What is Point Level Measurement?
Point Level Measurement refers to the use of a point level sensor to detect the material level in a storage tank or silo. Also called point level Indicators, Controls, and Switches. This type of equipment is used when it is not necessary to measure every possible intermediate level. Just like in the case of continuous level measurement.
The point level sensor measures the preset level of liquid, mud, or solid media. And open or close the electrical contact at the desired set point. In some applications, sensors are also used to trigger pumps, valves, or other controls. To return the media to the preset level. Capacitive, ultrasonic, rotary, and vibrating liquid level switches are suitable for almost all applications from bulk solids to liquids and in between.
What is a point level sensor?
Liquid level measurement usually has two forms: continuous liquid level detection and point liquid level detection. In continuous level detection, the sensor continuously measures the level of liquid or solid in the tank. The point level sensor measures the preset level of liquid, mud or solid media, and opens or closes the electrical contact at the desired set point.
Point level sensor is also called liquid level switch, or liquid level controller. Point level sensor is used for point level detection. The sensor will detect the liquid at a certain point in the tank or chamber. Generally, this applies to processes that need to be managed at a high or low level.
Point level sensor is suitable for liquid, paste, powder, or bulk solid in a silo. You may encounter problems with property changes, turbulence, foam, vibration, or accumulation, but a wide range of sizes, installations and materials make inspection easy.
Common point level sensors, such as photoelectric level switch (SST sensor), horizontal float switch, vertical float switch, ultrasonic level sensor, tuning fork level switch.
Extended reading: Radar level sensor for solids – Dust solid level measurement
What is a continuous level sensor?
The continuous level sensor is designed to provide level detection through every point in the tank or chamber. This means that regardless of the liquid level, it can provide feedback across the entire range of the container. This is very useful for processes where knowing the level is always important and for applications that require increased accuracy.
Common continuous level sensors, such as submersible level sensors, ultrasonic level sensors, capacitive level sensors.
- Media type (e.g. bulk, powder, liquid, paste, etc.)
- Media properties (e.g. bulk density, conductivity, viscosity, etc.)
- Input conditions (e.g. tank material, tank geometry, installation position, installations within the tank, etc.)
- Process conditions (e.g. pressure, temperature, ambient conditions, explosion protection, hygiene requirements, etc.)
Extended reading: Applicaitons Of Magnetostrictive Level Transmitters
Point level sensor
A sensor designed for point detection will detect liquid at a certain point in the tank or chamber. Generally, this applies to processes that require high-level or low-level management.
In most cases, they act as switches when the tank level rises or falls to a certain level. This could be an alarm or a bonding device. Essentially, the sensor detects when the liquid has reached the desired point, and it acts as a switch to activate the necessary response.
Read more about: Application 3: Level Measurement In Waste Water Treatment Plants
Continuous level sensor
The continuous level sensor is designed to detect the level through every point in the tank or chamber. This means that it provides feedback regardless of the level and the entire container range. This is great for processes where the level is always important, and for applications that require increased accuracy.
Extended reading: Radar Oil Tank Level Sensor
Looking for a specific type or a custom continuous liquid level sensor? Sino-Inst offers High-quality Liquid level sensors for continuous level measurement.
Level sensors are used in process control in many industries and they fall into two categories. Continuous level measurement sensors and Point level measurement sensors. The point level measurement sensor is used to indicate a single discrete level, that is, to indicate a preset level.
The function of this type of sensor is the upper limit alarm, which indicates the overfill condition, or the lower limit alarm condition. Continuous level sensors are more complex, allowing level monitoring of the entire system. They measure the level of the liquid level in a range, not the level of a point. Continuous level sensors produce an analog output that is directly related to the liquid level in the container. To build a level measurement system, this output signal is transmitted to the process control loop and visual indicators.
Read More: Continuous Liquid Level Measurement
Types of Point level measurement
Liquid level measurement is a key link to realize the automated production of industrial processes. According to the difference of its output, it can be divided into Point level measurement and continuous quantity measurement. A wide variety of liquid level switches have caused many obstacles to the correct selection of users. For this reason, the common classifications of liquid level switches are introduced as follows. Hope to be helpful to instrument users.
Extended Reading: What is level transmitter working principle?
After the probe of the capacitive liquid level switch is exposed to liquid, it detects the change of the capacitance value and outputs the contact signal. Generally speaking, capacitive liquid level switches have certain advantages in the measurement of slightly viscous media.
Extended reading: Capacitance level sensor advantages and disadvantages
The electrode type liquid level switch mainly uses the conductivity of the liquid to detect the height of the liquid level. Once the measured medium touches the pole, it will conduct electricity and detect the signal. After the signal is amplified by the controller, it will output a contact signal to realize the control of the liquid level.
The magnetic float of the float level switch rises or falls with the liquid level so that the sensor detects the reed switch chip at the set position in the tube. It sends out contact on/off switch signal. Due to the simple structure of the float level switch, it is economical and practical. It is widely used in the civilian market. But compared with industrial-grade products, its stability is relatively poor.
Extended reading: Oil-water interface measurement-Magtech magnetic level indicator
The photoelectric liquid level switch mainly uses the principle of light refraction and reflection. It is detected by infrared rays. Because the light will reflect or refract at the interface of two different media. When the measured liquid is at a high level, the measured liquid and the photoelectric switch A kind of interface is formed. When the measured liquid is at a low position, the air and the photoelectric switch from another interface. These two interfaces make the reflected light intensity received by the light-receiving crystal inside the photoelectric switch different. That is to say, there are two corresponding interfaces. Different switch states. Generally speaking, the applicability of photoelectric switches is poor compared with other measuring instruments.
Extended reading: Non contact level measurement
The instrument probe of the ultrasonic external liquid level switch emits ultrasonic waves and detects its after-vibration signal in the container wall. When the liquid flows over the probe, the amplitude of the after-vibration signal will become smaller. The instrument will output a signal after detecting the change Switch signal. Because the ultrasonic external liquid level switch is a non-contact measuring instrument, it is mostly used in the scene where it is not easy to open holes and high risk. But relatively speaking, its cost is relatively high.
Extended reading: The Secret of Ultrasonic Level Measurement
The tuning fork liquid level switch mainly outputs a switch signal by detecting the changes in the frequency and amplitude of the fork vibration. Its versatility is strong, but it is necessary to consult the manufacturer for working conditions with high viscosity. For working conditions that are easy to crystallize, it is not recommended.
Extended reading: Solid flow meter | For bulk solids-powder-soybean-cement
Featured Level switches for point level measurement
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Sino-Inst offers over 10 Point Level Measurement Sensors. About 50% of these are liquid level meters, 40% is the tank level sensor.
A wide variety of Point Level Measurement Sensors options are available to you, such as free samples, paid samples.
Sino-Inst is a globally recognized supplier and manufacturer of Point Level Measurement Sensors instrumentation, located in China.
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Wu Peng, born in 1980, is a highly respected and accomplished male engineer with extensive experience in the field of automation. With over 20 years of industry experience, Wu has made significant contributions to both academia and engineering projects.
Throughout his career, Wu Peng has participated in numerous national and international engineering projects. Some of his most notable projects include the development of an intelligent control system for oil refineries, the design of a cutting-edge distributed control system for petrochemical plants, and the optimization of control algorithms for natural gas pipelines.