A Leakwise system consists of a controller and one or more sensors.
The ID-221 sensor has a current line high-frequency transmitter mounted on a float that maintains its position precisely at the liquid/air interface, despite fluctuations in liquid level up to 45 m (150 ft.) variation. A single ID-221 sensor is controlled by the analog PS-220 Controller, which has two field-adjustable alarm points:
The ID-221 can detect as little as 0.3 mm (0.01 in) oil layer on water reliably, repeatedly and without false alarms. It also monitors online changes in oil layer thickness up to 25 mm (1.0 in) and report it through a 4-20 mA output signal from the controller. Controller relays are used for local and remote alarms and control. Continuous built-in diagnostics monitor sensor operation. The SLC-220 digital controller handles up to four sensors. A stilling well is recommended for all ID-221 installations (available as an optional accessory).
Leakwise sensors use a high-frequency Electromagnetic Absorption technique. Each floating sensor houses high-frequency electromagnetic energy transmitting and receiving antennas that continuously monitor the liquid surface. Since water absorbs more electromagnetic energy than hydrocarbons, changes in the absorption rate of water indicate the presence or buildup of hydrocarbons. Leakwise sensors are used for detection and monitoring the buildup of separated or emulsified non-soluble hydrocarbons on water and other aqueous solutions. In addition, the sensors differentiate between a wet and a dry sump. No other oil sheen monitoring system does this.