Peter Davey Heater

[storre]

I wonder if it is possible to calculate the exact size of the bell so that it matches the 50Hz?

Yes technically but I think it will be more feasible to just make it a little bigger and then grind it down. Should be easy to grind down a small soft metal bell like he is using. I think the frequency needs to be dead on to be the most efficient. Once you make one and grind it down then each subsequent bell you could make a little closer to the final size so you have less adjustments to make.

[Nali2001]

Hi again,
Well there is one thing that I am not sure about since I did never ask Jan Pajak.
And that is WHICH dome is actually tuned? The inner or outer, and does it matter at all? I think the inner is the tuned one. But since Pajak is a very friendly guy you might as well ask him yourself some questions. Maybe he had some contact with Davey lately. It been like 3 years ago when I had my conversation with Pajak. So maybe he knows some new things.

One other thing, and keep in mind I don't intent in any way to bring Davey?s insight down. But this thing is not rocket science and one should not spend too much time 'analyzing' his pictures and wonder why this and that. He very likely did never made a single dome himself. He just uses dome shapes like the bells from bicycle old bells and clock bells.
http://uk.geocities.com/brettoliver@btinternet.com/images/Masterclock/Chimebell2.jpg
http://libizblog.files.wordpress.com/2007/09/fire-bell-alarm-clock-1.jpg
http://img.alibaba.com/photo/50969516/Bell_Alarm_Clock.jpg

And stuff like that. And it is doubtful that there are any formula's formed by him to predict various behaviors. It is a hands on thing. Get two bells try to tune one to 50 hz harmonics. See it it responds to the sound of a nearby played 50hz source. Or get a frequency generator program and do a frequency sweep while holding the dome near the speaker or something. And to tune just sand the dome shorter and check for freq. again. Keep also in mind that the freq. of the dome is also depending on the structure it is attached to. So tuning the dome free hanging from a cable or something and then bolting it down to a handle is not smart. The thing must be tuned while connected to the structure  it is supposed to be on in the long run.

Regards,
Steven

[devrimogun]

@ devrimogun:

As you said the tuning of the 2 bells should be easy. I know I can do it by ear because I've done a lot of piano tuning but it could be done using a computer or other device. The other parameter is the distance between the 2 bells. My feeling is that it just needs to be at a distance such that the node of the vibrations coming off the bells hit the opposite bell with the node of the wave. I think though it would be much easier to just mount the upper bell on a post that is a screw and fix a nut on the top bell. This way you could wind up and down the outer bell and change the distance in a very controlled way. Just wind up to increase the distance between the bells and wind down to decrease. Finer thread on the screw would make for finder adjustments. The screw would either have to be non metal or if using a metal post/screw then it would have to be hollow so the inner bell could be attached to another post (could be metal) that fits inside the post. Then just insulate the inner pole that secures to the inner bell from the outer bells post/screw. It should be a tight fit. Then just screw up and down and wait for the sweet spot by testing the speed of the water boiling. Once the water boils instantly then that's the spot.

I personally will try to make or find a teflon screw and drill it open to make it a thick tube basically with threads on the outside. Then the inner bell will be attached permanently to a metal rod that fits tightly in the drilled out teflon screw. The outer bell would have a nut welded to it so it can be screwed up and down to find the right distance. I don't see it as a tuning to get this distance. The only things that are tuned as far as frequency is concerned are the 2 bells. The distance between the bells we can start as a guesstimate using the photos. It appears to be about a 1/4" but I would start close and wind out or the opposite. The right spot will cause instant boiling.

@storre I really do not think that you should deal with all those details like teflon etc. Remember that if something works it will work in many different ways. We now know almost everything about this device. Just put together the same stuff that Davey did all simple materials screws and washers. BTW I also think that the tuned one is the inner one from what I read at the mentioned sites above.

I also agree with you to try a larger set of bells for larger amounts of water but hey; do you realize what a successful replication of a basic  setup means already?

Maybe I can find bell company around here

[hartiberlin]

Yes technically but I think it will be more feasible to just make it a little bigger and then grind it down. Should be easy to grind down a small soft metal bell like he is using. I think the frequency needs to be dead on to be the most efficient. Once you make one and grind it down then each subsequent bell you could make a little closer to the final size so you have less adjustments to make.

Hmm,
I guess it might be easier to buy 2 stainless steel salat bowls and
hook them next to each other maybe a few millimeters away ( the distnace depends on the
wavelength of the resonance frequency in water probably....)
and then pulse this thing with the resonance frequency via a MOSFET circuit...
Then you can also add a big choke as the inductance L component,
so you have a real LC circuit.
Then just tune to the resonance frequency and pulse it at this frequency.
then adjust the distance of the 2 bowls and retune for optimum
resonance frequency and watch the water temperature...

Maybe someone can do this,as I am busy right now
with other things as WM2D simulations..

[ramset]

The Amish make bells maybe I could order a set from Mr Thrapp?    if the resonance is trapped between 2 bells there may not be a front or back   just a sender and bouncer