Vibrating tuning fork devices for monitoring liquid level and activating switch contacts at predetermined liquid level thresholds.
A vibrating tuning fork liquid level switch is an instrument for monitoring the height of a liquid and tripping a relay contact switch or transmitting a solid state relay switch output when a maximum, minimum or intermediate level has been reached. The liquid level switch output can then be utilised by other instrumentation to open a valve, illuminate a warning lamp, activate an audible alarm, or switch on a pump.
Featured liquid level measurement products
4-20mA Output Hydrostatic Level Transmitters & Sensors - Explore industrial 4-20mA hydrostatic level transmitters for reliable liquid depth measurement. Ideal for tank gauging, borehole control & process monitoring applications.
ATEX Approved Liquid Level Sensors for Hazardous Areas - European hazardous area ATEX approved sensors for liquid level measurement in intrinsically safe installations on petrochemical, pharmaceutical, landfill and sewage treatment sites.
Vibrating tuning fork liquid level switches are threshold contact trip devices which typically consist of a tuning fork which extends out from the switch housing.
In operation a piezoelectric oscillator is used to vibrate the tuning fork at its natural frequency for air.
A second piezoelectric device is used to pick-up the frequency of the vibrating tuning fork. When the liquid level rises and covers the tuning fork it will vibrate at a lower frequency.
This change in vibration frequency is used to detect when the required liquid level has been reached.
Featured liquid level measurement products
IMSTL IP68 Water Temperature and Depth Transmitter - Stainless steel 316L waterproof probe for measuring both water temperature and depth and generating two separate 4-20mA current loop measurement signals.- Underground rainwater collection tank level transmitter with 2.5m range and 4-20mA output for BMS integration - Monitor water levels in your 2.5m deep underground tank with this submersible 4-20mA level transmitter. Ideal for rainwater harvesting and BMS integration.
A vibrating tuning fork liquid level switch makes direct contact with the liquid to be measured, and therefore material compatibility has to be a consideration.
Since there are no pressure sensitive components exposed to the inside of the tank it is possible to fit tuning fork level switches to sealed pressurised tanks.
Also, since there is no sensitive components immersed in the fluid it is possible to use them on higher temperature media that would not be tolerated by other types of liquid level switch.
Vibrating tuning fork liquid level switches are generally mounted through the top or side of the tank with the tuning fork protruding horizontally into the tank.
Featured liquid level measurement products
River level sensor for run-of-the-river hydropower monitoring up to 4m - Vented pressure river level sensor for measuring water level up to 0.4 bar in run-of-the-river hydroelectricity systems.- Submersible water level and temperature probe with SDI-12/USB interface for freshwater monitoring - Versatile 10m water level and temperature probe with USB and SDI-12 connectivity, designed for hydrological studies and long-term environmental monitoring programs.
Advantages
- Not affected by any surface disturbances such turbulence, foaming, vibration
- High temperature fluid compatibility since no sensitive components make contact with the fluid
- Small compact size
- Sealed pressurised or evacuated vessels will not affect performance
Disadvantages
- Thick or sticky media will leave a coating on the probe which will affect vibration frequency
- Fouling can interfere with resonant frequency causing false switch activation
- Tuning fork protruding into liquid causing obstruction, attracting fouling and hygienic cleanliness issues
- High cost
Featured liquid level measurement products
Storm surge protected low range submersible river level transmitter - This submersible level transmitter offers accurate low range water level monitoring with high overpressure resistance for storm surge protection in rivers- IMSL IP68 Stainless Steel 316L Hydrostatic Pressure Sensor - Water resistant pressure sensor for measuring hydrostatic pressures in the range of 0-0.5 mWC up to 0-100 mWC.
Related Help Guides
- Determining the hydrostatic pressure range for a tank level sensor
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Related Technical Terms
- Capacitive Fluid Level Measurement
- cmH2O – Centimetres of Water Column at 4 deg C Pressure Unit
- Conductive Fluid Level Detection
- Float Fluid Level Detection
- ftH2O – Feet of Water Column at 4 deg C Pressure Unit
- mH2O – Metres of Water Gauge at 4 deg C Pressure Unit
- mmH2O – Millimetres of Water Column at 4 deg C Pressure Unit
- Specific Gravity
- Vibrating Tuning Fork Fluid Level Detection
Related Online Tools
- Liquid Level to Hydrostatic Pressure Calculator
- Fluid Depth, Density, Gravity, and Pressure Calculator
- Liquid Level Transmitter 4-20mA Current Output Calculator
- Vertical Cylindrical Shaped Tank Contents Calculator
- Horizontal Cylindrical Shaped Tank Contents Calculator
- Rectangular Shaped Tank Contents Calculator
- Pressure to Liquid Level Calculator
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