Grinder for BFR or wood chips

[chatelot16]

with the trima has a single toothed wheel, the wood is cut between the wheel and the plate: it must be cut because there are no games ... it is also deformed , so each piece cut clean by the tooth is also fragmented into smaller piece by the squawking

with 2 wheel is even better because the wood finds more room in the teeth of the 2 wheel so less crush, and it remains above all the clean cut by the tooth that meet

less crushing means especially less energy loss

this kind of gear already exists for something else, a vintage crusher, with the same principle of 2 toothed roller has 2 different speed, but alas not strong enough to cut wood: we get an idea in the absence of apples: she do not crash as if the rollers were spinning at the same speed: they are cut in small pieces!

Another thing to see: trima or bosch, it's universsel engine type drill, so poor performance, like 60%, we can do much better

[Ahmed]

There is a type of device that I already told you about, Chatelot, and which can be seen on Youtube with the keyword "rebak"; it is about two wheels provided with blades which turn in the same direction, in a synchronous way, so that the blades are always in opposition.
The advantages are an excellent drive and low energy consumption, the disadvantage being that on these models intended to manufacture kindling for gasifier, the pieces are too long: a design inspired by them and allowing closer cuts does not seem to me. not impossible.

Regarding the grinders of branching, I think to have a pretty big experience, that's why I do not follow you in all your remarks.
Thus, the disc crushers, as you say, have the disadvantage of badly managing the advance and especially everything that is very flexible: ivy, very leafy branches (even in the case of crushers equipped with drive rollers) , on the other hand, the drum systems have a good traction capacity, as well as ejection; they also have interesting self-regulating characteristics: the small branches which arrive below the diameter (due to the rotation of the rotor which tends to press them down, on the counter blade) are swallowed quickly, since the tool traction is maximum at this location; a larger wood is in the middle position, at a neutral point; a wood with the maximum diameter will meet the upper part of the rotor which tends to push it back (working in opposition).

It is difficult to define le ideal shredder (for the BRF enthusiast), I would be tempted to say that it would be a drum driven by a belt and a 13 HP heat engine and an ejection chute high enough to be able to fill a wheelbarrow, but, of on the other hand, the weight (not to mention the price ...) is a preponderant factor in this non-professional use: a light device, allowing to meet instantaneous needs without heavy logistics (planning of use, transport ... .) pleads for mechanical concessions towards a disc fixed at the end of the crankshaft (which is less satisfactory from a purely mechanical point of view).

[Did67]

Goods.

I understood everything.

And indeed, it would be "better", with this "opposition" of teeth.

It is we "turn at different speeds", chatelot, which had troubled me.

We are there with two "toothed" rollers whose knives are always in opposition.


There, yes, it will be improved "Bosch", less friction against the hoof. And possibly the engine for better - indeed.

Now, I repeat myself, the energy balance of my annual grinding is negligible in the consumption of my home! So do not get excited on the straws, when there are beams ... [I speak for myself]. And I'm not talking about my gains in "gray energy" by going without fertilizers, pesticides, tillage ...

Overall, I had to significantly improve my "energy balance"!

[Ahmed]

Yes, I'm waiting for more explanations for this strange configuration of toothed rollers with different speeds ...

It would already be possible to significantly reduce friction against the fixed shoe by replacing it with a simple rotary roller ...
This would be interesting because if the consumption of the machine is actually marginal, its limitations due to its low power deserve some improvement ...

[chatelot16]

in the case of the trima, which passes the wood between a toothed wheel and a plate: if I replace the plate by a smooth wheel, it swallows too quickly and it gets stuck

with the opposing tooth wheel that rotates more slowly than the first wheel it limits the advance at a reasonable speed

this is exactly the principle of the cylinder machine in the flour mill, except that the ribs are very fine suited to wheat, and not toddler

on the cylinder machine we see the same principle of the slowest cylinder with teeth in opposition with the fast cylinder

the last stages of the flour making are done with smooth cylinder, but always with a difference of speed, not to simply crush

I can not find a clear website on the internet ... I know to have seen live in an association of amateur old mill

I also need to pulverize plastic to make rotomolding ... so this toothed cylinder crusher can also be used for a much finer job, simply by changing the cylinders

[Ahmed]

I understand that you wish to use this configuration to add a shredding effect to that of cutting.
But the case of the grain does not seem to me to be usefully transferable to that of the branch since energy will be wasted unnecessarily in this extra effort, while the quantity available is potentially quite small.
If you only want to reduce the speed, it would be more logical to reduce the number of revolutions / Mn of the gear wheel, which would increase the torque by the same amount ...
In the case of the "rebak" videos, the wheels go at the same speed and act as a continuous pruner.

[Did67]

But why don't you spin your wheels, perfectly in opposition, perfectly synchronous, at a very slow rotating speed, like that of my turbine? Suddenly they "swallow" the branches at a reasonable speed ...

Of course, in an option where you would like well "cut" and not "torn" pads ...

I should measure its speed, but as an indication, you see the knives very well. So there is a big reduction after the engine ...

Ah well, we find everything on the internet: 40 revolutions / mn

http://www.rotopino.fr/broyeur-bosch-axt-25tc,7969

Here, by clicking on the image, you will have a reconstitution in computer-generated image: http://www.bosch-garden.com/fr/fr/outil ... 199967.jsp

[edit: Ahmed took me speed, while I was looking for these videos!]

[chatelot16]

2 wheel with big tooth at equal speed it works if the teeth are big enough: bigger than the diameter of the branch

but I want it to pass also bigger wood: therefore it is necessary that the wood advances a little less quickly than the gear, so that the teeth cut big chips

this is what happens with the current trima, when the branch is bigger than the teeth, the teeth are fully filled and it moves less quickly and it works not too bad ... except some wood too dry it must push ... or with some woods that are swallowed too quickly and block all

with the 2eme slow wheel, it will allow a more stable operation

the trima rotates slowly too: less than 1t / s or 60t / mn

[Ahmed]

OKAY! A toothed wheel to cut and a wheel that regulates the progress ...
I can not see the interaction of the two ... Is the regulating wheel synchronized with the other?

Which motor powers and which diameters of branches do you envisage?

[Did67]

the trima rotates slowly too: less than 1t / s or 60t / mn

I finally found a bad video of the trimma (there are two "m" a priori).

I think it's a neighboring technology.

There is in fact a whole series of comparable slow-rotor shredders. The ones I had found were more or less sub-brands, cheaper Chinese copies of brands (such as "Garden", "Einhell", etc ...). As I am considering a fairly intensive use, I typed in the mark.

Trimma, I did not find any offer / price.

Let there be no misunderstanding: I testify of what I have. I don't mean at all that it's the top or the only one. I was positively surprised by comparison to a Viking with a friend's fast-rotating blade-holder disc system (which I had found quite "crappy" despite the famous brand and very loud, indeed).