Hydrostatic Level Sensors

Hydrostatic pressure sensing devices for measuring liquid level and converting it to an electrical signal to send to other instrumentation.

Hydrostatic level sensors for measuring the pressure generated by a static head of liquid. Use hydrostatic level sensors to measure fluid level in storage tanks, processing vessels, header tanks, pump inlet head and other applications where hydrostatic pressure is used to determine liquid height.

Contents

Products

Select a hydrostatic level sensor for your application from the choices below.

LMK458 Marine Approved Hydrostatic Level Transmitter - Marine approved level transmitter with 4-20mA output for measuring level of contents inside ship ballast, fuel, liquid cargo or wastewater tanks
LMK331 Screw-In Ceramic Level Transmitter - Level pressure sensor with semi-flush ceramic diaphragm and stainless steel or PVDF wetted parts in ranges from 0-4 to 600mH2O gauge.
S12S SDI-12 Coms IP68 Pressure and Temperature Sensor - Combined pressure and temperature sensor with a 1200 baud rate serial data interface as defined by the SDI-12 support group.
IMCL Low Cost Submersible Pressure Sensor - Economical IP68 protected sensor with stainless steel 316L housing and Ceramic strain gauge sensing diaphragm for measuring liquid depth pressure.
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.
18.605 G Low Cost Submersible Diesel Fuel and Water Tank Level Sensor - Low cost OEM diesel fuel or water level sensor for installing inside or outside a storage tank.
DCL 531 Modbus RTU RS 485 Submersible Stainless Steel Liquid Level Sensor - Digital submersible stainless steel liquid level sensor with a Modbus RTU protocol RS 485 serial bus interface.
LMP305 Borehole Level Transmitter - Submersible stainless steel pressure transmitter ideal for geotechnical surveying with a 19mm diameter for measuring hydrostatic water level in bore-holes.
LMK 487 Submersible Ballast Tank and Draught Level Pressure Transmitter - A 22mm diameter titanium body seawater depth and level probe with a 4-20mA output with Lloyds and DNV-GL ship approval, for monitoring the quantity of ballast or the draft of a ship’s hull.
DCL 571 RS485 Modbus RTU Submersible 22mm dia Groundwater & Wastewater Level Probe - 22mm diameter digital interface submersible liquid level probe with RS 485 Modbus RTU protocol serial bus communications for installing in 1" diameter tubes to measure groundwater level and measuring wastewater with nose cone removed.
DCL 551 RS485 Modbus RTU Submersible Low Range Fuel, Oil & Wastewater Level Probe - Low range digital interface submersible liquid level probe with RS 485 Modbus RTU protocol serial bus communications for measuring level of fuel, oil and wastewater in low fill height open tanks.
LMK306 Ground Water Level Transmitter - IP68 sealed hydrostatic level transmitter with a 17mm diameter for lowering into ground water boreholes for environmental monitoring of water level.

Description

Hydrostatic level sensors are pressure sensing devices specifically designed for use on liquid level measurement applications.

All liquids which are under the influence of gravity generate a hydrostatic pressure. This pressure is similar to the weight of a solid object, but because of the fluid state it is possible to measure how the weight of the liquid varies with height.

The resulting pressure at different heights is directly proportional to the weight of a liquid between the surface and a specific height point. The weight of the liquid can be derived from the mass and force (gravity). The mass can be derived from the density and volume of the liquid. The volume of a liquid can be derived from the dimensions of the vessel containing the liquid. If the vessel has a fixed length and width, then the height is directly proportional to the volume, mass, weight and therefore the pressure.

A hydrostatic level sensor is an instrument for measuring the height of a liquid and converting it to an electrical signal. The hydrostatic level signal output can then be utilised by other instrumentation to display, monitor, log or control the liquid level.

There are many different types of technology used to measure liquid level, there are sensors that can be mounted above the liquid such as ultrasonic or radar which bounce a sound or electromagnetic wave off the surface of the liquid and use the travel time to determine the distance from the liquid surface.

For liquid filled tanks a pressure sensor can be installed in a hole at the bottom of the tank which measures the hydrostatic pressure generated by gravity acting on the liquid.

Another method is to lower a hydrostatic level sensing probe into the tank and immerse it in the liquid to measure the pressure generated by gravity acting on the surrounding liquid.

Advantages

Easily fitted at ground level to any port or take off, which is also convenient for maintenance
No protrusion inside vessel
Not affected by any surface disturbances such turbulence, foaming, vibration
Small compact size possible
Compatible for conductive or non-conductive fluids
Flush diaphragm types prevent clogging and works with thick liquids and slurries containing solids

Disadvantages

Pressurised or vacuum sealed vessels require a more complex installation
SG or density change affects calibration
Flush diaphragm types vulnerable to mechanical damage from debris, cleaning processes
Requires regular calibration due to gradual error shifts
Installed in a position below the lowest required liquid level
Fittings must be leak tight
Diaphragm movement vulnerable to clogging, wear and tear
High cost