Originally Posted by stud1

Dear All,

How to calculate the rate of travel or velocity of material on feeder if we know the stroke angle, motion type (linear/ circular), speed of feeder in RPM?

As per VSMA for horizontal screen it is 45 fpm and for inclined screen 75 fpm, but what is the formula for exact velocity of material?

Regards,

StuD

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You have overlooked but one issue, being; IS it a screener or a feeder your asking about!!!!!!!!!!!!!!!!!!!!!

They are not the same!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! y7ou can compare the two broadly only!!!!!!!!!!!!

What you have is a problem with 20,000

plus or minus variables for one product or material.

Unless you take the time and do the math to do the following.

for one product ALONE.

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1. compare bulk materials of all types

2. the many sizes of bulk materials being finished product or run of mine product

a. the friability of the product

3. hopper volume-YES IT DOES MATTER

4. the hopper design-YES IT DOES MATTER

5 the friction created by the product at its various sizes agaisnt the hopper walls, the material itself, and the feeder itself

6.the numerous feeder types-YES IT DOES MATTER

7. The drawpoint size in square area

8. The area of the feeder exposed to the drawpoint square area

9. hopper feed opening size or sizes

10. take away speeds of conveying systems

11. finished or run of mine material size

12. whether bagging is done of finished product

13. down stream issues

a. further finishing,polishing, dry grinding or milling, wet grinding or milling,

shear strength of finished material and many, many other issues

b. speed of packaging

c. down time from breakdowns of downstream processes

d. delays in movement of finished material in bulk or bag

e. lack of storage space for excess product in finished form

Since you are student in the engineering sciences you should already know this.

Further, do not expect us to give you an answer unless you provide us with more

information and desire to hire the required engineering professional for your inquiry.

I have given you 13 answers in general that still tell you nothing. As the advice is free,

experience is what costs you. ■

...they were all this simple. Consider the feeder as a screen with openings less then the bottom material size.

Bed depth is lurking somewhere in the screen formulae.

Apply the screen formulae and the discharge velocity is surely the rate of discharge divided by the exigent cross-section.

This should be near enough: or what? Why would you want to know the speed of burden on the vibrating machine anyway? Different layers will move at different speeds. Its a job for DEM. ■

below pages from:

Conveying Machines, by A. O. Spivakovsky

maybe useful in calculating linear velocity of vibrating equipment.

Attachments

pages 161-162 (PDF)

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Originally Posted by mohandes

below pages from:

Conveying Machines, by A. O. Spivakovsky

maybe useful in calculating linear velocity of vibrating equipment.

Hi.

How can I access this handbook? Is there any link to download it? Or Is it possible to send it by email?

Best Regards.

Masoud Borjian

borjian@gmail.com ■

Here's the ISBN to get you started: 9781905862153. ■

Originally Posted by johngateley

Here's the ISBN to get you started: 9781905862153.

I couldn't find the book by this ISBN No.

Is there any link or web site for free download this book?

Best Regards.

Masoud Borjian ■

I believe this one is in English. http://urss.ru/cgi-bin/db.pl?lang=en...=Book&id=10857

You will not find a free download as that would be illegal to post and very poor business. ■

As Gary says it is not likely to be available for free. Publishers of technical books are on a par with diamond dealers. The smaller the market the higher the price. Publishers forget that the books have little resale value. This adversely affects the spread of knowledge but it also perversely stimulates design progress. If you can't find the information you need then either the information is not so important, because it has to be protected, or you can probably design a better alternative without too much trouble. We have to do it all the time in the pursuit of progress!

Why can't the Ruskies put the keys on their typewriters the correct way round?

Several people I know say Russian is just a tedious code to crack.

Thank Ms Mohandes for her link, I do, and get on with it.

One cheap way to calculate this obscure velocity would surely be to introduce a few painted rocks into the feed and measure their progress with a video camera. It would be cheaper than buying a book and far more accurate and reliable. Too easy? Students are taught to compare test results against theoretical predictions. When they start work the practical stuff often goes out of the window because of commercial short-sightedness. ■

Hi Roland,

I have to agree with most of your 2nd paragraph. The academic standards in Russia and Eastern Europe leave the rest of us in the shade with or without computers. I fondly remember that half Irish/Ukrainian, Tim O'Shenko! I was trying to point out that Coptic characters arouse the unlearned Westerner because when we see letters that are familiar but pointed the wrong way round we assume that they were changed from the original and earlier Roman alignment either as code or just simply to be different, dare I say Un-Orthodox?

I still think that measuring the timed progress of coloured lumps with a video camera at x frames per second would give better results quicker than procuring a textbook, digesting it, designing the machine, testing the machine and probably having to repeat the later stages if the book led you up the garden path. Obscure texts are hardly ever proof read and I have often had to check unrealistic results of calculations because the formulae had bracketed terms in the wrong place, exponentials wrongly signed and factors undefined. I haven't bought a textbook since 1995 and I left that one somewhere in between Dubai and Newcastle-upon-Tyne because it wasn't worth paying the excess baggage.

I am, of course, assuming that Mr Borijan has access to a vibrating gadget on which he can observe the speed since, as you point out, he seems to be rather immersed in the subject.

Have a nice weekend. ■

Originally Posted by borjian

Hi.

How can I access this handbook? Is there any link to download it? Or Is it possible to send it by email?

Best Regards.

Masoud Borjian

borjian@gmail.com

If you are living in Iran, you can find it in the library of Sharif University of Technology. ■

The formula for FPM (Foot per minute travel) is in fact inherint in the mathematical forumula for travel rate factors for horizontal screens and feeders.

on a VGF (vibrating grizzly feeder) at o degree incline, at a standard 45 deg straight line stroke angle, the FPM travel rate is about 45 feet per min...780 RPM +-

same for an elliptical stroke or a flywheel with removable plug weights). you of couse, can spray paint some rocks, toss them into the pan and time the rocks to determine how many seconds to travel from the feed end to the discharge end.

inclined screen = plus minus 75 FPM travel rate which assumes 20 deg incline angle, per the standard VSMA calc, plug in factor constant. can paint and time also.

Hoping this shakes up this concept a bit........

George Baker

FORUM MODERATOR

.......

How to calculate the rate of travel or velocity of material on feeder if we know the stroke angle, motion type (linear/ circular), speed of feeder in RPM?

As per VSMA for horizontal screen it is 45 fpm and for inclined screen 75 fpm, but what is the formula for exact velocity of material?

Regards,

StuD[/QUOTE] ■

Hello, can you upload the page with the table 13.1?

Thanks in advance and best regards

Luis Salazar

Originally Posted by mohandes

below pages from:

Conveying Machines, by A. O. Spivakovsky

maybe useful in calculating linear velocity of vibrating equipment.

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Yes please table 13.1 is missing and formula 2.8 also.

Mohandes, please could you check again the book.

Thanks,

Thomas from Slovenia ■

@ George Baker

I see the academics are still hovering overhead...where they belong.

Surley if a textbook, or similar, is going to be taken seriously then the theory is borne out in practice. In most enginerring textbooks there is very little mention of actual test results. The same is also true of much of the software presented to youngsters: although in those cases the crap comes to the surface that much quicker.

The only test technique elaborated in these forums was the method for draught surveying. Draught is being spelled correctly in deference to the Royal Navy and probably Captain James Cook. (Prior to the RN landing troops on the Heights of Abraham, Cook was charged with sounding out the river bed: under sniper fire. NASA found that Cook's work was in error. Some months later NASA had to whisper an apology, and admit that Cook's 200+ year old calculations were actually correct. So it seems that tests have their value after all: even in this precocious age. Especially if they are accurate.) ■

Originally Posted by stud1

Dear All,

How to calculate the rate of travel or velocity of material on feeder if we know the stroke angle, motion type (linear/ circular), speed of feeder in RPM?

As per VSMA for horizontal screen it is 45 fpm and for inclined screen 75 fpm, but what is the formula for exact velocity of material?

Regards,

StuD

There is no real way to actually calculate the material velocity because of the many variables stated but as a guide i use 0,15 m/sec for a 6 mm stroke at 960 RPM on the horizontal with clean dry sand. If you increase the stoke so the velocity will increase. if you decline the feeder or screen and gravity is helping then there is again a increase.

Hennie Nageol ■

Better Late than never on the answer:

Specifically: on Zero degree FLAT horizontal Brute Force Feeders at factory standard 45 deg stroke angle:

plus minus 45 FPM (Foot per minute travel of rock on the machine)

how to check, EASY, take a rock paint it FLORESCENT ORANGE, toss it on the front of the feeder, watch it stroke up into air and move towards the discharge end and time it, in seconds til it drops on the discharge lip = X seconds = percentage of a minute. Should be around 45 FPM.

FORMULA: EQUATES to SPEED (780rmp as an example/ STROKE = nominal 1/2" lift off the deck by offset eccentric in the shaft, SLOPE: 0 degree is typical. but could be 2, 3, 5, 7, 10 degrees max depending on flowability of the material.

George Baker

FORUM Moderator

Consultant

519-242-6664 cell

gggman353@gmail.com

Originally Posted by stud1

Dear All,

How to calculate the rate of travel or velocity of material on feeder if we know the stroke angle, motion type (linear/ circular), speed of feeder in RPM?

As per VSMA for horizontal screen it is 45 fpm and for inclined screen 75 fpm, but what is the formula for exact velocity of material?

Regards,

StuD

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