Micro dispensing of oil or water 1

[graviton]

Hello everyone.
I am looking for a way to dispense very small amounts of water or oil (about 2 drops per hour range). I have tried searching for similar issues on the forum but have not come accross anything so far. If anyone knows of a thread that they could point me to or has a suggestion for this problem I would be very thankfull.
The optimum solution for a continuous discharge system would be to have a system that has no moving parts and does not require a power source.
So far we have experimented with wicks, capilary action, and siphon action with mixed results.
We are also considering a system that did not dispense on a continuous bases but would dispense a larger amound at longer intervals.
The goal is to create a thin layer of oil on top of water or similar liquid in a 1/2" diameter tube.
Let me know if you need additional info.
Many thanks in advance.

 

[m777182]

Maybe you can try with a bubble column filled with oil : bubbles will trap very minute quantities of oil that will be carried away by the air flow.You can manipulate the trapping rate by the height and dia of the column and the air flow rate.
m777182

 

[graviton]

Thanks for the reply m777182,
The way I understand you suggestion is that a vertical tube filled with oil at the bottom will have an air inlet at the bottom to generate bubbles. Is this correct? Good Idea!
Is there a way to generate the bubbles passivly (without an air pump)? The cartridge that the 1/2" diameter tube resides in does not have access to a power source or compressed air.
It is possible to use a battery operated pump but the cartridge unit needs to last for at least 4 months and there are environmental issues with using batteries because at the end of its life the cartridge will be thrown away.
The thin oil layer that forms in the 1/2" diameter tube will be periodically lost due to flushing by water, so a new layer needs to form within let's say 6 hours.
We are also investigating for simple passive "intelligent" systems that could sense the presence of the oil layer and stop dispensing, then resume dispensing when the layer is lost.
Any further input is greatly appreciated.

 

[m777182]

Correct.You can generate suction and air intake with some Venturi acting injector if your liquid is flowing through the tube.
With no external power supply and stagnant liquid the task is more difficult and then the bubble column is not a good solution, but what else? Then I would think of a diffusion based process designed in mechanical sence in such a way that at occurence of a flash and restart more parallel acting diffusive sources would be included.
m777182

 

[bimr]

You should contact some of the lab equipment suppliers. They will have something:

http://www.labequipmag.com/