Delta Mobrey 003 Series Ultrasonic Liquid Level Switch

Delta Mobrey 003 Series Ultrasonic Liquid Level Switch  is designed for high or low-level alarm duties to give a voltage-free changeover contact or dual solid-state transistor output for alarm signaling or as part of a pump control system.

Manufactured in Polyphenylene Sulphide (PPS) for corrosion resistance in most liquids, the 003 switch range of sensors can be mounted in any position in a tank using either a 1” or 3/4” thread available in BSPP, BSPT, and NPT thread forms.

A thread is provided on each side of a hexagonal boss to allow either external or internal / pole mounting of the sensor. Comprising a one-piece molded body with an integral PCB, the 003 switch is factory sealed and supplied with a 3m flying lead for customer connection.

Delta Mobrey 003 Series Operation

The molded body contains two piezo-electric crystals, one on each side of a gap at the tip of the sensor. An ultrasonic signal is transmitted from one crystal into the gap, but if there is air or gas in the sensor gap then the signal is not received by the other crystal. However, if there is a liquid present, the signal will be transmitted and the integral electronics will switch the output circuitry to signal the presence of a liquid.


  • Manufactured in Polyphenylene Sulphide (PPS) for corrosion resistance in most liquids.
  • Top, bottom, or side-installation flexibility in tanks.
  • Small, light, robust, and easy to install.
  • No moving parts.


  • Low-level alarms in header tanks
  • Pump control duty in feeder tanks
  • High or low alarms in storage tanks
  • Level or pump control in storage tanks
  • Small or thin wall tanks
  • Bund level detection
  • Steering gear oil


  • Relay or solid-state output
  • Corrosion resistant PPS construction
  • 1-in. or ¾-in. threaded mounting
  • Small in-tank dimensions
  • 24 Vac or dc powered
  • Lightweight

Delta Mobrey 003 Series Specification:

  • Operating pressure: 72.5 psi (5 bar)
  • Ambient and operating temperature: –4 to 158°F (–20 to 70 °C)
  • Minimum liquid specific gravity: 0.50
  • Maximum viscosity: 5000 cSt. at 68 °F (20 °C)
  • Switching response: 50 ms dry-to-wet; 0.5 s wet-to-dry
  • Hysteresis: < 0.12 in. (4 mm)
  • Repeatability: ±0.08 in. (2 mm)
  • Overall length: 4.33 in. (110 mm)
  • Length into the tank (external mount): 3.11 in. (79 mm)
  • Body diameter: 0.87 in. (22 mm)
  • Switching function
    • SPCO relay (energized wet)
    • Maximum switched current:
      • 1 A at 30 V resistive; 0.25 A at 30 V inductive
      • 30 V maximum switched voltage
  • Power supply: 18 to 30 Vdc or ac
  • Current drawn when dry: 10 mA nominal
  • Current drawn when wet: 25 mA maximum
  • Cable: 10 ft. (3 m); 5-core 7/0.2 mm(0.008 in.), PVC cable sheathing
  • IP Rating of Sensor: NEMA 6P (10 ft.) / IP66/IP68 (3 m)

Download Data Sheet: Ultrasonic Liquid Level Switch 003 Series


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