Your question has a problem attached to it,

you have not told us what you are conveying as far as bulk product etc.

An apron feeder is ment to be horizontal in discharge. I have never seen an apron feeder discharging at an incline in 28 years.

The conveyor belt which takes away the material is either horizontal or at an incline to take away product from the apron feeder for the simple reason that it runs at a higher RPM than the apron feeder- the apron feeders are set through a reduction gear for a reason- very low rpm/high torque to move material en mass across the feeder width and length and out of the hopper. Also the feeder may or may not have a restrictor plate across the width of the feeder to slow material feed rates to the take away conveyor-due to the high volume potential.

Do not forget that the apron feeder is using huge amounts of torque to the final drive and sprokets to drive the feeder.

You should look at what is already available in

apron feeders as the manufacturers have done all the design work and testing etc.

lzaharis ■

Dear rachna

even if you provide inclined apron feeder 20 degree inclination will be too steep for 600 mm lumps and same will slide back

A R SINGH ■

DEAR RACHNA

YOU CAN FIND MAXIMUM INCLINATION IN CEMA FOR DIFFERENT MATERIALS

A R SINGH ■

Dear Sirs:

Modern apron feeders are used to feed primary gyratory crushers from a truck dump pocket such as used in copper mining. The material is transported up an incline of 20-22 degrees and discharged into the crusher bowl. The angle may vary slightly. There are many such installations in North and South America.

There are many aspect to a proper design learned over many years. I would not advise to make a design from scratch. Especially since the physics is not known to you based on your question. There is much to know of such a design beyond some simple geometry.

Seek a reputable manufacturer of such equipment including Krupp, FFE Minerals, ManTakraf, Metso and others. ■

You can likely find apron feeder literature references in the Australian iron ore industry as well. These feeders usually feed a jaw crusher.

THese sites have a very simple open loop circuit from: truck dump pocket, apron feeder, primary crusher, to belt conveyor.

THe Apron feeder flight pitch permit small granular material to pass between flights and directly bed the short intermediate inspection and weightometer collecting belt conveyor. THe over and undersized product is then discharged onto an overland.

Use your BSH search engine to become more informed. ■

Hello Rachana,

The apron feeder design exact procedure cannot be explained in this forum. Various resistances are to be calculated to decide the chain pull, power, etc. The chain pitch will be the consequence of apron feeder size and chain pull. If you are a buyer you can make some design as a check / feel, however, if your design requirement is for manufacturing, it is a specialised subject.

Referring to the installation list of a premier German company also known for manufacturing heavy duty crushers and apron feeders, they have often given apron feeders for handling limestone, for inclination up to 25 degree. The limestone being handled is often large in excess of 1m size. The apron feeder has uneven conveying surface and hence its capability to support the material on inclined zone is different then smooth surface conveyors.

Regards,

Ishwar G Mulani.

Author of Book : Engineering Science and Application Design for Belt Conveyors.

Author of Book : Belt Feeder Design and Hopper Bin Silo

Advisor / Consultant for Bulk Material Handling System & Issues.

Email : parimul@pn2.vsnl.net.in

Tel.: 0091 (0)20 25882916 ■

OK

Adding to Larry's post - also try RCR ENgineering in Bunbury - WA. They make rock solid apron feeders and cheaper than some of those mentioned by Larry....one even had a powder monkey set off a charge in one due to oversize rock and still came out OK.

Sizing

Width - suit max. lump size and capacity

Speed - less than 300mm/sec - typ.

Consider apparent bulk density and slippage up slope. May need to run feeder faster than first thought due to rock size.

Feeder will slip less with smaller lumps.

Larger lumps interact with other large lumps and this can slow down rate.

Feed hopper design at tail end is important - assuming U have a dump hopper.

After calc. power have chain tension.

Select CAT chain - small pitch and less chordal action at pulleys/sprockets

Use CAT type rollers - earth moving machinery - for feeder support.

Also, use railway iron steel for impact skid bars/support in the middle - esp. with wide feeders...pans will flex/bow.

Can use hyd. or elec./mech drives.

Use scraper chain conveyor underneathe for spoillage control.

Do not much around trying to design it yourself, go to the experts and get peace of mind.

Cheers

James ■

Rachana

Honestly I do not believe that design a chain for your apron feeder is a good idea. Most of the guys use caterpillar chains or equivalent. You can also get good chains from Italy and Germany. I have recently selected an apron feeder for a mine (Tom Price) and the customer specifically requested caterpillar chain. Apron feeder was going under stockpile so if the chain breaks you have a big problem.

RCR is a good manufacturer and Krupp are also good guys if you wanted an apron feeder.

regards

Ziggy Gregory ■

Marty

Why do you recommend installing the apron feeder on an incline?You increase power requirement(possible bigger chain and drives) and can have material slippage. As far as I am concerned incline on apron feeders is to be avoided if possible.

Ziggy ■

Marty

Do you think about decline? Apron feeder is actually going down not up?

Ziggy ■

Marty

I have not seen an installation when the apron feeder is going down - under the stockpile or primary crusher so horizontal or incline position are the only options .

Ziggy ■

There is a previous reference to flight pitch. Are you all talking about apron feeders, with flat topped pans, or variants of a moving bed bunker?

Whatever.

Some respondents refer to increased hopper capacity which suggests bunkering is the direction of the thread. A hopper is defined as the tapering bit underneath a bin by the way, not any old box that holds lumps!

Large stones will not roll back if there are similar large stones above, which themselves will not roll back if there are large stones above them etc etc. That is regardless of what is slipping and sliding along underneath the lot of them.

I have never encountered an inclined apron feeder and partly assume this is because of the traction limits. Bunkering out up a slope was always thought possible but highly uneconomic.

To bunker out up a slope the sidewall friction force will deteriorate along the directionof travel. So; you are installing equipment with the structural & mechanical capacity to move the tail depth burden while at the discharge end you only need a few kW. It would take a more than a few good lunches to sell me one!

However, the easy answer to the query is ...how long is the 20 degree gadget. If the total lift is 600mm then the rock cannot geometrically roll back. If its that short then it really isn't worth the paper.

Since when has a rock and earth ramp for dump trucks been more expensive for a quarry owner than some nanowatt gadget?

The stores building for the spares costs more than the ramp! ■

Dear Sirs

our company is experienced in this type of apron feeders

and we have many plants of this kind working satisfactory .

Please send us an inquiry in case of interest .

Our website : www.gambarotta.it

Best regards

F.Gambarotta ■

Inclined apron feeders are common.

Guess is to save height in dump stations.

Be warned....rock behaviour has amind of its own.

We had to speed up our apron feeder over 2 x to get the capcity due to rocks rolling back - large ones are the issue and faster also means that the problem gets worse.

Smaller rocks are OK

Even with nibs on the pans - rocks will roll back.

Another design moot point is the bed depth - with no shear gate > what is the rock bed depth when pulling out a hopper for an inclined feeder - no one knows....so it is best guess.

Take care with capacity margins when doing inclined feeders.

RCR Bunbury WA make good feeders - because they have not sold us many spares over the last 10 years and are almost trouble free - very solid indeed.

Cheers

James ■

I assume PHD stands for Piled Higher & Deeper. Ho Ho Ho. Several replies started off with an inclination & ran down to a flat feeder in the end. Izaharis said so at the start. ■