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.

  1. Sticky Media
  2. Conductive Media
  3. Corrosive Media
  4. 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 - Sticky Material

Ketchup

Paint - Sticky Material

Paint

Honey - Sticky Material

Honey

Recommended Products

Admittance based Level Sensor

Coat-Endure

RF Admittance Level Sensor

Compact coat-immune admittance level switch for sticky solids, pastes and slurries.

Admittance based Level Sensor

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 - Conductive Material

Water

Milk - Conductive Material

Milk

Juices - Conductive Material

Juices

Recommended Products

Vibrating Fork Level Sensor

Elixir

Vibrating Fork Level Sensor

Vibrating Fork Liquid Level Switch suitable for level detection in storage tanks, mixing containers etc.

Capacitance based Level Sensor

SLC Series

Capacitance Level Sensor

Capacitance based level switch offers level detection solution for non-sticky slurries and liquids.

Conductive Level Sensor

SLW

Conductive Level Sensor

SLW can be used for level limit switching applications for single/two point action for conductive liquids.

Capacitance based Level Sensor

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 - Corrosive Materials

Chemicals

Recommended Products

Fork Type Level Sensor

Elixir

Vibrating Fork Level Sensor

Vibrating Fork Liquid Level Switch suitable for level detection in storage tanks, mixing containers etc.

Capacitance based Level Sensor

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 - Foam Detection

Brewery

Milk - Foam Detection

Milk

Paint - Foam Detection

Paint

Recommended Products

Admittance based Level Sensor

Coat-Endure

RF Admittance Level Sensor

Compact coat-immune admittance level switch for sticky solids, pastes and slurries.

Conductivitiy Level Sensor

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.

  1. PTFE Insulation
  2. Ceramic Insulation

Recommended Products

Admittance based Level Sensor

Coat-Endure

RF Admittance Level Sensor

Compact coat-immune admittance level switch for sticky solids, pastes and slurries.

Admittance based Level Sensor

SLA Series

RF Admittance Level Sensor

Compact coat-immune admittance level switch for sticky solids, pastes and slurries.

Capacitance based Level Sensor

SLC Series

Capacitance Level Sensor

Capacitance based level switch offers level detection solution for fine, coarse, non-sticky slurries and liquids.

Capacitance based Level Sensor

Capvel-ICT

Capacitance Level Sensor

RISC based processor to perform all the complicated jobs of evaluating the level out of the capacitance.

Conductive Level Sensor

SLW

Conductive Level Sensor

SLW can be used for level limit switching applications for single/two point action for conductive liquids.

Liquid Level Controller & Transmitter

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.

  1. Surface Finish
  2. Geometry Considerations
  3. Mounting Arrangement

Recommended Products

Tuning Fork Level Sensor

Elixir-T-Uni

Vibrating Fork Level Sensor

Compact tubular vibrating fork level switch suitable for all kinds of liquids.

Admittance based Level Sensor

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.

Megha Parolkar - Sapcon instruments

Modified on Feb 8, 2021

Sapcon Instruments


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