TECHNICAL DETAILS

Resistance to ageing

The duration of a Caravel rubber bearing depends on the working conditions to which it is subject, the degree of abrasion and the temperature of the liquid, as well as the speed of the shaft. Where there is the possibility of lubricating with perfectly clean water, the duration of the rubber bearing is only four times higher than that of a bearing of hard metal; but where the lubricating liquid contains high quantities of abrasive, its duration results, as per laboratory tests which were effected, fifteen-eighteen times higher. Since in the majority of the cases it is not possible to depurate the lubrificating water, because it would require the adoption of costly installations, it is not necessary to emphasize that the rubber bearings are extremely convenient.

Low friction coefficient

Caravel rubber bearings have an extremely low friction coefficient because, during the rotation of the shaft, between shaft and bearing a series of liquid elements with cuneiform lift are created, on which any friction is annulled. It can be asserted without any doubt that the rubber bearing friction, if it works under the requested conditions, is not higher than that of a good ball-bearing.

High speeds

Caravel rubber bearings are suitable to tolerate safely peripheral speeds of the shaft that are around 10 meters per second.

Radial loads

For items with internal poligonal figures, it is necessary to foresee a maximum radial load of 3,5 kg/cm². For the bearings with internal radius figure, the maximum radial charge is of 5 kg/cm²

Rubber denominated PV 68 K

Nitrilic, anti-oil, this rubber resists to the corrosion and the wear provoked by greases and by petroleum residuals. It has a medium hardness of 68° Shore and is suitable for the work in waters that contain traces of common acids. The rubber PV 68 K has to be lubrified with waters that do not present high quantities of sand in suspension.

Rubber denominated CAR 71 K

Anti-abrasive, it is recommended where the lubricating water drags along sands in large quantities (irrigation pumps). Of medium hardness, 68° Shore, the CAR 71 K rubber, resists to the wear provoked by the sands interposing between the rubber itself and the rotating shaft; it resists to corrosion and rejects the solid body until it is dragged along the outlet channels. The cooling liquid thus becomes the vector of the sand particles which are expulsed leaving the shaft or its protection perfectly intact.