Device with marine approval certification for use on ships, and protected from liquid ingress when completely immersed in a fluid, to measure liquid level and convert it to an electrical signal to send to other instrumentation.
- LMK 487 Submersible Ballast Tank and Draught Level Pressure Transmitter
- LMK458 Marine Approved Hydrostatic Level Transmitter
- LMK457 Marine Approved Level Transmitter
All voyage and safety critical equipment on a ship must be certified by the same marine approval body that audited and registered the whole ship.
A marine approved device is one that has been tested and certified by a recognised body such as LR (Lloyd’s Register), GL (Germanischer Lloyd), DNV (Det Norske Veritas), ABS (American Bureau of Shipping) and CCS (China Classification Society) for use on a ship.
The marine approval process involves an initial and continuous periodic product assessment to inspect random production samples, ensure adequate production and inspection processes, procedures, documentation and quality control, and review the current product design and any future design iterations for compliance with the type approval.
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.