Multi-Channel Pump Question

[GVowles]

i’m An IP owner involved in the development of a portable/wearable artificial kidney but am not a pump person per se so have a question regarding external gear pumps as one of several options being investigated as alternatives to peristaltics. Is it, in fact possible/practical to use an external gear pump with one drive gear and two (or more) idler gears to pump two (or more) separate streams from a single prime mover pump? The key point, however, is that the displacements of each pumping section need to be different. It seems the easiest way to accomplish this is to make the depth of the chambers/cavities different and, therefore, the thickness of their corresponding idlers. My 2-part question is (1) Is this actually doable and (2) if yes, which of the gears/cavities cavities (drive and idler) must have the lesser or greater depth.
Thanks kindly,
Gerry

 

[btrueblood]

Gear pumps work best when the gears are the same height, so that a close tolerance condition can be obtained, to minimize slip (leakage back from the high pressure to low pressure side of the gears). What you are proposing might work, but the slip due to differing gear heights might make the pump fairly lossy. Also, if a single drive gear rotates several other gears, there will be some cross-contamination - some of the fluid in chamber b will stick to the drive gear and be passed over to chamber a, if you get my drift.

 

[LittleInch]

I really don't think this is feasible.

why not try drawing this to see why or to put up as an idea.

The fluid travels inside the cogs. Can't see how how different entry points won't mix.

http://www.pumpschool.com/principles/external.asp

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[GVowles]

Thank you very much betrueblood and Littleinch. Those were the two main issues I'd wondered about but didn't feel confident about. Your timely feedback was much appreciated and is a timesaver.