Oil Water Detector
Oil water detector, abbreviated as OWD, or cut probe, is an instrument that measures the percentage of oil or water in a process stream. It is a device used to detect the interface between oil and water in various industrial applications, particularly in oil and gas production, wastewater treatment, environmental monitoring, and marine industries. The detection of oil and water interfaces is important for separating and controlling the flow of these fluids in processes, preventing pollution, and ensuring regulatory compliance. For LACT applications, oil is the continuous phase.
On a Piping and Instrumentation Diagram, a cut probe is characterized as an analyzer and contains an element (AE) and a transmitter (AT). The cut probe sends an analog signal to the PLC which is used to for surveillance or process control.
Key Features and Functions of an Oil-water Detector
Detection Principle - Oil water detectors typically utilize different physical properties of oil and water to detect their interface. Common detection principles include capacitance, conductivity, ultrasonic, optical, and infrared techniques.
Capacitance Detection - Capacitance based oil water detectors measure the dielectric constant of the medium between two electrodes. Since the dielectric constant of oil is lower than that of water, changes in capacitance indicate the presence of oil or water, allowing the interface to be detected.
Conductivity Detection - Conductivity based detectors measure the electrical conductivity of the medium between two electrodes. Since water is a better conductor of electricity than oil, changes in conductivity indicate the presence of water, allowing the interface to be detected.
Ultrasonic Detection - Ultrasonic oil water detectors emit ultrasonic waves into the medium and measure the time it takes for the waves to reflect back to the sensor. Changes in the speed of sound indicate the presence of oil or water, allowing the interface to be detected.
Optical and Infrared Detection - Optical and infrared detectors use light beams to detect changes in the medium's optical properties. Differences in absorption, reflection, or refraction of light indicate the presence of oil or water, allowing the interface to be detected.
Alarm and Control Systems - Oil water detectors are often integrated with alarm and control systems to alert operators when the oil water interface reaches a certain level. These systems may trigger alarms, shut off valves, or activate pumps to prevent oil and water from mixing or contaminating sensitive environments.
Remote Monitoring and Data Logging - Some oil water detectors feature remote monitoring capabilities and data logging functions, allowing operators to monitor interface levels in real time and store historical data for analysis and reporting purposes.
Oil water detectors are essential tools for maintaining environmental compliance, preventing oil spills, optimizing process efficiency, and protecting equipment in various industries where oil and water separation is critical. The choice of detector depends on factors such as the type of fluids, operating conditions, accuracy requirements, and regulatory standards.
