Integral pump question

[geesamand]

I would like to integrate a pump within a gearbox to lift oil from the sump level to above the bearings. Forgive me as pump selection/design is absolutely not in my background.

I would prefer a non-wearing design (e.g. centrifugal) that will last a long time. Efficiency and pressure are less important than reliability and ability to continue to move fluid over a wide range of fluid viscosities (e.g. 50,000 cP to 10cP). I wish to attach the pump impeller on either the 1800rpm input shaft or 350rpm intermediate shaft. I expect to build a scroll around the pump impeller to pipe the pressure side upward to a trough where gravity will take over. Flow would need to be 1gpm minimum and head would be around 2ft. Specific speed is therefore very low.

I've done some homework but it seems all of the guidance seems to be based on optimal efficiency for a given specific speed, and there are no clear winners. As I mentioned already, optimal efficiency is less important than a robust, maintenance free design.

What kind of pump might be capable of doing this?

Where might I be able to buy the pump impeller alone, for integration into my machine?

Thanks,

David

 

[JJPellin]

This is very common inside gearboxes such as those built as part of integrally geared centrifugal pumps. All of those that I have seen use gear pumps. Given the range of properties you describe and the very low flow rate, I would recommend a gear pump for you, as well. Running in lube oil, wear should not be a great concern. The internal oil pumps inside Sundyne gearboxes often run for a decade, or more. I have seen this same type of external-gear pump used to lift oil in the governor drive assembly on a steam turbine. The pump I am describing is about 1.5 inch diameter and about 1.5 inch long. I have included a sketch of the governor drive application I mentioned. In this application, the little gear pump pushes oil up the hollow shaft where it lubricates a spline drive, a worm gear drive and a ball bearing. I think these little pumps are made by Roper or at least Roper makes one very similar.



Johnny Pellin

 

[DubMac]

Gear pump definitely; don't even consider a centrifugal. Yes, it is Roper that makes a good one. It would be similar to a gear pump in the crankcase of your car (at least the old cars I worked on).

 

[Artisi]

Can you adapt an internal engine lube pump to suit your application.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)