Ships take in water from outside the hull to cool the engines and other auxiliary equipment. The water usually comes in through a sea chest. “The sea chest provides an intake reservoir from which piping systems draw raw water. Most sea chests are protected by removable gratings (trash screen), and contain baffle plates to dampen the effects of vessel speed or sea state. The intake size of sea chests varies from less than 10 cm² to several square meters“(Wikipedia).

Frazil are small ice crystals that form in the water column during supercooling events. Frazil forms below the surface making it difficult to detect. Frazil comes in two types, active and passive; passive frazil passes through the ship’s trash screen without a problem. Active frazil sticks to everything and can cause problems with water intake. In colder climates, frazil forms in rivers, lakes and seaports. When it gets sucked into the sea chest it can create blockages, causing damage to the ships engines or other auxiliary equipment such as steering gear. A local University, researching detection methods for ice content in water, came to MTI Instruments to determine if capacitance probes could detect the percentage of ice in brackish water. A capacitance probe was placed in a PVC tube and tuned to detect the change in dielectric constant of the water ice mixture.

Results:
This collaboration between MTII engineering and the University could result in ships having an alarm warning of inlet cooling blockage due to ice. Initial lab test results are good and sea trials are pending the appropriate conditions. Capacitance probes can also be used to detect ice buildup in compressor evaporator coils or on wind turbines potentially saving millions of dollars in repairs and outages. Don’t be left out in the cold. When you need critical, innovative solutions MTI Instruments is here to help, regardless of the temperature.