Level Sensors | Types of Level Sensors |Applications of Level Sensors

Summary

In this video, Neeta's Communication Tutorial explores level sensors, crucial in various consumer and industrial applications. The tutorial covers two main types: point level sensors, which detect liquid presence at specific points, and continuous level sensors, which measure liquid levels continuously. Point level sensors include capacitance, optical, conductivity, vibrating, and float switch types, each with unique advantages and applications. Continuous level sensors encompass ultrasonic and radar types, known for their non-invasiveness and accuracy. The video provides insights into the working principles and ideal use cases for each sensor type, making it an informative resource for those in industries dealing with liquid, slurry, and granular material levels.

Takeaways

• 🔍 Level sensors are crucial in various industries for detecting the level of liquids, fluids, and fluidized solids.
• 📊 They are categorized into point level measurement and continuous level measurement, each serving different monitoring needs.
• 📛 Point level sensors indicate presence at a specific point, whereas continuous level sensors track the level as it changes.
• 🌊 Capacitive sensors use an electric field affected by the dielectric constant of the liquid to measure level.
• 💡 Optical sensors function by reflecting light from a cone-shaped tip, which changes state when submerged.
• 💧 Conductivity sensors rely on the electric current flow through conductive liquids to signal level changes.
• 🔊 Vibrating fork sensors detect level by measuring changes in the oscillation frequency of a piezo ceramic crystal.
• 🔄 Float switches use a mechanical float to indicate level by opening or closing an electrical circuit.
• 📈 Ultrasonic sensors measure level by timing the echo of emitted sound waves, unaffected by material properties.
• 📡 Radar sensors use microwaves to determine level, offering accuracy without contact and resistance to environmental factors.

Q & A

What are level sensors and why are they important?

Level sensors are devices that detect the level of liquids, fluids, and fluidized solids, including slurries, granular materials, and powders. They play a crucial role in a variety of consumer and industrial applications by ensuring the correct amount of liquid or material is present in a given process or container.

What are the two main types of level sensors discussed in the script?

The two main types of level sensors discussed are point level measurement and continuous level measurement. Point level measurement indicates when a product is present at a certain point, while continuous level measurement indicates the continuous level of a product as it rises or falls.

How do capacitive level sensors work?

Capacitive level sensors work by giving off an electric field and detecting the level by the effect of its electric field. They use a probe to check changes in the level, which are then converted into analog signals. The principle is based on the capacitance equation where capacitance is directly proportional to the permittivity of the liquid.

What are the advantages of using optical level sensors?

Optical level sensors have the advantage of being non-invasive and providing a direct indication of the level. They work by converting light rays into electrical signals, which measure the physical quantity of light and translate it into a measurement.

How do conductivity type level sensors operate?

Conductivity level sensors operate on the principle that most liquids conduct electricity. They use a probe with a pair of electrodes, and when the liquid covers the probe, it forms an electric circuit, causing current to flow and signaling the level.

What are the benefits of using vibrating or tuning fork type level sensors?

Vibrating or tuning fork type level sensors are cost-effective, compact, easy to install, and maintenance-free. They operate by detecting changes in the frequency of a piezo ceramic crystal as the level changes.

How does a float switch work as a point level sensor?

A float switch works by using a float that raises or lowers when a product is applied or removed, which in turn opens or closes a circuit as the level raises or lowers. This movement provides an indication for high or low levels.

What is the principle behind ultrasonic level sensors?

Ultrasonic level sensors work by emitting and receiving ultrasonic waves. The time it takes for the waves to reflect back is used to measure the distance to the liquid surface, indicating the level.

How do radar level sensors measure the level of a product?

Radar level sensors transmit microwaves using an antenna. The product reflects the microwaves back to the antenna, and the time from emission to reception of the signal is proportional to the level of the product. The level in the tank is calculated by subtracting the distance between the sensor and the liquid surface from the height of the radar level sensor.

What are the applications of level sensors in various industries?

Level sensors are used in a variety of industries, including automobile, oil manufacturing, water treatment, chemical industries, and many others. They ensure proper levels of liquids or materials are maintained for efficient and safe operations.

Outlines

00:00

📡 Introduction to Level Sensors

This paragraph introduces the topic of level sensors, emphasizing their importance in various consumer and industrial applications. It outlines the video's agenda, which includes an introduction to level sensors, their applications, and types. The types are further divided into point level measurement and continuous level measurement. Point level measurement is explained with examples like capacitance, optical, conductivity, vibrating, and float switch types. Continuous level measurement covers ultrasonic and radar types. The paragraph also discusses the role of level sensors in detecting the level of liquids, fluids, and fluidized solids, and the importance of selecting an appropriate sensor based on application requirements.

05:01

🔍 Detailed Explanation of Point Level Measurement Sensors

Paragraph 2 delves into the specifics of point level measurement sensors, starting with capacitive sensors that operate on the principle of electric fields and capacitance changes to detect liquid levels. Optical level sensors are explained next, which use light reflection to measure level changes. Conductivity or resistance type sensors are then discussed, which rely on the electrical conductivity of liquids to determine level. The vibrating or tuning fork type sensors are described, highlighting their operation based on frequency changes due to level fluctuations. Lastly, float switches are introduced, which use a mechanical float to indicate level changes by making or breaking an electrical circuit. The advantages and disadvantages of each sensor type are briefly mentioned, along with their typical applications in industries such as mining, food processing, and chemical industries.

Keywords

💡Level Sensors

Level sensors are devices that detect the level of liquids, fluids, and fluidized solids in various containers or tanks. They are crucial in industries such as automotive, oil manufacturing, water treatment, and chemical industries. In the video, level sensors are the main focus, with detailed explanations of their types and applications, highlighting their importance in maintaining process control and safety in industrial settings.

💡Point Level Measurement

Point level measurement refers to the detection of a liquid level at a specific point. This type of measurement is useful for triggering alarms or actions when the liquid reaches a certain height. The video explains that point level sensors provide a reading only when the liquid crosses the sensor's position, which is vital for applications requiring precise level detection at specific points.

💡Continuous Level Measurement

Continuous level measurement involves monitoring the level of a liquid as it changes continuously, providing a real-time measurement from the bottom to the top of a container. The video mentions that this type of sensor is used when it's necessary to track the entire range of liquid level changes, such as in tanks where water is being filled.

💡Capacitive Type Level Sensors

Capacitive level sensors work by emitting an electric field and detecting changes in level based on the effect of this field. They operate on the principle of capacitance, where the level of a liquid affects the capacitance between the sensor's probe and the tank wall. The video describes how these sensors convert level changes into analog signals, making them accurate and reliable for level detection.

💡Optical Type Level Sensors

Optical level sensors use light to detect the level of a liquid. They consist of a light source (LED) and a detector (photodiode). When the sensor tip is above the liquid, light is reflected back to the detector; when submerged, the light is directed into the liquid. The video explains how the change in light intensity is used to measure the liquid level, highlighting their non-contact and non-invasive nature.

💡Conductivity Type Level Sensors

Conductivity level sensors operate on the principle that most liquids conduct electricity. They use a probe with electrodes to measure the liquid's conductivity, which changes when the electrodes are covered by the liquid, forming an electric circuit. The video mentions that these sensors are cost-effective and simple to use but are limited to conductive liquids and can suffer from probe erosion over time.

💡Vibrating Type Level Sensors

Vibrating or tuning fork type level sensors use a piezo ceramic crystal that oscillates at a natural frequency. As the liquid level changes, it affects the oscillation frequency, which is detected to measure the level. The video highlights the advantages of these sensors, such as being cost-effective, compact, and maintenance-free, while also noting their invasive nature and limited use in certain applications.

💡Float Switch

A float switch is a point level sensor that uses a buoyant float to detect the level of a liquid. As the liquid level rises or falls, the float moves, opening or closing an electrical circuit. The video explains that float switches are simple, non-powered devices that provide direct level indication but are limited to indicating high or low levels and are not suitable for variable level measurement.

💡Ultrasonic Level Sensors

Ultrasonic level sensors emit and receive ultrasonic waves to measure the distance to the liquid surface. The time it takes for the waves to reflect back is used to calculate the level. The video emphasizes the non-invasive nature of these sensors, their ability to self-clean, and their lack of moving parts, making them suitable for various applications despite their higher cost.

💡Radar Level Sensors

Radar level sensors use microwaves to measure the level of a liquid. They transmit microwaves via an antenna, and the liquid reflects these waves back to the sensor. The time it takes for the signal to travel is proportional to the liquid level. The video explains that radar sensors are unaffected by temperature, pressure, or dust, and can measure various materials, including liquids, pastes, powders, and solids.

Highlights

Introduction to level sensors and their importance in detecting the level of liquids, fluids, and fluidized solids.

Explanation of point level measurement and continuous level measurement.

Discussion on capacitance type level sensors and their working principle.

Optical level sensors' operation and their advantages and disadvantages.

Conductivity type level sensors and their method of detecting liquid levels.

Vibrating or tuning fork type level sensors and their frequency-based level detection.

Float switch level sensors and their mechanism of operation.

Ultrasonic level sensors and their non-invasive measurement technique.

Radar or microwave level sensors and their method of level detection using microwaves.

Applications of level sensors in various industries such as automobile, oil manufacturing, and water treatment.

The importance of selecting an appropriate type of level sensor for specific application requirements.

How capacitive level sensors use changes in capacitance to measure liquid levels.

The principle behind optical level sensors and the role of LED and photodiode in their operation.

The working of conductivity level sensors and their reliance on the liquid's ability to conduct electricity.

Advantages of vibrating fork level sensors, such as cost-effectiveness and ease of installation.

The simplicity and direct indication provided by float switch level sensors.

Benefits of ultrasonic level sensors, including their self-cleaning feature and lack of moving parts.

Radar level sensors' ability to measure various materials like liquids, pastes, powders, and solids.

The formula used by radar level sensors to calculate liquid level in a tank.

Transcripts

hello everyone welcome to my channel at

neeta's communication tutorial

in this video i'll explain about level

sensors

topics which i'll cover under this are

introduction applications and types

covering point level measurement as well

as continuous level measurement

under point level measurement i'll cover

capacitance type optical type

conductivity type vibrating type and

float switch

continuous level measurement

will include ultrasonic and radar type

lever sensor is a type of sensor that

detects level of liquids fluids and

fluidized solids that includes slurries

granular materials and powders

level sensors play very important role

in variety of consumer and industrial

applications

like other types of sensors level

sensors are also available and can be

designed using variety of sensing

principles so selection of an

appropriate type of sensor suiting to

the application requirement is

important

moving on to the next slide that is

application of level sensors as told

earlier level sensors are used in

variety of consumer and industrial

applications like in automobile

industries oil manufacturing plants

water treatment plants chemical

industries and many other industries

coming to the next that is

classification of level sensors level

sensors are basically classified into

two types one is point level measurement

and the other is continuous level

measurement

point level measurement indicates when a

product is present at a certain point

and continuous level measurement

indicates continuous level of a product

as it rises or it falls

when we talk about point level

measurement suppose if we have placed a

sensor to measure the level and when the

liquid crosses that point where the

sensor is placed then only it will give

the reading but in case of continuous

type measurement suppose if we have a

tank and the water is getting filled

from bottom to top

then the sensor will measure the entire

level from bottom to top

under this point level measurement i'll

cover capacitance optical conductivity

vibrating and float type of

level sensors

under continuous level measurement we

have two types ultrasonic and radar

let's talk about point level measurement

so the first one in point level

measurement is the capacitive type of

level sensors

capacitive level sensors are the level

sensor that gives off an electric field

and detects the level by the effect of

its electric field

these sensors uses a prop for checking

the changes in the level

and then these level changes are further

converted into analog signals

it is based on the principle of

capacitance equation that is z is equal

to a epsilon naught upon d where c is

the capacitance epsilon is the

permittivity of the dielectric medium a

is the area between the plates and d is

the distance between the plates

here the probe will form one electrode

of the capacitor and the metal sheet

of the walls of the vessel will form the

other electrode the capacitance is

measured across the prop and the metal

plate on the wall

the liquid inside the tank forms the

dielectric material of the capacitor

here we can see the area is fixed d that

is the distance between the probe and

the vessel

is also constant therefore capacitance

is directly proportional to the

permittivity

now suppose

if there is no liquid

so the capacitance will be zero

but when the level of liquid increases

then dielectric constant will change and

accordingly capacitance will also change

which can be measured at the output

terminals

so here the level will be proportional

to the value of capacitance

the advantages of using capacitive level

sensors is that it is small less

expensive than other sensors also it is

accurate and invasive product however

they have to be calibrated and

they detects only certain

liquids optical level sensors work by

converting the light rays into

electrical signal which measure a

physical quantity of light and then

translate it into a measurement

it has a led as a light source and a

photodiode as detector we can see the

image on the right the light is directed

towards the cone shaped crisp that is

the sensor tip if the sensor tape or the

cone is above the liquid the light will

be reflected back from the cone to the

detector but if the cone is below or

submerged in the liquid

then the light will be reflected into

the liquid and it won't reach the

detector

the difference between the intensity of

light between these two when there is no

liquid and when there is liquid will

give the measurement of level

moving to the next that is conductivity

or resistance type level sensors

conductivity level sensors operate on

the principle that most liquid conduct

electricity

it uses a prob to read conductivity the

prob has a pair of electrodes and

alternating current is applied to them

when the liquid covers the probe its

electrodes form a part of electric

circuit causing the current to flow

which signals a high or low level

the advantage of using conductivity

level sensors are that there are no

moving parts they have low cost and are

fairly easy to use the disadvantages are

they are invasive meaning they must

touch the product they sense

they only sense conductive liquids and

the prob will erode over

time here you can see the image on the

right here the props are of different

lengths one long and one short and are

inserted into the tank to form the

circuit

moving on to the next that is vibrating

or tuning fork type level sensors here

there is a piezo ceramic crystal located

inside the fork assembly on the

application of voltage the crystal

oscillate at natural frequency of the

fork assembly as the level changes the

frequency of the fork will change

detecting the level

the advantages of these sensors are they

are cost effective compact easy to

install and maintenance free the

disadvantages is that they are invasive

they have unlimited use they are widely

used in mining food processing

industries and chemical industries

the last point level sensor is the float

switch it uses a float which is a device

that will raise or lower when a product

is applied or removed which will open or

close a circuit as the level raises or

lowers moving the float

the advantage of float switch is that it

is a non power device and it provides

direct indication disadvantages are they

are invasive and have moving parts and

also they are of large size float

switches will only give indication for a

high or low level but they cannot

measure a variable level they are mainly

used in liquid storage tanks for low or

high level indication

next let's talk about continuous level

measurement sensors starting with the

ultrasonic level sensors the ultrasonic

level sensors work by emitting and

receiving ultrasonic waves

the time it takes to reflect back

is how distance is measured

the benefits of using ultrasonic level

sensors is that they are non-invasive

they are unaffected by the properties of

the material

they are sensing and are self cleaning

because of the vibrations they give off

also they have no moving parts and are

compact

but the disadvantage is that they are

quite expensive and sometimes the

environment can have negative effect on

them

the next is radar or microwave level

sensors these sensors transmit

microwaves by an antenna on the radar

sensor

the product that is being sensed

reflects the microwave back to the

antenna and the time from the emission

to reception of the signal is

proportional to the level of the product

here we can see the formula is given d

is equal to c into t by 2

where this d is the distance between the

radar liquid level sensor and the liquid

surface that can be calculated by

dividing the time by 2 and multiplying

that by the speed of the light

liquid level in the tank can be

calculated by subtracting this distance

d from the height of the radar level

sensor which is given as lt is equal to

hd minus d

these sensors are not affected by

temperature pressure or dust they can

also measure liquid pastes powders and

solids

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