Adding hydraulic fluid 3

[Docbar99]

This is a real newbie question as I have never worked on a hydraulic system before. So I am planning a 4 point lift with a single acting pump and about 10 feet of hose on each.
I was thinking that I would need more oil that what fits in the pump reservoir. So the question- How do you add fluid without getting air into the lines?

https://res.cloudinary.com/engineering-com/image/upload/v1710728954/tips/Hydralic_concept_ktm0cv.png

 

[3DDave]

https://www.enerpac.com/en-us/pump-accessories/USPumpAccessoriesReservoirs

 

[3DDave]

What it looks like outside of the box:

https://www.amazon.com/Enerpac-MP-10T-Reservoir-Multi-Fluid/dp/B007INYDHI

 

[LittleInch]

Add more oil before you run out?

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

 

[Docbar99]

@3DDave- Thanks for the fast response. I had an idea that something like that may be needed. Do you know of any cheaper options?

 

[Docbar99]

@LittleInch I am new at this and I am not sure what additional information you would need. But here is what I can say:
This is what I was planning, but am not familiar with the process of adding oil without letting air in.

Enerpac P391, Single Speed, Hydraulic Hand Pump, 901cm³, 25.4mm Cylinder Stroke, 700 ba

https://uk.rs-online.com/web/p/hydraulic-hand-pumps/2831244?gb=s

Enerpac 3000mm PU Hydraulic Hose Assembly 700bar Max Pressure (10 feet) (4 each)

https://uk.rs-online.com/web/p/hydr...hId=56334c1e-42ed-4de4-a105-9e3c6202d61d&gb=s

Enerpac Hydraulic Manifold A66. 6 stations

https://uk.rs-online.com/web/p/hydr...hId=a19249a5-eee2-4072-a4a9-eddaf507a0a8&gb=s

Enerpac Single, Portable Low Height Hydraulic Cylinder, RSM50, 5t, 6mm stroke (4 each)

https://uk.rs-online.com/web/p/high...hId=b05c712e-bd97-407c-9d7a-ccb2ee37276f&gb=s

Enerpac Hydraulic Fluid HF95Y, 5 L, ISO Grade 32 (not sure how many)

https://uk.rs-online.com/web/p/hydraulic-fluid/2831519?gb=s

 

[FluidPowerUser]

You are always going to have some air in the system, as the cylinders and hoses will be supplied and assembled dry.

If possible, put a tee with a bleed screw in, with the tee on each cylinder at the highest point. That will give you the best chance of getting the air out.

It doesn't have to be just like this, but the air will rise to the highest point in the system, so it's about making the air collect where you want and having a means to let it out.

Mineral oil will absorb some air and since this is a static system, any additional air is not going to make much difference to the capacitance of the oil.

You will just pump the jack until the tank is supported. At this time, the air in the hoses will be at the same pressure as the oil and the volume will be much smaller as a result and as long as you pump slowly, there will be no risk of dieseling the oil (compression ignition).

On all hydraulic systems, there is the first fill that charges all of the lines and cylinders. once it's in, it won't come out until the system is drained. The working volume will be much less. so, as stated by others, just keep pumping and adding more oil until the system is full.

 

[Docbar99]

@FluidPowerUser- Thank you for some good advice.

So lets say I first fill the pump with fluid.
I then attach my hoses and start pumping.
Would I then periodically open the cap to check if my tank is below half.
Add Fluid.
Open the bleed valve and pump until my jacks start to go up to their max height with no load.
Close the bleed valve.
Repeat as necessary?

Let me know if that order is correct.

 

[FluidPowerUser]

If you know the volume of the tank and also the volume of the pump, you can work out the number of cycles of the pump you can do before the tank is empty. Just be conservative to reduce the risk of pumping more air into the system.

Keep pumping and topping up and extend all of the jacks. You need to aim to have the tank approximately half full with the jacks extended. This will give you room to contain the oil in jacks when they are retracted. Plus, enough oil to replace an air that you remove from the hoses.

To remove the air, extend the jacks fully and keep pumping to get something on the pressure gauge. You don’t need much, but you do need something to push the air out.

When you think the air is removed, tighten the bleed screw and repeat the bleeding after a few weeks and repeat as needed.

 

[Docbar99]

@FluidPowerUser- Thank you very much, that sounds like a very logical way to proceed.