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What about "Tubular-Hydraulic" suspended-key action?

Started by KB7DQH, May 10, 2010, 07:31:47 PM

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KB7DQH

Has anyone tried this?
May provide an "electricity-free" solution to a problem that manifest itself in the design of
this organ:
http://www.pasiorgans.com/instruments/opus19prop.html

My thought is to employ a "master/slave" cylinder mechanism not unlike what is employed automotively, to, well...   stop... or disengage the clutch if equipped with a manual transmission...
but scaled appropriately for use in opening pallets in windchests with reasonable touch.

Doing this would likely involve a hydraulic mechanism radically different from what one thinks about   
in the previous paragraph to accomplish this.

Tubing material is available from landscape irrigation supply points by the mile at really low cost.
The working fluid would depend on the environment of the organ installation I would think... and one would desire something with similar thermal expansion characteristics as the tubing, otherwise the keydesk could change height with temperature ;D  Nothing too exotic... One could "make do" with a 50/50 mix of glycol engine coolant and water  for starters.

Some low-cost facility would have to be provided upon installation and maintenance cycles to "bleed" the system.  Air in the hydraulics would be disastrous :o :o :o  resulting in a "spongy" action 
up to the extreme condition of a dead note >:(

Yes, something more for the engineers of the world who enjoy beautiful music to think about ;D

Eric
KB7DQH
The objective is to reach human immortality—that is, to create things which are necessary to mankind, necessary to the purpose of the existence of mankind, and which have become the fruit that drives the creation of a higher state of mankind than ever existed before."

revtonynewnham

Hi

It's significant that this idea has, as far as I know, never been tried commercially, whereas all sorts of pneumatic and electric actions have been built.  I suspect that the problems are size of the pistons needed - and the cost of the precision engineering to keep them leak free; and also the potential cost of maintenance (bleeding the system, etc.)

Also, I very much doubt that the resulting touch would come anywhere near that of a properly constructed tracker action.

Every Blessing

Tony

KB7DQH

Quote from: revtonynewnham on May 11, 2010, 09:59:16 AM
I suspect that the problems are size of the pistons needed - and the cost of the precision engineering to keep them leak free; and also the potential cost of maintenance (bleeding the system, etc.)

Pistons? I am thinking of a mechanism not unlike a toothpaste tube! One at each end of your choice of fluid conduction line... Sandwiched in between a fixed and movable block, hinged at the "flat" end of the "toothpaste tube".  Pallet spring at windchest end keeps that tube "deflated" and that volume of liquid fully occupies the space in the one located at the key... Pressing the key would force liquid through the fluid conduction line into the other one at the far end causing it to "inflate" and open the pallet. (until you release the key and the process reverses)  No precision machining required... A bit of "new design" required to create the fitting, likely a bleeding/charging Tee which would screw down onto the top of the "toothpaste tube" where the cap used to be... provided with an acceptable interface with whatever fluid conduction line one wishes to employ. 

Quote
Also, I very much doubt that the resulting touch would come anywhere near that of a properly constructed tracker action.

If its never been done,  how can anyone possibly know this ;) ;) ;)

This is where the "physics" gets in the way!  On the organ in question (Pasi Op. XIX)http://www.sacredhearthouston.org/OPUS19/index.html to mechanically link the pipework on the right side of the 30 or so foot wide window (plenty of space below) to the console
on the left, would have required  a horizontal mechanical connection of some sort, horizontal trackers out of the question because that distance regardless of material used would sag! (Gravity still works ;) Supports would have to be "friction free"... Yeah, right...  The sag would have to be "taken up" every time you pressed a key.   Rollers spanning that distance would have to have amazing torsional rigidity... no small order.  That kind of distance means in addition to "not twisting"
one still has to factor in the "gravity sag" and how far along one would need to install carrier bearings.   Bowden tubes (think shifter/brake cables on multispeed bicycles and similar)  have that constant friction issue to deal with also and in a much bigger way as the line running through it is in constant contact with the tube over its full length. 

"Notwithstanding the paragraph above"  there are obvious issues with "hydraulic action"... Gravity, inertia and Friction.  In the case of Pasi Opus XIX  the gravity thing would be much less of a problem as the majority of distance to cover is horizontal.  (Vertical arrangement would add the weight of the working fluid to the pallet spring pressure, how much in compared to a vertical tracker? Depends on tubing diameter.)   The friction issue would be related to the volume (not much) and pressure (not much, depends on how hard the key is struck by the organist ;) of the liquid going through an n-sized tube for d distance. ( A firefighter friend  of mine could likely work this all out in his head :)  Another frictional loss would be in the material being squeezed at either end of this "circuit" to move the liquid back and forth-- and I should not neglect the viscosity of our liquid!   The inertia in this case comes from the volume of liquid being moved about.

Pasi's solution was to use an "off-the-shelf" proportional electric action...  Something I am considering for the "hypothetical Concert Touring Pipe Organ"  8) 8) 8)



The objective is to reach human immortality—that is, to create things which are necessary to mankind, necessary to the purpose of the existence of mankind, and which have become the fruit that drives the creation of a higher state of mankind than ever existed before."

revtonynewnham

Hi

Hydraulics have been widely used in various fields, and I suspect that organ builders have experimented, but other forms of action are used because, over time, they have been shown to work - and in the main, to work reliably over 25 or more years, which means consideration of moving parts, wear & tear, etc.  Have you considered the additional weight of the fluid - especially for a transportable organ?

A well designed tracker action can (and often does) overcome the issues that you mention - especially where a "suspended" action can be employed - then the touch can be very light.  Tracker also has the advantage of the feedback to the player's fingers as to exactly when the pallet starts to open, and the possibility of controlling the starting transients of certain stops (depending on the voicing).

Every Blessing

Tony

David Pinnegar

Hi!

My gut feeling is that hydraulic fluid has more mass than air and hydraulics have to be hermetically sealed. Using conventional pistons with ring seals which deteriorate and introduce friction together with the mass of a piston, will all add forces to the touch. In contrast, a minor leak on a pneumatic will contaminate only air with air and with the low mass of a gas and low mass of, for instance, pneumatic pouches, other than electrics, pneumatics are the right way to have gone . . .

If you ever have the opportunity to play a French suspended action tracker instrument, you would not dream of wanting anything else

Best wishes

David P

KB7DQH

#5
The three traditional manual divisions, Great, Positive and Swell, are housed with the console on the left side of the window and have normal suspended mechanical key action and mechanical couplers. The Grand Choir and Pedal divisions are modeled after the Resonance division in the famous 1775 Jean-Esprit Isnard organ at St. Maximin, Provence, and share their stops, using independent stop actions to each division. Running a traditional mechanical key action from the console in the left case past the 22'  width of the large window would have been impractical. Our solution is to use the electric proportional key action developed by NovelOrg of Longueuil (Montreal), Québec www.novelorg.com.

Quoted from the Pasi Organs website ;)

Which is why I brought the subject up...

Reviewing the Novelorg www.novelorg.com website I find their solution for a great many design problems an elegant one... but the electronic aspect of it can be both a "blessing and a curse".   The concept sure gives a whole new meaning to the term "electronic extension" of conventional pipe instruments 8)

If installed as the only keying mechanism for an entire instrument it does provide proportional pallet opening but no mechanical feedback.

Their system can be utilized as an "electromechanical amplifier" to make playing a mechanical action instrument easier, especially under conditions where many couplers are engaged. The same installation could also be used to add a remote, movable console also.

Or, "piggybacked" onto an existing tracker mechanism to  allow for installing windchests and thus additional pipe ranks at locations impractical for tracker connection, and provide the control of a tracker with the flexibility of installation (and no real limits on instrument size except space and budget) only possible with non-proportional electric, or the dreaded "tubular-pneumatic" maintenance pig...

If a purely hydraulic system was a realistic possibility it would solve the mechanical feedback issue
and not require semiconductors or other electronic components which face extinction before the devices they are installed in have ended their reasonable service life... nor would it require electricity. 
The objective is to reach human immortality—that is, to create things which are necessary to mankind, necessary to the purpose of the existence of mankind, and which have become the fruit that drives the creation of a higher state of mankind than ever existed before."

revtonynewnham

Quote from: David Pinnegar on May 12, 2010, 11:20:02 AM
Hi!



If you ever have the opportunity to play a French suspended action tracker instrument, you would not dream of wanting anything else

Best wishes

David P

Hi

Definitely.  A couple of years ago I had the opportunity to play the 4 manual tracker organ by St. Martin (Swiss organ builders) in Girton College, Cambridge.  It's basically a French design (complete with the Grande Orgue on the lowest manual).  The action is lighter than some electric & pneumatic organs that I've played, and we were told that organ scholars often couple the manuals together to increase the weight of touch when practising for recitals elsewhere!  (Even 2 manuals coupled is still very light!)

Granted,a suspended action isn't possible in all situations - it needs height - but given sensible organ layout, mechanical action in most cases far surpasses anything else.  The only exception I would make is where heavy pressure reeds are part of the tonal design (high wind pressures do make tracker action heavy!)

Every Blessing

Tony