The throatbush is the part of the slurry pump that often has the shortest wear life, compared to the impeller and liners, when used in different mining applications.
Weir Minerals explained that by adjusting the gap between the throatbush and the impeller front shroud, hydraulic recirculation can be reduced in the pump. This in turn can prevent localised wear on the throatbush, improve hydraulic efficiency and lower the total ownership cost for the operator.
To avoid impacting the plant's production, these adjustments are often performed while the pump is operating. However, this can have safety implications for individuals working at the front of the pump unit.
"Manually adjusting an alloy throatbush on a large pump requires several people and is labour intensive," said Marcus Lane, global product manager for centrifugal pumps for Weir Minerals.
"It requires mechanical tools to adjust the four pusher bolts, one at a time, in order to reduce the gap between the throatbush and impeller."
Accordingly, the company wanted to find a safer and quicker way to extend the wear life of the pump with regular adjustments, which led to the development of this technology.
"Our automated throatbush adjustment solutions are available for pumps fitted with either rubber or alloy throatbushes on Warman slurry pumps used in the most arduous applications," said Ron Bourgeois, director of Slurry Pumping Technology Group for Weir Minerals.
"By mechanising the adjustment procedure, personnel are removed from the line of fire, and the accuracy of axial movement is increased," he added.
When maintaining an alloy throatbush with the automated adjustment system, all four bolts are adjusted at the same time to ensure even adjustment and accurate positioning, thus improving the wear life of the throatbush.
Rubber throatbush adjustment is considerably different because it poses the risk of hysteresis and premature failure of the throatbush. The goal is not to adjust to a minimum clearance but to maintain a standard gap to ensure that there is no contact between the impeller and throatbush, Weir explained, while periodically rotating the throatbush face to avoid acceleration of localised wear.
"We developed an automated rotating solution which maintains an optimum gap between the throatbush and impeller front shroud for the particles to flow through without catching and tearing the rubber," said Claudio Needham, application engineer for Weir Minerals.
"The localised surface wear is usually near the discharge position, but by slowly rotating the throatbush, we even out the material loss over the entire face. Field results have been very positive, showing an average of 40% increase in wear life."
For the smaller Warman slurry pumps used in medium to heavy-duty applications, Weir Minerals offers a single-point adjustment mechanism, providing both axial and rotational repositioning. This allows one individual to safely stand to the side of the pump while making the adjustment.
Weir Minerals said mining operators that have trialled the adjustment technology have reported improved wear life and safer, simpler maintenance through the process of regular adjustment.
The company has also integrated the adjustment technology with its IIoT Synertrex platform to offer predictive maintenance feedback.
