Choosing the Right Liquid Level Sensor for Industrial Applications

Modern industrial processes rely on level measurements to detect the separation of phases. You have to have fairly consistent phase conditions under all process conditions to get a reliable result. This is where liquid level sensors come in.

Over the decades, technology has evolved for measuring and transmitting process levels. In updated installations, pulse lines are less frequent. In many existing installations, they are replaced. (Each requires special expertise during installation, maintenance, and design.)

With a water level detector sensor and data transmission innovations, installation costs are reduced, maintenance is simplified, and plant performance is improved.

Float sensors are used in industrial processes for safety and efficiency. Liquid level sensors are widely used in HVAC, water treatment, food and beverage production, petrochemical and chemical processing. The process of sorting through the sensing options, packaging, interfaces, and regulatory requirements can be lengthy, complex, and costly.

Picking a Liquid Level Sensor

It can provide alarms for dangerous levels of liquid, protect equipment from overheating, maintain proper ratios of materials being mixed, and reduce the risk of fires. Float liquid level switches are selected by considering the following aspects:

● How hot and how much pressure is the liquid?
● Should the switch be normally open or normally closed?
● What should be done when switching? SPST or SPDT?
● Can switches be mounted horizontally, top-mounted, or bottom-mounted?
● Do multiple levels of the liquid need to be monitored, or does a single level indicator such as “full,” “partially full,” or “empty” suffice?

Material selection for switch bodies depends on the liquid and its condition. The glass-filled polyphenylene sulfide housings are rated up to +130 degrees Celsius (°C) and 4.7 bar pressure.

A vertical liquid level switch can be made of plastic, brass, or stainless steel. For less demanding applications such as water tanks, acetal and foamed polypropylene bodies are available that are rated up to +60°C and 0.34 bar. A liquid level sensor’s switching technology, as well as its material, is crucial.

Reed Switches: Advantages

Reed switch technology is reliable and mature. A float liquid level switch uses reed switch technology and does not require external power. Permanent magnets in the float interact with stationary reed switches to initiate the switching action.

The reliability of these sensors comes from several factors. The single moving part, the liquid-compatible body, and the Ruthenium contact points have been proven to last over 10 million switching operations.

In high-temperature environments, reed switches perform well. Compared with solid-state switch technologies, their insulation rating is high when the switch is off. Reed switches simplify electromagnetic compatibility testing (EMC).

For harsh and demanding applications, reed switches provide long-term performance and reliability. Some switches can measure two liquid levels at once, while others can measure a single liquid level while others measure multiple levels. They can also meet EMC requirements without using external power sources.

Don’t know where you can find the perfect liquid continuous level sensor? Here, you can find a variety. Contact us today and get your sensors!