Model P21

SKU: P21

Capacitance Probe, Tubular Ground

The Delta Controls Model P21 Capacitance Probe has high intrinsic gain. It is equipped with a wrap around concentric ground reference sheath which acts as a ground reference when used in plastic and lined tanks. The linear ground sheath allows it to be used with transmitters in horizontal cylindrical tanks and other containers with nonlinear sidewalls.

The P21 requires a minimum process connection of a 1 inch NPT process connection. It has high inherent gain sensitivity and is useful on materials having low dielectric constants, such as light hydrocarbons. It allows full scale calibration over a modest level change and calibration can be done outside the vessel.


  • High inherent gain sensitivity
  • Allows full scale calibration over a modest level change
  • Insensitive to surface turbulence
  • Output signal is linear to liquid depth
  • Calibration can be done outside the vessel
  • Use for sensing light hydrocarbons and materials with low dielectric constants
  • Linear output in irregular tanks
  • Built-in ground reference for plastic and lined tanks


  • Working Pressure: +1500 psig (+103.4 bar)
  • Working Temperature: -460 °F to +450 °F (-273 °C to +232 °C)
  • Insertion Length: ≤ 20 ft (6 m)
  • Process Connection: 1 in MPT minimum
  • Threaded Process Connection: 1.0 in to 2.0 in
  • Flanged Process Connection: 1.5 in to 4.0 in
  • Flange Rating: ≤ 600 lb
  • Available Wetted Materials: 316 Stainless Steel, Hastelloy® C-276, PTFE, carbon steel
  • Ground Sheath:Stainless steel (other materials available)

Required Ordering Information

  • Detailed model number
  • Tag or nameplate detail (if required)
  • Documentation & testing packages (if required, refer to Additional Resources in the product catalog)
  • Process fluid or material name
  • Process fluid or material dieletric constant
  • Maximum process temperature
  • Maximum process pressure

Additional Information


Capacitance Probe, Tubular Ground

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