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Tuning fork level switch
Tuning fork Type Level Switch uses a metal tuning fork structure to detect the presence of a liquid or solid in a vessel. From acoustics to medical diagnostics, tuning forks are employed in a variety of disciplines. Quartz crystal tuning forks are used in timepieces as small tuning forks to measure time. The fork sensor’s two pointed tines begin vibrating at a set frequency when they make contact with any surface. The fork sensors are typically factory calibrated and set at a specific frequency depending on the type of industry. The length of the fork tines can affect the tuning fork’s pitch.
Working Principle of tuning fork level switch
Working principle of Tuning fork type level switch is based on the changes of vibration frequency of the tuning fork when it comes into contact with a liquid or solid material. When the fork comes into the contact with material the vibration of fork get weakened/dampened and results in frequency change which triggers the switch. The vibrating fork level sensor operates on the idea of constantly vibrating a tuning fork sensor at its natural frequency and sensing the change in frequency and amplitude in the presence of application media. Depending on the type of application medium, certain parameters must be monitored.
Amplitude of Vibration : Solids tuning fork Level Switch
The tuning fork level switch’s oscillation dampens as the material level rises and comes into contact with the tines of the vibrating fork. The outputs are altered by the onboard electronics when the amplitude falls below a predetermined threshold.
Frequency of Vibration: Liquid Tuning fork level switch
As the liquid application media covers the tuning fork level switch, its natural oscillation frequency lowers. The threshold frequency is selected to coincide with the natural frequency of a level switch of the tuning fork variety found underwater.
Reason of error
Material flow or an agitator or stirrer inside the silos can also generate turbulence. This may result in changes to the tuning fork’s operating frequency and amplitude. A switching hysteresis is maintained around the switching point for accurate level sensing.
This stops the switching point from being often toggled. Changing the sensitivity of a vibrating fork for solids may have an impact on the sensor’s hysteresis. Hysteresis margin typically shrinks as sensitivity rises. With an increase in tine length, a tuning fork’s inherent frequency rises.
The tuning fork’s tines vibrate in what way?
The diaphragm shears due to pressure from the piezoelectric stack, which in turn causes the tines of the tuning fork to separate from one another. To see a simulation of the procedure, refer to the diagram set aside. The fork tines return to their original position when the pressure is released.
The fork oscillates at its maximum amplitude for a given power when force is applied at its natural frequency.
Application of tuning fork level switch
Vibrating level switches are utilised as overfill prevention mechanisms or low-level indicators in liquids as well as granular and powdered bulk solids.