[Stoves] Malot-blower

[Boll, Martin Dr.]

Frank,
I fear, I do not understand what you are describing.

Any material is possible. The main idea is the geometry of a shaft with
equal diameter and tubes/rolls round that to hold the fins; the geometry of
7 equal circles/tubes forming a stable "bundle". Certainly you can make
holes everywhere into the shaft as well as into the surrounding
"rolls"/tubes.
But between the surrounding tubes, there is no space, that air could pass
(because of the geometry).
If you would take only three double fins, each fixed with its middle-part
under the first, third and fifth roll, and you would take only two short
rolls to keep the distance, instead of a roll reaching all the breadth of
the fin, you could get air out of holes in the shaft from the centre of the
shaft-tube, through the space between the two short rolls into the space
between the fins. If the fins are stable enough, you can possibly use only 3
double-fins to fit for all the 6 spaces between the rolls.

The other idea is:
Take bearing tubes instead of rolls. Close the first, third, fifth tube at
one side/end, close the second, forth, sixth tube on the other side/end. So
you can alternate the sucking side/end, when you put a plate at each end.
This plate must have holes on the place, when you need suction from that
side; e.g. first fresh air from bottom, second fresh air from bottom, third
re-suction from burning chamber, forth from fresh air, fifths from fresh air
sixth from burning chamber; and the same every rotation.
But think to test first if the re-suction from the bottom of the
burning-chamber does make the desired effect. All the fine mechanical work
would be for nothing, if the re-suction would not help.

Another idea:
Put a wall (even movable is possible) in the middle of the surrounding
tubes, make holes into the tubes near both ends to get a flow into the
inter-space of the fins. You get all the time suction from bottom (fresh
air) and from above (re-suction). The two streams are mixed in the
inter-space of the fins and get transported to the space between
burning-chamber and outer wall. If no mixture is desired, there must be a
septum to separate the inter-space of the fins with a circle-plate.

Regards

Martin


> -----Ursprüngliche Nachricht-----
> Von: frank [mailto:frank at compostlab.com]
> Gesendet: Sonntag, 8. Juli 2007 21:18
> An: Boll, Martin Dr.
> Cc: stoves at listserv.repp.org; 'Frans Peeters'; 'Peter Verhaart'
> Betreff: Re: Malot-blower
> 
> Martin, Frans and stovers,
> 
> You were right about my thinking in terms of a propeller-type fan and
> must say I was confused as to why you didn't angle your blades to
> achieve one. Thanks to your explanation of how this type of Malot radio-
> blower works moving air from the center to the outside makes a lot of
> sense and puts me back to the drawing board armed with a lot more
> knowledge.
> 
> Can the shaft be hollow with holes between the fins in the center. One
> end of the shaft pocked out the bottom of a closed end pipe and the
> other sealed so air must suck into the shaft and out at the fins to
> finally blow air up the pipe? Something like that?
> 
> Boll, Martin Dr. wrote:
> 
> > Malot blower: Here theme-branched to / intermediate reflux of burning
> > gasses
> >
> > Frank,
> >
> > You think of the action of a propeller-type fan. Thereby the draft
> > moves in different directions, when driven by a bow. But this works
> > one to one in each direction. -But that is originally not my
> > intention. I t is simply to blow in one direction.
> >
> > I don’t think, it would be possible to drive such a “propeller”-fan
> > with a bow so fast, to get a usable blow. Out of that reason the
> > Malot-blower is a radial-blower, with the effect, that it blows always
> > from axle to peripheral area. Mostly that is good, but you do not want
> > this.
> >
> > So the new idea you have, inverting the draft in a T-LUD for a short
> > time will not work in the sense you thought.
> >
> > But there are two basic different methods to get nearly the
> > draft-inverting as you think:
> >
> > 1. If you block for a short time the off-gas of the T-LUD, the
> > creating process of burning gasses goes on. But if the way upwards is
> > blocked, the gasses steam downward, that is nearly what you want to
> reach.
> >
> Perhaps that will put out the secondary combustion? I am thinking the
> area between the primary and secondary will need to buffer the flow of
> pyrolysis gases to still have a steady outflow of gases to the secondary..
> 
> > 2. If you take a radial-rotor, which is heat-resistant, e.g. the
> > malot-rotor made of tubes and sheet-metal, you can put it into a tube
> > of which the bottom is closed. The rotor sucks then from the
> > shaft-near area (in this case from above) and blows to the periphery
> > of the rotor. By this you can get a suction downward through the grate
> > and a blow upward through the peripheral gap between the burning
> > chamber and the outer wall, in direction of the secondary-holes/jets.
> > In the time, when the rotor is not moved, there is normal natural draft.
> >
> > I think, between the central (sucking-) area and the peripheral
> > (blowing-) area, it will be best to separate by a metal-circle-plate
> > with a central hole. This central hole must not be too big, but big
> > enough to get the desired suck.
> >
> > 3. _/If !!/_ that would work, you could try to make a central hole on
> > the downside as well, which can be closed, but from size a lot bigger.
> >
> > When the hole on the bottom is open, the suction from down is more
> > easy (more effective), and the suction from above (trough the grate)
> > is possible not big enough to invert the natural upward
> > draft-direction. When the bottom-hole is open, the suction of
> > fresh-air is bigger.Then you have the normal T-LUD function with some
> > secondary-air-blow.
> >
> > 4. Possibly another idea will work better: If you would take on the
> > same shaft two (connected) rotors, separated by a sheet-metal, into an
> > upper and under section, the upper rotor served for the suction from
> > above, and the lower rotor served for the suction of fresh air from
> > under. There must be two slide-shutters one closing the centre against
> > the grate and the other between the two rotors. One of the shutters
> > must be closed while the other must be open.
> >
> Lots of great ideas above. Do you have pictures! : )
> 
> > Before creating complicated mechanisms, it would be helpful to know,
> > if tidal reverse air-flow would better the burn of a T-LUD. That would
> > spare a lot of work.
> >
> This is what I want to do but need to figure out a way to set of the lab
> equipment and way to change the air flow in a timely manner with the
> equipment I have available. (and the time!)
> 
> > Regards
> >
> > Martin
> >
> Thanks
> Frank
> 
> 
> --
> Frank Shields
> Soil Control Lab
> 42 Hangar way
> Watsonville, CA  95076
> (831) 724-5422 tel
> (831) 724-3188 fax
> frank at compostlab.com
> www.compostlab.com
>