Liquid Level Sensor

Introduction

The level sensor is an equipment that measures or detects the level of application material kept in vessels, tanks, silos, hoppers, etc. The process material may be any liquid or solid depending upon the type of industry. Particularly in this article, we are going to discuss about the level instruments that detect liquid level. These level instruments are two types namely

• Liquid Level Switch
• Liquid Level Transmitter

Liquid Level Switch - It is also known as Point Level Sensor  which determines the level only at specific points. These types of level sensors are used to detect the level at high or low point. These types of level measuring devices can be helpful to prevent overflow and dry run conditions. This measuring device gives alarm at preset point.

Liquid Level Transmitter - It is also known as Continuous Level Sensor  which continuously measures the liquid. This type of level sensors, monitors the level at every certain period and gives correct results.

Selection based on Application Material

Products are recommended according to type of process material whose names are given below:

1. Sticky Material
2. Conductive Material
3. Corrosive Material
4. Foaming Material

Sticky Material

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.

• Selection Parameter
1. Viscosity - Viscosity means the resistance of a liquid to flow. This play important role to understand the behavior of the liquid material. A higher value of viscosity shows the material is viscous or sticky whereas lower value shows that the material is free-flowing. Its value is measured in centipoise.
2. Dielectric Constant - Dielectric Constant is the capability of a material to store electrical energy. Higher dielectric value means it has a greater ability to stabilize charges.
• 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 Material

Conductive materials give resistance to flow an electric current and it causes short circuits when it comes in contact with the metal directly.

• Selection Parameter
1. Conductivity - Conductivity means the ability to pass an electrical current through a material.
• 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 Material

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.

• Selection Parameter
1. pH Value - It is used to analyze the nature of a chemical whether it is acidic or basic. The lower value of pH indicate it is acidic in nature, whereas higher value shows that it is a basic solution.
• 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 Material

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.

Selection based on Factors

• Temperature
• Hygiene

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


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.

1. Surface Finish
2. Geometry Considerations
3. 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.