Wärtsilä iPhase

Wärtsilä’s iPhase rod measures the vertical profile of separator contents and detects the interface between oil and water.

It is especially suited for use in the oil industry for the accurate detection of the interface level between water and crude oil in production separators. It uses an inductive measurement principle that measures the conductivity of materials enclosing the iPhase rod.

Wärtsilä’s iPhase offers very accurate detection of the interface level due to a very high relative difference in the conductivity of produced water and crude oil, as opposed to competing technologies based on density differences.

In addition to detecting the interface level, the conductivity measurements allow iPhase to provide an oil-in-water profile inside the separator.

    Technical data

    The iPhase rod consists of several sensors placed on top of each other, where each sensor measures the bulk properties of the surrounding material. The measurements are conducted without electrodes over an extended volume, which makes it less sensitive to deposits.

    The iPhase uses intrinsically safe electronics with no active components inside the vessel.


    Conductivity measurement range1: 3 S/m < _ < 50 S/m
    Resolution: 20 mS/m
    Measurement update rate: Typ. 5 sec
    Level measurement range (short rod): 1430 mm
    Level measurement range (long rod): 2200 mm
    Interface accuracy (short rod): ±20 mm
    Interface accuracy (long rod): ±40 mm
    Process operating temperature: -20 °C < T < 120°C
    Ambient operating temperature:  -20 °C < T < 75 °C

    Instrument housing: 316L
    Ingress protection electronics: IP 66/UL 50 Type 4X
    Measurement rod: Sensors moulded in epoxy
    Pressure barrier/ flange: 22 Cr Duplex
    Electronics encapsulated in polyurethane / aluminium
    316L support structure (Other materials available on request) 

    Minimum required sizes of vessel nozzle:
    Nozzle mounted: 4”
    Nozzle mounted, split extension design: 6”
    Vessel mounted, manhole entered: 2”
    Minimum installation headroom above vessel nozzle:
    Nozzle mounted short rod: 2200 mm
    Nozzle mounted long rod: 3000 mm
    Vessel mounted: 1200 mm
    Electrical Supply (via IS-isolator):
    Max current consumption: 70 mA
    Typical current consumption: 50 mA
    Minimum supply voltage at full load: 11.7 V

    MODBUS Interface

    The electronic module interfaces a control system via MODBUS RTU transmitted over RS485 at 19200bps. The iPhase is connected to the control system through an intrinsically safe barrier and it must be the only node connected to the hazardous side of the barrier.


    The iPhase can be used in any separator, vessel or tank that contains liquids with large relative differences in conductivity.

    It is especially suited for use in the oil industry for the accurate detection of the interface level between water and crude oil in production separators.

    The high accuracy of level detection provided by iPhase allows for improved separator control, which in turn allows for more optimized use of the internal volume for oil or water separation.

    The measurement principle of the iPhase gives it a high tolerance against deposits, making it ideal for use in cases where scale could be an issue.

    Key benefits
    • High tolerance to deposits
    • High accuracy oil/water interface determination
    • Provides oil-in-water profile inside the separator
    • Detection of sand build-up
    • No radioactive sources required.

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