Water Level Sensors Overview

Stevens is the original water level measurement instrumentation company with the introduction of the widely known chart recorders introduced in 1911. Today, Stevens offers a wide selection of water level measurement sensors including robust ceramic pressure sensors, shaft encoders, acoustical sensors, and visual reference staff gages. Stevens still offers the low-powered, mechanical chart recorders for long-term uninterrupted, real-time chart of water level. Here is an overview of the different types of instrumentation for monitoring water level.

Pressure sensors (also called pressure transducers or pneumatic pressure sensors) preform liquid level measurement by having the sensor submerged at a fixed depth under the water surface. The pressure sensor measures the equivalent hydrostatic pressure of the water above the sensor diaphragm, using this to calculate the total liquid depth. This function of a pressure sensor can be compared to “weighing the water”. Pressure sensors are ideal for ground and surface water level applications. Variances in accuracy of measurement depend on the model of pressure sensor used. The following parameters will influence the accuracy of the pressure sensor: Non-linearity: the deviation of the sensor’s signal curve from that of a straight line. Repeatability: the ability of the sensor to reproduce an output reading when subjected to identical pressures. Hysteresis: the difference in value for the same measured point when pressure is rst increased, then decreased past the point.

Smart PT delivers accurate results for a wide range of fluid level measurement applications. In addition to simple instantaneous measurements, this smart sensor features the ability to capture peak crest levels, and to automatically sample and report basic statistics on a configurable time interval.

Ground water level monitoring Ground water slug testing

Output can be analog or digital depending on model Smaller diameter stilling well or pipe can be used for installation. A low profile installation site can be achieved using pressure sensors with internal data logging. Easy to install, maintain and calibrate.

Typically subject to long-term drift and variations with temperatures. However, they are in the water where the temperature is usually fairly stable. It’s a good idea to check calibration every 6 months. Fouling or corrosion with direct exposure to the water can affect the readings. Models are available in a broad pressure range that needs to be known at time of purchases. Some models require breather tube in the cable to reference to atmospheric pressure for best accuracy. Some models have a sensor head that can be easily damaged by human touch or other objects.

Absolute pressure sensors respond to both atmospheric (barometric) pressure as well as the pressure head of water above the sensor. Therefore, an absolute sensors installation will work provided that a barometric measurement is made at the time of the pressure sensor measurement to compensate for the barometric fluxes. This typically requires a separate barometric measurement instrument and post-processing of the data to compensate for the barometric pressure. Vented pressure sensors utilize a vented cable—a very small vent tube that run down the length of cable from the surface and terminates behind the pressure transducer. This vent tube acts as a conduit to compensate for barometric pressure changes at the surface, thereby, allowing the barometric pressure on the water column to be cancelled out by the pressure transmitted in the tube.

The suspension cable or direct read cable deployment for absolute sensors is less costly than that required for vented communication cable. An absolute sensor typically requires less maintenance, whereas the use of vented cable requires at the very least annual vent tube maintenance and assessment, the purchase of hydrophobic membranes or desiccants to keep moisture out of the tube. However, the absolute method requires a separate barometric measurement that may require additional calibration and maintenance. Vent tubing can crimp, become flooded or blocked by moisture, debris or provide a conduit for water to enter the instrument. Vented sensors require no post processing of the data to compensate for the effects of barometric pressure. Vented sensor measures true water level elevations in that no separate sensor to measure and report on barometric pressure is required. Also, there are no maintenance or calibration requirements of a separate sensor. With absolute sensors there is a higher risk of less accurate results when correcting absolute data with barometric data.

Cost-effective and reliable, compact groundwater logging sensors like the Van Essen TD-Diver provide accurate and reliable long-term measurements of water levels, temperature, and conductivity—essential data needed for effective water resource management, environmental remediation, mine dewatering, and slope stability. The Diver family of pressure sensors from Van Essen provide robust level measurement for environmental professionals. Hermetically sealed to external influences—electrical and/or environmental effects cannot affect the measurement results. Include an internal data logger that measures up to 48,000 measurements per parameter. Measure temperature and provide temperature compensated level measurement. Come with internal battery with an extended life up to 10 years. Absolute pressure sensors with ceramic pressure sensor head. All Diver sensors have a 3 year warranty, up to 10 years battery life, and can be used from 300 m below to 5000 m above sea level. We offer the entire family of Diver sensors and other logging sensors.

Van Essen Diver logging sensors are submersible pressure transducers and data loggers for long-term uninterrupted, real-time water level monitoring when submerged at a fixed level under the water surface.

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Lorem ipsum dolor sit amet, ConnectEDU advising elite. Curator scelerisque temper lore in facilities.

Lorem ipsum dolor sit amet, ConnectEDU advising elite. Curator scelerisque temper lore in facilities.