Sewer inspection light and easy

Around the clock, all over the world, waste water is produced, flowing through widely ramified drainage systems to sewage treatment plants. Constant monitoring and maintenance is required to ensure that the sewers are absolute watertight and passable. For approximately 50 years, camera systems have been used to inspect the sewers and these camera systems have been since improved several times.
Europe's leading manufacturer of sewer inspection-systems uses aluminium materials to produce integral components for specific inspection carriages. These materials are easier to machine than ferrous materials and the carriages are thus easier to transport and to handle due to their relatively low weight. The camera carriages are fed in the supply pipe via a flexible plastic tubing, fitted with an internal cable for the camera and a fiber optic rod. This procedure causes substantial wear of the aluminium casing and the other components due to the abrasive movements against the pipe walls and soiling and corrosion by the residual waste water.

Such wear demands a suitable coating of the casing and other aluminium components. In this case, a 45 µm thick hard anodic layer, called HART-COAT®, has proven to be the best. The coating is formed by means of anodic oxidation in a cooled acid electrolyte whereby the surface of the aluminium base material is converted into an aluminium oxide layer. This oxide layer grows equally inwardly as outwardly, thus creating a specific change in dimension of the component.

Particularly noteworthy is the very good bond with the base material whence the layer is generated and this bonding is based on atomic binding forces. The hardness of the aluminium oxide grants high wear resistance to the layer and thus to the aluminium casing. In order to facilitate cleaning procedures and to achieve a rolling off like mercury droplets of the cleaning liquid, the HART-COAT® layer has additionally embedded PTFE lubricants.

The good optical characteristics of the camera carriage in use in general public is not to be underestimated and this is substantially achieved by the coating.