My little fat Huky --- Spare parts united

[beananimal]

My little fat Huky Pevolution --- Spare parts united 

During winter time my little Huky gained some fat: The drum is now 6mm thick in total and about 4kg. Exactly twice the original weight.


About 3 years ago I bought my Huky, #363, perforated drum, J-pipe and as several others I bought in parallel the other drum, the other motor and some additional probes.
Not so long ago I bought a T-conversion kit, but never changed the configuration I really used.

Since a while I have some new possibilities in my hobby room and started to think about building a new Spare-parts-Huky.

First I played on modifications on my Huky and the plexigas Huky to understand what is going on inside the Huky regarding probe-placement, bean mass distribution front-back, beans in the the exhaust pipe and effects related to rotation speed of the drum.


Here are some impressions of some of my handicraft and experiments the last months:
On the pictures you see several intentional features and some DIY solutions - as good as I could solve it. I hope you like it. The test runs of this version just started.
 


































































peter

[Turboner]

Huky on steroids!

Can't wait for your follow up report.

[beananimal]

Here is some background information, about the features of the little fat Huky:

1) Additional probes:
a) In the exhaust - for me very useful with the perforated drum, J-pipe
but after some roasts it seems to be not so important with a solid drum.

After the first roasts with the double drum it seems to be almost obsolete.

b) BTmod, very close to the blades. Very good for small batches down to 100g (verified with the plexiglass version).
The probe is on 40mm radius from the center. Now in the steel version it is exactly on the same height as the axis, to gain some distance from original BT, to avoid blocking of beans. I think that some day I will check the bean-mass-distribution with 80g or 50.

With the first roasts I could see that it is much more reactive on BT temperature than the normal BT probe. I could see that the shown change of BT is up to 2 - 3 times higher than with original BT. 
In the plexiglass model I could see that around the normal BT there is always quite a mixture of beans and hot air - independent if it is a small batch or a full batch.

2) My main starter for all the handicraft:
Double wall drum - to roast like the pro's do
It is now: Inner drum, original 2.4mm, close to 2kg weight, (~1950g)
plus outside pipe 3.6mm thick, exactly the same weight.

4kg steel for 0.5kg beans is close to several large roasters.
And this installation of the double wall pipe is fully reversible, so it is possible to give it a chance without ruining the Huky somehow. Even no additional holes needed.

On the backside I almost doubled the holes, to allow even more air flow

The material of the outer pipe is carbon steel due to better heat conduction. The surface is sand blasted.
The stainless drum itself is also sandblasted, as the radiation coefficient of shiny stainless steel is very, very low and is changing by a factor up to ten, depending on the exact surface conditions.

(The inside volume of 2 liter for 500g is about only the half, compared to the other small / medium roasters I checked, but it seems to work based on a strong stove and a very strong fan for the Huky.)

3) Motor housing
The support is modified in a way that you can easily change the motor.
It is neither necessary to dismantle the Huky, nor is it that tricky in the motor housing.
The main intention, to reduce that squeaking sound was not yet successful.
I'll have to exchange the aluminum main plate, as the heat-transfer to motor housing is to much. The housing gets to hot.

4) Variable power supply
As it is a DC motor and the speed can be adjusted by changing the voltage,
I took the 72 rpm motor (at 24V) and tested it with the possible voltage.
It is (without load) directly proportional: 12V = 36 rpm, 16=48, 20=60 and 24V = 72 rpm.
Less speed is less noisy.

The speed will be subject of playing around with heat conduction from the drum and convection from hot air flow.
My idea is to switch around 180°C from low speed to high speed, so that most of the inside  volume is a mixture of beans and air, so that with an increase airflow the temperature control is more connected to the intake air temperature and therefore flexible, while the temperature of the drum itself remains almost unchanged.

There are many things to be improved for a nice look, but it is an experimental Huky up to now and I am starting right now with the roasting practice.

The first beta test run dispatched some adrenalin, as the front bean hatch was not tight enough at the start and during Second Crack I realized that it would be very nice to have some funnel to get the bean into the round sieve (mind the gap ... ).

[SusanJoM]

2) My main starter for all the handicraft:
Double wall drum - to roast like the pro's do
It is now: Inner drum, original 2.4mm, close to 2kg weight, (~1950g)
plus outside pipe 3.6mm thick, exactly the same weight.

Does this mean you now have a perforated inner drum and a solid outer drum?

   Well, sorry, all I had to do was go back and look at the pictures to answer that for myself.
Having spent so much time focusing on the difference between the airflow in solid vs perforated drums, I'll be very interested to hear whether your new model functions more like one or like the other or is yet another entirely different beast. 

 

[beananimal]

Hello Susan, with that thick double pipe there is almost no gap between the two pipes and therfore there no airflow, and no difference if the drum itself is perforated or solid.

What you are thinking about is more like the following picture with the second pipe only 2mm thick. But then either the outside pipe or the drum-end-plate need some additional holes to allow enough air flow:


Here two Artisan graphs from the first roast


In the second one the probes are clearly named.
Here the exhaust probe is somehow obsolete.
The BTmod is the short probe directly at the blades. In this area there is no double-drum and there is probably some airflow through the gap between frontplate and drum.  I think this explains why at heating up BTmod goes up to 220°C while the others remain lower and relaxed stable.



The roasting is relaxed. My nervous tendency to fiddle and adjust the curve of ROR is gone. On the other hand I am still convinced that either with high air flow, combined with 72rpm to get the beans away from the wall - but tumbling through the drum, I am able to adjust the curve if I want.

What I do not yet fully understand is that the temperature of the drum seems to be almost stable at quite low 150°C and the bean temperature increases during all the time, but not only at the well known point before FC.





This morning I bent some stainless steel. Looks much nicer now.
And it is to reduce the outside surface temperature and act as some insulation as well.
(Did I mention that I did not remove the first carbon steel housing, so that also the housing is double-walled now. At the end there shall be a gap of about 4mm in between).
My little fat Huky is now right above 10 kg.

[Brent]

That's pretty darn cool.  You're quite the handyman