Adaptability Analysis of the Applications of Fork Level Switch and Vibrating Rod Level Switch

Fork Level Switch and the Vibrating Rod Level Switch are point level switches, which are commonly used for high and low level alarms in solid level measurement to prevent overflow and dry operation.

Fork Level Switch and Vibrating Rod Level Switch are both based on the vibration principle of the cantilever beam. The probe (fork tines or rod tube) is driven by a piezo-crystal assembly to oscillate at a natural frequency. When in air, the probe vibrates at its natural frequency; when solids cover the probe, the frequency of oscillation drops and is detected by the integrated circuit, which in turn changes the output state.

The probe of Fork Level Switch is composed of two enlarged fork tines. By reasonably widening the fork bodies and precisely tuning, the measurement sensitivity is significantly improved. With a minimum measurable density of 0.008g/cm ³, Fork Level Switch is ideal for the level measurement of fine sand, flour, foam particles and powders. However, there are some limitations in some of the applications. Due to the large amplitude of the forks, when measuring the fine powder, the forks might be in a hollow state, resulting in delay or false alarm. In addition, for materials with large diameter or high viscosity and humidity, Fork Level Switch is not recommended to use in those applications, because the media are prone to sticking between the two tines.

The probe of Tube-11 Vibrating Rod Level Switch is designed with double vibrating tubes. The inner vibrating tube nests with the outer vibrating tube. When resonant frequency of inner and outer vibrating tubes is finely adjusted to the same value, the reliability and sensitivity are extremely high. So, the measurable medium density can be as low as 0.02 g/cm³. Besides, the probe is a round rod-shaped integrated structure, it can effectively avoid material hanging. This feature is superior to other contact level switches like Fork Level Switch or RF Admittance Level Switch. Vibrating Rod Level Switch is ideal for most particles and powders’ level measurement, such as sand, sodium hydroxide, lime, clay, coke particles, glass, etc.

From the above analysis, Fork Level Switch and the Vibrating Rod Level Switch are interchangeable and universal in most applications. For a better selection, particle size, process temperature and pressure, medium humidity and viscosity shall be comprehensively taken into consideration.