Oval vs triangular gear

[Slava]

Helo everyone!
I'm new to forum. And naturally have a question)
I am projecting fluid meter with non-circular gears. I understand that in any case the development of the drawing gear takes a lot of time. But in the begining I want to choose type of gear. Triangular or oval?
Can you help me? what's better to use?
in the same chamber which gear will create lower flow resistance? triangular or oval?
Maybe you can steer me to some documents or sites...
Than's a lot!

[ArtF]

Hi Slava:

  If you intend to meter liquid, you would be better off with a roots blower. The program will generate the blower for you, if you do a google for roots blowers you will see how just a circle around the blower with an intake and output would allow
you to make a geared pump that is very accurate in how much liquid is put out for a given number of turns. The accuracy will depend on how tight a fit you make the blower to its encompassing circle. For metering liquid the roots is one of the best methods.

Art

[Slava]

Thanks for answer.
I think that roots are less dust resistant. I mean that sand in a diesel can dammage it. what do you think?

[ArtF]

Hi Slava:

  Dust in a diesle is damaging because the fuel injectors are lapped to very tight tolerances, but with roots you can set that tolerance yourself
as the clearance of the outside enclosure to the blower itself. It should be much more tolerant than a diesel.

Art

[Mooselake]

Sand can damage almost any machined device.  That's why they use it to cover paper (cloth, plastic, etc) and remove material, and call it sandpaper.  If that's an issue perhaps the system needs a filter.

OTOH it can take scruffy looking pieces of wood and make them beautiful looking objects with amazing patterns and depth.  You can even take construction 2x4s, turn them on a lathe, and make them look interesting - although not as much as a nice piece of birdseye.

Kirk