Blew Hydraulic hose on FEL, instant drop.

[aczlan]

A perfect vacuum is like -14.5 psi. Not nearly enough to hold the load.

And you can't get to that for the loader lift cylinders as the rod end will be in a vacuum and the rod seals are meant to keep fluid in, not keep air out.

Aaron Z

 

[Fallon]

And you can't get to that for the loader lift cylinders as the rod end will be in a vacuum and the rod seals are meant to keep fluid in, not keep air out.

Aaron Z

Water boils at low pressures at room temperature. I assume hydraulic oil does as well. Which would let the cylinder move as well.

 

[FTG-05]

As far as using the FEL as a man-lift, I do it all the time. Safety is as easy as a 2x6 or a 4x4 under the FEL cross tube or frame or you can use something like this:

Tractor Loader Cylinder Safety Stops- Ask Tractor Mike

As someone mentioned, it's still a risk, but I think a far lower risk than using a ladder, especially at the heights I normally use my man lift for i.e. +10' high.

 

[npalen]

I use adjustable aluminum clamps on the lift cylinders for safety with the manlift as well as props clamped to the outer end of the pallet. The aluminum will clamp tight and hold the weight yet slide without damaging the cylinder rods if hydraulic down pressure is applied. The two halves of each clamp were precision bored to be about a thousandth smaller than the cylinder rod diameter with a pair of 3/8" hex-bolts clamping them together.

 

[npalen]

And you can't get to that for the loader lift cylinders as the rod end will be in a vacuum and the rod seals are meant to keep fluid in, not keep air out.

Aaron Z

So do the piston seals fail immediately in this situation? The pressure against the seals is being applied in the same direction even though its air pressure rather than oil pressure when the hose fails. What happens to the 14.5 negative pressure as the load drops but the seals don't completely fail?

I'm asking because I don't understand the dynamics of this scenario but its very interesting.

 

[aczlan]

So do the piston seals fail immediately in this situation? The pressure against the seals is being applied in the same direction even though its air pressure rather than oil pressure when the hose fails. What happens to the 14.5 negative pressure as the load drops but the seals don't completely fail?

I'm asking because I don't understand the dynamics of this scenario but its very interesting.

It might slow it down a little, but not enough to really notice.
If it takes 500 PSI to lift the loader arms up from the base end of the cylinder, negative 14.7 PSI isn't going to do anything to hold it up from the rod side of the cylinder.

Aaron Z

 

[MHarryE]

Combines are mandatory equipped with safety ram stops. My BIL bought a used combine cheap because it was a killer. The first time the owner was working under the header and it dropped it only pinned a leg and he was able to work his way out. Second time it didn’t kill him outright - there were lots of scratch marks made as he died of asphyxiation. Most frequent loader drop I’ve heard of is hammering on something, miss and hammer hits fitting, instant crash to the ground.

 

[npalen]

It might slow it down a little, but not enough to really notice.
If it takes 500 PSI to lift the loader arms up from the base end of the cylinder, negative 14.7 PSI isn't going to do anything to hold it up from the rod side of the cylinder.

Aaron Z

So what happens inside the cylinder once the perfect vacuum is reached assuming the piston seals hold? I understand that the load continues to drop as the vacuum is not enough to hold the load. It's almost like we create a perfect vacuum but then the piston continues to "increase the perfect vacuum". What is actually happening in this scenario?

 

[CoyPatton]

So what happens inside the cylinder once the perfect vacuum is reached assuming the piston seals hold? I understand that the load continues to drop as the vacuum is not enough to hold the load. It's almost like we create a perfect vacuum but then the piston continues to "increase the perfect vacuum". What is actually happening in this scenario?

What vacuum?
A 2 way cylinder works by the reverse direction of fluid flow. The 1 way cylinder (most 3PH) works on fluid flow in the (usually) lift direction and gravity (weight) reversing the flow when the pressure is reduced. (Yes oversimplified, but still no vacuum is present.) most hydraulic systems are self bleeding.

 

[cmyoung2]

Was using an old Ford tractor with loader to put wool bags into the rear of a tractor trailer. Was able to pick up 3 at a time, about 200 lbs each. As I was moving toward the rear of the trailer, with the load about 5' high, just enough to be able to see where I was going, one of the hoses on the control valve blew. Bucket hit the ground like a ton of bricks, all the fluid hit me in the face. One time I was really glad I wear glasses. Probably 20 people were there, working so several were close to the tractor. No one was under the loader, so no one got hurt. Scared the -- out of everyone. Then we had to load the rest of the wool by hand. Believe me, if a hose breaks, the loader is going down, as fast as gravity will take it.