drawing of a chest organ

    Hallo Xiaohu . Das Gebläse mit den 60mm und 1,8m3 habe ich auch in meiner Truhe. Ich habe es noch für unter 800€ bekommen . Bei der Windversorgung solltest Du nicht sparen. Wie Jens schon sagte kannst du es mit Papstgebläse ausprobieren , aber ich bin da eher skeptisch ob es für 8+4Fuß ausreicht. Bei der Vorplanung ist es ja auch wichtig das Gebläse vernünftig unterzubringen. Wenn du später deswegen die Konstruktion umändern musst , kann es mitunter schwierig werden. Es gibt schon mal Orgelgebläse bei ebay oder ähnliche Portale , aber solche Kleingebläse sind dort eher selten oder gar nicht zu finden. Falls du ein größeres Orgelgebläse findest , kannst du es auch neben die Truhe in einem schallgedämmten Kasten aufstellen , oder in die Sitzbank einbauen. Bei https://www.gebrauchtorgel.eu/de/orgelteile solltest du auch öfters reinschauen. Die bieten schonmal gebrauchte Orgelgebläse an.

    Viel Freude bei der Planung.

    Grüße Jürgen


    Hello Xiaohu . I also have the blower with the 60mm and 1.8m3 in my chest. I got it for less than 800€. You should not save on the wind supply. As Jens already said, you can try it with the Papst blower, but I am rather sceptical whether it is sufficient for 8+4 feet. In the preliminary planning it is also important to accommodate the blower reasonably. If you have to change the construction later, it can be difficult. There are sometimes organ blowers on ebay or similar portals, but such small blowers are rare or even impossible to find there. If you find a larger organ blower, you can also place it next to the chest in a sound-insulated box or build it into the bench. You should also check https://www.gebrauchtorgel.eu/de/orgelteile more often. They sometimes offer used organ blowers.


    Have fun with your planning.

    Greetings Jürgen


    Translated with http://www.DeepL.com/Translator (free version)

    Zitat von JGB

    Hi Xiaohu, pressure in Pascal is about ten times the pressure in millimeters of water column. If you want 45mm or 450 Pascal in your instrument you have to add a little bit in order to have some margin for pressure regulation with the bellows/ventil combination. So I would suggest having a blower that can deliver 60mm or 600 Pa. There are also special organ blowers in the market like the ones from organparts.info but they are rather expensive. If you can afford it, take such a special blower: they just work as intended. Else, you have to experiment a little bit. I use a 2nd hand ebm RG148 blower (now ebmpapst) that can be regulated. But it can only handle about 1 or 2 organ stops. Regards, Jens

    Hello Jens, Could I ask for the parameters of your RG148 blower? the electric power and air flow and wind pressure etc.? Since I could not afford an special organ blower I am searching for alternatives. Best, Xiaohu

    Hello dear friends of organ building, sorry to interrupt, but I found another blower seems to be better, this one has a dimension of 277mm by 272 mm by 126mm. and has an air flow of 210 m3/hour (3.5 m3/min), 120W of input power with pressure 1200pa, the pressure maynot be too accurate I think it would be lower than the marked value. Looking forward to hearing your comments. Xiaohu



    Regarding the rg148: Just Google for "ebmpapst rg148 data Sheet", then you find the PDF. It can deliver 1,9 cubic meters at 3200 Pa (320mm) so you have to regulate it down in pressure. The blower can do that but you need to build the electronic interface for that. If you're interested: There was a whole thread in this topic which you can find in the forum here. Nice thing about the blower ist that it is very compact in size. Regards, Jens

    Hi Jens, thank you for your advice, I've just found the data sheet of your blower and the input power is 50Watts.

    The blower which I have found normally has a input power of 120Watts, I wonder whether they are too big for the chest organ.

    Meanwhile, to regulate the blower to you mean by reducing the drive current of the engine so that the speed drops while both the air flow and the pressure go down? Thanks, Xiaohu.



    I got the RG148-1200-3633 that runs on 230v instead of 24 Volt. Maybe the Power rating is different for that model. That blower has a regulation input to adjust the RPM. Btw: There ist no "too big": If you draw less wind from the blower, the power goes down automatically. The 120W of your blower will be the maximum when you let it blow out freely without air flow restriktion. Regards, Jens

    Here are a few more pictures of my harmonium's transposition setup!

    The first picture shows the groove (red arrow) on the case wherein a protrusion on the back of the keyboard frame slides. The groove and protrusion go the full width of the keyboard, but of course that's not necessary!


    The second picture shows the keyboard frame from below. The nails at the bottom of the keys meet the heads of the valve levers. The single nail at the front of the frame engages the holes in the iron transposition strip, which thus defines the position in the semitone grid and prevents the keyboard from shifting without being raised at the front.


    The next picture shows this iron strip and behind it the valve levers. The valves themselves are covered by a small resonance box. On the harmonium, the reeds are installed under the valves. The white is all lambskin, which I put on to replace the 170 year old and hardened leather. I also repaired a few cracks in the windchest with it.


    Finally, the last picture shows the replacement keys in the bass. They are covered by a wooden plate, which is not mounted here right now.

    Hello Samuel,


    Thank you for the nice tour of your harmonium's transposition setup, I understand how it works now. It is interesting that the transposition strip covers an octave. Therefore, the keyboard should have at least 12 extra keys?


    Best wishes,

    Xiaohu

    Indeed it has 11 extra keys. It transposes 7 semitones down and 4 up. So the extra keys you missed here, are on the high end of the keyboard, you can see them on picture 1. The sounding compass is four octaves C to c''' and depicted is the position for normal pitch.

    Dear ogan builders,


    I have finished the drawing of the keyboard and the frame, the height with out the wind system appears to be already 69cm, approximately the height of a desk. But if I put the wind system below this frame, which add up another 20cm of height, the overall height is reaching 90cm, it is a bit too high? the player needs to sit on a tall chair to play the instrument.


    Best regards,

    Xiaohu



    Hi Xiaohu,


    you're asking many questions. That's fine, keep going... But if you feel the need for some basic literature, let me know. This may answer many questions. Here's one page where you could order the "Bouwplan voor Kistorgel" book: https://www.johnboersma.nl/bouwboek3-english.html but I don't know the regulations for sending to China. I would certainly build details differently that described in that book, but I like it as a source of inspiration. In general, get as much inspiration as possible and look at many different instruments as possible, live or via internet or books. There will be many "aha" effects where you will think: That's a neat solution, I'll take that one!


    Back to your question: It doesn't matter how the air arrives at the pallet box as long as it is stabilized (pressure regulated) and the opening to the box is big enough. You can pressure regulate externally by a bellows/ventil combination or you can build it into the pallet box. Having an external bellows can make maintenance of it easier but it makes the instrument bigger. One solution for that is building it into organ bench. There are even builders that build whole pedal registers into the bench like this one: https://www.youtube.com/watch?v=vfAWUfV-tsY.


    Regards, Jens

    Hello Jens,


    Thank you for the link to the book, I learnt about this book for quite a while, but it is a bit difficult to deliver it to China.

    I would like the bellow/ventil combination to put under the under the pallet box but I really would like to find a reference to figure it out.


    Thanks and regards,

    Xiaohu

    Ah, nice that you found the preview. If you want the rest of the book, maybe we can find out a way that I can send it to you (for example you send me money, I buy it for you, scan it and send it through e-mail). We have to find a "legal" way though so we don't violate copyright. Just let me know if I can help you out.#


    Maybe, the author also has the possibility to provide you an electronic version if you ask him kindly ;-)

    Thanks Jens! From the preview, this book is surely worth buying and it is like a LEGO Instructions! I really would like to buy one as well, the only problem is how could I transfer the money to you. I do have a few Chinese friends in Germany probably I could transfer the money to them and ask them to help make another transfer to you or directly to help me buy it. Regards, Xiaohu.

    This is what the transopsition keyboard of my harmonium looks like when assembled. I finished the restoration, replaced all the felts and a lot of leather, and it almost doesn't rattle at all now. A little noise is of course allowed after 170 years! The lid is still missing, I just have to replace a few screws. Nice is the strip with the French tone names above the keyboard, so you know which tone sounds on which key when the keyboard is transposed.

    The sound is really great for 1 1/2 stops and has a wide dynamic range. This is a pressure wind instrument with very powerful reeds. Unfortunately, no percussion mechanism as on the great French instruments of that time. Therefore a bit slow responding in the bass....

    Greetings! Samuel


    Thanks so much for sharing Samuel! I wonder what is the height of this instrument? And what are the function of the five knobs below the keyboard?

    I know little about the harmonium although this is a more widely used instrument in China before the 1990's where the music class of the elementary schools in China used harmonium to teach music before it was replaced by the piano later.

    Just a quick search from the Wikipedia I found that the mechanism is actually from a triditional Chinese instrument, amazing!


    The pump organ is a type of free-reed organ that generates sound as air flows past a vibrating piece of thin metal in a frame. The piece of metal is called a reed. Specific types of pump organ include the reed organ, harmonium, and melodeon. The idea for the free reed was imported from China through Russia after 1750, and the first Western free-reed instrument was made in 1780 in Denmark.

    https://en.wikipedia.org/wiki/Pump_organ#Harmonium