Marine Sensors

How It Works

The reason for Metritape’s success is its simple principle of operation and the high quality materials used in its construction. The sensor consists of a gold plated, stainless steel base strip, partially insulated from a gold plated wire that is wound around the base strip to form a helix (figure 1). This helix is sheathed in either Polypropylene or HastelloyTM to insulate the sensor’s inner elements from the liquid to be measured. Sliding the sheathed helix into a protective channel that leaves the front of the sensor exposed then completes the sensor. The sensor is generally contained within a still pipe suspended from the top of the tank.
diagram of a 3D sensor
diagram of marine sensing

Resistance-Tape Operation Principle

When the sensor is installed (figure 2), the outer envelope jacket (1) is compressed by the hydrostatic pressure of the liquid (2). This causes the gold wire winding to contact the gold plated base strip. The resulting change in the resistance of the gold wire (3) indicates the length of active helix and the distance from sensor top to liquid surface. The helix is wound at 4 turns per inch, 1000 ohms per meter (305 ohms per foot) resistance gradient providing ¼ inch resolution. Metritape sensors are easily installed from the tank top by dispensing the flexible sensor from its cardboard shipping reel into a customer supplied still pipe.


  • Available lengths from 1 - 36 meter (3 - 120 feet)
  • Intrinsically safe; combined level and temperature capability
  • Polypropylene or Hastelloy C276TM construction


  • Tank top mounted for easy installation
  • Virtually maintenance-free; just a 5 minute filter change every 24 to 48 months
  • All electric resistance-tape sensor for stable output; no moving parts to stick or break


  • Water, Wastewater, Sewage
  • Crude Oil, Petroleum Products
  • Chemicals, Solvents

ServiceSensor TypeWetted MaterialsTemperature RangeLevel RangePressure Range
Water, Wastewater, SewageLAPolyester, Epoxy, Glass-filled Polypropylene, Stainless Steel5° - 158°F
(-15° to 70°C)
3 - 120 feet (1-36 M)±15 PSI
(±1 atm)
Crude Oil, Petroleum ProductsLA-HNHastelloy C276,
Nylon 12
5° - 225°F
(-15° to 107°C)
3 - 120 feet
(1-36 M)
±15 PSI
(±1 atm)
Chemicals, SolventsLA-HPHastelloy C276, Polypropylene5° - 225°F
(-15° to 107°C)
3 - 120 feet
(1-36 M)
±15 PSI
(±1 atm)

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