What are the common liquid level sensors?
Liquid level sensors have been around for decades. Leak detection or level measurement in food and beverage, industrial, medical and household, printing, agricultural, automotive and white goods markets. We often wonder why customers choose one technology over another. This is a common question we get asked. Some device manufacturers may also be surprised by the variety and intelligence of liquid level sensing alternatives available on the market.
Why choose a liquid level sensor：
In the past, those expensive technologies involved the inspection process of equipment. It can now be achieved using advanced, innovative and intelligent methods. These technologies are cost-effective, reliable, and robust. Highly accurate and easy to install features. Historically known, extremely challenging fluids. Examples include soaps that contain bubbles/foams, milk, and viscous substances (such as glue and ink) that are now proven to be possible and easily detected by various liquid level sensing technologies.
However, whether customers need such sensors or devices developed from sensors is a concern for many people. And, with the industry becoming competitive and always wanting to improve quality and reduce costs. The purpose of improving efficiency and reducing waste of resources. No company wants to take a chance on that kind of unsatisfactory solution. Therefore, I am familiar with the working principle and advantages and disadvantages of different liquid level sensors. Helps us to choose a more appropriate level sensor.
Ultrasonic level gauge:
Advantages: No moving parts, compact, reliable, not affected by media characteristics.
Disadvantages: expensive, intrusive, performance can be affected by various elements in the environment.
Application: Non-contact applications with high viscosity and solid particles. For systems requiring remote monitoring.
Ultrasonic level meter is a distance measuring instrument based on the principle of ultrasonic wave. It calculates distance by measuring the time at the receiving end of the transmitted acoustic pulse. The ultrasonic level meter is made of ABS material and is light in weight. It does not require maintenance or on-site calibration. It can be used with computers, data collectors or other acquisition devices that meet rs485 standards.
Capacitive liquid level sensor：
Advantages: Solid state, can be non-invasive, compact, accurate.
Disadvantages: May require calibration and can only be used in certain liquids.
Application: Tank level monitoring for chemical, food, water treatment, power and brewing industries.
Capacitive level sensors work in such a way that the process fluid has a dielectric constant that is significantly different from that of air. They measure changes in capacitance between two plates resulting from changes in level. There are two versions, one for fluids with a high dielectric constant and one for fluids with a low dielectric constant.
Capacitive level sensors are suitable for a variety of solid, liquid and mixed materials. They also come in contact and contactless configurations, meaning some of them can be attached outside the container/tank. When selecting a device, it is important to know that not every capacitive sensor is suitable for all types of materials or slots. In addition, sensors need to be calibrated to specific materials to avoid differences in dielectric constants and tank designs. Because this type of technology is contact-based, the reliability of these sensors can be severely affected by the flow attached to the probe.
Pros: Very accurate, no calibration required, multiple output options.
Disadvantages: expensive, can be affected by the environment, detection range is limited.
Application: damp, odorous and dusty environments. They are also used in systems with varying temperatures .
In principle, radar works in a manner similar to ultrasound, but the pulses travel again at the speed of light. Reliability and repeatability are affected. But this time it's caused by the permittivity of the fluid. However, the radar can provide very accurate information about the level level and compensate for the fixed structure inside the vessel. The disadvantage may be that the initial cost of sensors is relatively high. But some manufacturers are working to make the technology more accessible to the wider market. These sensors are among the few technologies that work with foams and sticky substances.
Drop-in liquid level gauge-liquid level sensor:
The liquid level sensor and water level gauge adopt imported silicon wafer diffused silicon core and stainless steel fully sealed welding structure design. It has good moisture-proof performance and strong compatibility of media. Can be used in many industrial weak corrosive media, can be immersed in water for a long time. Good anti-interference, good stability, can ensure the correct transmission of signals. The rectangular circuit board design can be used for regular wiring and installation of circuit elements on the circuit board. Limited space can effectively carry out heat dissipation. Ensure the stability, anti-interference and service life of circuit components. The 45° cut surface design effectively reduces the wear of the shell by impurities at the bottom of the liquid. Allow the bottom pressure of the liquid to enter the pressure hole smoothly. Anti-stamping hole design, diameter 3MM, anti-clogging, four-hole multi-directional pressure induction. The shell is made of 304 stainless steel. As a widely used steel, 304 stainless steel has good corrosion resistance, heat resistance, low temperature strength and mechanical properties. Good stamping, bending and other thermal processing properties, corrosion resistance in the atmosphere.