Canister Prepackaged High Silicon Cast Iron Anode
This canister anode consists of a tubular high silicon cast iron anode firmly pre-packaged in a large spirally wound galvanized mild steel canister that is filled with calcined petroleum coke backfill. The canister is capped with the cable which extends out the top of the anode cap.
The metallic canister housing is only intended to last through transportation and installation. Once installed, the exterior housing is part of the anode system and it is expected to be consumed quickly, leaving behind the anode and coke backfill. The stable anode element passes current to highly conductive coke backfill, and then the current is discharged from the external metallic housing.
Canistered pre-packed high silicon cast iron anodes are normally used in areas with a high water table or where it is difficult to install loose coke backfill which is normally provided around anodes. Our canistered high silicon cast iron anodes are a perfect impressed current cathodic protection material for low resistivity soils, shallow vertical and horizontal surface ground beds, as well as wet, marshy soil conditions where caving is likely to occur.
Description
Low Consumption Rate
Our tubular high silicon cast iron anode is centrifugal chill casted. The casting mold rotates at over 1000rpm producing a g-force that eliminates any trapped gas from silicon iron and throws any impurities to the inside bore of the anode where they do not hinder anode performance. Hence, the metal matrix is tight and dense; increasing the life of the anode.
Strengthened Canister Housing
The anode is installed in a spirally welding 0.65 mm thick galvanized steel canister. The canister is biodegradable and will corrode in service. It should be stored in a dry place before installation to avoid corrosion and perforation.
Uniform Coke Filled with Centralizer
The canister may be supplied in a variety of diameters and lengths to suit the specific anode/groundbed design. Preloaded canister ensures the anodes are evenly surrounded with the proper amount of compacted coke breeze backfill.
Low Ground Resistance
The coke backfill provides a homogenous environment for high silicon cast iron anode and can substantially lower the anode to earth resistance. It is an ideal cathodic protection material for high soil resistivity.
Easy Installation
Canister high silicon cast iron anodes reduce installation costs by providing the anode and coke backfill in a self contained package. The assembly process is finished within our foundary instead of in the field, which effectively guarantees field installation quality of anode bed.
Chemical Composition
| Element | ASTM A518 / A518M | BS 1591 1975 | |
| Grade 1 (Si – Fe) | Grade 3 (Si – Fe – Cr) | ||
| Silicon (Si) | 14.2 – 14.75% | 14.2 – 14.75% | 14.25 – 15.25% |
| Chromium (Cr) | 0.5% Max. | 3.25 – 5.0% | 0.5% Max. |
| Manganese (Mn) | 1.5% Max. | 1.5% Max. | 0.5% Max. |
| Carbon (C) | 0.65 – 1.1% | 0.7– 1.1% | 1.4% Max. |
| Molybdenum (Mo) | 0.5% Max. | 0.2% Max. | — |
| Copper (Cu) | 0.5% Max. | 0.5% Max. | — |
| Sulphur | — | — | 0.1% Max. |
| Phosphorus | — | — | 0.25% Max. |
| Iron (Fe) | Remainder | Remainder | Remainder |
Note: ASTM A518 Grade 3 chemistry is particularly suited for electrolytes rich with chloride ions, where the level of chromium is elevated to enhance anode performance.
Electrochemical Properties
For anodes of the same chemistry and microstructure, variance in consumption is primarily due to the chemical and physical characteristics of the anode environment. The consumption rate does not appear to be significantly affected by current density (amperes per unit area of anode surface).
| Environment | Nominal Current Density | Consumption Rate |
| Soil / Fresh Water | 2 – 5 A/m² | 0.1 – 0.5 kg/A-y |
| 0.2 – 0.5 A/ft² | 0.2 – 1.2 lbs/A-y | |
| Carbon Backfill | 5.0 – 10 A/m² | 0.05 – 0.3 kg/A-y |
| 0.5 – 1 A/ft² | 0.1- 0.7 lbs/A-y | |
| Seawater | 10 – 50 A/m² | 0.3 – 0.5 kg/A-y |
| 1 – 5 A/ft² | 0.7 – 1 lbs/A-y |
Physical Properties
| Tubular Anode Size | Canister Size |
| 1.5″ x 48″ (38×1524 mm) | 200×2000 mm |
| 2″ x 60″ (51×1524 mm) | 200×2000 mm |
| 3″ x 60″ (76×1524 mm) | 200×2000 mm |
| 2.3″ x 84″ (58×2134 mm) | 200×3000 mm |
| 2.8″ x 84″ (71×2134 mm) | 200×3000 mm |
| 3.8″ x 84″ (96x2134mm) | 200×3000 mm |
Remarks: All dimensions and weights shown are normal. Non-standard sizes and weights of the anode are available upon request.
