Subsea Acoustics For Commercial Diving

[GTDan]

I work for an offshore construction company and would like to take a new safety measure in one of our common practices. Below is a brief description of the practice. I am not looking to invent/patent anything, I am looking for an already made product.

Currently, when laying pipelines, commercial divers check the line as it is being laid for proper execution. If there is a buckle/dent/kink/etc that can create an opening in the line, there is a pressure differential as the line is now being filled with water through the opening. We currently have safety precautions in place to avoid injury to the diver, but I would like to take this to the next level.

I am looking for an acoustic device, something handheld such as a transducer, that the diver can hold to the pipeline. If there is a leak in the line, the transducer will pick up the extra noise/vibration and relay it to the appropriate personnel to all-stop the diver and the pipelay.

The transducer cable will be married to the diver's umbilical and the transmitter will be with the diving supervisor.

Any thoughts?

Regards, Dan

 

[unclesyd]

I would give Aquarian a call to discuss your application.

http://www.aquarianaudio.com/

Also there are some ultrasonic flow meters that have an audible output.

 

[Compositepro]

Are you sure the human ear will not work all by itself for this purpose?

 

[GTDan]

The diver wears a hat. He will not be able to hear that. Also note that if visibility is poor, they will not be able to see well, or at all.

 

[unclesyd]

I was just getting ready to post that the few times I've had on commercial diving gear you couldn't hear anything other than a hard rap on some metal and the air in and out of the mask.

 

[unclesyd]

Here is another approach you might use to make a few test runs. This is one of several on the market and is probably rugged enough for testing. It the idea works out you could should go with a more robust setup.

http://www.dolphinear.com/de-what.htm

 

[GregLocock]

If you are wedded to using noise then a hydrophone might do. Bruel and Kjaer make them.

http://www.bksv.com/Products/TransducersConditioning/AcousticTransducers/Hydrophones.aspx

You might have more luck with an accelerometer, possibly with a magnetic base.

Cheers

Greg Locock


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[GTDan]

Thank you for the comments. This is a good starting point. Time to start making phone calls.

 

[GTDan]

Thank you for the comments. This is a good starting point. Time to start making phone calls.

 

[GTDan]

A hydrophone may not be the right answer as it will be picking up too much background noise. I am looking for something that is applied similar to a doctor's stethoscope. Any ideas?

 

[MadMango]

I have the same thought as Greg, use a hydrophone and encase it in a custom housing (a potted tube perhaps?) that will cancel out the ambient noise but when held against the pipes will still conduct sound.

http://www.aqaud.com/product.php?productid=22&cat=1&page=1

"Art without engineering is dreaming; Engineering without art is calculating."

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[MadMango]

Oops, posted too soon, they even make a cap that fits over teh above linked hydrophone to do what you want.

http://www.aqaud.com/product.php?productid=11&cat=35&page=1

"Art without engineering is dreaming; Engineering without art is calculating."

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[unclesyd]

You beat me to posting about the accessory that convert their hydrophone to a contact mic. I would also imagine that they can filter out the unwanted noise on the surface if required as OP posted someone on the surface is to interpret the signal. They state they don't sell software but have several links to various sources.

If you go to the Dolphin Ear site there are some sounds samples over a wide spectrum of frequencies. There software is free.

I don't think the listening and interpretation part is going to be any problem. The problem as I see it is to get the equipment hardened and rugged enough for divers to use without any added finesse.

 

[GregLocock]

One of the most useful tools under a car is a pointy stick with an accelerometer on it. You could jam that up against the pipe with ease.

Cheers

Greg Locock


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