The decision was made in favour of a version with 2 boilers. Of course, before making such a far-reaching decision, we also considered whether other concepts would not get us there better. In order not to present the reasons for the decision in detail here, I will only refer to the article https://www.xenia-espresso.de/en/xenia- ... r-konzept/ and there on the last paragraph "other concepts in comparison – E61 and thermoblocks".
Those interested in the beginnings and history can find everything here: https://www.xenia-espresso.de/en/xenia- ... r-konzept/
The current thread is: https://www.kaffee-netz.de/threads/xenia-2023.150370/
So for the time being, we went with the traditional boiler and a relatively massive brew group. The brewing kettle is dimensioned in such a way that it holds enough water for the espresso-pulling (5 times the amount of a double draw). It thus ensures that there are no fluctuations due to the flow rate. The brew group is given a way to monitor and influence the temperature.
The essential components from the CAD programme:
So, when the draw starts, the whole brewing system has exactly the brewing temperature: the insulated boiler, the water in the boiler (~270 ml) and the group. The advantage: during the draw, there is no need for regulation and the associated challenges and uncertainties are eliminated. Of course, the boiler may not always be 100% at temperature. This can be caused, for example, by the incoming water. That's why we first direct the fresh water in the heater to the floor, where it can now -- already preheated -- hardly interfere. And if there are still minor deviations in the brewing water, the 3-kilogram sensor-controlled brewing group ensures that these are compensated for.
In order for the user to have access to these options, the system has a second processor running a web server that displays all settings in the form of web pages. The advantage is that the user's access is in the form familiar from the internet and is independent of the operating system compared to an app. The presentation of the information is clearly and thematically structured and the essential information is clearly summarised on the start page.
Registration for use with us as the manufacturer is not envisaged and data is not passed on. Updates to the system are simply uploaded.
All in all, a lot of effort was put into the creation of these web pages and so the operation has become intuitive and the system is free of teething troubles right from the start. The software itself is extremely flexible and future-proof and currently has 152 parameters that can be used to make changes and improvements very quickly.
In order to set up a good system, it is also important that the entire structure of the machine keeps up with the concept and the hardware and software. We worked for a long time on the internal structure, on the optimal routing of the water pipes and hoses and on the cabling. The result was an optimal use of the available installation space, and when you open this machine, even a layman can see how consistently this principle has been implemented. Apart from the fact that it looks interesting and confidence-inspiring, this very complex machine is therefore easy to maintain.
This also makes it clear that we have not suddenly started to become economical in our choice of materials. Plastics are only used if they have advantages over stainless steel, copper or brass in terms of function. The boilers are always made of stainless steel and become more energy-efficient with an insulation of needle felt and another stainless-steel shell. The sheet thicknesses of all parts (1, 2 or 5mm) are more than adequate and give the machine a high degree of stability.
The pump is mounted in such a way that the vibrations and noise are significantly damped and the pump hums along comparatively discreetly. The version with the power regulator also has a digital pressure sensor and thus the power of the pump can be regulated during pulling espresso. And this version can control the pump with reduced power, so that the operating noise is reduced even more. The control is also done in such a way that there is no rattling, which is familiar from some other machines.
The steam boiler is relatively large and does not have to give off any heat to the brewing water. It can be heated to up to 2 bar and thus holds large amounts of steam for cappuccino and the like.
All in all, the Xenia's dual boiler has once again become a beautiful machine, both inside and outside, as well as in its operation via the web interface. The combination of conventional technology (such as the use of boilers) and modern technology (software distributed over 2 processors) has resulted in a coherent machine that can deliver results with a high degree of consistency. In addition, the user has a lot of freedom to intervene himself (depending on the configuration) or simply to let the software do the work. After all, it is a machine for everyone and not just for enthusiasts who like to try out and optimise everything.
Further additions, such as a flowmeter, are on our to-do list and an access option for third-party app providers is under discussion, so that further functions may one day be possible—beyond those that we will gradually add specifically in consultation with users.
However, all these brilliant advantages also have their price—this should not be concealed here. However, as you can see from the above explanations, we have ensured that the user gets a high value for his investment. And we are pleased that this is obviously recognised, because the order list is long and we keep getting new orders. For us, this is positive—but for the one or other interested party, it also means that they will need some patience until they can get their machine.
The year 2022 was a bit strange due to the war and the shortage of material, but now we look forward with well-founded confidence and look forward to building many dual boilers and receiving feedback from our customers.
And finally we are going to concentrate more on the machine 303: https://www.xenia-espresso.de/en/maschine-303/
Finally some pictures:
