Need Hydraulic Tips

[CarlLucas]

I'm making a custom hydraulic hand pump and a cylinder. But before I start, I need some tips/answers from you expert engineers.

Why Guide/Wear ring is used ? I read some place it absorbs transverse forces and it prevents metal-to-metal contact. I do understand how guide ring works, but why ? What wrong with metal to metal contact ? and how can it absorbs transverse better than metal touching the metal ?

Another question is, what seal is better for pump piston ? Usually I see O-ring is used with a backup ring. But I think O-Ring doesn't last long. In some hand pump piston, I saw leather seal. But what is the best seal for 12mm pump piston ? Can I use V-Seal for it ?

 

[hydtools]

You do not 'need' guide/wear ring in a piston pump if the pump I properly made. Fit, finish, compatible materials, good L/D ratio, pumped fluid provides lubrication.
V-shaped seals will work.
What is the fluid and pressure?

Ted

 

[CarlLucas]

No no, I'm not using guide ring for pump piston but for the piston of cylinder, 32mm in diameter.

For pump piston, I just need to know which seal should I use ? O-Ring or V-Ring ? The problem with V-Ring is that, the pump piston diameter is 12mm and I cant seem to find V-Ring with 12mm OD.

I'm not sure about fluid and pressure. I'm thinking of using general hydraulic oil and cylinder should be able to lift 5-10 ton.

 

[hydtools]

Put the v-ring in the pump bore, not on the pump piston. Don't forget a wiper to keep the pump piston clean.

Same answer re guide rings on the cylinder piston, assuming ram style cylinder. Guide rings allow larger piston tolerance and prevent metal to metal scoring.

Ted

 

[CarlLucas]

That's s very good idea to install ring in pump bore. I will try to implement it.


And if I use polished cylinder and Piston without guide ring, would they still make scratches ? I can put guide ring on cylinder Piston but it won't be easier to put guide ring inside a bore for rod. Because there is a rod attached to Piston that will do the lift.