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Screen selection??

Discussion in 'Screen/Wash Plants' started by squidrig, Nov 1, 2011.

  1. squidrig

    squidrig Well-Known Member

    Joined:
    Dec 4, 2009
    Messages:
    78
    Occupation:
    cranberry grower
    Location:
    southeastern mass
    Hey all, recently purchased a used small shaker box screener , Thomas 400. It came with a 1.5" square top deck and a 3/4" slotted deck on the bottom. The top deck is in fair condition but is bellied out pretty bad impeding the flow of rock off the top section but more importantly the material (sand and gravel) has a lot of 1.5" stone which is plugging the top deck even where the screen is in good condition (not bent down or bellied out). My question is can i put a 3" square top deck on and not destroy the bottom deck which i have changed to a 3/8" slotted. Any input greatly appreciated..
     
  2. grandpa

    grandpa Senior Member

    Joined:
    Oct 16, 2009
    Messages:
    1,789
    Location:
    northern minnesota
    I don't think
    putting a three inch screen on top is gonna work for you... three inch rock will really pound on that 3/8's screen.

    If your doing it to stop the 11/2" from plugging (called pegging) your not going to help your problem. The reason the 11/2" rock is sticking in your screen is because you don't have enough throw in your screen. What I mean by throw is your screen does not come up high enought to throw the rocks out of the holes.... I don't know if your screen has any adjustment to the rate of throw or not.... good luck Gramps.
     
  3. squidrig

    squidrig Well-Known Member

    Joined:
    Dec 4, 2009
    Messages:
    78
    Occupation:
    cranberry grower
    Location:
    southeastern mass
    Thanks for the info Gramps. No adjustment on throw..deck is torsion mounted..cant change position of shaker shaft..I'm afraid to add more weight to the shaker shaft (might put it out of balance, or overlload the bearings.) I straightened out the bellies in the screen by removing the screen and carefully running the track from my excavator on it and used a couple of blocks and the bucket on it. I am going to reinstall tomorrow after I pick up new screen tensioning bolts that my HOT wrench made quick work out of. I'll probably try increasing the rpm's on the engine slightly to see if that helps.
     
  4. grandpa

    grandpa Senior Member

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    Before you do any adjustments to your screen deck, tape a piece of paper to the side of the screen box, then with the screen running, rest a pencil,pen, or blackmarker, on something stationary and then push it up to the paper. This will then mark the paper to the pattern of throw and lift on your screen box. Remove the paper and keep it as a record. Then any changes you make as far as speed or weights you can record on a fresh piece of paper and then compare the new results to the first paper. That way you really know whats going on..... hope this helps...... Grandpa.
     
  5. squidrig

    squidrig Well-Known Member

    Joined:
    Dec 4, 2009
    Messages:
    78
    Occupation:
    cranberry grower
    Location:
    southeastern mass
    More useful info Grandpa Thank you I'll try that tomorrow. Today I got new bolts and reinstalled the straightened screen and moved the screener to a slightly sloped area to increase the screen angle. I ran some more sand and gravel and watched what was going on more closely. As Grandpa said, the deck is moving aggressively even when overloaded but the motion appears to be much more horizontal rather than vertical. The rock is just hanging around on the top deck especially at the top of the deck. It appears that the lower portion of the deck is moving more than the upper portion as far as the throw goes. It took longer to get the deck pegged out than before because of the improved condition and slope of the screen. Hhhmmm.
     
  6. grandpa

    grandpa Senior Member

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    I am not familiar with your type of screen.... could it possibly be running backwards? The way you describe the rocks hanging around the feed end makes me wonder if this might not be the case, but at anyrate your paper pencil record should give you an ider.
     
  7. squidrig

    squidrig Well-Known Member

    Joined:
    Dec 4, 2009
    Messages:
    78
    Occupation:
    cranberry grower
    Location:
    southeastern mass
    factory welded a stop block to prevent reverse rotation of shaker head unlike some of the other similar manufacturers of comparable sized screens such as the vibroscreen/vibrotech unless someone switched the two lines at the valve or on the shaker motor
     
  8. grandpa

    grandpa Senior Member

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    Location:
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    Lol.... you really can't take nothing for granted on a used machine,,,, or even a new machine for that matter....i bought a new primary jaw once and the flywheels came out of time from the factory... so you can't assume anything.... you know the two words from assume.... lol
     
  9. FNick

    FNick Member

    Joined:
    Nov 14, 2011
    Messages:
    16
    Location:
    Wyoming
    I bought my bobcat off of ebay. NEVER AGAIN!!! You can never know what to expect from used machines. :beatsme
     
  10. ctkiteboarding

    ctkiteboarding Senior Member

    Joined:
    Feb 12, 2007
    Messages:
    386
    Location:
    sw ct.
    old thread but.............i just bought a pro 300 and have been lucky enough to get a wealth of knowledge from this gentleman 800-567-3168 he has all the parts you might need as well,,, good guy ,, good company.... fyi ck the hoses as some run these reversed to have the material sit on the screen longer
     
    Last edited: Jul 28, 2013
  11. Tags

    Tags Senior Member

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    Feb 19, 2012
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    Location:
    Connecticut
    Do you happen to have the name of the company, I have a pro tough 400 and am always earmarking places to get parts.