Electric valves for reproducing pianos
By Robbie Rhodes
John, the IMI Cassette Converter prototype was originally built with the Reisner valves you described, and was thus quite bulky. The production units featured a tiny magnet valve about 1/2-inch square by 2.5 inches long, with a spring-loaded rubber-sealed armature of about 0.016 steel only 0.150 diameter -- very low mass.
It was capable of very high repetition rates, and no degradation in piano performance was observed. With a 15-volt power supply the valve was good for 40-inches vacuum in an Ampico B. (The valve failed to open in a DuoArt when the crash valve drove the pressure to 70 inches!)
The small size was the only reason it was used instead of the Reisner valve, even though it cost considerably more. Technician Randy Cox and I priced the components for a new production run, and the cost was about the same as your design: more than $6 each in a run of 1000 units. Too expensive for us....
What's the performance of your design like? I'm skeptical about repetition rate if you're moving a massive solenoid slug around.
Keep the ideas flowing!
-- Robbie Rhodes
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(Message sent Fri 1 Dec 1995, 07:38:24 GMT, from time zone GMT-0800.) |
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