-approved food contact gaskets.
- Range: Must cover from water (low conductivity, µS/cm) to concentrated detergent (high conductivity, mS/cm).
- Temperature and pressure range: Compatible with sanitization conditions at high temperatures (for example, 90-140 °C) and system pressure.
- Compensation: Conductivity depends on temperature; many transmitters compensate at 25 °C. It is key for comparing values.
4. Validation and traceability
To meet standards such as HACCP, FDA 21 CFR Part 11 or pharmaceutical GMP, the system must:
- Automatically record conductivity, temperature, flow, times and alarms per batch or cycle.
- Generate compliance reports for each phase (minimum temperature, contact time, concentration within limits).
- Allow exporting or integrating history to supervisory systems for complete traceability.
Conclusion
Inline conductivity, temperature and flow instrumentation is the heart of an efficient and traceable CIP system. Correct sensor sizing and interface detection reduce water and chemical consumption, improve cleaning quality and facilitate regulatory compliance.
MARPATECH SAC represents in Peru, Argentina and Colombia process instrumentation for food and pharmaceutical industry, including conductivity and temperature sensors from Bürkert and JUMO, ideal for CIP and sanitization applications.
Frequently asked questions
Because caustic soda and alkaline detergents have high conductivity, while water has low. Measuring the sharp conductivity change detects the interface between water and chemical, allowing separation of the rinse and optimization of the cycle.
In CIP the inductive is usually preferred because it has no electrodes that scale and tolerates dirty and highly conductive solutions. The conductive is suitable for water and low-to-medium conductivity applications with clean fluids.
It requires recording per cycle: dates, phases, minimum temperature, contact times, concentration (by conductivity) and flow readings, along with alarms or deviations. This allows demonstrating that cleaning was effective in quality audits.