An apparatus may mount an in-stream, continuous contact, visible, sacrificial anode in a fluid passage for the electrolytic corrosion protection. The apparatus may function to protect heat exchangers and/or other metallically connected system components that share contact with electrolytically active fluids. The apparatus may consist of an in-line anode cartridge including a collar body and a viewing port. The apparatus may include a site glass and compression fittings which seals the device causing corrosive fluids to flow past a sacrificial anode. The apparatus may include a visual indicator and an elastically compressed member (e.g., spring) which facilitate continuous metallic/electrical contact and inspection of the anode through the viewing port without system shut down or disassembly. The elastically compressed member and gauge assembly fills the view-ports with a bright indicator as the anode dissolves and the elastically compressed member expands. The apparatus improves inspection, replacement and effectiveness of sacrificial anodes in electrolytically corrosive environments.

An electrical contact element formed of sheet metal having a first region and a second region. Each one of the first and second regions is coated with a coating including a first layer containing a first material having a lower standard electrode potential than the sheet metal material. The coating includes a second layer in the first region which is absent in the second region. The second layer is arranged underneath the first layer and contains a second material that has a lower standard electrode potential than the first material.

A system comprises a cathodic protection system having an anode and configured to protect a protected structure from corrosion. The system comprises a monitoring circuit operatively coupled to the cathodic protection system. The monitoring circuit comprises an electrical-to-optical transducer. The electrical-to-optical transducer is configured to generate a light signal in response to electrical current flowing between the protected structure and the anode of the cathodic protection system, the protected structure and a reference electrode, or the reference electrode and the anode.

A pipeline comprising one or more pipes, the pipeline having: one or more sacrificial anodes to provide cathodic protection; one or more pre-formed one-piece integral metallic rings around at least one pipe; and one or more electrical connectors attached to the or each metallic ring and to at least one sacrificial anode to allow an electrical current to flow between the pipeline and one or more of the sacrificial anodes. Each metallic ring has a one-piece form and can be fitted to the pipe without welding.