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650 views
01:09 Feb-25-2002
wangdongbiao
Delay line

I want a delay line (Max.200 celsius degree), which is about 3" long. But I am not sure If I can get signal because the delay line is too long.
Who can recommend a delay line, which is about 3" long and can get good signal.




 
06:47 Feb-25-2002

Tom Nelligan

Engineering,
retired,
USA,
Joined Nov 1998
390
Re: Delay line : I want a delay line (Max.200 celsius degree), which is about 3" long. But I am not sure If I can get signal because the delay line is too long.
: Who can recommend a delay line, which is about 3" long and can get good signal.

What type of test are you trying to do with it?

In general, it is certainly possible to make long, high temperature delay lines for use with large diameter, low frequency transducers, but not for high frequency, small diameter transducers. That is because you must maintain a length-to-diamter ratio that does not exceed 5:1, preferably 3:1, to avoid excessive sidewall mode conversion effects. Also, the polymers usually used for high temperature delay lines are too attenuating for higher frequencies, although they work fine at lower frequencies (under 5 MHz).

If you can let us know more about your application, we may be able to supply an appropriate transducer and delay line.

--Tom Nelligan
Panametrics, Inc.
www.panametrics.com



 
01:17 Feb-26-2002

Joe Buckley, Sonatest Plc

Consultant, ASNT L-III, Honorary Secretary of BINDT
Level X NDT, BINDT,
United Kingdom,
Joined Oct 1999
512
Re: Delay line : I want a delay line (Max.200 celsius degree), which is about 3" long. But I am not sure If I can get signal because the delay line is too long.
: Who can recommend a delay line, which is about 3" long and can get good signal.
.

We've had quite good results in a similar application (except a LOT hotter) with fused silica - works OK up to around 10-15 MHz, but its physically a difficult material to work with. We dont have any regular products however.


 


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