Which crusher to produce BRF (Raméal Fragmented Wood)?

Agriculture and soil. Pollution control, soil remediation, humus and new agricultural techniques.
Ahmed
Econologue expert
Econologue expert
posts: 12298
Registration: 25/02/08, 18:54
Location: Burgundy
x 2963

Which crusher to produce BRF (Raméal Fragmented Wood)?




by Ahmed » 25/06/17, 18:38

Initially published in the thread of the "garden of the lazy", already intrinsically abundant (which I am delighted about!), I bring here this subject whose text here is, so that it does not quickly disappear in the meanders of the forum and that it can thus be visible and therefore useful:
Ahmed »23 / 06 / 17, 15: 26
I have finally the answers concerning this drum-branch crusher which I had already mentioned.
From the point of view of construction, the assembly is well designed, correctly executed for the principal, but requires some retouching on, it is true, modest details.
Side performance, next to my old crusher (equipped with an equivalent engine), it is day and night! What makes the difference is:
1- the entry chute which is wide (which no longer requires pruning each branch protruding from the axis) and does not "saturate".
2- the rotor shape which literally "sucks" the branches.
What limits now, finally it is the capacity of the weak link that is located in front of the machine and that is not able to bake the branches at the speed at which they disappear! : Oops:
By purchasing Chinese (because this is the type of material I was looking for), I am conscious of contributing paradoxically * to their economic decline (which is the other side of their initial success) ... : Wink:

* The paradox is only apparent, of course ...


I assume that the self-production of BRF by gardeners, who are consuming them and at the same time unwanted producers of branches, is highly desirable, but that it comes up against this thorny question (sic!) Of the material.
I will try, in the course of some messages, to undertake an analysis, not of the various materials, which would be tedious, useless and moreover beyond my competence, but different types of machines, with their respective advantages and disadvantages.
0 x
"Please don't believe what I'm telling you."
Ahmed
Econologue expert
Econologue expert
posts: 12298
Registration: 25/02/08, 18:54
Location: Burgundy
x 2963

Re: What mill to produce BRF?




by Ahmed » 25/06/17, 21:55

Pursuing. 8)
As is well known, there is a supplied category of small electric shredders for plants and small branches. Often largely made of plastic, they are fragile materials and with very limited capacities, although some are clearly better than others ... By bias assumed, I would not dwell on these devices which have for them only a low price (although relatively high compared to their possibilities) and a certain ease of use (low weight, limited congestion); Their modest consumption must, however, be related to the volume processed, a comparison which is then much less favorable to them. I see this as troubleshooting solutions and a fairly rapid bulk of waste dumps ...
Yet the success of these small shredders is due to the enormous prices of professional entry-level devices, which are rarely equipped with major improvements: there are 6000 € machines which, despite their high weight, are not driven and must be Displaced with difficulty by hand ...

Let us now examine the various categories of entry-level thermal mills. Of course, we are no longer in the same price as supermarket crushers, but it is always possible to pool their use according to various particular possibilities and thus dispose of a durable, efficient and finally economic equipment.

The category of vegetable crushers, equipped with a large feed hopper, must be distinguished first and foremost, the cutting system is a drum equipped with flails. A priori, this type of grinders is not adapted to BRF and the possibility of chopping tender plants (grasses and leaves, even mixed with soil or gravel) is hardly relevant for the garden of the lazy ...

However, this kind of material allows us to approach a more interesting material, which can be qualified as mixed (and which also exists in reduced versions of the "supermarket" type): it has two feed hoppers, one similar. to the previous one and also intended for plants and everything coming from cleaning a garden and another, smaller and tubular format intended to receive woody and resistant materials; the latter opens onto blades located on the side of the drum and can therefore be likened to an element of a disc crusher. The shavings from the blades are taken up by the central flails to undergo a second fragmentation and be ejected by centrifugation. The disadvantage of this device is that it only allows "broom handles" to be passed, due to the narrowness of the feed tube: it is only a small addition to the main device, allowing a few branches to be treated. too big to be swallowed by plagues.
Another category devoted solely to the crushing of branches is strongly similar to the preceding one, except that it comprises only a medium hopper and that the flails serve only for the refining of the chips of the disk. This category is well represented by the Italian industry, which seems to be able to produce quality equipment at reasonable prices (due to the complexity of the cutting system), but I do not see much interest in our objective, Since the regularity and the fineness of the crushed stone are by no means imperative for us.

To be continued... : Wink:
0 x
"Please don't believe what I'm telling you."
Ahmed
Econologue expert
Econologue expert
posts: 12298
Registration: 25/02/08, 18:54
Location: Burgundy
x 2963

Re: What mill to produce BRF?




by Ahmed » 26/06/17, 00:20

And even...

As far as concerns us, there are two main techniques for chopping our branches: the disk and the rotor.
Until recently (I am still talking about "medium" shredders) there were hardly any disc devices which have the advantage of a low manufacturing cost and of being able to be easily fitted, on the rear face, with paddles. ejection (because the discs do not really evacuate the chips without an additional trick). The ability of the discs (which do not include mechanical drivers in this category) to "suck" branches depends mainly) on 2 factors: the good state of sharpening and the angle of attack, hence the angle formed by the hopper with the body of the appliance. This capacity is variable according to the models and it is a decisive factor of ease and productivity. Technically speaking, it is not really satisfying to have blade parts that work at different linear speeds depending on their distance from the center of the disc (in practice and on average devices, this is less critical than on formats industrial).
Another possibility (which has my preference), the rotor, although it presents, like the disc, advantages and disadvantages. Its advantages lie in an optimum blade arrangement and a good capacity to absorb a large volume, due to a large cutting section (dimensions of the hopper at the level of the blades), also able to aspirate the branches with a hopper in the The axis of the apparatus, this last point (the aspiration) seems to me essential, both from the point of view of productivity and the possibility of treating thorny woods. Possibility of ejection of the crushed without additional device, therefore mechanical very simple.
The disadvantages are of various kinds: randomness of the chips (on the discs it is easy to correct this same defect), but this is not important for the intended use; The chip evacuation is spontaneous, but remains weak because of the lower diameter (to the discs) and a tendency to stuffing is observed as soon as the speed decreases or when light elements (dry reeds ...) are ground. It is therefore important (but also valid for discs that are far from being exempt) to anticipate the jamming by mixing hard elements with possible light materials (for which this material is not really Designed) and retaining the biggest branches to spread out the force of the engine over time. The ejection of the crushed material must be monitored at all times in order to quickly detect any beginning of stuffing and thus avoid or at least limit it.

A motorization of 6 / 7 horses is sufficient for the diameters which interest us, the weight remains reasonable and the assembly easy to move, on the other hand, the consumption remains really moderate, provided the corresponding treated volume is sufficient, this Which depends, as we have seen, not only on the cutting system used, but also on the particular design of each manufacturer, the correct follow-up of the sharpening, as regards the impact of the equipment. The organization of the construction site is also very important, especially as the equipment is efficient; Being two is a plus.

NB: an indirect drive by belt, whatever the cutting system is a plus since it avoids the blows to the crankshaft and thus manages the life of the engine; This makes it possible to insert a centrifugal clutch on the drivetrain, which greatly facilitates the start-up of the engine and, in the event of a jam, avoids systematically stalling the engine (it is then possible to reduce the gases and quietly debug ).

This is basically yours now to ask questions that I will try to answer ... : Wink:
0 x
"Please don't believe what I'm telling you."
User avatar
chatelot16
Econologue expert
Econologue expert
posts: 6960
Registration: 11/11/07, 17:33
Location: Angouleme
x 264

Re: What mill to produce BRF?




by chatelot16 » 26/06/17, 00:23

I have the impression that you describe a shredder that I already have: Chinese with 13ch motor: big hopper above, drum with blade more or less cutting, and exit by a grille underneath which only leaves out what is Thin enough and lets in it turn what is too big ... other entered on the side for big and right branch

The system has a grid is bad: it lets out a bunch of straight and long piece, so not enough to grind well ... and it lets turn a lot of thing too long so grind unnecessarily too thin and too energy consuming

The 2 inputs are equipped with safety protection which make them completely usable

To operate the machine at full flow it is necessary to suppress these security so that the entrances is completely open and to make a wooden tool to push: species of big cross of wood having just the right length to push in the tremie without firing

The same is true for the tube on the side: the big wood be descends only when it is long, but the end does not pass, and the wooden bundle following the wedge instead of pushing it: to grow well it requires a piece of wood Of the maximum diameter, but if this wood is pushed too far it is pruned at an angle and no longer serves nothing to push: therefore it is necessary to make a real tool that just stumbles at the right depth and that always serves

I will have to make pictures

I used it quite intensively and it needed to reinforce what lache
0 x
Ahmed
Econologue expert
Econologue expert
posts: 12298
Registration: 25/02/08, 18:54
Location: Burgundy
x 2963

Re: What mill to produce BRF?




by Ahmed » 26/06/17, 11:26

I see what you mean, I described this type of crusher above, but it is not the one I bought: mine is lower in motorization, does not have a grid output and n A feed hopper; But I would have the opportunity to come back, since it was the starting point of this thread ...
I understand the little inconveniences you point out and the way you do it. In the case of my machine, forced pushing is only necessary when grinding small, short and abundant hedges: I take a branch made in forks to help swallow, otherwise there is need nothing.
You make me think that there is a crusher system, which I did not mention, that must be operated with a grid, because the branches are first cut into strips and have to turn a moment before having characteristics I was able to use one of these devices (expensive), because a friend had one, but I find this bazaar of a perfectly distressing efficiency (I attended a demonstration ... :frown: ) And, by charity, I would keep the name.
0 x
"Please don't believe what I'm telling you."
Ahmed
Econologue expert
Econologue expert
posts: 12298
Registration: 25/02/08, 18:54
Location: Burgundy
x 2963

Re: What mill to produce BRF?




by Ahmed » 26/06/17, 11:49

As I said above, discs are rather cheaper to manufacture, which explains why the use of the drum has long been reserved for industrial and high power models. There are several ways of making this type of rotor: it can be several parallel disks (general case of very large grinders) or a solid rotor; The Chinese who designed my crusher opted for a clever compromise: the drum is hollow, made up of curved sheets (and folded to protect the ejection pallet), simply welded on two lateral flanges and, of course, solidarized by the same Way to the central axis. It is a cheap solution that now allows to dispose of it on small grinders ... 8)
0 x
"Please don't believe what I'm telling you."
Ahmed
Econologue expert
Econologue expert
posts: 12298
Registration: 25/02/08, 18:54
Location: Burgundy
x 2963

Re: What mill to produce BRF?




by Ahmed » 26/06/17, 12:24

I was just looking at the prices of the best amateur electric shredders, it's still about 440 €, whereas for only double one can have a machine that does not compare to the previous one, nor in terms of performance , Nor in robustness and durability ... It is to weigh well before investing.
0 x
"Please don't believe what I'm telling you."
User avatar
Macro
Econologue expert
Econologue expert
posts: 6459
Registration: 04/12/08, 14:34
x 1610

Re: What mill to produce BRF?




by Macro » 26/06/17, 13:10

My crusher bosch axt25tc cost me this price order (in the 450 €) To know to date ... After having rented it about twenty days between 15 and 20 € the day .... It is for my Part amortized ... and still under guarantee ... Its main disadvantage is the ridiculous size of its basket of recovery ... But its working silence .... Compensates allegre the disadvantage of the basket ... Question feed it holds its Promises and boie up to the 45mm of predicted diameter (and even one more on oval shapes of branches) perso I used it only with linden oars ... So soft enough wood .. But those who have I rented it and passed various essences and every time I had the same returns ... Everything that enters the chute ends in the basket without flinching ...

Just for my personal use ... He had to give me about 6 cubic meters of brf
0 x
The only thing safe in the future. It is that there may chance that it conforms to our expectations ...
Ahmed
Econologue expert
Econologue expert
posts: 12298
Registration: 25/02/08, 18:54
Location: Burgundy
x 2963

Re: What mill to produce BRF?




by Ahmed » 26/06/17, 19:33

It is to this kind of grinder that I alluded above. It is an excellent choice and the criterion of silence can be heard ... : Wink: . More generally, knowing the various peculiarities of the various grinders on the market, it is important to make its choice according to its own criteria, its specifications; For me: autonomy, reduced consumption, limited weight and correct flow (see a little more! 8) ). On other points, it is obviously necessary to make concessions: I would prefer a device less noisy, but it is not unacceptable for me.
0 x
"Please don't believe what I'm telling you."
Ahmed
Econologue expert
Econologue expert
posts: 12298
Registration: 25/02/08, 18:54
Location: Burgundy
x 2963

Re: What mill to produce BRF?




by Ahmed » 02/08/17, 22:50

I would like to come back to an important point, already mentioned: productivity. I consider grinding to be an activity that is not very exciting in itself and, unless it is limited to an optic of disposing of its own waste, it is a decisive factor in terms of the quantities useful to a garden. Many opportunities can be seized, since the proposed volume no longer imposes insurmountable constraints in terms of time spent crushing. The energy aspect is not to be neglected either, but both are virtually symmetrical ... 8)
This last point can be optimized (in the case of a high-performance crusher) by the presence of two operators: the aim being to feed the device as regularly as possible (not too much, which would cause stuffing or abnormal effort of the engine), to maximize the overall throughput: only one operator really needs to provide ...

I also spoke about the organization of the upstream work: how to stack the branches (or at least spread them) and the method of cutting that must avoid the perpendicular forks and favor maximum lengths (within the limit of which is easily manipulable) greatly influence the final result.
A counter-example: I recently crushed leafy branches faded, but soaked with water by recent storms. The leaves, especially those of a willow variety, formed a kind of sticky mass before grinding and caused repeated jamming from the start. Fortunately, things have improved rapidly; probably the branches below were less dripping with water ... but this is not a favorable circumstance and I will take care to avoid it carefully in the future ... :?
0 x
"Please don't believe what I'm telling you."

 


  • Similar topics
    Replies
    views
    Last message

Back to "Agriculture: problems and pollution, new techniques and solutions"

Who is online ?

Users browsing this forum : No registered users and 311 guests