Coil for plastic pvc pipe

[mikey]

How would i put the tx rx coils on a pvc plastoc pipe? Would i wrap the Tx coil first then the rx coild right next to it? Im trying to deteact metal going thru a plastic pipe. The plastic pipe will be 4 inches wide.

Thanks mike

[Sid]

Hello, this case I met. Divide the Rx winding in two and put it on the right and left side of the Tx coil. connect the antiserial way and get IB-PI. Nice day. Sid.

[mikey]

What do you mean by connect the antiserial way and get IB-PI ?


mikey

[mikey]

One more thing, What distance do i put the windings next to each other?

Thanks mikey

[Sid]

Hi, the Tx coil was fed by pulses, that´s PI and the Rx coils were placed symmetrically in a distance about half inch, so IB. It can work with sinusoidal signal as well. Antiserially means, that the polarity of coils compensated the induced signal to zero. Sid.

[mikey]

Thanks for all the help Sid.

Thanks
mikey

[Radioactive]

Question

Four inch wide pipe, is that the pipe circumference or the distance between the ring? If it's PVC, how are you going to lift it? I presume you mean that the pipe is say 3/4 inch and you wind it. I made a PVC ring. I first made a template on a board with nails. I measured the inside diameter of the ring and then cut the pipe (I used 1/2 inch PVC light wall). I then took the pipe and heated it in mineral oil. I made a heater box (6 feet long, 3 inches wide, 4 inches deep) left it in for about three minutes then removed it (it was like a slippery noodle) and then placed it around the template to harden. After which I cleaned it with Dawn liquid, attached the ends with PVC cement. I then did the winding, starting on the right over the top, 168 turns, then drilled a hole to lock it and feed it back to the beginning, this was the Tx side. I then did the same for the other side starting over the top 168 turns then back. So i then had two winding, one for RX and one for TX. I then placed my antenna analyzer on it to make sure that the 168 turns were close to the frequency of 100 Hz. I had to make some tweaking to obtain a perfect match on each side. Because I started each turn over the top, the winding were 180 degrees out of phase. I was not concerned with this as much as the matching of the RX and TX winding. Anyway, it worked great, but I must give the credit for this out of a Nuts and Volts article I read. I got the idea for the mineral oil box from a friends electric company that would pre-bend 12 foot sections in an mineral oil bath and set them on a wood template. I've made some great projects this way. I took a BIG 8 inch heavy wall pipe in the oil (with one cut end to end) then would open it up, and lay it flat. When it hardened, I had a nice flat 1/4 PVC square. I've found a lot of scrap pipe pieces around construction sites for free! I've made some nice PVC boxes for projects, and nice curved pipe for detectors.

Thats enough ranting! Hope it gives you some ideas.

[Radioactive]

Correction

Correction:

100 kHz.

[Carlos]

Coil for plastic pvc pipe

Can you put any phtograpies of your proyects of coils?

[diggerbarns]

I think that what you are trying to build is what is called an Aperture detector. This is a 4 inch diameter pipe with coil/coils on the outside. If its a pulse induction you can use just one coil, or if its an induction balance you use three coils TX in the middle and a RX each side. If you go to Google and put in "Aperture metal detector" there is quite a lot of info on this type of detector. Usually for detecting metal in food and other materials. There is also some info at www.saxons.uk.com/aper.htm if you are trying to build an IB type it will be more difficult. The two RX coils will have to be moved gradually very small amounts until there is a balance situation. Then fixed very securely.

[Steve Norman]

Great idea on using heated mineral oil to mold pvc.

I would like to try and build something like this too.

Do you guys and gals think a cheap detector like the one sold at http://www.harborfreight.com/cpi/cta...emnumber=43150 will work using the TX in the middle and a RX each side?

I figuer i can undo the winding on the coil and rerind the winding on a plastic pipe if it will work.

[Radioactive]

Which one?

No Steve,

It's a BFO type and is not very good. I would recommend Carls Hammerhead.
He has the board in two types, Surface Mount (hard for newbies with glasses)
or thru-hole type. The system is all set for you to put it together at your own
pace. If you are going to purchase a detector (all ready to go) you have to
look at what you want to search for. Expect to pay some good money for a
new one out of the box that searches deep and has some spot on finder
display (not just a meter or noise). There are a lot out there, check out the
other forums here about detectors, and check out the For Sale Forum. You
never know Steve, building your own could give you a new hobby. There are
a lot of us out here that will be glad to help you, and walk you through the
rough areas.

I will try to post some photos of the PVC. Now, I should give all of you a
WARNING! The mineral oil will burn you! I use Sterno (little cans of flames)
and give it a while to heat it up. The my friends electric company uses a
gas heater under the oil. It will boil!!! They use full face shields, heavy
gloves that have wrist shields, a leather smock, and leather upper
body chaps (like a shirt with just sleeves and no back. If it splashes, you
don't get burned.

They had a bunch of the old gray PVC (out lawed and could not be used) so
we worked a lot of it into a large PVC ball (we were told to get rid of it)
and it looked great! We painted it. and it was put in front of the building
as a sculpture! About a year later i was told he sold it for a lot of money
to some art collector! I did not see any of the money for my part of the
creation!

[Steve Norman]

Do you have a site for this Carls Hammerhead


Thanks

[miqui]

carls hammerhead

Do you have a site for this Carls Hammerhead


Thanks

this is the site:

http://www.thunting.com/cgi-bin/geot...head/index.dat

enjoy it,

miqui

[markII]

Wouldn't a bfo detector work if he just trying to detect metal going thru a 4" pvc pipe. Since he your only talking about 2" to center of the pipe.