Coytee Posted May 14, 2015 Share Posted May 14, 2015 Just been wondering about some of the mechanics. I get the overall program of how a pipe organ works. Couple things I'm wondering about: 1. How much air flow is needed? (I realize different flows for different locations) I doubt a hair dryer would provide enough flow....how about a fan the size of a whole house exhaust fan? 2. During moments when 100% of the air flow isn't required..... where does it go? Does it stay in the plenum (that I understand is under the pipes) 3. If it stays there, what happens when it reaches "X" pressure? Does the source stop? Does it bypass and blow out somewhere? 4. If it blows out somewhere via bypass, where? Out of the building? I've never seen anyones hair get poofed by a pipe organ but, I've experienced them enough to feel the guts get shaken (an experience I've loved since childhood) 5. When the air is moving through the pipe....does it simply exit out the top of the pipe, into the larger room space that it's all sitting in? (into the church for example) Just some meandering questions. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted May 14, 2015 Share Posted May 14, 2015 Tigerman should be the one to ask, or maybe Dave. We had an organ in the church I went to when I was young. Before confirmation class we'd fire up the organ and play phantom of the opera. I remember having to start some sort of compressor to make the thing work. I don't recall a fan. Quote Link to comment Share on other sites More sharing options...
Chris A Posted May 14, 2015 Share Posted May 14, 2015 (edited) See http://en.wikipedia.org/wiki/Pipe_organ#Wind_system http://pipedreams.publicradio.org/articles/how_a_pipe_organ_works/howapipeorganworks.shtml http://en.wikipedia.org/wiki/Wikipedia_talk:WikiProject_PipeOrgan/Windchest_designs Chris Edited May 14, 2015 by Chris A Quote Link to comment Share on other sites More sharing options...
Mallette Posted May 14, 2015 Share Posted May 14, 2015 Tigerman is the expert, but in his absence... Blower motors are quite large as you have a LOT (as I will briefly explain) of area to maintain a positive air pressure in. 1/2 to 10 HP or more, much more for a theater organ. Air pressure in organs, for reasons going way back in history, is still most often quoted as "inches of water." A German baroque all mechanical tracker organ might only require 2 inches of water, about .07 PSI. The American Schantz at my parish requires 5.5, about 2 psi. A theater organ can sometimes run 100 inches or 3.6 psi. The air is held in weighted chambers with pleated leather that expands to the required pressure and the weights ensure that the pressure remains constant. If it didn't the instrument would lose both tuning and the volume would vary when played. The blower motor maintains the pressure and the air goes nowhere. Sort of like one of those inflatable buildings with the constantly running blowers. Other than through leaks...which are inevitable in such a large system...the air only exits through the pipes when they are sounded. Hope that helps. Dave Quote Link to comment Share on other sites More sharing options...
Mallette Posted May 14, 2015 Share Posted May 14, 2015 (edited) Forgot I had this. Used it for my parish vestry during the acquisition of our pipe organ. This is a tracker, or mechanical instrument. The only electric part of it is the blower motor. Editing to explain one thing: Stops. That picture says "Other stops, chest valves closed." Note the pipes that aren't sounding draw their air from the same airs source as the one that IS sounding. By pulling one or more stops the organist adds resources, such that pressing that single key can sound (in the case of this illustration) 1, 2, or 3 pipes. Will leave it at that to avoid TMI. Dave Edited May 14, 2015 by Mallette 1 Quote Link to comment Share on other sites More sharing options...
AudioJag Posted May 14, 2015 Share Posted May 14, 2015 Coytee..... you can always check for info with the ATOS.org ... American Theater Organ Society. You might be able to find answers to all your questions there. http://http://www.atos.org 2 Quote Link to comment Share on other sites More sharing options...
Marvel Posted May 14, 2015 Share Posted May 14, 2015 (edited) Tigerman is the expert, but in his absence... Blower motors are quite large as you have a LOT (as I will briefly explain) of area to maintain a positive air pressure in. 1/2 to 10 HP or more, much more for a theater organ. Air pressure in organs, for reasons going way back in history, is still most often quoted as "inches of water." A German baroque all mechanical tracker organ might only require 2 inches of water, about .07 PSI. The American Schantz at my parish requires 5.5, about 2 psi. A theater organ can sometimes run 100 inches or 3.6 psi. The air is held in weighted chambers with pleated leather that expands to the required pressure and the weights ensure that the pressure remains constant. If it didn't the instrument would lose both tuning and the volume would vary when played. The blower motor maintains the pressure and the air goes nowhere. Sort of like one of those inflatable buildings with the constantly running blowers. Other than through leaks...which are inevitable in such a large system...the air only exits through the pipes when they are sounded. Hope that helps. Dave On a smaller scale, that is how the drone notes on bagpipes work. Bruce Edited May 14, 2015 by Marvel 2 Quote Link to comment Share on other sites More sharing options...
Mallette Posted May 14, 2015 Share Posted May 14, 2015 On a smaller scale, that is how the drone notes on bagpipes work. Yes, sir. Those drones also provide the bagpiper with a constant tuning note. With no weights on the wind chest (bag, in this case) even pressure is maintained by the musician...and the drone provides a cue as correct pressure. Thanks for the reminder, Bruce! Excellent point. Dave 2 Quote Link to comment Share on other sites More sharing options...
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