Through Wall Reference Electrodes
Through-wall reference electrodes are used for measuring corrosion potential on the inside of condenser waterboxes, circulating pipes, tanks and vessels. These electrodes are installed by threading into a tapped hole on the wall; a junction box is typically attached to the other end to protect the wiring connections. Through-wall reference electrodes can be ordered with any of the sensing elements listed in the adjacent sidebar.
The Standard Probe (Model FS) uses a CPVC extension tube and a ¾ inch NPS PVC nipple for attachment. It can be used at pressures up to 40 psi (270 kPa) and intermittent temperatures up to 180°F (82°C). The Heavy Duty Probe (Model FH) has a glass reinforced epoxy (G-10 GRE) extension tube and a 316L stainless steel nipple. It can be used at pressures up to 75 psi (0.5 MPa) and intermittent temperatures up to 210°F (98°C). Model FH is available in three size variations: Model FH10 is threaded into a 1 inch NPT hole, Model FH7 is threaded into a 3/4 inch NPT hole, Model FH5 is threaded into a 1/2 inch NPT hole; all three variations have a 1 inch NPT thread on the termination side.
The temperature limits stated are those for the wetted materials of construction. Through-wall reference electrodes should generally not be continuously used at temperatures exceeding 110°F (45°C) because the reference potential will be significantly different from its value at ambient temperature and the electrode service life will be drastically shortened. The product will survive occasional brief temperature excursions up to the limits stated in the preceding paragraph. For applications involving continuous exposure to temperatures over 110°F (45°C), our Process Vessel Reference Electrode is recommended.