book material feeders

8/13/2019 Book Material Feeders

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eedingfrenzyExamining solutions from

a variety of differentmanufacturers, IM looks at

the different feeders

available on the market

This crushing plant in Canadaincludes three FAM AF3400x21apron feeders

Feeders must provide reliable and

uninterrupted flow from some upstream

source. It must be a method of controlling

the flow. When a feeder stops, solids flow

should cease1. It must provide the desired

degree of control of discharge rate over the

necessary range.

The feeder must provide an effective interface

with the source of material flowing on to it such

that loads acting on the feeder from upstream

are minimal. This minimises the power required

to operate the feeder, particle attrition and

wear on the feeders component parts.

A vibrating feeder is a steel trough or a

grizzly, or a combination of the two, which is

vibrated by either an electrical or mechanical

unit attached to the frame. They all use the

same principle, which is to feed bulk material

in at the top in an uncontrolled fashion and

take material out at the bottom at a controlled

and steady rate. Such a feeder will comprise a

vibrating frame, spring, vibrator, motor

vibrating device and motor. The rotation of

two eccentric shafts causes the feeder to

vibrate. Vibrating feeders should offer long life,

should be easy to adjust (grizzly opening and

deck slope) and maintain and should give

reliable operation. They should be of rugged

but flexible design.

Metso says its feeder series is designed

particularly for continuous use with any hard

and abrasive materials. They combine a robust

frame design with high feeding capacity and a

limited overall height. These features [make

them] ideal for operation in restricted space,

and in both stationary and mobile plants.

Jeffrey Rader is a typical manufacturer,

offering EF and HP models that are

electromagnetic feeders. The NF models are

electromechanical feeders. Electromagnetic

units operate through a controlled high

frequency vibration. This is accomplished with

electrical pulses and a machine that is tuned to

a natural frequency that is higher than the

electrical frequency of the power supply (sub-

resonant tuning). Electromechanical vibrating

feeders are designed such that burden does

not dampen vibration, but actually boosts

BULK MATERIAL FEEDERS

MAY 2010 International Mining 47


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performance. The feeders are tuned near their

own natural frequencies putting them in tune

with the materials they carry.

The Centroload Feeder is the latest

addition to the Jeffrey Rader line; designed to

evenly distribute material directly to the

crusher or Vertical Shaft Impactor. The

company reports users have experienced at

least a 15-20% higher production rate, better

gradation of materials and at least a 10%

improved liner wear in the crusher.

The vibrating chute is another type, and

here again, Metso provides an interesting

example. Its Nordberg TK-Series feeders areavailable with a solid pan, screen mesh or

grizzly bars. They have been designed to be

compact in size, light in weight, yet well suited

to hard rock applications. These vibrating

feeders use grease lubricated unbalanced

vibratory motors to create a linear motion.

They can be used for feeding, transporting,

scalping and screening of materials. Most of

the TK-Series vibrating feeders are available

with either squirrel cage motors or hydraulic

drives.

A variety of liners can be used on thesefeeders. Ceramic liners deliver longer life and

less wear when handling extremely abrasive

materials. Rubber liners are used for mild

abrasives and for their flip flop type of self-

cleaning effect on hard to move or sticky

materials, such as wet coal.

Haver & Boecker recently developed and

produced a heavy-duty Haver Niagara T-Class

vibrating screen along with a weighty Haver

Niagara vibrating feeder for track-mounted

operation in Arctic conditions. Both were

specially adapted to the requirements of

Haahjem, a manufacturer of mobile plants,

known for its heavy-duty CTC mobile plants

with total weights of over 100 t.

The focus here was on the adaptability of

the units to achieve the desired performance

as well as high flexibility. In addition,

paramount importance was given to the

machines availability and functionality in a

harsh environment with extreme weather

conditions as part of a Haahjem CTC 136 S3M

track-mobile secondary crushing and classifying

plant with a feed rate of up to 500 t//h. The

unbalance parameters can be quickly adjusted

over a broad range.

The Niagara vibrating screen has been

equipped with pre-heatable oil lubrication

circulation, which allows for a safe machine

start and a long bearing service life in these

low ambient temperatures. The drive of theNiagara UF vibrating feeder consists of

robustly built unbalanced motors.

Two of the CTC 136 S3Ms, equipped with a

Niagara UF vibrating feeder 1200 x 4500 and a

Niagara T-Class vibrating screen S150 1800 x

6000 3D, have been sold. One has gone to

Karelia in Russia and the other to Jamal in

Siberia. Haver & Boecker says the Managing

Partner of Haahjem, Kristian Haahjem, is

enormously satisfied with the highly

sophisticated machines made by Haver &

Boecker. This statement is substantiated by trialruns with material on the premises of Haahjem

at Vigra in Norway.

Belt feedersThis is usually a conveyor belt that is supported

by rollers, ideal when there is a need to feed

material from an elongated hopper outlet.

They are well suited to handling cohesive,

friable, coarse and/or sticky bulk solids. Belt

feeders are designed to introduce large

quantities of bulk material evenly and

consistently into crushing, washing or

screening plants.

In the case of the Nordberg belt feeders

from Metso, the length can vary from 1.5 to 3

m and speed from 0.005 to 0.5 m/s. Power

requirements vary from 2 to 22 kW. This

feeder type is ideal for close volume control of

dry and fine materials. It has a simple and

cheap structure, easy to adjust. The power

requirement is low, and the volume can be

controlled within 1% from a remote station

and with over-riding tie-in to any load.

Belt feeders can of course incorporate

weighing systems for throughput

measurement.

Apron feedersAn apron feeder is ideal for controlled

volumetric feeding or blending of bulk

materials. Apron feeders solve flooding

problems by regulating delivery of material,

and they help control surge loads and prevent

chute jamming. They can be operated at fixed

or variable feeding rates, and when installed at

the bottom of a bin or hopper, apron feeders

permit drawing on stored capacity as needed.

They consist of two strands of tractor-type

chain fitted with fabricated or casted pans. The

chain is supported on standard tractor-type

carrying rollers and plain rollers at the feeders

return side. The equipment design is based on

continuous operations, built to withstand high-

impact loads and therefore suitable for coarse

and abrasive materials. ThyssenKrupp hasengineered apron feeders with pan widths

from 800 to 4,000 mm, lengths as great as 30

m, and capacities of up to 14,000 t/h. Special

designs allow inclinations up to 28 from the

horizontal. The drive system features fixed or

variable speeds, with either a low-speed high-

torque or high-speed low-torque hydraulic

motor combined with planetary reducers or

electro-mechanical drive units.

The new near-pit ThyssenKrupp semi-mobile

crushing system for the Asarco Ray mine is

comprised of a dual truck dump and aninclined apron feeder, which feeds the ore

from the hopper into a gyratory crusher. The

width between the skirt boards of the apron

feeder is 2.4 m and the centre distance

(length) is about 23.5 m and a conveying

inclination of some 24. It uses a D 9 H

lifetime lubricated chain and three 224 kW

hydraulic drives.

FLSmidth Minerals offers inclined apron

feeders for extracting from a dump hopper

and feeding to a crusher. This feeder is of

heavy-duty design with two roller chains,

travelling wheels and links, and heavy-duty

apron plates bolted to the chain links and

overlapping each other. The machinery frame

is a sturdy welded and bolted mainframe

construction with flat steel rails for the

48 International Mining MAY 2010

This track-mounted rig for operation in the Arctic has

a weighty Haver Niagara vibrating feeder


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travelling wheels of the roller chains and

carrying the components of the apron feeder.

The feeders are driven by a dual drive

arrangement with a heavy main shaft, directly

coupled to the motors at both sides of the

main shaft. The main shaft is supported in

double row self-aligning roller bearings

mounted in heavy steel housings bolted to the

machinery frame. The chain wheels are parted

in halves and are turnable to reverse direction.Features include a hydraulic take-up station

with two single-acting hydraulic cylinders. The

cylinders are pressure-regulated by an

accumulator and a hand pump. There is a

high-pressure grease supply unit for easy

lubrication of the roller chains and the sleeve

bearings of the roller support, including

connecting pipes, high-pressure hose, ball

valves, and grease gun.

There is a chain scraper for collecting and

conveying the spillage from the apron feeder

to the product conveyor. It is a heavyhorizontal angle-iron scraper mounted on

three heavy duty steel chains, powered by a

shaft mounted single or double gear motor

unit at the scraper front end.

To complement the capacity and strength of

the MMD Twin Shaft Mineral Sizer, its heavy-

duty apron plate feeder is designed to handle

the high impact loads created from large ROM

material directly dumped onto it. MMD plate

feeders are often arranged beneath tipping

points, where their combination of reliability

and robustness have proven to give many years

of trouble free operation, the company says.

Apron plate feeders are not all the same, as

MMD found out when it addressed the

requirement for a suitable feeder to install on

its mobile units. The fact that no manufacturer

was able/prepared to supply a feeder capable

of regularly being fed directly on to the empty

apron plates lead MMD to develop its own

range of apron plate feeders capable of being

fed without a protective layer of material on

the flights; a prerequisite for mobile units.

Although the MMD range of apron plate

feeders does not, at first glance, appear to

differ greatly from others on the market, they

do have a number ofunique features whose

benefits, and the fact

that these feeders are

available as a

standalone

units, rapidly became

apparent to users

worldwide, the

company reports. As a

result, they are used

not only on MMD

installations and/ormobile units, but

also in general

applications which call

for a robust easily

maintained long-life

feeding unit, such

as extracting hard

aggressive materials

from stockpiles. The

single most significant

of said features is the

use of rolled rather

than cast or fabricated

plates, which not only

makes the

flights lighter and

stronger but

significantly diminishes the impact energy of

falling lumps by allowing these to deform

within their elastic limits and then having the

impact rails dissipate those forces into the

mainframe. The closer manufacturing

tolerances were made possible by using rolled

plate and by incorporating an overlapping

tongue assisting to minimise leakages between

the plates. This is a particularly important

attribute when working with aggressive

material where spillage in the sprocket area

can result in high wear.

When designing the plate feeder MMD

placed particular emphasis on reducing

maintenance using only genuine Cat SALT

(sealed and lubricated) rollers and chains,

replaceable wear segments on the sprockets

and automatic lubrication of the shaft

bearings. The range uses the Cat D4, D7, D9

and D11 configurations with units ranging

from 1.5 to 4 m in width. All the

feeders have been designed to be fitted

with variable speed drives, both direct drive

shaft mounted hydraulic motors or

electro mechanical drives with their high

torque and capacity capabilities.

They are constructed from a series of

Metso says the tractor-type apron feeder remains

the preferred design throughout the world


MAY 2010 International Mining 49

Screening & Processing Size Reduction Storage & Reclaim

Pneumatic Conveying Vibratory Feeders Material Handling

USA: CORPORATE HEADQUARTERSJeffrey Rader Corporation398 Willis RoadWoodruff, SC, USA 29388Phone: 864.476.7523Fax: 864.476.7510

learn more at www.jeffreyrader.com/im

Jeffrey Rader is a leading manufacturer of Vibratory Feeders,Conveyors and Crushers for the Mining Industry.Our Electromagnetic, Electromechanical and Brute Force Feedersare unsurpassed in quality and output. With one of the quickestdelivery schedules in the industry, we can build and ship yourequipment when you need it and guarantee it to work.

Our crushers are equipped with our EZ Access technologyallowing quicker and safer access to the crusher for maintaininghammers, Duratip replaceable tips and Slant-Flow grates.When you want your equipment to meet specifications forfeeding and crushing projects, the easy choice is Jeffrey Rader.


4/550 International Mining MAY 2010


specially rolled steel plates bolted to two

strands of heavy duty Caterpillar chain. Both

the plates and chain are supported by

Caterpillar rollers, which are in turn attached

to a fully welded one-piece steel frame. This

design provides maximum strength throughout

the entire feeder and optimal impact

dissipation.

Metsos NICO hydrastroke feeder is a heavy-

duty, high tonnage feeder of rugged steel

construction. It is easily adapted to almost any

application and designed to provide low

installation, operating and maintenance costs.

Such feeders are available as rod-suspended,

rocker-mounted and roller-mounted.

Chain feedersFLSmidth ABON chain feeders are designed to

transfer material from the feed side towards

the discharge head chute side of the feeder

at a constant volumetric rate. The feeder

electric motor drives the feeder head shaft via

a torque limiting coupling and bevel helical

reducer. Sprockets on the head shaft mesh

with two strands of the feeder chain, each

strand is situated on either side of the deck.

Flightbars are attached between the two

feeder chains. These flightbars transfer the

material constant volumetric rate to the

discharge end.

The company says ABON feeders haveseveral unique features. The modular design

of the feeder allows the unit to be easily

broken down into components, no more than

10 t, allowing the unit to be easily barged to

site and easily assembled in-situ. All modules

are keyed and bolted, and when connected will

hold its own load.

Wobbler feedersMetso says the unique action of its wobbler

feeder provides feeding and scalping of

materials in a single

machine. Even wet, sticky

materials can often be

handled due to the

specially designed self-

cleaning, non-clogging

elliptical bars. Our wobbler

feeders operate with low

power and headroom

requirements, and without

vibration, noise or

transmitted stresses,

making them ideal for

both stationary and

portable applications.

Hazemag notes: Most

raw materials that have to

be pre-crushed for

subsequent processing already contain a

considerable percentage of fines which do not

actually require further crushing. These fine

fractions often have a fairly high moisturecontent as well as featuring abrasive inclusions.

It goes without saying, therefore, that it is

expedient to separate such fine fractions from

the feed material flow prior to entry into the

crusher. Hazemag wobbler feeders are

particularly suited to this task.

Wobbler feeders can increase a systems

throughput by scalping out material fines and

letting a crusher handle only the material that

needs to be crushed.

Universal explains that wobbler feeders

provide two functions, feeding oversized

material at a controlled rate and also scalping

out the fines from the fed material. This is

accomplished by football (rugby or American not soccer) shaped elliptical bars that are timed

with a continuous triple strand roller chain

drive and timed bar sprockets. Each elliptical

bar is timed 90 apart, one bar is tipped up

and the next bar rotated with the tip in a

horizontal position. All bars rotate at the same

rate of speed and this motion moves the

loaded material along the bars until it is

discharged off the feeder. Each bar is

maintained with a fixed gap between

themselves which allows the fines to pass

through the bar gaps providing the undersizedscalped material.

Wobblers are self-cleaning, and can handle

wet sticky material and are very good with

clay. Shot material can be dumped directly

onto the wobbler bed of material or fed with

an apron feeder. With higher capacities and

larger material lump sizes Universal

recommends using an apron/wobbler feeder

combination to reduce the impacting and to

increase the scalping area.

The apron feeder for the new

semi-mobile crushing plant at

the Asarco Ray copper mine

in Arizona was supplied by

ThyssenKrupp Robins in co-

operation with ThyssenKrupp

Frdertechnik, BU Mining

ABONs standard chain has a 152-mm pitch. Chain

breakage is practically designed out because chain

pull is 240 t/strand. This chain feeder operates at low

speeds (0.08-0.35 m/s), which promote long wear life

of chain, sprockets and flight bars


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52 International Mining MAY 2010

Universal has four models, each withdifferent standard widths and number of bar

combinations. Each one is custom designed to

meet a wide range of tonnage and application

requirements. They are designed to scalp

material from 13 to 152 mm lump size and

tonnages up to 2,500 t/h.

Hazemag & EPR says its VARIOwobbler

represents a new generation of wobbler

feeders for pre-screening operations in

crushing plants. An outstanding feature of the

wobbler is the facility for infinitely varying the

gap between the individual shafts by

means of an effective hydro-

mechanical control system, in order to

determine the screened product

granulometry at the touch of a button

and without the use of any tools. This

system allows for quick and flexible

reaction to changing requirements and

ensures that the feeder is always

adjusted to the correct setting.

Such a system is of particular benefit

when weather conditions fluctuate,

creating changes in the moisture

content, and consequently in the

screening behaviour of the material to

be processed. The gap setting

adjustment facility provides the

optimum means to compensate for any

such variations during the screening

operation. The characteristics and

properties of the recovered material

for instance, the proportion of actual

suitable material, and thus the

screening behaviour can vary. In such

cases, the optimum setting can be

selected similarly at the touch of a

button. Should a coarser product be

desired, the gap setting is simply

widened, and likewise, if a finer product is

called for, the gap can be reduced

appropriately.In a conventional vibrating screen, to

undertake such changes involves considerable

time and effort in changing the actual screen

grates. The new VARIOwobbler screens can

replace a conventional screen in a crushing

plant without any problem; they can be

designed as single- or multi-stage machines,

according to whether or not existing machine

height differences need to be overcome.

Thanks to the various stages, the material flow

is agitated several times, facilitating the

downward flow of the fine material from the

upper layers of the material bed and

separating these fines from the coarse

material. Additionally, the fines which oftencontain a high percentage of the material's

moisture content are removed prior to

feeding to the crusher, avoiding the potential

danger of clogging and caking in the crusher.

The wobbler itself is not affected by sticky

material. All the shafts of the VARIOwobbler

are individually driven.

The use of these units can lead to increased

operational safety and reduced energy and

operating costs. Thanks to the horizontal

material flow on the roller screen, the

downstream crusher is fed evenly anduniformly in a controlled manner. By separating

the fines, the load on the crusher is reduced,

resulting in less wear and reduced power

requirements, and may even possibly allow the

use of a smaller crusher.

The VARIOwobbler has been designed for

feed sizes up to 1,500 mm, separation:

15-150 mm and capacity up to 2,500 t/h. Its

width is up to about 3.5 m. IM

References1.Carson, John and Petro, Greg, How to design

efficient and reliable feeders for bulk solids, Jenike &

Johanson, www.jenike.com

Action of a Universal Wobbler Feeder

Stockpiling is usually the final stage of dry bulk

material handling. Sandvik's WE8000i

telescopic chute minimises dust emissions in

the working environment and surrounding

area, as well as reducing stockpile segregation.

Key specifications are a belt width of 800-1,200 mm,

material size 0-32 mm and a maximum of 15 cones

in its make up about 16.5 m

A three-stage Hazemag VARIOwobbler feeder, which

is very suited to separating fines

book material feeders

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