Oil Water Detector

Written by Jerry Ratzlaff. Posted in Instrumentation

A oil water detector or cut probe is an instrument that measures the percentage of oil or water in a process stream.   When they are specified, the continuous phase needs to be determined.  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.  

  • Abbreviated as OWD

Cut Probes can be used in:

  • Well test applications
  • Group test facilities
  • Custody Transfer
  • LACT Units
  • Pipeline
  • Drainage and urban runoff processing

Types of Oil Water Detectors

Capacitance

Capacitance level detectors are also referred to as radio frequency (RF) or admittance level sensors.

Microwave

Microwave probes detect the amount of hydrocarbons in water.  This style of probe operate on the same principal as putting a Styrofoam cup filled with water in the microwave.  The water reacts differently than the petroleum based Styrofoam.  By sensing the way the microwaves react as the oil and water passes through it the amount of hydrocarbons can be measured with a very high accuracy.  The strength of a microwave probe comes from its ability to measure 0 to 100 percent water.