Analytical sensors

Conductivity sensors

Conductive level sensors are designed to monitor the filling levels of conductive liquids in containers, tanks, and silos. They are pre-destined for use in the food industry. They detect the conductivity and concentration of different media and can differentiate between e.g. cleaning agents, rinsing water, and the food product. This means that it is not only possible to constantly track the product but also to reduce the waste of product and rinsing water – all possible without making adjustments to the sensor.

Oil sensors monitor the quality of hydraulic fluids and lubrication oils. To be more precise the particle monitor type LDP detects the purity level / level of contamination of mineral-, ester- and bio-oils. The oil humidity sensor type LDH measures the relative humidity and concentration of water in oil.

Analytical sensors make an important contribution to condition-based monitoring and the avoidance of downtime.

What is a Conductivity Sensor?

A conductivity sensor measures the ability of a liquid to conduct electrical current, which correlates with the concentration of ions in the solution. This measurement is vital for monitoring the purity or concentration of solutions in various industrial processes. Conductivity sensors are widely used in applications like water quality monitoring, chemical processing, and food and beverage production to ensure consistency and safety.

Conductivity Sensor Types

ifm provides two main types of conductivity sensors:

• Conductive (Galvanic) Sensors: These sensors use two metal electrodes to measure the conductivity of a liquid. The current flows through the liquid between the electrodes, and the sensor measures the voltage drop to determine conductivity. They are suitable for applications with low to medium conductivity ranges. 

• Inductive (Toroidal) Sensors: These sensors use electromagnetic fields to induce a current in the liquid without direct contact. They are ideal for high-conductivity applications and are less prone to fouling and corrosion. The LDL2xx series from ifm is an example of inductive conductivity sensors.

Working Principle:
A conductive level sensor operates based on the electrical conductivity of liquids. It typically consists of multiple electrodes that are immersed in a tank or pipe. When a conductive liquid (e.g. water or acid) contacts the probe, it completes an electrical circuit between the reference electrode and the measuring electrode. The sensor detects this change and signals the presence of the liquid at that level.

Use Case:
Ideal for point level detection in conductive media such as water, acids, alkalis, and emulsions. Frequently used in water treatment, chemical plants, and food industries.

Conductivity Sensor for Water

ifm’s conductivity sensors (e.g. LDL101, LDL200 series) are tailored for water-related processes:

Working Principle (Water-Specific Use):
Sensors detect the ionic content of water by analysing how easily electricity flows through it. In ultrapure water, conductivity is very low—requiring sensors with high sensitivity (as low as 0.04 µS/cm).

Applications:

• Drinking water: Ensures purity and detects contamination.

• Wastewater: Monitors ionic pollution for legal discharge limits.

• Industrial processes: Controls water quality in cooling systems or boilers.

Liquid Analytical Sensors

ifm offers a range of liquid analytical sensors that provide real-time monitoring of various parameters in liquids. These sensors are essential for ensuring product quality and process efficiency in industries like food and beverage, pharmaceuticals, and water treatment. They help in detecting anomalies, maintaining compliance with standards, and optimising processes.

Conductivity sensors in the food and beverage industry

In the food and beverage industry, conductivity sensors play a critical role in monitoring and controlling CIP (Clean-in-Place) processes, where they help distinguish between product, water, and cleaning agents based on their conductivity values. This ensures efficient rinsing, prevents cross-contamination, and reduces waste of both product and cleaning fluids. By providing precise, real-time measurements, conductivity sensors support compliance with hygiene regulations and optimise production uptime, making them indispensable in dairy, brewery, and beverage applications.