總要做點有趣的事情：1.2kg的直火烘豆機

談不上多高明的想法，重點是在設計的過程中，有沒有什麼問題是可能這樣設計就能解決或改善的？

這是近來設計的直火烘豆機，設計的初衷是因為大多數的烘豆機都長的差不多，然而去翻看一、二次世界大戰時期的烘豆機專利文件，會發現各式各樣的烘豆機在當時是蓬勃生長，出現各種樣式的烘豆機，而非現今烘豆機的結構幾乎已經定型了，在"有趣"的大前提下，有什麼思考的方向呢？

一開始是以德國的G.W Barth Menado 60kg的烘豆機為雛型，後來為了延續之前設計的L1.5的線條，於是出現了上圖的造型，以拆卸組裝方便的大原則下，大量的螺絲是無法避免的。
這次希望能解決的是什麼問題呢？終究還是烘焙時所產生的煙與銀皮，直火烘豆機一直很難避開的就是火源在正下方造成落下的銀皮燃燒的狀況，在小型機器上的影響不大，但是3公斤以上的直火烘豆機，大量銀皮燃燒是無法避免的，早期常使用的狀況，在富士皇家的烘豆機上採用的方式是在火排底部的銀皮盤加水，使大量的銀皮堆積降溫避免燃燒。

而義大利的做法則是將火源上移，銀皮由烘焙桶下方抽離，優點是銀皮經過火排的燃燒所形成的煙不會通過烘焙桶，然而這樣的設計，風門的效果與一般的下方火源的直火烘豆機完全不同，形成對流設比例更高的系統，迄今，義大利的IMF就是這種設計類型的主要廠商之一。

以個人設計為主的小型工作室規模，當然很難去思考動輒30~90公斤的中大型烘豆機，但是小型烘豆機的發想倒是可以試試，在這年頭，萬事皆備，只欠圖紙的狀況下，當然絞盡所剩不多的腦汁，來設計一台可以盡可能避免銀皮燃燒的直火烘豆機了。
目前能想到的處理方式就是側火，而側火必須搭配穩定的氣流移動路徑，抽風較強是必須的，而常見的狀況是早期富士皇家的直火烘豆機會用到悶這個手法，這是機械風門的優勢，但是在維持相對較強的抽風狀態又能夠有一定的風門效果，也只能從變頻風機下手。

組裝上考驗的是加工廠的精度，而採用的材料包括了黑鐵與不鏽鋼，兩者的誤差值各有不同，目前看起來也算有驚無險的組裝完成。

至於實際烘焙的效果如何？就等電路的部分完成後就開始來試試。

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Facinating! 1.2kg Conduction Coffee Bean Roaster

April 27, 2019

Although it cannot describe as new or intelligent ideas, but main focus on enhancing the design process to resolve previous issues and improve the performance.

This is a recently designed direct fire coffee roaster. The original intention of the design is that most of the coffee roaster are look a same. However, look back the patent documents of the coffee roaster during World War I and World War II, you will find various type of coffee roaster were flourishing at that period, created different styles and shapes of coffee roaster. While the structure of today's coffee bean roasting machines have almost been molded in standard form. Under the enthusiasm interest as driven force, if there are any thoughts that could lead us breakthrough current barriers?

At the beginning, use the GW Barth Menado 60kg coffee  bean roaster  from Germany as the prototype. Later, in order to continue the chassis of L 1.5 from the previous design, the structure of above feature appeared. Under the principle of convenience on assemble and disassemble of the roaster, a large amount of screws are inevitable.

What type of problem to be solve this time? The smokes and chaff produced during roasting are still the major issues, it is difficult to avoid conduction coffee bean roaster to burn the falling chaff as the fire source is directly below roasting drum. The impact on smaller machine is not effective, but 3kg and above conduction coffee bean roaster which burns large amount of chaff is unavoidable. In the old days, the method applied in the Fuji Royal coffee bean roaster by adding water to the chaff collecting tray at the bottom of the gas burner, to make sure accumulated chaff get wet and cools off while eliminate burning take placed.

In Italy, the designer moves up fire source, and the chaff is removed from the bottom of the roasting drum by the suction fan, the advantage that smokes produced from burning chaff will not get into the roasting drum and spoil coffee flavors. However, with this design the effectiveness of damper is different to the ordinary conduction coffee bean roasters which placed fire source direct underneath of roasting drum, forming with a higher convection ratio system. So far, IMF in Italy is one of the main manufacturer of this type of design.

It is understandable for a small studio that based on personal capacity is hard to design medium or larger size of coffee bean roasters at a capability of 30 to 90 kilograms per single roast, but one can try on the fundamental theories on smaller coffee bean roaster design. In the current era, great design is most important target to achieve and one should crunch every single brain power that available to design a conduction coffee bean roaster that minimize burning of chaff.

The current conceivable adjustment is side fire, and the side fire must be matched with condition of stable air flow path and strong ventilation. The early design of Fuji Royal conduction coffee roasting machine is commonly use this stuffy technique with advantage of the mechanical damper, to have a certain damper effect while maintaining a relatively strong ventilation state, variable frequency conversion fan is only choose for this application.

The assembled roaster system could also demonstrate the accuracy of processing plant, including the materials used such as black iron and stainless steel, the tolerate values ​​of the two materials are different. At present, it seems that the assembly is completed seamlessly without any error.

As for the actual roasting result, patiently wait for the electric circuit part to be complete and starts test run!

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This article was translated by George, thank you very much.