Conductivity Analyzers

A conductivity analyzer works by measuring the electrical conductivity of a solution as it flows through the system, providing real-time monitoring of the ionic content. The principle involves applying an electrical voltage across electrodes in contact with the sample. The conductivity is determined by the ability of ions in the liquid to carry electrical current between the electrodes.

METTLER TOLEDO in-line conductivity analyzers use the same principle but with advanced sensor and transmitter technology. They are designed for continuous, real-time monitoring in demanding industrial processes.

In-line conductivity measurement is the continuous monitoring of the electrical conductivity of a solution directly within a pipeline or system, without the need to extract samples for laboratory analysis. This method provides real-time data on the ionic content of a solution, allowing for immediate control and adjustments in various industrial processes.

Temperature significantly affects conductivity by influencing the speed and number of ions in a solution. As temperature increases, ions move faster, enhancing conductivity, especially in pure water where more water molecules dissociate into ions. Thus, temperature compensation is crucial for accurate conductivity measurements, normalizing readings to a standard reference temperature such as 25 °C.

METTLER TOLEDO in-line conductivity analyzers are equipped with advanced temperature compensation features. These analyzers automatically adjust the conductivity reading based on the measured temperature, ensuring highly accurate and reliable results across varying process conditions.

Most conductivity analyzers use either two or four electrodes:

• Two-electrode systems have two conductive electrodes that apply a voltage and measure the current, suitable for simpler applications.
• Four-electrode systems, often used in more precise or challenging environments, have two current-carrying electrodes and two voltage-sensing electrodes, which help minimize the effect of electrode polarization and improve measurement accuracy.

The choice depends on the specific application and required measurement accuracy.

To understand more about two-electrode and four-electrode conductivity analyzers, we recommend you read our article, Conductivity Sensors Explained, to understand how they work and their applications.

Calibrating conductivity analyzers is crucial for obtaining accurate and reliable measurements. Over time, the sensor components may drift, become fouled, or undergo changes due to environmental factors, which can result in incorrect readings.

Regularly calibrating the analyzers against standard solutions helps maintain measurement precision, supports process control, and ensures compliance with quality standards.

In-line conductivity analyzers are used for continuous monitoring and control of processes across various industries. 

Key applications of conductivity analyzers:

• Pharmaceutical and Life Sciences: Monitoring Water for Injection (WFI) and purified water systems to ensure compliance with strict standards like USP <645> prevent microbial growth or contamination.
• Microelectronics Industry: Measuring the extremely low conductivity of UltraPure Water (UPW) in semiconductor manufacturing. Maintaining precise UPW quality is vital for preventing contamination of microchips.
• Power Plants: Monitoring pure water chemistry in high-purity steam, boiler water, and cooling systems. This helps detect mineral buildup, contamination, and corrosion before they cause expensive damage.
• Chemical Industry: Controlling liquid concentration and detecting interfaces between different liquids to ensure product quality and process efficiency.
• Food and Beverage: Controlling liquid concentration and detecting phase separation during processes like cleaning cycles to prevent product contamination.
• Wastewater Treatment: Ensuring that discharged wastewater meets environmental regulations by monitoring the concentration of dissolved ions.

The measurement range of a conductivity analyzer can vary significantly, from extremely low values for ultrapure water to very high values for brines and concentrated acids.

Typical measurement ranges for high-quality sensors often span from 0.055 µS/cm up to 50,000 µS/cm.

The UniCond conductivity sensors from METTLER TOLEDO Thornton have one of the widest measurement ranges on the market. These sensors are capable of measuring accurately from ultrapure water (UPW) to brackish water, covering a very broad conductivity range.

An in-line conductivity analyzer is a system with three key components working together to measure conductivity directly within a process.

• Sensor: This is the probe that makes physical contact with the sample.
• Transmitter: The control unit that receives the sensor's signal, converts it into a conductivity reading, and applies temperature compensation.
• Sensor Housing: The mechanical fitting that holds the sensor securely in the pipe or tank, allowing for continuous measurement within the process.