Questions for Commercial Roasters in the know

[sergvoloshyn]

What materila used for drum?

[at535]

Re: Questions for Commercial Roasters in the know

"when filled to capacity, how high does the load of beans come?"  (or stated differently...) "What is the ratio of the load volume to the drum volume?"

as a very rough guesstimate, Id say no more than about 20-25% 

Really, that low. I would have thought more like 40-50%

[Dennis]

Re: Questions for Commercial Roasters in the know

Having said that however, the certifications are only required if for commercial use and sale.

WHOA!!!

In NSW, "The Gas Supply (Consumer Safety) Regulation 2004 prohibits the sale of uncertified gas appliances. It also prohibits the connection of an uncertified gas appliance." Dept. of Fair Trading.

I suspect that the regulations dont differ too much in other States.

[saoye]

Re: Questions for Commercial Roasters in the know

Keep in mind that gas roasters are classified as type B appliances and must by law comply with the specific regulations applicable in your state. Make sure you check them and if need be, speak with an appropriately qualified person.

The regulations are there for obvious safety reasons. Electrical appliances also have its own regulations and certifications that are applicable. AGA for gas and TUV for electrical. Having said that however, the certifications are only required if for commercial use and sale. It is still in your best interest to understand these regulations and safety standards to avoid burning down your house and or having your prototype blow up in your face. I am sure you have an understanding of electricals since you are endeavouring on this project. Best of luck.

[TC]

Re: Questions for Commercial Roasters in the know

Hi Ralph- as a very rough guesstimate, Id say no more than about 20-25% :-/

Keep in mind that gas roasters are classified as type B appliances and must by law comply with the specific regulations applicable in your state. Make sure you check them and if need be, speak with an appropriately qualified person.

Good luck.

Chris

Re: Questions for Commercial Roasters in the know

It looks like this topic has been dormant for a while so my apologies for resurrecting it...

Warren, I have been asking all the same questions in my process of doing research for the very same reasons.  I too am a tinkerer.  I also have access to an incredible machine shop.  My goal is a 1-1/2 kg roaster that resembles a professionally made one. 

All my questions have been answered in this thread except, "when filled to capacity, how high does the load of beans come?"  (or stated differently...) "What is the ratio of the load volume to the drum volume?"

Can anyone help me out?

Thanks,  Ralph

[Dennis]

Re: Questions for Commercial Roasters in the know

Ive been researching roasters for quite some time and finally settled on a roaster that should satisfy the upgraditis bug

thanks mate, thought your opening line is quite funny.....in hindsight ;D

Yeah, I had intended it as a home roaster before a bout of mania set in! ;D

[WSullivan]

Re: Questions for Commercial Roasters in the know

Ive been researching roasters for quite some time and finally settled on a roaster that should satisfy the upgraditis bug

thanks mate, thought your opening line is quite funny.....in hindsight ;D

[Dennis]

Re: Questions for Commercial Roasters in the know

Do you still have this pic Den?

http://coffeesnobs.com.au/YaBB.pl?num=1195714810/0

[WSullivan]

Re: Questions for Commercial Roasters in the know

Dennis has a picture of a Diedrich drum which hes posted before I believe? It shows the axial vanes nicely.

Do you still have this pic Den?

[WSullivan]

Re: Questions for Commercial Roasters in the know

Thank you all so much, im pretty excited about this project, it will be a while off as i said, and im sure there will be tonnes of tweaking, and re-doing but thats what its all about as far as im concerned, if, at the end of the day i can produce a roaster that is reliable, controlable, and solid ill be one very happy camper!

Awesome info so far, thanks again to all those who have chucked in their 2 cents worth, and i appreciate the fact that no one has really said.....you cant do that, why would you bother etc.......its clear to me that you all understand how crazy we all are ;D ;D

KK posted a link to a probat site, it is pretty amazing, prolly the best ive seen, its in my other thread so ill crosspost it here


Here it is http://www.whydontwehavethisguy.com/portfolio/Showcase/PBAT101.swf

[ccc2]

Re: Questions for Commercial Roasters in the know

Some roasters employ a deflection plate above the burner and directly under the drum - being a different concept to the "hot-box". This is designed to minimize the direct flame on drum contact that can sometimes lead to tipping/scorching.
As per Denniss comments, the design of the drum, the size, shape and positioning of the paddles/vanes, rotation speed, airflow through the drum, thermal energy output from the burners and about a dozen other factors affect the operation. All these need to be calculated according to some deep secret formulas that roaster manufacturers are very sensitive about and you can almost bet there are dependencies and relationships between certain variables.
Here are some pics from a 10kg roaster where the drum was removed and I "enhanced" the paddles/vanes.

[stuartgrant]

Re: Questions for Commercial Roasters in the know

Hi Warren,

"No Im Spartacus... I mean also planning a drum roaster build..."

Youll find heaps of useful threads over on homeroasters.org - many clever people have succeeded in what the rest of us are aiming for!

Just to add to the replies above regarding Q.4 (how the vanes work). I asked the same question somewhere on HR.org and got my head around it from the responses. Like Attilio said, the drum is level, and the vanes are angled to push the beans forward. Because of this, the beans become more piled up towards the front door than the other end. BUT some roasters have a second set of axial vanes - attached to the axle of the drum rather than the walls - which pull beans away from the door. Axial vanes only scoops up beans from the top of the pile, so when the door is opened, the axial vanes no longer reach the beans and the beans can all be scooped out by the normal vanes.

I hope that made sense. If not - Dennis has a picture of a Diedrich drum which hes posted before I believe? It shows the axial vanes nicely.


Also, regarding Q.1 (wheres the heat?), both the Diedrich and Probat websites have some decent info on how theyre fired. Diedrich IR-series use a very indirect heating method whereas Probat and many others are directly-fired. Ive heard people say that its almost impossible to get scorching on a Diedrich (though Im sure its an exaggeration) - Ive also heard people say that you need the extra guts of the direct-fired types to have "real" control... so there are pros and cons, Im sure.

Im not really in the know, but I thought Id add what Ive found out so far.
Cheers
Stu.

[WSullivan]

Re: Questions for Commercial Roasters in the know

Not trying to rain on anyones parade, but a lot of these questions have been asked and answered previously.

Every question in the world has been asked before dennis ;D its just not easy to get ALL the answers i was after

If I were wanting to have a 2kg roaster, Id pay the asking price of something commercial and proven

Unfortunatly the money i have is well and truly tied up in property, 5k is not justifiable at the moment, plus im a tinker...er and i love to play and whether it works or not, ill have a ball trying, i 100% understand what your saying, the ppl designing these commercial roaster have been trying, testing and perfecting for scores of years......im just a noob :

Either way, I reckon you get what you pay for

Always true dennis, i understand that......cheers heaps for your input, i really appreciate it

regards
warren

[cuppacoffee]

Re: Questions for Commercial Roasters in the know

Is there like a baffle type thing to prevent direct heating to one spot of the drum for to long, like to try and spread the heat of the burners more?

Uhm, the drum rotates. Stopping the rotation while the drum is hot would not be a good idea.

Not trying to rain on anyones parade, but a lot of these questions have been asked and answered previously.

There is no reason why someone cant build their own roaster though its doubtful you will get it right the first time unless you have a blueprint of a commercial roaster available.

The drum is of a particular length and diameter to suit a number of variables, eg. capacity, burner configuration, etc. The baffles are designed to move the coffee forward at a certain rate. The drum itself rotates at a determined speed that will create a wave effect ie. too fast and the coffee will be plastered up against the wall of the drum, while too slow and the beans will remain in continuous contact with the drum and slide.

Fans that pull too much air through the drum, I think are detrimental rather than beneficial; how thick, and what material you use will have an effect on the outcome, and the list goes on and on.

If I were wanting to have a 2kg roaster, Id pay the asking price of something commercial and proven, or content myself with something like fatboys bbq roaster setup.

Either way, I reckon you get what you pay for.