Retractable Element Electrical Resistance (ER) Probe 3520/3520HT

Model 3520 retractable process probes are designed for particularly severe or toxic duty service, where fixed thread probes are not permitted by plant or other regulations.

The all-welded construction of the cylindrical probe element provides the highest integrity for a corrosion measurement element. Only the material under evaluation is exposed to the process fluid. Even with any localized attack or physical damage to the element, the back of the probe provides process containment with high pressure glass-to-metal seals.

Device Length Calculator

Need help figuring out what length ER Probe is required based on your pipeline size and application? Try Cosasco's new Device Length Calculator.


  • Mounting — 1” Full Port Valve Minimum
  • Temperature Rating
    -Model 3520 — +500° F (+260° C)
    -Model 3520HT — +1000° F (+520° C)
  • Pressure Rating
    -Model 3520 — 1500 PSI (10.3 MPa) subject to flange rating
    -Model 3520HT — 1000 PSI (6.9 MPa) subject to flange rating
  • Seal Material — Element seal all welded
  • Process Containment Seal — High pressure glass-metal seal Connector and Teflon packing
  • Fill Material — Ceramic
  • Body Material — As element


  • Gas Plants
  • Refineries
  • Offshore platforms
  • Tank Farms
  • Chemical and Petrochemical Plants


Related Products