Model P31

SKU: P31

RF Admittance Probe, Externally Caged

The Delta Controls Model P31 external caged probe is primarily used in the chemical, petrochemical, refining and other continuous process industries. This probe design can be tested, calibrated, and maintained without shutting down or disturbing the process. Common applications include Dowtherm® heating fluid, interface position, tower bottoms; water knockout traps, etc. The P31 probe is equipped with an external (to the process vessel or tank) cage. This cage is a vertical cylindrical pressure vessel containing the probe. Block valves are normally installed (by the user) between the cage connection ports and the process vessel or tank. This allows the instrument to be isolated from the process pressure (or partially full tank) for testing and calibration purposes without blow down or draining the process. The cage serves as the ground reference for the sensing rod. This is the same principle employed by the Series 20 probes with tubular ground sheaths. The P31 is essentially an “external cage” version of the Series 20 internal caged probes. A signal linear to the liquid level or an interface position is generated for alarm or signal transmission outputs.

Features

  • High inherent gain sensitivity
  • Can be calibrated, tested, or inspected without disturbing a continuous process
  • Avoids problems due to turbulence and splashing
  • Temperature and pressure service range is -15 to 425 PSIG (-1 to 30 BAR) @ 750°F (400°C)
  • Low temperature is -350 to +750°F (-210 to +400°C)
  • Works in highly corrosive service and is also available with all PVC or PVDF wetted parts
  • Full scale 4-20mA output signal change achievable over a few inches of level change

Specifications

Wetted Cage Materials: Steel, 316 S.S., Hastelloy® "C", PVC, or PVDF.

Working Pressure:

Wetted Materials Maximum Working PSIG @ °F
Cage Insulation 100 250 400 500 750
Metal PTFE 1440 500 25 N/A N/A
Metal Alumina 720 690 665 625 425
Wetted Materials Maximum Working PSIG @ °F
Cage Insulation 100 140 180 220 280
PVC PTFE 150 50 N/A N/A N/A
PVDF PVDF 150 150 115 80 25

Applications

The Delta Controls Model P31 external caged probe is primarily used in the chemical, petrochemical, refining and other continuous process industries. This probe design can be tested, calibrated, and maintained without shutting down the process. Common applications include Dowtherm® heating fluid, interface position, tower bottoms; water knockout traps, etc.

The Delta Controls P31 probe is equipped with an external (to the process vessel or tank) cage. This cage is a vertical cylindrical pressure vessel containing the probe. Block valves are normally installed (by the user) between the cage connection ports and the process vessel or tank. This allows the instrument to be isolated from the process pressure (or partially full tank) for testing and calibration purposes without blow down or draining.

The cage serves as the ground reference for the sensing rod. This is the same principle employed by the Series 20 probes with tubular ground sheaths. The P31 is essentially an "external cage" version of the Series 20 internal caged probes. A signal linear to the level or an interface position is generated for alarm or signal transmission outputs.

The Delta Controls P31 cage serves as the vessel for calibration purposes, eliminating the need to calibrate the probe in actual service. The calibration may be performed prior to operation by filling the cage with the liquid to be measured, varying the level and making the necessary zero and span or alarm adjustments. Likewise, the procedures may be used for testing or recalibration after installation. A means of ventilating and draining the cage is recommended to facilitate the adjustment of the fluid level during calibration and testing. The basic configuration has side/bottom process connections; others are available, consult the factory.

The basic model P31 unit with NPT connections is limited to a maximum working pressure of 1500 PSIG (95 bar) @ 175°F (80°C); higher is available with optional temperature extensions. For other configurations, materials and applications requirements, consult the factory.

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