Making a Ultrasonic cleaner???
I am rrealy interested in the ultrsonic cleaners from companys like omegasonic and I think the other company is prosonics. But the price of these things makes them unatainable for me . The size I need would cost about $8500.00 .
They do not seem to be to involved in making, They use a stainless steel tank , a heater, a timer and some sort of noise device that makes the ultra sonic = sound waves.
Any of you guys ever attempted to make one?
I am thinking of giving it a go.
European supermarkets such as Aldi exist in the USA. They sell small cleaners from time to time at prices like £17 in the UK.
At that sort of price, you can throw them at the cat- or clean the wife's diamonds bought from the money you saved from making one.
Have repaired a few large hospital units years ago, they had multiple 2" dia piezo elements glued to the base of the stainless steel tank which was about as thick as stainless kitchen sinks in appearance. The unit had a high voltage push pull MOSFET driver circuit to drive the piezo's. I understand that driving audio piezo's with a square wave can shorten their life and that they prefer a pure sine wave to drive them but don't know if this would apply to ultra sonic cleaners in practice.
I'd imagine that some experimentation would apply with driver positioning maybe using a microphone hooked up to a CRO to gauge sound levels in an empty tank to make sure it's not cancelling out and then moving onto the aluminium foil cavitation tests.
Last edited by SAG 180; 03-15-2010 at 03:59 AM.
Reason: Added "with a square wave"
You need to find a surplus unit you can afford. Unless you're an electronics wiz, the high voltage circuitry and magnetics will be a significant development effort. There's very little good circuit info on the 'net. The PZT elements are typically stacked up between heavy steel disks, with a group of periphery bolts acting as springs, with the whole mess operating at mechanical resonance. Another significant development effort. Do a Google search on "Langevin vibrator". Small tanks will often just epoxy a piece of thin fiberglass material to the bottom of the tank as an insulator, then epoxy a disk or two (side by side) to the cloth. Better circuitry will modulate the frequency (or amplitude?) to break up standing waves.
Thanks for the replys.
What is a PZT element?
I will do a google search
A PZT is a piezoelectric transducer. It's a solid state (read, not using copper coils or anything like that) linear motor which converts an applied electric voltage into force (or vice versa). It's a pretty cool application of solid-state physics, but I digress (P.S. It turns out bone has piezoelectric properties... Go figure!)
Piezoelectricity - Wikipedia, the free encyclopedia
Basically, a PZT is what is used to actuate high-frequency speaker drivers and the drivers for ultrasonic baths. It is very difficult to drive a high-mass (heavy) linear motor periodically (back and forth, like a sine wave) at a high frequency (read: speed, sort of), so magnetic drivers for ultrasonic cleaners are apparently not used very often (copper is heavy). PZT's are great for generating high-frequency, low amplitude vibration, which is what you need for an ultrasonic cleaner.
I imagine you could make a small-ish, reasonable power ultrasonic cleaner with an elliptical tank and two powerful high-frequency drivers mounted at the foci of the ellipse. Then just drive a frequency modulated 10-35kHz (whatever you need) sound wave through the drivers using a regular home stereo amplifier, and your computer (or $50 ipod) to spit out the HF signal. Maybe the details of this are more complicated, though. I do know most stereo amps can output at least 15-22kHz, since the human ear can easily hear 15kHz, and 22kHz is not unheard of (sorry, that pun was bad).
Personally, I'd just buy one used or surplus.
Good thought on the elliptical focus idea. Questionable thought on the hi-fi amp. Two things will conspire to blow it up. First, the piezo elements (PZT- short for lead-zirconate-titanate ceramic) are almost pure capacitors. The hi-fi amp is likely to have trouble (trouble is the polite word for smoke) driving a capacitive load. There are also many hi-fi amps that have good response up beyond 20kHz, but when asked to deliver any power, the outputs switch too slowly and short out the power supply- taking the amp stage along with it. I'm not saying it can't be done, in fact it almost certainly can, but be prepared for some trial and error!
Most hi-fi amps deliberately roll off gain at these frequencies to reduce the likelihood of high frequency oscillation etc. You could certainly build an audio amplifier to do the job, but expect you would be disappointed if you just plugged in an unmodified amp and expected it to drive the transducer.
As far as the cheap ultrasonic units, I have a basic HF unit and reckon it's 9/10 next to useless for other than gathering dust. Occasionally I drag it out and humour myself that it does something the solvents wouldn't just do by themselves. The basket is handy and the tank SS so that's generally the most that can be said. I don't know what their larger units are like, but just how many times can you clean your wedding ring as I'd suggest that's all they're good for.
Decent cleaning tanks pack quite a punch, indeed I know of repeated ultrasonic cleaning of some fuel/vapour separators in an aircraft that caused the very fine holes they contained to actually become smaller (ultrasonically peened the holes smaller would you believe). It took a LOT of investigating to find that one I can tell you! Anyway, I think it's safe to say it's not a problem you're likely to come across with a HF or Aldi unit
Personally I think making one would be a complete PIA when used units are freely available and not THAT expensive if you add up the cost of trying to DIY. However if you insist on pursuing that path maybe look at some of the lower frequency echo sounder transducers? I could be completely talking out my clacker of course, as it's been years since I was working on them, but as I recall they could pack a reasonable punch in the test tank, the units designed for deep water operation would be an appropriate frequency, and I seem to recall they were even driven by square waves (not that's much an issue anyway).
Here's a basic schematic down the page for a cleaner: Various Schematics and Diagrams
It's a self excited sine wave driver similar to battery fluoro inverters only higher voltage.
Wow !!! Lots of good info .
Alot to absorb.
I think it can be done cheaper than they are selling them for . These days I have more time than I have $$$.
Do you think a welded stainless tank would be good or should it be seemless?
I wonder if the sounds will break the welds down over time ??
Thanks for all the input!
It probably would not be a problem with a push pull driver, but you need to be careful with single ended ones. I have never made a cleaner like this, but I did work on ultrasonic tooth scalers. They used a magnetostrictive element made of nickel strips. The original design I inherited from some unknown engineer gave erratic results. It turned out that it needed a means of unloading the energy in the transducer at the end of the wave peak. He had used a rather poor transistor, which usually leaked enough to do it. When I substituted a better one, it wouldn't work at all. The transducer just scrunched up and stayed there. I had to add a diode and resistor to absorb the rebound.
Originally Posted by SAG 180
I have a commercial seamless tank (about 3 gallons) that has developed cracks at some bends on the top. My guess is that good welds would hold up just as well, but even slightly less than good welds would fail quickly.
I do not think it is practical to make a ultrasonic cleaner. Two issues that I am aware of are the tank, it must be drawn and stress relieved. A welded tank will fail. The mechanical attachment of the transducers to the tank is done with some rather special epoxy or so i have been told. The energy delivered to the transducer will destroy most bonding agents. Loss of the bond will destroy the transducer. This is what I was told when I had a ultrasonic cleaner repaired. The repair included replacing the tank with the transducers attached and the electronics. I got back my old enclosure, power cord and on off switch. As I recall the repair was 20% of a new unit. Go figure! Maybe they liked me
Watch the Dog
If you intend to accomplish this dream, AND use it near your, or someone else's, home, watch for any dog's reaction when you first turn it on.
If the dog goes stark raving bonkers, then the frequency of your assembly, plus the related harmonics, will be within the dog's hearing frequency range.
And depending on distance to those tender ears, and the power being applied, your cleaner might become a real painful applicance.
Been there, done that, had to clean the wet yellow puddle.
3 Lead Piezo Disk (Pkg of 2)-The Electronic Goldmine
Cheep enough to experiment with. The green ones near the bottom come with a schematic for a drive diagram. I have ordered from them before and like them. I would think that something like Goop would work well to glue them down.
I did a disk replacement on a small ultrasonic cleaner and it's still holding together with J.B. Weld. The secret is probably cleaning and surface treatment. I suspect the larger units get sandblasted, etched and who knows what else, before bonding.
Beyond a certain size, commercial units abandon built in transducers in favor of immersible units. Rather than coming from a single side mounted outside the tank (the bottom), they are placed on two sides inside the tank (left and right) for greater energy transfer (and cleaning). They can be mounted or dropped in or out as needed.
Originally Posted by Air Chunk
How about building your own tank and just adding a few ready made transducers?:
Immersible Ultrasonic Transducers
That is good to know . It might be easier to make that way .
I am shooting for around 20 gallon size.