@all

Since I last posted here I tried a few things regarding Davey heater and here are some conclusions:

First, there is something indeed with this device when the inner bell reaches resonance. Even I was not able to reach full resonance (due to misleading frequency data on my side), the heating process amplified at the proper distance between the bells (about 4 millimeters, as stated in the documentation). Also another mistake that I made was that I made the outer bell bigger (longer) than the inner one. This design made steam building up inside the outer bell and by pushing the water down, disconnected the inner bell from contacting the water.
So always made the inner bell bigger or have holes in the top of the outer bell for steam venting.

After seeing how my device worked and studying the Davey's movies, I concluded that in his last design, the sphere is the inner "bell", the resonator, and the top bell is the outer bell (there is no "protection" bell, as in the first sketches using semi-spherical bells). The sphere has that hole at the bottom, because it needed tunning, so it has to be machined. The covering plate I think it's just a try to make the sphere back as perfect as possible, but still not affecting its resonance.

Also, there is a problem with the voltage of the mains. At the so small distance between the bells, we face a process that normally happens outside the resonance too: the device will start heating the water by dragging a lot of amperage, somewhere beyond 20A. So either the resonance will cause this effect to be dramatically reduced (as a previous poster suggested too), either we should go for a smaller voltage (or else there will be no efficiency).

So my future tries will involve a better tunned inner bell with a smaller voltage. Maybe also a spherical design too.

Overall, I think Davey's device uses the same principle as WITS' water heater, just he tunes his device to the mains frequency, while WITS is going with the frequency after the sphere resonance. Of course, WITS' device is more efficient, as it resonate the sphere at its fundamental frequency, while Davey's is running on an octave.

See the WITS heater here:
http://youtube.com/watch?v=ZxnEQssJ4FQ

Regarding the patent, I say forget about it, as it's early work and even Davey dropped the idea long time ago.

way back in the 1940s, either Peter Davey, or someone he worked with, discovered something important enough for him to submit a patent for it

the patent application expired after 1 year - it was never pursued!

although Davey went on to build handheld heaters for himself & modified the design - he obviously never believed he had found anything as significant as the first discovery - there were no more Patent applications after the first one!

what does this tell us?  it says that the most important features already exist in the first patent!  ie. Davey modified the design in a way that was unimportant to its operation

if we ignore the only Patent we have then we start wasting a LOT of time

Davey has already admitted publicly, on the video, that he's keeping something back

the only thing which is in the patent, and which he doesn't talk about in any interviews, is the loose arrangement of the electrodes

(the Patent begins by saying that concentric element electric water heaters are already a known art - the novel features of this one, at that time, were just the the rapid operation, the loose electrodes and the safety aspects)


in general, the current draw depends on the electrode gap - more gap, less current - less current, less heat


so, if there is anything anomalous happening at all in this heater, i strongly suggest that it's to do with the only thing which Davey DOESN'T talk about - the looseness of the electrodes - they can vibrate

note that in the Patent they don't have to resonate, or be tuned - they can just vibrate

this will happen either with the mains freq. or with the bubbling action of the steam & water - tests will be needed to see which is more important


the very small outer 'bell', between the handle & the sphere, is not a part of the heating process - when the water boils, steam & hot water bubble out the top of the heater, as cooler water enters at the bottom

that small outer bell is there to deflect the steam & water back down into the glass/cup & give some protection to the user - it doesn't need to go under the surface of the water (see the 'Twister' photo above), in fact, as a vent it SHOULDN'T go under the water


NerzhDishual has made a start (& already got some near OU results!) - build on that experience

i bet ND was too good a constructor to leave anything loose - am i right?

so, repeat the experiments with one or both loose electrodes (may have to be loose electrically as well as physically - see my comments above about possible mechanical SCR action)

maybe increase the electrode gap if it's pulling too much current

start testing - run some tests with anything concentric (bells, tubes, cones, whatever) - vary the parameters - look for a performance curve - find which parameters can be tuned for improvement

don't spend time with acoustic tuning of bells - until you know for a fact that bells are actually necessary!


...was i little too outspoken there?  ...not like me at all!  i just don't like to see people wasting their valuable time & effort 

good luck
sandy

@nul-points

that small outer bell is there to deflect the steam & water back down into the glass/cup & give some protection to the user - it doesn't need to go under the surface of the water (see the 'Twister' photo above), in fact, as a vent it SHOULDN'T go under the water

There is no "twister" in that photo. Watch it carefully and see that the apparent twister is just the continuation of the wire that the third hand is inserting into the glass, most probably a temperature sensor (I suppose it's the hand of the DSIR professor that tested the device).

Watch the video again also and see that there is no twister:
http://video.google.com/videoplay?docid=-1527526922275986120&hl=en

Also notice that the boiling actually starts when the top bell hits the water. So that's an electrode too

@nul-points
Also notice that the boiling actually starts when the top bell hits the water. So that's an electrode too

Good point! I think that electrodes may be placed in such combination:
- center one (not visible)   bell - first phase of AC
- cover spherical - neutral ground (safety device)
- outer one  -deflector - second AC phase - carefully insulated and placed above neutral with a gap between them

@edelind:

Looking at your spectrum analyzer I would say your mains are 50Hz? Is that right?

Yes. I was wrong saying it is 56Hz (old uncalibrated oscilloscope ). It's 50Hz sharp.

There is one more thing : in older device the spherical cover looks like painted while in new one it's shiny metalic. Is that correct ? But anyway both are spherical.I bet it's important - maybe that cover is not only neutral ground but also resonant cavity like in Thrapp device ?

I feel we are very close ... If a retired musician could done it why not me ?

Do you saw any pictures of original devices which could prove which way the water flows into it ? I see two possibilities : from the top hole hidden under the second electrode 'cap' , or from the bottom through not visible hole. Hard to guess actually...

I have another idea about how he is able to limit current. Look how carefully he puts this device into water cup or fill the cap slowly.If that device is heating a small amount of water first with large current then a steam generated probably CHANGE the resistance of path between electrodes and that way maybe the current drops !

Interesting...Look here : http://www.hydrodynamics.com/technology_review.htm

Cavitation at 3600 rpm. Isn't that 60hz ? 3600 /60 s= 60 rps=60hz