Mechanical Technology March 2015

Mechanical Technology — March 2015

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On the cover

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Above:

Assembly of a 750 rubber-lined mill circuit pump

at the Weir heavy bay foundry.

Left:

Weir Minerals offers a range of equipment solutions

including hydrocylones, rubber lining, hoses and slurry

valves.

mining efficiencies

hydrocyclones and Isogate

valves.

“The market has definitely changed.

What is vital is the duration of any shut-

downs and improving intervals between

these shutdowns. Equally critical are the

health and safety considerations around

handling and repairing equipment.”

Weir Minerals Africa has ISO 9001,

ISO 14001 and OHSAS 18001 ac-

creditation, and considers these factors

in product development decisions and

holistically in terms of repeatability and

reliability.

“Another major consideration is the

environmental impact of the products we

produce. A good example is being able to

reclaim scrap metal from our customers

and to reprocess that at our Heavy Bay

Foundry (HBF) in Port Elizabeth and

at our Isando foundry facility to limit

the impact on raw materials usage and

improve costs. The quality of our raw ma-

terial stock is a major factor in ensuring

our products meet stringent quality and

performance standards,” Fawcett says.

“We have sophisticated design pack-

ages that allow us to optimise both

performance and materials of construc-

tion, which means employing the right

material where it is required. In addi-

tion, we investigate the root causes of

wear occurring in specific areas and use

this data for product and future product

enhancements,” Fawcett says.

Such enhancements flow through

to the existing Warman AH

range in

order to increase efficiency and wear

performance. “The new Warman WRT

impeller and throatbush upgrade kit has

been used to make significant improve-

ment to the design of the component

combination,” Fawcett explains. These

are integral components of the pump

that impact on its hydraulic and wear

performance.

The Warman WBH

slurry pump of-

fers more than a dozen enhancements

to the already state-of-the-art Warman

slurry pump range. Here the main fo-

cus is on meeting the productivity and

cost demands of Weir Minerals Africa’s

customers in different operating environ-

ments. “This pump is destined to set a

new benchmark in slurry pumping stan-

dards, as the Warman AH range is widely

accepted as the benchmark for many

applications over the last few decades,”

Fawcett says.

The Warman SLR

pump is designed

specifically for medium-duty slurry han-

dling where conditions are not arduous

enough to justify a heavy-duty slurry

pump. “We revisited the way our pumps

are put together from a maintenance

perspective. Traditionally, components

were split radially, which was the easi-

est way to strip a pump down and then

reassemble it. Our particular innova-

tion in this regard is to split the pump

axially and fit it with a one-piece volute

that reduces the assembly and risk of

any potential component mismatch.

The overall outcome is a pump unit

with a significantly smaller footprint

to what is currently in the market.”

Looking at general sump applications,

Fawcett says the Warman WBV

ultra

heavy-duty range of vertical cantilevered

slurry pumps has been launched and he

believes that this too will be set to rede-

fine these applications. The new design

features internal agitation as opposed to

a mechanical agitator attached to the

impeller. The impeller has specialised

vanes that take up a certain amount of

the flow and divert it back into the sump

to produce the agitation required. This

feature is proving far more successful

than the traditional mechanical or water

assisted agitation mechanisms.

Several of these next generation

sump pumps are being trialed. “We have

completed the test periods and have

removed the pump units to evaluate

the wear performance. The result has

exceeded our expectations and it will

be a game changer for our customers,”

Fawcett says.

“This development is emblematic of

our approach to develop products for

specific applications, rolling them out

across our entire product offering and

then standardising at a higher level. This

means that all design changes are incor-

porated into subsequent improvements

and then finally in the standard product

offerings. This, in turn, means that these

improvements are passed on to all of our

customers. Thus, as replacement compo-

nents are purchased, the full benefits are

realised,” Fawcett concludes.