Breakthrough in Screw Feeders!
CeraMetal s.e. has developed a hardfaced system to protect screw feeders against abrasive wear that promises to vastly extend screw life resulting in considerable cost savings.

Asked to help the cement giant AGET at their Volos plant in Greece, CeraMetal designed and built the feeder screws used in their quayside Babcock Material Handling system loading cement clinker into bulk container ships.

Previously, screw flights manufactured in 10mm thick hardened steel plate had been completely destroyed after loading 100,000 tonnes of material and AGET were faced with the severe problem of the cost of replacement being frequently repeated.

The system contains 6 enclosed screw feeders with a screw flight diameter of about 760mm and lengths up to 7.35m used in tandem to directly load the very abrasive product into the hull of the ship.The application involved selecting hardfacing materials to withstand varying wear conditions dependent on the position in the system. Whilst severe gouging abrasion is predominant throughout, areas under the entrance gates of each section suffer impact and with operating speeds up to 200rpm, there is inevitably some erosion by impingement. This called for more than one hardfacing material and more than one application process.

CeraMetal were ideally placed to find a solution because of their strong complementary production facilities. Manufacturing their own hardfacing wires enabled them to produce the special wires thought necessary and their large volume hardfacing, wear plate cladding and fabrication facilities gave them full control of their proposed solution to the problem. The installation was made in September 2002 and a preliminary inspection after loading 105,000 tonnes has revealed only a light 'polishing' of the CeraMetal hardfacing materials.

Photographs reproduced here confirm the thinking that the screw feeder life can be expected to exceed 5 times the original manufactured in hardened steel. This represents considerable savings in downtime and with the manufacturing costs said not to be exceeding the original costs, overall savings could to be considerable. CeraMetal hope to be allowed to quantify this saving at a later date. Yet another CeraMetal WearSolution.
Images
Img.1: Screw feeders for cement clinker hardfaced with CeraMetal materials Img.2: Sections of screws showing only partial polishing of the hardfacing
Img.3: Sections of screws showing only partial polishing of the hardfacing Img.4: Sections of screws showing only partial polishing of the hardfacing