How much pressure?
What type of axle oil? i.e., what viscosity?
I think that your biggest problem will be getting the fluid to enter your pump. Refineries that deal with (much larger) pumps to move asphalt and the like usually have an inlet heater to heat up a bellmouth inlet on the suction side of the pump. You might consider putting a quarter to a half of your power budget into heating the fluid on the inside of a bellmouth inlet heater that is insulated to prevent heat loss into the fluid tank.
Whether you use the heater or not, I would think that you could match a small 20-gpm (nominal at full motor speed) hydraulic gear pump to a motor with a 10:1 reduction gear as a pretty straightforward concept.
I am thinking of a 20-gpm hydraulic pump as a minimum because you want your inlet port to be as absolutely large as possible. You might even go with a bigger pump and greater reduction ratio for the sole purpose of increasing the size of the inlet port.
It's an interesting question.
-T
Engineering is not the science behind building things. It is the science behind not building things.
Interesting if someone else had to deal with it. The oil is highly viscous at -30, 20000 (yes, 20K) cSt. I have typically used shop air to push the oil through, but this time, that solution wont work.
thanks for the input, every one, mintjulep, you too. If I could regulate my shoveling at precisley 2 gpm, you might be on to something!
"I have typically used shop air to push the oil through..."
Maybe I envisioned your system incorrectly. Is this a continuous, open loop system used for lubricating an axle?
I ask because when you say that you used shop air in the past, it sounds to me like there's a fixed amount of oil that will be delivered through the system. Is that the case? If so, (and it's not continuous circulation) then I would suggest using an inexpensive hydraulic cylinder. Try filling the retract side of a large-sized hydraulic cylinder with the oil and connect your shop air to the extend side. If you use a 4-1/2" bore cylinder with a nice fat rod, you would receive the benefit of pressure multiplication due to the differential areas. An added benefit is that the position of the end of the rod tells you exactly how much oil is left in the "reservoir."
Unless I'm not envisioning the situation correctly.
If you have used shop air you should give the air some help by checking out some of the air powered grease pumps. There are sizes for all occasions.
There are also a few electric ones out there.
