I had previously responded off list to Carl Dodrill about using a
vacuum pump converted to produce pressure to operate an Aeolian Pipe
Organ Harp in a church installation.

It is easy to convert vacuum pumps by enclosing them to produce
pressure, but the conversion is not the problem.  Reproducing piano
pumps are generally positive displacement type pumps.  This means the
pump can produce high vacuum at low volume air flow.  Player pianos
require very small volumes of air flow, and the pumps for them are
matched accordingly.

On the other hand, pipe organs and accessories for them, use much
greater airflow.  In the case of the Aeolian Pipe Organ Harp, there
are 49 large, single accordion-style pneumatics, one for each note.
In addition, each note has two valves, a large secondary pouch, a large
recoil pouch, and a large damper pouch.  Each note also has three
felted action bushings that are pressurized and leak a small amount of
air constantly.

It is possible that the harp could consume as much as 10 cfm of air at
7 inches positive pressure.  That would near the limit of the positive
displacement pump.  Therefore, that match is really not recommended.
In other words, use a blower.

Bob Taylor - Aeolian Opus 1280
http://members.socket.net/~rtaylor/aeolian_pipe_organ.html

 [ Wow, that's an impressive instrument, not the "Aeolian harp" that
 [ I imagined.  I thought a bellows pump could operate most any organ
 [ device, since most fair organs and orchestrions use a bellows for
 [ wind instead of a turbine.  -- Robbie