Outotec recently announced two products aimed at facilitating and improving grinding mill maintenance and reliability.
Outotec’s hydraulic inching drive is an auxiliary system that has been developed to assist in safe and efficient mill installation and maintenance. The drive, capable of rotating a mill in either direction, consists of a planetary gearbox powered by a hydraulic drive motor. Its portability, said Outotec, allows it to be used with more than one mill, therefore requiring fewer inching drives in a multi-line plant. A joystick control allows for variable speed mill rotation, enabling precise mill positioning during installation and maintenance. A captive key interlock prevents operator bypass and ensures safety of personnel and equipment.
The drive unit is equipped with a pressure release brake that will automatically hold the mill’s position in the event of hydraulic pressure loss. The gearbox drive shaft is fitted with a moveable coupling to engage the pinion shaft. Proximity sensors located on the coupling guard indicate coupling position. A Kirk key interlock is also provided to ensure the main drive and inching drive cannot operate simultaneously. The interlock system is a genuine captive key arrangement in which the key may not be removed unless the coupling is fully disengaged.
According to the company, the hydraulic power unit, or HPU, is supplied with all instrumentation, hydraulic hoses and controls necessary for operation. It is equipped with a remote pendant control that allows control of HPU operation from a distance of up to 3 m, with additional cable available upon request. A linear joystick is utilized to control forward and reverse rotation of the mill. The joystick allows for continuously variable mill rotation speeds (up to the designed inching speed) for precise mill alignment.
The HPU is supplied with an onboard conditioning circuit to cool and filter the hydraulic oil.
Outotec said its new Barricade seal arrangement solves many issues involving the effective sealing of grinding mill main bearings, offering a design that incorporates protective properties claimed to be superior to any arrangement yet brought to market. The unique design—based on years of experience with V-ring seals, according to the company—replaces and improves older seal arrangements by incorporating uniform lip tension, enhanced seal stability and superior sealing performance.
The Barricade arrangement is now standard for all new Outotec mill installations and also can be retrofitted to many existing mills.