We are interested in piezo pumps and their efficiency. By efficient we
consider the amount of mechanical work produced in relation to the
electrical energy consumed. We would need an efficiency of at least
30% to be able to use this technology.

The pump would ideally pump with a speed of, in a pressure less state,
10-20 ml/minute, but 1-50ml/minute is still of interest. The pump must
also be able to withstand a pressure of at least 30kPa in the ideal
pump speed range. For lower speeds, a higher pressure tolerance is
critical. The pump shall also be pretty small, a few centimetres.

Are there any products on the market that can achieve this, if not,
which companies are developing _effective_ piezo pumps, and what time
to market can be expected for a pump with the given efficiency?

Sorry I can't answer, but others may find it useful if you could
indicate the fluid, and perhaps the temperature. Pressure differential
too.

Best

...more musings. I presume you?ve gone through the web and found things such as :-

http://www.spie.org/scripts/abstract.pl?bibcode=2001SPIE.4327..425B

But you?ve got me thinking (a rare event). Maybe any input I can give
has already been surpassed by you, but just in case....

Anyway, the efficiency of acoustic piezo drivers is high, maybe up to
30%, partly because the load is impedance matched. Unloaded they are
essentially capacitive. But that doesn?t necessarily preclude high
efficiency if driving variable loads, just that the drive circuitry
would have to be designed to accommodate. That means a resonant drive
rather than just blatting the thing on and off. Doubt manufacturers
are worried about efficiency when the power requirements are so low in
the first place so you may have to custom design the drive.

Have you considered experimenting with pies ink-jet heads, just to get
a feel for the thing?

Best

Sorry about the lack of information.

The fluid in the pump is water and the temperature range is 25-40
degrees Celsius. The pressure differential is at least 30kPa. When the
pump is not powered and not running it _must_ block the fluid and keep
the pressure stable between the two sides of the pump.

We have been doing experiments with piezo disks for audio
applications, which we are driving a lot slower to measure the force
they can give. We can then later create a resonance circuit for the
disk.
This needs however some development and research and a desired
shortcut would be to find an already manufactured pump, or good
information about how to build an effective pump under these
circumstances.

So far we have found this pump
http://www.thinxxs.com/products/index_products2.html
but we which to find other alternatives, and perhaps other solutions
for a pumping system.

Best regards
/Jens Thorvinger

Yea, that was the only one I found that looked kinda up the right street. Tricky.

Too old to work in pascals -- so 4.35 psi. I presume that you are
pumping from a reservoir -- or are you wanting to transfer between two
volumes? This (obviously) might be relevant in terms of the
displacement of the valve gear.

Sounds like an interesting wee project and you have done exactly what
I would have as a start. I?m almost tempted to experiment myself.

Gut feeling is that it should just about be realisable but not easy.
Reckon you worked this out yourself :-) Only other thought which might
be constructive is have you explored other piezo materials -- not
rochelle salt of course! Plastic Piezo films *may* be more efficient
or more amenable to your application.

Sorry I can?t do more. Perhaps some other kind soul can.

Best

PS Just noticed my spell check 'pies' for 'piezo' in previous. Duh.