The suitability of measurement methods for food or beverage production depends on a variety of factors. The most important are:
- Type, size, shape, and material of the container
- Required measurement accuracy
- Material properties of the media (liquid, pasty, adhesive, foaming, conductive/non-conductive, etc.)
- Media temperature and density, as well as their dynamic changes
- Changing media or consistent media in the process/tank
- Location (outdoor, indoor) and climatic requirements (condensation/humidity) for the instrumentation
- Pressure environment (atmospheric pressure or pressurized tank)
Hydrostatic Level Measurement
Here, the fill level is measured by pressure transmitters at the bottom of the container, and displayed and/or output to the PLC. The range of measurement technology extends from “simple” pressure transmitters to devices with additional functions integrated into the evaluation unit. Such “smart” sensors already offer tank linearization and density compensation in the electronics, making device configuration easier and data output more precise.
The classic application is large containers such as product receiving, storage, or mixing tanks. Thanks to exceptional performance characteristics and measurement accuracy, “smart” sensors with their highly accurate level measurement are also suitable for smaller buffer or process tanks, for which hydrostatic sensors were previously considered not precise enough. This significantly expands the application range of this easy-to-install, reliable, low-maintenance, and hygienic measurement technology:
- All types of liquids such as product, CIP media, water, regardless of conductivity, viscosity, density, etc.
- Vertical and horizontal tanks, regardless of height, volume, or shape
- Tanks indoors or outdoors, even in very humid environments
- Also for changing media with different densities
- Pressurized tanks such as fermenters (differential pressure transmitters)
- Rapid level changes such as during filling
- Non-metallic tanks
Potentiometric Level Measurement
The potentiometric measurement principle works with the detection of the change in voltage ratio in the sensor’s measuring rod, which extends into the liquid. Depending on the type, installation from above, below, diagonally, and, with a bent measuring rod, also in the side wall of a tank is possible. Length and shape can be precisely matched to the container. Modern measurement methods determine the immersion state of the electrode rod in the medium and ensure that incorrect measurements due to adhesions and foam are avoided.
Due to its insensitivity to foam and adhesions, excellent measurement accuracy, and extremely short response time, this measurement technology is suitable for a variety of media and applications in the beverage processing industry, such as:
- All liquids such as product, CIP media, water, etc., with conductivity <50μS/cm
- Applications such as pasteurizers, heaters, filling systems, carbonators, separators, horizontal tanks, etc.
- Strongly or variably foaming media
- Pasty or adhesive media such as syrups, ice cream, sauces, etc.
- Pressurized tanks
- Rapid level changes such as during filling
- Non-metallic tanks
- Different media in one tank (automatic adjustment to changing media)
Additional Selection Criteria
In addition to the measurement technology itself, other parameters must be considered when choosing a system or product, such as the hygienic design of the sensor and process connection, the lifespan of components, resistance to chemical or mechanical stress, base measurement accuracy and influence of temperature drift, installation environment and climatic requirements, data transmission (analog/digital), ease of use, accessibility of the display, etc.
Anderson-Negele offers a wide range of sensor types with extensive configuration options and a comprehensive consulting and field service, with a wealth of experience from countless applications worldwide.
New Whitepaper
In a whitepaper titled “Hygienic, Continuous Level Measurement Technology – Overview and Selection Criteria,” the sensor specialist Anderson-Negele has outlined selection criteria, suitability for applications, and product overviews.