Do you have stroke cards to check the elliptical orbit of the screener under both load and no load conditions?

If not several stroke cards have been discussed and down loaded here on the forum which you can down load at no charge.

my other question is whether the sand is an asphault make up sand from stone or sand from a gravel pit?

We have large amount of information with regard to screening here on the forum for you to investigate.

You should down load the stroke card examples and use heavy card stock for the cards to determine your elliptical orbit

following the instructions provided to mount the sgtroke cards on the screener and then proceed from there.

A lot of it will depend on the sand itself and whether it is washed while it is being screened as gravel sands are screend

and then washed down the floor of the screeener to the sand auger for discharge

which is the normal way of dealing with sand coming from a gravel pit. ■

The stroke cards are where you want to start first.

Tylers method of detemining what the best screenng angle is done this way-

fill a 12 quart pail full of the material you need to screen and then lift it chest high and dump it in one quick motion. this gives you the angle you need to screen your material at and it always works in proofing what angle is required for an inclined screen

Your 18 degree slope may be part of the problem and the tyler test will tell you quickly

lzaharis ■

Please download the stroke card files and print them on heavy paper or cardstock then tape them to the screen and run it empty and loaded to determine how well or poor it is operating.

george baker has a detailed explanation on the screening an feeding detailing how to examine a screen that is not working or behaving properly.

lzaharis ■

THANKYOU for your post.....lots of issues i can see here:

1.Sand not moving at all, accumulating on deck

RESPONSE: angle of 18 degrees is too shallow by the rules of VSMA & generally

hence, sand builds up on deck. FTPM.....is too low. Foot travel per minute, timed as the material moves down the deck from feed end to discharge end. IF too slow, material builds up and accumulates vs travelling down the deck.

2. VSMA standard angle is miniumum 20 degree angle for inclined screen. BUT, for this very fine screening....VSMA will call up more like 25-35 degrees depending on moisture content as a very very important consideration....more moist equals more angle to move.......MORE DRY...EQUALS less angle to move material...or more free flowing ...as we say.

3. RPM of this screener??? you DID NOT STATE. wild important. When we screen at such a small opening of 1-2 mm.....we must do a few things....run faster...to increase the frequency of introductions to the hole opening many times more on a smaller opening than a larger opening.....TO INCREASE the probability to have the unders or minus 1 or 2 mm to PASS thru that opening. IF too slow....fines pass over the top of the screencloth because BED DEPTH increases....if too slow.

4. WIRECLOTH wire diameter: could be too thick...CAUSING open area to be too small, making it difficult to pass the opening.

5. Is wirecloth STAINLESS Steel or just carbon steel??? IMPORTANT stuff here.

6. IS WIRECLOTH BLINDING???? or PLUGGING? it sounds to me like it should be.

7. STROKE Amplitude: you state 2-3mm equals 3mm equals .12 inches or 1/8" +-

must cross relate to SPEED AND SLOPE or it won't do a proper job.

8. RPM: pls tach the actual body speed and advise please.

9. HOW MANY TONS PER HOUR are you wanting to process please?

10. YOUR BED DEPTH is too DEEP for sure, which equals or means .... your width is too narrow to handle the TONNAGE you and putting to it.....MORE TPH = wider screen box.........and you are carrying over material....which means you probably should be LONGER to be more efficient....and remove more fines.

11. BUT, lets try to make what you got work if we can.......but, seems box is too small for the job

12. a last point to check: because you are GANGING UP on the screen deck.....NOT MOVING.....that tells me OVERLOADED..... when this occurs....the screen box HUMPS...kinda goes up and down statically BUT, MATERIAL does not move. You should check...2nd deck position...if you are PLUGGED THERE...make sure the cross supports (pipes or HSS OR angles....are not Obstructing the material flow...and stalling the material from moving down the deck and causing the OVERLOAD. the more weight that builds up....the deader the screen becomes and the more fines that should pass go over the deck openings vs pass thru.

13. REMEMBER all 3 things must be correct: SPEED STROKE SLOPE or it does not work right.

come back with some more info please. GOOD LUCK for now...

GOOD WORK Izaharis..... ■

You still need the stroke cards to start the trouble shooting process as you

still have problems. The stroke cards are your first investigative tool.

your weights are to heavy with your inclne screen now.

Can you lower the screener to zero degrees being the XY intersection this will

create a linear screening effect which would allow you to experiment with your

weights and have no issues with feeding as the results will be immediate and

not problematic as the feed will be even providing you do not flood the screener.

lzaharis ■

If travel rate is too fast, equals FINES CARRYOVER when they should pass

If slow down travel rate, proper separation takes place.

KEY POINT is usually to make proper separation.

RULE OF THUMB: WIDER WIDTH = MORE TPH

LONGER LENGTH = MORE EFFICIENT SEPARATION

Originally Posted by emretorun

thanks fpr your advices.

-there is no plugging and blinding at all.

-ı have increased the total eccentric mass from 18 kg to app. 40 kg. and now it vibrates quite good. but ı wonder whether it is too much or not.

-actually if we pour sand quickly it overloads and not screen very well. The sand poured comes to the end of the screen so quickly and not screen well. but if we pour sand slower, it becomes ok. that causes the capacity to decrease. ı want to increase the speed and decrease the eccentric masses to increase the capacity and ı think this will solve the problem of not being well screened.

-neverthless, the capacity is ok for us.

■

Emretorun

You do not give enough data to answer the question - no rpm and excentric on 60mm radius - a bit vague.

The screen is small and it is relatively easy to overload it and it is very detrimental to the fatigue life of your screen.

Regards

Ziggy Gregory ■

If you put too much exciter FORCE into the stroke...you can actually put your FACE close to the end of the deck at wirecloth level and YOU will actually see that the MATERIAL is too STRATIFIED...or it spends MORE time up in the air....and before it can have a chance to pass...it gets thrown back up into the air and HIGH...with an aggressive STROKE...and it never SCREENS the thrus OUT.

JUST another thought.

G BAKER - Moderator ■

another item to check.......is this: SIZE OF STROKE...

if YOU watch the material go down the screen deck length....put your eyes close to wirecloth surface........and look up.......(i wear glasses) so i am protected....BUT, you can easily see....if

the material is in fact STRATIFIED TOO HIGH IN THE AIR...COMING DOWN......soooooo...a couple of things to consider then:

1) reduce stroke size ...so when the screen strokes.....we DO NOT keep the material UP IN THE AIR too long.......vs allowing it to come down with a smaller stroke and attempt to pass thru the wirecloth OPENING.....

2) RPM: if too fast.....material is thrown back up in the air.....before it gets an opportunity to attempt to pass thru the holes in the wirecloth....

3) so the VSMA rules still apply as always: you need 3 things to screen properly and efficiently...SPEED/STROKE/SLOPE....if one of these factors is out of order.....equals a PROBLEM.

Happy Screening.........George. ■