Devices protected from liquid ingress when completely immersed in a fluid for measuring liquid level and converting it to an electrical signal to send to other instrumentation.
LMP307 Submersible Level Transmitter - Submersible level transmitter for measuring liquid level with a 4-20mA current loop or a 0-10V voltage output plus optional ATEX approval for intrinsically safe use in hazardous areas in ranges from 1mH2O up to 250mH2O. The LMP307 is suitable for use on potable water with no leaching, and can be supplied with a drinking water certificate according to DVGW and KTW.
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
LMK382 Low Range IP68 Waste Water Level Transmitter - Submersible Low Range waste water level transmitter with intrinsically safe option for monitoring the level of sewage and effluent in water treatment plants.
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.
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. 
LMK387 Cleanable Sewage and Sludge Pressure/Level Sensor - Rugged and easily cleanable pressure/level sensor for use with waste water sewage or sludge.
- Cement plant process water basin level sensor
- Stilling well 3ft range SDI-12 interface lake water level sensor
- Fleet management system submersible 3000mm height petrol tank level ATEX rated pressure sensor
- Floating dry dock ballast tank 14ft range 4-20mA output submersible seawater level sensor
- -5…+50degC temperature and 10m range level dual 4-20mA submersible borehole transmitter
- Irrigation water channel and storage dam 10m range SDI-12 submersible level sensor
- Filtered rainwater cistern 13ft range 4-20mA submersible drinking and cooking water level sensor
- 120in range 0-5Vdc output submersible river depth sensor
- Drinking water approved 5ft range 4-20mA output submersible reservoir level sensor
- Desalination plant seawater feed tanks 5m range 4-20mA output submersible level sensor
- 10ft range 4-20mA output submersible sea tide depth sensor
- 40m RS485 Modbus RTU submersible borehole pump drawdown depth sensor
A submersible device can be installed in liquid without causing any damage as long as the installation instructions are adhered to, and the specified depth and time duration limits for submersion are not exceeded.
Assembled devices are vulnerable to liquid ingress, which can enter the device through seals and joints or permeate through components that incorporate thin membranes or porous materials.
To achieve a long lasting submersible construction, the device is constructed from materials which will not easily corrode when exposed to a fluid. Corrosion may cause the material to fail and allow liquid to enter the device, or interfere with the seal joining the corroded material to another component.
The seals used to join device components together are pressure leak tight, resilient to the expected temperature variations and resist corrosion from the surrounding fluid.
All components and seals are designed to withstand the pressure expected at the maximum required liquid depth, and this may involve a series of seals and backfilling with a potting compound or other fill material to improve longevity and reliability at greater depths.
A liquid level sensor is an instrument for measuring the height of a liquid and converting it to an electrical signal which is sent to other instrumentation to display, monitor, log or control the liquid level. The probe is lowered into the tank and immerse in the liquid. A typical sensor technology employed is a pressure sensor which will measure the pressure generated by gravity acting on the surrounding liquid.