Aluminum "heater treater" anodes are used in a variety of cathodic protection solutions including oilfield tanks, production vessels and more. The "heater treater" name is taken from a common oilfield vessel used to separate crude oil from water. However, this anode type is also used for other applications in a variety of industries.
The typical "heater treater" anode is a 3" diameter cast anode with a length of either 30 or 60 inches. A 3/4" diameter all-thread rod is cast into the center of the anode and extends outside the anode from either one or both ends. It is this configuration that is then converted to a number of different mounting or installation methods as follows:
A 3" x 30" or 3" x 60" anode can be assembled with a length of insulated cable that connects the suspended anode to the roof of a vessel or tank. The cable-to-anode connection is finished with an epoxy cap to eliminate stress or fatigue on the cable-to-anode connection.
There are several standard roof mounting options used to suspend the anodes. These include custom fabricated blind flange assemblies, Victaulic cap assemblies, and other components used for the task. Consult with a Farwest customer service representative for assistance in the selection of the proper equipment.
Blind Flange Mount
Either anode size can be fitted to a blind flange, 4" or larger, for insertion through a common tank nozzle. Farwest welds the anode core to the interior of the blind flange, which is mated to the tank nozzle flange. As installation of this anode from the exterior of the tank can be tricky, due to the weight of the anode in a horizontal position, Farwest can weld a pipe coupling to the blind flange exterior for attaching a pipe used to support the anode during installation.
No cable is required for this type of installation IF a dielectric insulating gasket is NOT utilized. If a dielectric insulating gasket is used, however, a cable must be connected from the exterior of the blind flange to the vessel being protected.
Redhead or Bluehead Mount
Similar to the Blind Flange mount mentioned above, a Redhead or Bluehead mounting assembly can be provided for the purpose of inserting the anode into a Victaulic style tank nozzle. In this case, the Redhead (for standard 4" SCH 40 grooved Victaulic couplings) or Bluehead (for standard 4" SCH 80 grooved Victaulic couplings) is affixed to the aluminum anode and then inserted into the vessel via the Victaulic nozzle. A Victaulic coupling then secures the anode assembly to the nozzle.
A cable must be used to electrically connect the anode to the vessel as the Redhead and Bluehead electrically isolate the anode from the vessel. If desired, an optional shunt can be installed between the flanges or on the cable to monitor the current output of the anode.
Red-Cap, "Groove-Lock" Style Anode Cap
The Farwest Corrosion “Red-Cap” anode cap is designed for the installation of 3-inch diameter sacrificial anodes into oilfield style vessels or similar applications. The durable steel design is capable of withstanding demanding pressures while being easy to install.
The Red-Cap is designed to work with 4-inch “groove-lock” (Victaulic, Anvil or similar) style tank fittings for both SCH 40 and SCH 80 pipe nipple sizes. Once the anode is installed in the Red-Cap, the anode assembly can be inserted into a vessel nipple and secured to the nipple with a conventional 4-inch “groove-lock” coupling.
Popular anodes sizes are any 3-inch diameter sacrificial anode, typically aluminum, in 30-inch and 60-inch lengths. While the anode may be electrically continuous to the tank through the Red-Cap, to ensure positive continuity, it is recommended that a cable is attached from the provided ¾” threaded core directly to the vessel.
The Red-Cap is rated for a working pressures of 600 PSI. However, it is important to note that the actual operational pressure rating depends on the type of coupling selected to secure the anodes to the vessel. Check with tank fitting manufacturer to ensure fitting pressures are compliant for use in the application.
For your convenience, the anode is assembled into the Red-Cap fitting and ready to be installed in the vessel in question.