Leak detector

[CharlieVT]

Lots of help on this site. As a newbie, I've gotten lots of info. I realize many questions come up again and again. The kind folks on this site continue to answer time and again.

Maybe this is something new and may be helpful to someone.

I've been trying to find leaks in my vacuum dry line. I have a pretty long run between the vacuum pump and my releaser. As I was walking along, listening for leaks, using a stethoscope came to mind.

Here's a true maple industry leak detecting stethoscope. It actually works pretty well. I suppose if you have hearing loss at high frequencies it won't be as helpful, but so far my experimentation indicates that it is a lot easier to hear a leak with the stethoscope than with the naked ear. And if a leak is detected, it is easier to localize exactly where the leak is. I found a cam-lock connector that was leaking both at a pipe clamp connection and at the cam-lock seal. Listening with the naked ear, I could hear there was a leak but unable to localize it. With the stethoscope I could quickly tell exactly where the leaks were.

I wonder if a few curious folks might try making one and reporting their experiences back here.

Assembly is pretty straight forward from looking at the pictures here.
http://mapletrader.com/community/attachment.php?attachmentid=8404&d=1389986916


(Read for tongue in cheek humor where it seems to fit....)

Parts list:
1) Some 5/16th tubing. Technical details: use semi-rigid or rigid tubing for the two sections that go from the "Y" to the spouts (ear pieces). Orient these sections on the "Y" so that the curve that existing in the tubing as it comes off the roll causes the ear pieces to spring inward.
Use your most flexible tubing for the single section that is the "pick up sensor". More flexibility in this section makes it easier to point the "pick up" where you want without the ear pieces twisting in your ears. The length of this "pick up" tubing is a matter of preference; the over all length won't significantly affect function.

2) two spouts (in this application I think the non-check valve version is going to be better.)

3) one "Y". (So there is a use for "Y" fittings after all...)

Other details: Slightly melt the short pieces of tubing that are the ear pieces to get rid of rough edges and make 'em kinder to your ears.
The ear pieces should point slightly forward so that the orifice of the tubing aligns with your ear canal.
http://mapletrader.com/community/attachment.php?attachmentid=8405&d=1389987744

[maple flats]

Neat, and far cheaper than my $400+ unit too.

[happy thoughts]

wow, that's pretty ingenious! Nice job :). If you can find a cheap pediatric or infant sized stethoscope you could probably repurpose the head to make it even more sensitive. These can sometimes be found for under $10 like this one here: http://www.allheart.com/product.aspx?p=ahdst0600

[BreezyHill]

Looks great! should have used CV. burst of air wouldn't hurt your ear drum.

[WoodButcher]

awesome idea... i get such a kick out of homemade stuff.

heres something though that might work but if you run into a rut with your setup....

a mechanics stethoscope is fantastic. i use one for finding exhaust leaks on 2-stroke motors, vacuum leaks, etc.
cheap too .. very sensitive.
http://www.amazon.com/Lisle-52500-Mechanics-Stethoscope/dp/B0002SQYSM/ref=sr_1_2?ie=UTF8&qid=1391899877&sr=8-2&keywords=automotive+stethoscope

[Machinist67]

Check out this stethoscope http://www.harborfreight.com/mechanics-stethoscope-41966.html

[CharlieVT]

I think mechanic's stethoscopes typically have a solid rod as a sensor that then transmitts vibrations through the metal rod to a diaphram. The solid rod of a mechanic's stethoscope won't sense the sound of the air molecules rushing past the end of it the way a hollow tube will.

For picking up the high frequency sound of a vacuum leak, I think you want a hollow tube that goes all the way to the end of the sensor rod. You could take a standard medical stethoscope and pull off the diaphram assembly that is normally placed on the patient's skin and use the open end of the tube or replace that part with a hollow tube extension and use that for checking for vacuum leaks. Like this:

http://mapletrader.com/community/attachment.php?attachmentid=8682&d=1391951450

However, the reason I posted my homebrew "maple tubing" stethoscope was to share a low tech method for helping to find vacuum leaks with stuff sugarmakers would have on hand, without having to go shopping.

I also suspect that the stethoscope method will be inferior to the electronic leak detectors which amplify the sound of a vacuum leak and change the frequency into a range easier for most people to hear. A good electronic unit is going to work better, but the stethoscope method is cheap.

May your vacuum always be greater than 25mmHg at every tap. :)