Benefits of Replacing RF Admittance Level Switch with Vibrating Rod Level Switch

Level switches are an essential part of production operations and are used in harsh conditions where there are extremes in temperature, pressure, and vibrations. The diversity of level switches makes them applicable to any conditions for measuring a wide array of products. Their accuracy, reliability, and durability are a necessity for the efficiency of industrial applications.

Of the many kinds of level switches, the most commonly used are Tuning Fork Level Switch, Rotary Paddle Switch, RF Admittance Level Switch and Vibrating Rod Level Switch.

So, what are the benefits of replacing RF Admittance Level Switch with Vibrating Rod Level Switch?

RF Admittance Level Switch and Vibrating Rod Level Switch operate on distinct technologies. Vibrating Rod Level Switch has wider application range in harsh conditions.

RF Admittance Level Switch and Vibrating Rod Level Switch

For RF Admittance Level Switch, a probe is designed to detect the change of capacitance and impedance between probe and vessel wall to realize level measurement and control. In its electronic unit, reactance between the measurement electrode and the wall of an empty vessel constitutes a balanced bridge circuit which outputs a stable oscillation signal. As the level rises, the measurement electrode is covered by the medium, and reactance between the electrode and the wall of the vessel changes. It causes an imbalance of the bridge circuit and stops the oscillation as a result. A post-circuit is designed to detect the change of output signal from the bridge circuit and generate an alarm signal.

RF Admittance Level Switch Applied to Ash Level Measurement at Coal Plant

For Vibrating Rod Level Switch,when resonant frequency of inner and outer vibration rods is finely adjusted to the same value, both reliability and sensitivity of the Vibrating Rod Level Switch are at extremely high level. When vibration frequency of the inner and the outer vibration rod is finely adjusted to the same value, it results in the resonance of both inner and outer vibration rods. Until the vibration rod comes into contact with application medium, resonant frequency of the outer vibration rod will change, therefore destroying the resonant condition. Vibration amplitude of the probe will substantially decrease. The output signal from piezoelectric detection device will also decrease accordingly. An integrated electronic circuit is designed to analyze the amount of decrease and output a switch signal.

In brief, Vibrating Rod Level Switch is not affected by the dielectric constant, while the dielectric constant (affected by temperature and humidity, etc.) is a key factor for the reliability of RF Admittance Level Switch. So,Vibrating Rod Level Switch is suitable for virtually all applications in granular bulk solids.And this is also the technical basis for replacing RF Admittance Level Switch with Vibrating Rod Level Switch.

Compared to RF Admittance Level Switch, Vibrating Rod Level Switch has following benefits.

1、Measurement range

RF Admittance Level Switches are usually used for measuring fly ashes in thermal power plants. The Vibrating Rod Level Switch can measure other types of media other than ashes, such as granular, lumpy media, damp powdery, etc.

2. Dielectric constant

Based on the principle of RF Admittance Level Switch, the medium dielectric constant greatly affects measurement accuracy. The dielectric constant changes with the temperature and humidity. But Vibrating Rod Level Switch is independent of dielectric constant.

3. Impact resistance

The diameter of the probe for Vibrating Rod Level Switch is 16mm, and the diameter of the extended tube is 29mm. However, the diameter of the protective electrode for RF Admittance Level Switch is only 16mm, and the diameter of the end electrode probe rod is 8 or 10mm. So Vibrating Rod Level Switch is more capable of withstanding material impaction when under the same force. 

Probe Comparing

4、Anti-hanging performance

Tube-11 Vibrating Rod Level Switch adopts a unique double-tubes design with nested inner and outer settings. The inner and outer tubes resonate at a completely consistent resonant frequency, and the vibration probe works completely in a resonant state, concentrating vibration energy on the probe, thus having strong anti-hanging performance. Although the RF Admittance Level Switch can also be debugged to feature with anti-hanging function, but the performance of Vibrating Rod Level Switch is superior to that of the RF Admittance Level Switch in practical applications.

5、Maintenance

During rainy and humid seasons, materials are moisture, which causes changes in the medium dielectric constant, so frequent debugging is necessary. However, Vibrating Rod Level Switch does not need to be debugged after installation.