Too much pressure!?!

[AKfish]

The hydraulics on my JD110 TLB operates at something in the neighborhood of 3000psi. I have a single-acting hyd cylinder that maxes out at 2,500psi.

What can I do to avoid blowing the "guts" out of the cylinder with long term use?

(I know I could have posted this on the hydraulics forum... but, I was hoping that kennyd would give me some ideas!)

Thanks in advance.

AKfish

 

[tbenn7362]

add a presure relief valve for just this cylinder and adjust at ~ 2200 psi

 

[kennyd]

Well, a PRV (pressure relief valve) would ensure it never see's more than 2500PSI, but it would be a pain to plumb in...

But if you never hold the remote after the cylinder stop's moving it won't either. Maximum pressure would/can only build when the cylinder reaches it's travel limit. Also, cylinders are usually tested to at least 2x the rated operating pressure for safety reasons so I don't think you will have any problems. I say use it.:thumbsup:

 

[LD1]

How big is the cylinder??

If it is not a large cylinder, and you are still worried about the 3000psi, it may be cheaper to just get a 3000psi cylinder from a surplus store than it would be to plumb in a PRV.

 

[sunnyside360]

I have a very similar situation as you. The cylinder on my transport disc is rated at 2500 psi and my tractor hydraulics is around 3000 psi according to the shop manual. I watch the cylinder closely for when it is near fully extended and then release the pressure. I've been using it this way for 6 yrs and have had no issues at all.
This is basically what kennyd is saying.

 

[Rob-D]

But if you never hold the remote after the cylinder stop's moving it won't either. Maximum pressure would/can only build when the cylinder reaches it's travel limit.

Wait a minute Kenny, what about when you try to move the cylinder and the force is to great. The cylinder stops and it see max pressure. The cylinder may not be fully extended so that pressure won't be throughout it but it's still there.

It seems like you're saying two things here (after it stops; when it reaches its max limit). Any time it stops it sees max pressure if you're on the lever.

Am I wrong?

Rob

 

[jenkinsph]

AKfish,
I agree that a 2500lb rated cylinder should work with your tractor. I don't think I would use it in high load positions such as the fel, these are often maxed out and failure could be catastrophic. If you are using it for implement running gear or something similar you should be fine. I assume that is your intent since none of the cylinders on a 110 is single acting anyway.

 

[jd110]

There is another problem that might arise, depending on what you are using it on. A cylinder is rated at it's max pressure for lifting power. If you run it at past the max pressure, it will have a lot more power and could break the implement it is attached to.

 

[kennyd]

Wait a minute Kenny, what about when you try to move the cylinder and the force is to great. The cylinder stops and it see max pressure. The cylinder may not be fully extended so that pressure won't be throughout it but it's still there.

It seems like you're saying two things here (after it stops; when it reaches its max limit). Any time it stops it sees max pressure if you're on the lever.

Am I wrong?

Rob

I can wait all day:laughing:

I will answer your question with a question: What happens when an outside force is applied to the cylinder when the valve is in neutral and the work ports are blocked, say in a FEL while transporting a bucket full of dirt over bumpy terrain? Do you not think that the mechanical force applied to the cylinder from the bucket bouncing will cause pressure in the cylinder/s to exceed 2500 or 3000PSI? You better believe it does!

The rating of 2500PSI is the "working pressure", not the pressure at which the cylinder will fail. That is why they are tested at least 2x the working pressure.

Clear as mud?

 

[Rob-D]

I can wait all day:laughing:

I will answer your question with a question: What happens when an outside force is applied to the cylinder when the valve is in neutral and the work ports are blocked, say in a FEL while transporting a bucket full of dirt over bumpy terrain? Do you not think that the mechanical force applied to the cylinder from the bucket bouncing will cause pressure in the cylinder/s to exceed 2500 or 3000PSI? You better believe it does!

The rating of 2500PSI is the "working pressure", not the pressure at which the cylinder will fail. That is why they are tested at least 2x the working pressure.

Clear as mud?

I think using the cylinder above its rated working pressure will cause premature failures. The working pressure is there for a reason.

A closed cylinder with a full bucket on it may not see the 3000# pressure of a pump attempting to move it against an immovable force. A cylinder with 2500# moving against an immovable force will have less internal stresses also. A bouncing bucket may not exhibit the same duration of forces as a constant pump exceeding the cylinder's working pressure.

Because a cylinder can withstand twice its working pressure for a specific interval does not mean it can be run above its working pressure on a daily basis.

Rob