Because it is a *vacuum* leak and I suspect they don't want their expensive
equipment full of soapy water....

Regards

Mike Rigby-Jones

> jones_gl@EFN.ORG wrote:
>
> why not just use soapy water to find the leak?
>
> --------------------------------------------------------------------------
> ----
> A member of the PI-100 Club:
> 3.1415926535897932384626433832795028841971693993751
> 058209749445923078164062862089986280348253421170679
>
> On Tue, 29 Jun 1999, Graeme Smith wrote:
>
> > Now this might seem low tech....
> >
> > But air leaks are high frequency noise.
> >
> > add to this the fact that they tend to be fairly localized, and the
> answer
> > turns out to be a long tube not too dissimilar to a straw...
> >
> > Kind a reminds me of ballancing two venturi carbs....
> >
> > You feed the microphone into the straw, blocking side noise, to create
> > a sort of directional pickup. Then you monitor loudness of high
> frequency
> > noise components.... (High pass filter?) as volume increases, led scale
> > advances...
> >
> > The neat thing about this is you can set the zero point to near to a
> place
> > that doesn't leak, and then trace the seals etc, with the sensor tip,
> and
> > actually pick out the place where the seal is leaking. Not only that,
> but
> > it saves on thickening of eardrums because you are not exposing the
> > workers ears to focussed high frequency sound.
> >
> > Getting the sensitivity/frequency cut-offs will require some work, but
> > then, I don't get any money for the idea....;)
> >
> >                                 Grey
> >
> > GRAEME SMITH                         email:
> grysmith@freenet.edmonton.ab.ca
> > YMCA Edmonton
> >
> > Address has changed with little warning!
> > (I moved across the hall! :) )
> >
> > Email will remain constant... at least for now.
> >
> >
> > On Tue, 29 Jun 1999, Roger, in Bangkok wrote:
> >
> > > I have a customer having problems with vacuum leaks (-50 kpa or so
> > > range) in equipment that they manufacture.  I expect their
> > > problem is with connectors and seals, and they have asked for help to
> > > locate and correct the problem.  Seems simple enough to sniff around
> > > with a tiny microphone.
> > >
> > > Thought...why not develop a simple handheld field
> > > tester...PIC...active filtering...LED bargraph...etc
> > >
> > > Unknowns...are there audio signatures that would allow this...has it
> > > already been cheaply and efficiently done...
> > >
> > > Appreciate any input.
> > >
> > > Regards/Roger, in Bangkok
> > > Roger N. Shane
> > > Suncolor Co., Ltd.
> > > P.O. Box 11-303
> > > Prakanong, Bangkok 10110
> > > Thailand
> > > Email:  roger@wnet.net.th
> > > FAX:    +1 (707) 276-1170
> > >         +66 (2) 291-3826
> > > ICQ     2152164
> > >
> > > SAHA GROUP...Thailand's Best!
> > >
> >