Oil Pump Design

[mickey]

Good afternoon all!
can anyone recommend a good book/document to better unerstand oil pump design! Do understand the fundamental principles but would like to learn the essentail to design an own little pump!
thx
Michael

 

[minh-thanh]

Hi !
I make the oil pump the way I think .It has a pressure regulator - to maintain a pressure in the oil line and not put too much pressure on the oil pump. The system has a screw to adjust the amount of oil to lubricate the cylinder head . It's pretty good .
post #80 + 81
https://www.homemodelenginemachinis...engine-kromhout-gardner-4lw-1940.33617/page-4

 

[TonyM]

What type of oil pump and what will it be used for. There are many varieties from oil well pumps through to fuel pumps. Piston pumps, gear pumps, hand pumps etc.

 

[timo_gross]

What type of oil pump and what will it be used for. There are many varieties from oil well pumps through to fuel pumps. Piston pumps, gear pumps, hand pumps etc.

As you say. I was thinking of gear pumps when I read the question, but even then there are different types.

I wonder how much different requirements play a role. -it seems to be an opinion-mix. In the RC constructon model forum the message was: "impossible to diy" and in some other forum "just do it and it will work".
Mismatching expectations and different rewquirements I guess.

2nd thought: I realize how many oil pumps I already own, this

probably not the type in question. (still useful).

Greetings Timo

 

[gbritnell]

Probably the easiest type, which I have used many times, would be the 2 spur gear type. You make a cavity with two bores to accommodate the diameters and depth of the gears As the gears rotate in mesh the action draws oil into the cavity where the teeth are opening from each other. The oil fills the tooth cavities and as the gear teeth start to close the oil is sqeezed into the outlet port. To make sure the oil doesn't hydrolock into the closing tooth space the outlet port has a small channel cut under the mesh point.

 

[petertha]

A related discussion was recently initiated on the MEM forum. A few months ago I was downloading all kinds of online documents but always seem to missing puzzle pieces. When I recently found this MEM post I plagiarized a spreadsheet by model engineer (steamer) so I could use module vs. imperial gears. He based his gear sizing on some industry pump literature & did some preliminary tests to validate flow & pressure. There is a short YouTube video linked in post, discussion starts post #634
https://www.modelenginemaker.com/index.php/topic,10504.630.html
But we are still collectively scratching our heads a bit on the equations/results. It appears to calculate high flow. Could be a conversion error on my part but the gear cavity layout input parameters seem pretty straightforward regardless of module/DP gear, so we have not got to the bottom of this yet. The discussion went quiet past couple weeks & its also spread out among a few different topic posts so a bit hard to follow right now. I was just meaning to return to this issue when I had some time because if I recall, Terry @mayhugh1 built an Offy from Ron's plans & did a nice writeup of his gear pump & test results. I need to go back & read it or maybe he can chime in.

Here is what I have so far. If someone can spot any errors or provide input I'll happily make amendments. It would be nice to have a simple input/output tool.
And as George just pointed out, there also seems to be some sizing criteria to the intersecting gear inlet/outlet area which is another mystery to me. I've heard a rule of thumb line '2 gear tooth widths' but maybe there is more to it than that.

 

[Steamchick]

Hi Michael,
1: Piston pumps are used on many motorcycles - of an era lasting around 70 years.
2: the design of water-pump as per Blackgates Engineering castings kits:

Basic designs were used in Oil mixing plants for pumping oil between tanks in tank farms. - I saw a dozen in a pump-house in a Texaco Oil mixing plant - like the central one, lying horizontally.
3: Lubricating pumps for model locomotives tend to follow this design, that has a small single cylinder pump inside the oil tank, that is like a tiny oscillating engine:

4: "Nodding Donkey pumps" pump oil from wells - typically seen in old pictures of oil extraction in Texas, etc.

https://www.ebay.co.uk/itm/16591241...6&customid=MVyEktkYAAAA1zmW6a3YA3aUD2EwAAAAAA

What you do not mention is the type of oil pump you wish to make, and what size and pumping do you want to do with it?
Please give us a clue?

 

[mickey]

Thx all for your comments/contributions. Learned that I need to ask more specific questions and give more context in future.

Never worked with model engines running 'real' oil pumps and oil circuits. In the process of examining two L. Chenery drawings I see two spur gear oil pumps - fundamentally similar designs of course but quite different gears used. I was wondering if there is more science or at least ‘recipes’ to design these spur gear pumps - gears, clearance to the housing etc.
Michael