Point level measurement in transition: From simple measured values to smart safety systems

A wide variety of physical principles are used in point level detection – from capacitive and conductive methods to microwaves, as well as radiometric and mechanical techniques. Not every measuring principle is suitable for every application. Differences exist primarily in media dependency, maintenance requirements and reliability under challenging process conditions such as foam, high viscosity or extreme temperatures.
The following overview shows how common level switch technologies differ in specific terms:

 

Conclusion: While capacitive, conductive or mechanical methods are often media-dependent or maintenance-intensive, the vibrating level switch impresses users with its universal application, simple integration and absolute reliability. Vibrating level switches have established themselves as the optimal solution, particularly with liquids. By combining the most important requirements – media independence, calibration-free, maintenance-free and high robustness – it is both economical and safe, making it ideal for any application of point level detection in industrial processes.

Practical daily use shows how versatile modern vibrating level switches really are. They perform crucial functions in countless processes – reliably, safely and without the need for maintenance.

1. Overfill protection & leak detection

Vibrating level switches are often used as overfill protection in storage tanks, reactors or containers. Their WHG (German Water Resources Act) approval makes them ideal for liquids that are hazardous to water. They accurately detect the maximum permissible level, thereby preventing leaks and environmental hazards.

Hygienic versions are the standard in the food and pharmaceutical industries. Polished surfaces, gap free process connections, CIP/SIP resistance and EHEDG compliance guarantee cleanliness and cleanability – even in processes with viscous media or heavy foam.

VEGA sensors, such as the VEGASWING series of vibrating level switches, are also available in hygienic versions and are therefore perfectly suited to the critical aspects of CIP and SIP processes in the food and pharmaceutical industries.

2. Dry-run protection

As dry-run protection devices,  vibrating level switches protect conveying and dosing pumps as well as compressors from damage. As soon as the liquid level drops, the point level sensor detects the empty state and shuts down the system. This prevents downtime, cavitation and energy loss – a measurable contribution to energy efficiency.

Piezoelectric vibrating level switches, which operate according to the tuning fork principle, are especially interesting due to their versatility: A vibrating fork oscillates freely in the air and changes its frequency and amplitude upon contact with liquid. This triggers a precise switching signal, indicating that a defined level has been reached. This principle works regardless of medium density, viscosity, or foaming – a decisive advantage over capacitive or conductive methods.

The most important advantages:

• Independent of the medium – no parameterisation necessary, even if the product changes
• Maintenance-free thanks to operation without moving parts and wear
• Maximum operational safety with SIL2/3 certification, WHG approval and Ex protection
• Temperature and pressure resistant up to 450 °C and 160 bar
• Hygienic, approved materials in accordance with EC 1935/2004, EHEDG, FDA, 3-A and CIP/SIP resistant

The technology of point level detection is undergoing a transformation. Point evel sensors have long been more than just binary switches – they are now sources of digital information. Features like self-diagnosis, Bluetooth communication, automatic test reports and real-time data transmission make them an integral part of highly automated industrial plants.

Besides that, modern vibrating level switches actively contribute to greater sustainability:

• Resource-saving as a result of precise process control
• Less chemical consumption thanks to exact point level detection
• Reduced energy consumption through optimised pump control

Modern level switches combine ecological responsibility with economic efficiency – a decisive factor for future-oriented plant design.