Liquid Level Sensor
Beginner
By Megha Parolkar on September 20, 2019
Introduction: Liquid Level Sensor
The fastest-growing industries change its requirement at every passing hour and demands level instruments that maintain standard quality with lower cost. Sapcon is a trustworthy partner to fulfill the demands of level measuring devices and considered as one of the efficient choices.
Detection of liquid levels in industries is quite challenging as compared to solid media due to its properties and behavior. The stringent performance of liquids engages costly equipment to manage the process of level measurement. To make this operation economical, liquid level sensors are introduced. The liquid level sensor is the type of level instrument used in the process automation industry to detect the presence of liquids kept in process vessels, tanks, silos, hoppers, etc. The process followed by this level measurement is known as liquid level measurement.
How does a Liquid Level Sensor works?
The working principle of the liquid level sensor depends on the type of technology selected. Sapcon has an array of liquid level sensors that are based on Vibrating Fork, Capacitance, RF Admittance, and Conductivity principle. The following are the principle which can be useful in liquid type of application media:
- Vibrating Fork: The vibration type level switch works on the tuning fork principle which vibrates at its natural frequency in the absence of material. The vibrating fork level sensors are available with hygienic mountings that support to mount the level sensor in a hygienic environment. The compact size and fast switching of these devices make it fruitful for packaging machines.
- Capacitance: The capacitive level switch works on the capacitance principle which detects the changing value of capacitance. The properties of liquid material are precisely taken into account while designing the capacitance based level sensor. The Twin Probe and Still Well arrangement plays crucial role in these capacitive liquid level switches for material having lower dielectric media.
- RF-Admittance: The admittance based level switch works on the capacitance measurement principle with heavy build-up. These admittance based level sensors provide exceptional services even in sticky media. The designing part of the admittance level sensor is introduced with "Shield" which identifies the difference between coating and the real material.
- Conductivity: The conductivity based level sensor is also known as water level sensor which is specially designed to sense the water level. These water level sensor is generally mounted in water tanks where water are stored in large quantity.
Liquid Level Sensor Types
The liquid level sensors are broadly categorized into two parts:
- Liquid Level Switch - It is also known as Point Level Switch which determines the level only at specific points. These types of level sensors are used to detect the level at high or low points. These types of level measuring devices can be helpful to prevent overflow and dry run conditions.
- Liquid Level Transmitter - It is also known as a Continuous Level Transmitter which continuously measures the liquid. This type of level sensors monitors the level at every certain period and gives real-time results.
Product Selection: Based on Application Media
Different types of level instruments are available for level detection but before selecting the sensors, the exact type of application media should be known for betterment of output and process.
- Sticky Media
- Conductive Media
- Corrosive Media
- Foaming Media
Sticky Media
Material that can adhere to the surface of the instrument or create a coating on the probe of the level sensor is known as sticky material. Viscosity is the main parameter used to identify whether the material is sticky or not.
Examples
Ketchup
Paint
Honey
Recommended Products
Coat-Endure
RF Admittance Level Sensor
Compact coat-immune admittance level switch for sticky solids, pastes and slurries.
SLA Series
RF Admittance Level Sensor
Compact coat-immune admittance level switch for sticky solids, pastes and slurries.
Conductive Media
It give resistance to flow an electric current and it causes short circuits when it comes in contact with the metal directly.
Examples
Water
Milk
Juices
Recommended Products
Elixir
Vibrating Fork Level Sensor
Vibrating Fork Liquid Level Switch suitable for level detection in storage tanks, mixing containers etc.
SLC Series
Capacitance Level Sensor
Capacitance based level switch offers level detection solution for non-sticky slurries and liquids.
SLW
Conductive Level Sensor
SLW can be used for level limit switching applications for single/two point action for conductive liquids.
Capvel-ICT
Capacitance Level Sensor
RISC based processor to perform all the complicated jobs of evaluating the level out of the capacitance.
Corrosive Media
A highly reactive material which damages the external body directly or through chemical reaction is known as corrosive material. Acids and Bases are the most common types of corrosive material.
Examples
Chemicals
Recommended Products
Elixir
Vibrating Fork Level Sensor
Vibrating Fork Liquid Level Switch suitable for level detection in storage tanks, mixing containers etc.
SLC Series
Capacitance Level Sensor
Capacitance based level switch offers level detection solution for fine, coarse, non-sticky slurries and liquids.
Foaming Media
Liquids that build foam on the surface of the material are known as foaming material and require detection for precise level measurement.
Examples
Brewery
Milk
Paint
Recommended Products
Coat-Endure
RF Admittance Level Sensor
Compact coat-immune admittance level switch for sticky solids, pastes and slurries.
SLW
Conductive Level Sensor
SLW can be used for level limit switching applications for single/two point action for conductive liquids.
Product Selection: Based on Parameters
Temperature
The liquid materials are processed at a high temperature which requires standoff arrangement and insulation protection to isolate sense and ground to protect the level instruments.
- PTFE Insulation
- Ceramic Insulation
Recommended Products
Coat-Endure
RF Admittance Level Sensor
Compact coat-immune admittance level switch for sticky solids, pastes and slurries.
SLA Series
RF Admittance Level Sensor
Compact coat-immune admittance level switch for sticky solids, pastes and slurries.
SLC Series
Capacitance Level Sensor
Capacitance based level switch offers level detection solution for fine, coarse, non-sticky slurries and liquids.
Capvel-ICT
Capacitance Level Sensor
RISC based processor to perform all the complicated jobs of evaluating the level out of the capacitance.
SLW
Conductive Level Sensor
SLW can be used for level limit switching applications for single/two point action for conductive liquids.
MPILC
Liquid Level Transmitter
MPILC consists of an electronic evaluation unit, an insert and a probe.
Hygiene
Hygiene is the critical requirement of Dairy and pharmaceutical industries as it deals with perishable material that are sensitive to contamination. To meet the hygienic standard following points should be taken into account while designing the level instruments.
- Surface Finish
- Geometry Considerations
- Mounting Arrangement
Recommended Products
Elixir-T-Uni
Vibrating Fork Level Sensor
Compact tubular vibrating fork level switch suitable for all kinds of liquids.
Elixir
Vibrating Fork Level Sensor
Vibrating Fork Liquid Level Switch suitable for level detection in storage tanks, mixing containers etc.
For more details on hygienic requirements, refer EHEDG Certification for Fork Level Sensor article.
Modified on Feb 8, 2021
Sapcon Instruments
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