Some of the MMD group may be interested in a piece of equipment which I
have built in order to _measure_ the leakage in pneumatic components.

Most of the existing leak detection techniques, no matter how sensitive or
elegant, are comparative in nature only.  In an attempt to put more
science and less "black magic" into my piano restoration I have
developed a quantitative leak measurement system.

Using this equipment the actual leakage of pneumatic parts can be
measured in cubic inches per minute.  (Ampico certainly used to measure
component air consumption and leakage.  In a series of technical ads in
1929 Ampico boasted of their research labs ability to measure leakage in
cubic inches per minute.  See AMICA News Bulletin March\April 1992 pages
15-24.)

The equipment can measure leaks from about 3 to 30,000 cubic inches per
minute.  To put some meaning to these figures, here are a few measurement
which I have made:
•
    New unsealed pouch            25  cubic inches per minute
    Stack valve lower seat        15          "
    Piano reservoir              500          "
    Piano stack                 1000          "
    Leaky foot pump piano     20,000          "
•
The variety of components that can be tested is virtually unlimited:
pouches, bleeds, leather samples, porous wood, complete pianos before and
after restoration, etc., etc.  If any one is interested I could provide
further technical details.  This is probably not the time to do it.

I am absolutely convinced of the value of quantitative measurement.
Any comments?

Philip Dayson

 [ I'm in absolute agreement with you, Philip.  Could you begin by
 [ telling us how to measure the airflow of bleeds and small hoses,
 [ for example?  Can your technique be used over a wide range of
 [ pressure?  Can it measure in-line airflow?  Please tell us more.
 [ -- Robbie