Hydraulic Jack Questions

[CarlLucas]

I'm building own hydraulic jack. But before finish it completely I have few questions and confusions.

Lets say I have a tank filled with hydraulic oil and completely sealed so no air can get in. Now, if I raise the handle to fill the smaller pipe. The smaller piston will try to **** oil from tank but if it ***** the oil from tank, wouldn't it fail ? because there is no air to come in tank to fill the empty space after oil is passed, if no air, it will be like nothing in that empty space ? Im bit confused.


Second question, can seating work on drilled hole or some kind of clearing is required to wipe off the scratches, I think not required because it needs very little space to seat.


Third question, on this tutorial, I read that back up was/is used. But why using a backup important ? I mean the inset in piston is already providing backup to the seal. Why plastic backup is necessary ?


Forth question, whats best for Ram Seal, Ucup, leather seal or O-ring or something else ?
and whats best for smaller piston seal ? the one that takes oil from tank and pushes to bigger piston.
I'm looking for something that lasts longer without any service.


Thank you

 

[Hiball]

I'm building own hydraulic jack. But before finish it completely I have few questions and confusions.

Lets say I have a tank filled with hydraulic oil and completely sealed so no air can get in. Now, if I raise the handle to fill the smaller pipe. The smaller piston will try to **** oil from tank but if it ***** the oil from tank, wouldn't it fail ? because there is no air to come in tank to fill the empty space after oil is passed, if no air, it will be like nothing in that empty space ? Im bit confused.


Second question, can seating work on drilled hole or some kind of clearing is required to wipe off the scratches, I think not required because it needs very little space to seat.


Third question, on this tutorial, I read that back up was/is used. But why using a backup important ? I mean the inset in piston is already providing backup to the seal. Why plastic backup is necessary ?


Forth question, whats best for Ram Seal, Ucup, leather seal or O-ring or something else ?
and whats best for smaller piston seal ? the one that takes oil from tank and pushes to bigger piston.
I'm looking for something that lasts longer without any service.


Thank you

1. If you completely fill the reservoir on a sealed unit, you will run into vaccum issues, the reservoir needs to have some headspace to account for negative/positive pressures. Is there a reason you are choosing a sealed reservoir?

2. A seat needs to have a slight bevel, I not really sure what you are asking in regards to "wipe off scratches". The seat needs to have a very clean mating surface, I expect the seat material is a very important aspect, to Hard or Soft of a material will cause issues.

3. There is No One Correct answer to whether a backup needs to be utilized, it all depends on the application/Type of seal, Material used, clearances along with the PSI range you will be working with.

4. A Poly Ucup is Probably the Easiest to work with, it's a much cleaner seal versus a typical piston seal made from leather.

Pictures of this Homemade Jack?

 

[CarlLucas]

I'm using sealed reservoir so the oil doesn't leak out or spill while moving/vibrating the jack.

The base metal is MS and the ball will be of SS. I hope it will work well for seating.

I have no idea how much PSI I will be needed for something I'm trying to build but when it will be completed I will measure and make changes appropriately.

If leather seal last long ? then I would like to use it.

There are no pictures, yet. Sorry It's still in designing state.

Thank you for quick reply.