A retrofitable over-bath spinning technology
Scheffer’s new Twister is an easy option for galvanizers to extend their existing processes with spinning of small galvanized parts. The Twister can be picked up by normal transport systems – such as overhead cranes or drive units - and moved with them through the galvanizing process.
The pre-treatment of the small parts has to be done, for example, in baskets, drums or open bottom containers which will be mounted on the normal jigs. After pre-treatment, the material will be placed into the galvanizing baskets (different versions – depending on size and form of the material, filled with up to 60 kg each). These baskets can then be picked up by the Twister with its gripping function. Because of this gripping function, the Twister has no down time, e.g., when pre-filling the galvanizing baskets. After picking up, the Twister will be moved above the zinc bath and the dipping process begins.
The process is done with slow rotation to ensure a movement of the material while dipping. Also the dipped basket can be moved through the bath. After the “cooking” process the basket will be pulled out and the splash guard of the Twister will be moved down around the basket. The splash guard is made to dip a bit into the zinc to ensure maximum user safety while spinning. The splash guard is also equipped with a vibration unit to ensure that almost no waste zinc will stick on it during the subsequent spinning process.
With the closed splash guard the spinning process can be started (for safety reasons it is not possible to spin while the splash guard is open). The material will be rotated with a speed of 400-500 revolutions per minute with an acceleration speed up to maximum of below 2 seconds. The excess zinc on the material will be thrown against the splash guard and will be immediately redirected into the zinc bath. After the spinning process the splash guard can be opened and the Twister will be moved above the discharge station. The galvanizing basket will be placed on this station. Now the emptying process of the basket can begin after the Twister has been moved away. Meanwhile, the Twister can start the galvanizing process with the next, already prefilled, galvanizing basket.