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Getting the rotor out

  1. Nov 30, 2005 #1

    wolram

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    The picture is the rotor that runs in a stator with similar teeth, the stator is
    aprox 18 inches long and has 21 rows of teeth, if a forign object gets into this
    mixing head the teeth can bend makeing it imposible to disasemble, anyone
    have an idea how to straighten bent rotor teeth ?

    http://www.tanisfoodtec.com/
     
  2. jcsd
  3. Nov 30, 2005 #2

    brewnog

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    Pick a thread, any thread....


    Tricky one. What are they made of? What speed does the rotor run at in service? Look a bit cast aluminiumy to me, would they just shear and snap off if you tried to forcibly pull the rotor out? Can you see if any/which/how many teeth are damaged? Any more pics?
     
  4. Nov 30, 2005 #3

    wolram

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    Hi, Brewy, they are made of stainless steel and about 1mm thick, the stator is made by spark errosion, i am told a 48 hr job so you can imagine the cost, yes
    the bent teeth can be seen.
     
  5. Nov 30, 2005 #4

    wolram

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    I don't know how this was post so many times, i only sent it the once :confused:
     
  6. Nov 30, 2005 #5

    FredGarvin

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    That sounds like a design flaw to me. The stator should be separateable into two pices. That way if this does happen you can still get the rotor out.

    Let me make sure that I am understanding you correctly that the only way to disassemble it is to pull the rotor out?

    If it's stainless, I'd consider cutting off the effected teeth and welding on replacements if loading permits.

    Give us some more details about the usage of this beast.
     
  7. Nov 30, 2005 #6

    wolram

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    The rotor is the fixed part, it is secured to a motor driven shaft by one end bolt,
    normal removal is to take the stator off, in this case the end rotor bolt had to
    be undone and the rotor came off still in the stator, this whole thing is a multi
    purpose food mixing devise used in our case for whiping cream, the stator is double skined so it can water cooled.
    as far as i can see there is no way to get at the teeth to cut them off, i agree about the design, this is a very expensive machine and a few bent teeth costs 11 grand .
     
  8. Nov 30, 2005 #7

    Danger

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    If I'm understanding correctly, the teeth of the rotor overlap those of the stator in eggbeater style. Assuming that's correct, there certainly wouldn't seem to be any room to manipulate a tool of any kind in there.
    This might be way off base, but I'd seriously consider trying to get my mitts on a cutting laser to shear off the offending parts (maybe even a water-jet cutter, but I don't know how well it would work on stainless).
    I'd also, while the thing is apart anyhow, modify the stupid case to be separable if it happens again. Maybe you could even slice it open first, and then yard the rotor out. There must be some way that you could weld on assembly flanges and install seals where needed.
    I'd also take whatever steps are necessary to keep out any future foreign objects.

    PS: We should get this new fellow ricardo kuhn looking at it. He certainly has a way with offbeat machinery.
     
    Last edited: Nov 30, 2005
  9. Nov 30, 2005 #8

    wolram

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    It is certainly a crazy piece of kit, i think it has been made this way to force
    people into buying new parts, as for how the foreign object got in is another
    matter, the machine is CIP, clean in place, and only took apart when service
    is needed so the only way some thing can get in is via the product hopper.
     
  10. Nov 30, 2005 #9

    Danger

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    They weren't trying to make 'Crunchy Frog' whipped cream, were they? Everyone knows that only works in chocolates.

    Any chance that you can post some pics of your actual machine as is, rather than that partial from your link? Even some diagrams would help. In particular, I'd like to know more about the housing/stator, and how it's mounted in the machine.
     
  11. Nov 30, 2005 #10

    wolram

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    I don't have a scanner :grumpy: i will try and find a pic from tanis.

    The stator housing has a flange that matches one on the back mounting plate, a hinged circular
    clip contoured with an id to fit over the two flanges is secured by a clamping action with a single
    bolt, so after removing the water cooling hoses and product in/out pipes you only have to release this clamp to remove the stator.
    the actual stator is tubular about 18 inches long by 8 inch dia closed off at one end, this end is slightly domed with a threaded pipe flange in the center for the product out feed, the product is
    fed in through a similar arrangment in the center of the length wise dim, almost un noticeable
    the od is a water jacket, looking down the water feed connection it sits only .5mm from the inner
    stator housing.
     
    Last edited: Nov 30, 2005
  12. Nov 30, 2005 #11

    Danger

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    Considering that I usually need illustrations of some kind, that's a pretty clear description. I can sort of picture it. Slicing the damned thing open still seems like the best approach to me, but that cooling jacket would complicate the matter if it isn't removeable. You'd have to cut it off first, then go at the stator housing. (I'm thinking a cut-off wheel on a grinder.) You could replace the kerf-loss metal with food-safe gaskets to maintain the proper dimensions. That's all pretty speculative, though, without being able to get my hands on it.
    This thing wasn't manufactured by the same folks who made your haunted Gilmer drive, was it?
     
  13. Nov 30, 2005 #12

    wolram

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    You don't know the food industry Danger, some times any old machine will do
    as long as it almost works, other times a nice simple little bit of kit that works
    fine will be chucked out for a super duper all singing and dancing piece of crap,
    we have certain types of machine from a manufacturer that deposits various
    stuff, the principal is the same but every one has different inards why ??
    we have machines that should work at 30 cycles a minute but struggle to do
    25, and dick head managers that insist they must run at 30 :rofl: you should see the result, a mega custard pie fight is the best analogy, add to all this the
    "cleaners", who fill every thing with water and use parts that cost hundreds of pounds as hammers, oh joy, then you get the top brass on your back as soon a
    machine stops working, i bet you can guess how i respond :biggrin:
     
  14. Dec 1, 2005 #13

    FredGarvin

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    Admittedly, I am at a loss for what you can do with the current equipment. Everything that I can think of is along the lines of redesign. The waterjacket makes sense now, but I didn't think of that in the beginning. It sounds like a basic V-band clamp holding the two together at the base.

    I hate to say it, but it sounsd like a machine with a very strict intent in its use. I would think you'd be a bit better off taking the time to come up with process checks that will prevent foreign matter from getting in the thing. Does the product feed have an upstream strainer?

    I would be curious to see how the manufacturer would handle getting a rotor out if there were enough bad blades.
     
  15. Dec 1, 2005 #14

    wolram

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    The manufacturers can only straighten teeth up to six rows in, ours has at least one ten rows in :grumpy: And for some crazy reason they don't design filters into the system, i would have loved to fix this one, maybe i can set the rotor stator on a jig, then shape a length of steel to fit between the stator teeth then turn the rotor with a long bar, if that worked on one then it would be a matter of repeating the process for every bent tooth ?
     
  16. Dec 1, 2005 #15

    Danger

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    That's sort of what I was originally thinking, but threw it out right away because I didn't think that you'd have the clearance to insert a strong enough bar. There's always also the possibility that the bent teeth will just snap off rather than straighten up, or even end up bend at an angle that you can't do anything with (ie: 45* from current).
    Sorry Fred; I wrote down the degree code on the work computer, but I'm on the not-wife's now and can't remember it. :redface:
     
    Last edited: Dec 1, 2005
  17. Dec 1, 2005 #16

    FredGarvin

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    You are forgiven Danger.....this time. PS I can't do it on my laptop either.
     
  18. Dec 3, 2005 #17

    Danger

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    So... it's been a couple of days with no progress report, Woolie. You didn't go and get stuck in the damned thing, did you?
     
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