Systems for the automation of measuring loops
The challenge: Why pH measuring loops require so much effort
In many process plants, pH measurement is one of the most critical process variables – and also the most failure-prone. This is especially true for media that are aggressive, abrasive, form deposits, or cause sensor contamination: The pH electrode drifts, becomes contaminated, and requires regular manual intervention.
For engineers and maintenance personnel, this means:
- High maintenance costs and staffing requirements
Depending on the process conditions, calibrations may be required daily or weekly. This means a significant time investment, and sometimes also equipment downtime and frequent trips to measurement points that are difficult to access or spread out over a large area. - Measurement error and unreliable data
Deposits, abrasion, contamination of the reference electrode, and temperature changes are factors that cause drift or even a total failure. As a result, processes run inefficiently or out of specification – often gradually and unnoticed for too long. - Unplanned disruptions and production risks
When a pH sensor suddenly fails, it can shut down the entire process chain. From defective batches in pharmaceutical fermenters to blocked CIP processes in the food industry or excessive wastewater levels: The financial damage is rarely linked to a single electrode, but rather to the consequences of that electrode’s failure. - High operating costs
Labor hours, buffer solutions, cleaning agents, replacement sensors, and downtime: operators know that reliable pH measurements require expensive maintenance.
The solution: Automated pH sensor maintenance for pH measuring loops
Automated pH measuring loops largely eliminate the need for manual intervention. Cleaning and calibration are fully automated, reproducible, and documented – anytime, anywhere, and no matter who is running the operation.
Your benefits
- Consistently reliable measured pH values through fully automated maintenance and calibration
- Significantly lower maintenance work and costs
- Longer sensor service life and lower spare part costs
- Higher process reliability thanks to reproducible, documented procedures
- Integration into existing control systems and end-to-end digitalization
- Increased system availability through stable measuring loops
- Reduced workload for personnel and less dependence on expertise on site
cCare – Fully automated sensor maintenance system
cCare automates all the maintenance and calibration processes of your pH sensors. The system performs predefined, traceable procedures – including rinsing, cleaning, conditioning, and calibration. It ensures a consistently high measurement quality and minimizes the need for manual intervention.
More about the fully automated cCare sensor maintenance system
cCare pHarma – Automated pH sensor maintenance for GMP processes
cCare pHarma is specifically designed to meet the requirements of regulated industries. The system offers fully validatable workflows, GMP-compliant documentation, and reproducible calibration and maintenance procedures – ideal for bioprocesses, fermentation, and pharmaceutical production.
Uniclean 700 Series – Configurable sensor cleaning in static or retractable fittings
The electro-pneumatic controller has a modular and scalable design. Rinsing processes can be triggered by a simple switch signal (relay contact on the transmitter or pushbutton) or by the time control of the Stratos Multi transmitter. The system is a non-ex version and offers the advantages of easy integration, short lead times, and high modularity, making it ideal for retrofitting existing measuring loops.
Cleaning
The sensor is cleaned with water or chemicals in interval-based or on-demand cycles. This prevents deposits, biofouling, and the buildup of grease or particles and ensures that the sensor always measures under optimal conditions.
Sterilization
If required by the application – for example, in pharmaceutical or food production – the sensor and the entire calibration chamber can also be automatically sterilized by superheated steam (SIP).
Calibration
Calibration is fully automatic within closed calibration chambers under reproducible conditions. Depending on requirements, 1-point calibration, 2-point calibration, or 2-point calibration with a reference value (verification) can be provided. The audit trail feature enables the transfer of calibration data and values to a process control system in full compliance with pharmaceutical regulations. This eliminates all risks and deviations associated with manual handling.
Integrated Diagnostics and Predictive Maintenance
Thanks to modern sensor technology – in particular Memosens, which stores extensive sensor data, such as the calibration record, directly in the sensor head – the measuring loop provides comprehensive information on sensor wear. This can be used as the basis for true predictive maintenance.
Central Control and Monitoring via Process Control Systems
Our automated systems can be integrated with the process control systems of production plants. Communication takes place via the transmitter, such as via PROFINET and PROFIBUS PA – for initiating and monitoring the cleaning and calibration processes.
Sensor Storage and Short-Term Measurements
Measuring loops with retractable fitting and electro-pneumatic controllers can also be used for applications where the sensor needs to be temporarily stored outside the process – e.g., when a long cleaning cycle at high temperature is taking place in the process, or when only a short-term measurement is recommended.
Why Knick?
By developing our cCare system, we have set the standards. For more than 20 years, it has been used in countless applications, including some that are extremely demanding. Thanks to this extensive experience in development, we know exactly why our systems are designed the way they are. Many competitors today model their designs after ours, but what sets us apart is our in-depth understanding of the processes we have built over the decades.
A key factor here is our leading expertise in retractable fitting technology – with sophisticated valve concepts, modular assembly groups, high-quality materials, and process connections for every installation scenario.
We have been developing systems for automated sensor maintenance since 1979 – working consistently ever since to perfect the technology.
Automation that fits your processes – Overview of our system solutions
Every pH measuring loop has different requirements: the number of cleaning media and buffer solutions, hygiene specifications, regulatory requirements, and ambient conditions. For complex requirements as well as simple cleaning tasks, we offer automation solutions precisely tailored to the specific conditions.
Take a look below to see three system families that cover the entire spectrum from chemicals to food and biopharmaceuticals to wastewater management – from highly regulated environments to robust, modular entry-level solutions.
cCare – Cleaning, Calibration, Conservation
For demanding pH measuring loops in chemical and food processes cCare offers fully automatic cleaning, calibration, and preservation, CIP, and SIP – in both Ex and non-Ex versions. The system ensures stable measured values even for aggressive media, high loads, and continuous operation.
More about the fully automated cCare sensor maintenance systemcCare pHarma – For the demands of biopharmaceutical production
cCare pHarma is based on the same powerful automation platform as cCare, but has been further developed specifically for biopharmaceutical processes. With components made of FDA-compliant materials, CIP/SIP-capable components, Ex and non-Ex variants, and an audit trail, it meets the stringent regulatory and quality requirements of the industry.
To cCare pHarma for biopharmaceutical requirements
Uniclean 700 Series – Configurable sensor cleaning in static or retractable fittings
The electro-pneumatic controller has a modular and scalable design. Rinsing processes can be triggered by a simple switch signal (relay contact on the transmitter or pushbutton) or by the time control of the Stratos Multi transmitter. The system is a non-Ex version and offers the advantages of easy integration, short lead times, and high modularity, making it ideal for retrofitting existing measuring loops.
The combination of the Uniclean 7xx with the Stratos Multi transmitter and the ARD75 plastic immersion fitting provides a robust, quick-to-install, cost-effective solution for the automated cleaning of pH sensors in water and wastewater applications.
To the Uniclean 700 electro-pneumatic controller
If you are interested in this solution, we will gladly help you.
Minimize your process risks through full automation!
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Frequently Asked Questions (FAQ)
How quickly does an automated measuring loop pay for itself?
It depends on the process conditions and how often the sensor needs to be cleaned and calibrated. The higher the maintenance costs at the measuring loop and the more sensitive the process, the faster the system pays for itself due to automation and measurement accuracy.
What configuration options are available? What components are required for an automated measuring loop?
All automation systems are modular combinations of components. In principle, there are 2 different sets:
- The cCare System, which always consists of a SensoGate or Ceramat, the Unical 9000 controller, and the Protos transmitter, plus the media containers.
- The electro-pneumatic Uniclean 700 series, which is configured from a range of valves and can be easily installed by the user. The cleaning process can be triggered by a simple switch signal, e.g., via the relay contact of a transmitter, a simple pushbutton, or adjustable cleaning procedures in Stratos Multi.
How many kinds of media can be controlled by the electro-pneumatic controllers?
That depends on the version:
- cCare 6 media (e.g., 4 buffer solutions, cleaning solutions, water)
- cCare Pharma 8 media (e.g., 4 buffer solutions, WFI, sterile air, cleaning solution, superheated steam)
- Uniclean 7xx up to 3 rinsing media (e.g., water, cleaning agent, air)
Can the maintenance systems also be controlled and monitored from the process control system?
Yes, communication takes place via the transmitter and the communication module installed in it. Centralized maintenance control can be performed via fieldbus, e.g., via PROFINET or PROFIBUS PA. For systems with the Protos II transmitter, all events can also be transmitted directly via a fieldbus for audit trails.
Are there also solutions for potentially explosive atmospheres?
Yes, the cCare systems are certified for potentially explosive atmospheres.
Can I also use the automation systems for sensors other than pH sensors?
Yes, the cleaning function can be used for other sensors, such as optical sensors.
How reliable are automated sensor maintenance systems in daily operations?
Automated sensor maintenance systems from Knick operate according to validated, reproducible procedures and ensure that maintenance and calibration are always performed consistently. This ensures long-term measurement consistency – regardless of personnel, shift schedules, or ambient conditions. The result is a significant reduction in maintenance errors and drift.
What requirements does my system need to meet?
In general, our automation systems can be integrated into most existing systems. During the consultation, we will work with you to assess your current infrastructure and show you the best way to automate your measuring loop.
Can I retrofit an existing pH measuring loop, or do I need new sensors?
In many cases, a retrofit is possible: The existing sensor can continue to be used while an automatic cleaning/calibration unit is being retrofitted. For special applications (e.g., high temperatures, abrasive media), robust compatible sensors may be recommended.
Do automated systems also work in heavily contaminated media or where biofouling is present?
Yes. This is precisely where automation shows its greatest strength. Regular automatic flushing and cleaning cycles prevent deposits that would otherwise lead to drift or failure within a short time. This keeps the measuring loop stable and reliable.
How reliable are automatic calibrations compared to manual ones?
Automatic calibrations are generally more precise and reproducible because they are performed under identical, controlled conditions. This eliminates errors caused by faulty operation, contamination, incorrect documentation of values, or incorrectly dosed buffer solutions.
Is an automated pH measuring loop also suitable for GMP/FDA-regulated areas?
Yes. Automated systems with a Protos II transmitter can fully document audit trail events and transfer the complete calibration record. This creates a seamless electronic history for the audit trail.