Seeking a source for very small diameter water pump /motor

[BlueZango]

Seeking a source for very small diameter water pump /motor::

I am making a device to pump a small volume of water.
(it will be on a timer, hence it will only run for 4 minutes every 4 hours)
It is a design and source for production of 100k units. (not just a few)

KEY:All components need to fit inside a tube that is 10, 11, or 12mm diameter.
We cannot use centrifugal pump due to the perpendicular angles involved.
We cannot use tiny piezo pumps, not enough volume.
We cannot use a small diameter medical device motor and impeller due to high cost.
Another issue: most small motors run at very high RPM.

OUR REQUIREMENTS:
Diameter of device housing (a plastic tube): 10, 11, 12, 13, 14mm
Max Diameter of Motor or Pump: 9mm/10mm (can be 6,7,8mm)
Power: 2 AA Cells, 3 volts DC
Operating Current: 30-38 mA

IF IT IS A MOTOR WITH IMPELLER
Output: 350-950 RPM
Torque: > 3 nMn
Motor has impeller: yes
Motor encased for waterproof: yes
Water Pump Flow Rate: 66ounces in 3-4 minutes
Water is not for human consumption, hence, not a sterile solution.

Thanks for your thoughts and ideas.
Warm Regards,
Walt

[Externet]

Welcome to the forum.

Sourcing would be custom made.

Dozens of ways to come up with a way that could work.
The motor size is not a problem. From a few in my parts bins, measured a couple 7mm, one 6mm diameter. That leaves a good 2mm external annular gap for axial fluid flow all around worst case. And that is only one method.
Your "...issue: most small motors run at very high RPM...." Yes, free spinning, when not loaded.

66 ounces =~ 2 litres in 3 minutes; will take some tests as an important factor is missing from your specifications : pumping head/pressure. May be marginal.
Another unknown is the static pressure the unit will be subjected to; as in how deep water column will the pump operate.

3V at 0.03A = 0.09W... THAT may be a problem...Smells waaaay underpowered, very pessimistic on that; to be seen if the head/pressure calculations allow. Just imagine putting two wimpy AA batteries to do the work of lifting a 2 litre soda bottle (2 Kg = 4.4 pounds) in 3 minutes of less than 100 milliwatts to the unspecified height
A hurdle is hermetism for some type of pumps, unless the water flowing is allowed to carry tiny air bubbles with it. Then can be bypassed.

The orifice for passing motor wires trough the hose wall is not a problem, and can be the inlet for micro bubbles, IF the static pressure during off times is low enough.
The location of the pump relative to surface levels is also unknown from your specifications.
Self-priming or not also not specified. Conductivity of the impure water also not specified.

So, can be calculated/designed/prototyped/evaluated/tested. What is your budget for design/prototype ?

Miguel

[BlueZango]

Hi Miguel;
Good questions and issues. Sounds like you have experience in this area.
The bottom 7-8-9 inches of the device will always be submerged.
The top 4-5-6 inches of the device will be above water level and hold cells, controller, and switch.
The motor and impeller (or pump) will be in the bottom tip.
There also will be a physical filter and charcoal resin filter before the pump.
Think like a fish aquarium, but simple, like goldfish.

Additional Specs/Info:
Head Height 11in.
Static Pressure 10in.
Therefore it brings the water from bottom to 1inch above water surface.

Yes, high RPM is OK, as long as it is quiet and does not create many air bubbles.

Power: 3VDC is fact, must be 2 AA or AAA cells.
Watts/Amps = can be any.

Hermetic Seal = no big deal, most of the device is submerged. Just need to keep water away from electronics.

Conductivity of water = tap water.

Budget 3-4k

Walt Johnson
Johnson Pacific Design
512-568-5684 CST
Austin Texas.

[BlueZango]

Here is an illustration.
Also a photo of existing battery powered water pump for 5 gallon containers.
We wish to have same thing but much thinner and a bit shorter.
Also, ours will have a timer and filter tip.

[BlueZango]

Here is another existing battery-powered water pump.
This one is no good as an example because motor is in top and run by very long axle.

[Externet]

Hi.
A private direct message within the forum has been sent.
Miguel