Diversified engineering group Metso in April launched a range of MDM and MDR hard metal mill discharge slurry pumps designed specifically for mill circuit applications.

The company states that the pumps, which are locally manufactured, enhance its “world renowned” offering of pumps, many of which, it states, have been on the market for decades.

“The series offers sustained performance with maximum time between mill shutdowns, with each pump being developed with consistent state-of-the-art hydraulics, limiting inlet velocity at design best efficiency point, which ensures impact damage from coarse heavy solids is kept to an absolute minimum,” explains the company.

The pumps’ large-diameter high-aspect ratio impellers further provide for significant hydraulic efficiency with minimum turbulence at minimum rotational speed, which reduces rate of wear.

The MDM range features a conventional single-stage, end-suction overhung centrifugal design, extra-thick casing, a high-efficiency solids handling impeller, an adjustable suction side liner and gland side liner.

The MDR range, in turn, has a double casing with gland side rubber liners housed in stiff cast iron outer casing halves. Both pumps are manufactured from high chrome iron alloy with a guaranteed minimum hardness of 650 BHN.

The pump’s impeller is screwed to an oversized steel pump shaft running in an oil or grease lubricated, axially adjustable taper roller bearing cartridge. It has an impeller release mechanism that ensures safe and simple impeller removal after long periods of operation.

“The pump’s careful design provides reduced impeller overhang, restricting shaft deflection across a wide range of flows, and, in so doing, maximising shaft seal and radial bearing life,” says Metso.

In addition, the range boasts a double adjustment design feature that enables front and back impeller clearances to be reset after components eventually wear. This adjustment is achieved by the adjustable suction sideliner and the axially adjustable cartridge.

The shaft seal is housed in a split stuffing box and gland protected by a suitable gland guard, which is split for ease of maintenance. Standard options include the water flushed and the mechanical models, as well as the unique Metso EnviroSet.