Hydraulic question -non tractor

[firemanpat2910]

I have a cyl in a paper cutter, about 6" dia. 12" stroke. rated somewhere between 3300 lbs and 5000lbs. The end of the casing broke off the piston is half showing and fluid shooting every where. The customer said he was using it heard a BANG and noticed fluid pouring out. Luckily the cyl is inside the machine covered up with steel side covers or it might have hurt him! My reason for posting is to see if Mad or anyone has ever seen a cyl "explode" under normal use. The way this machine is designed there is no way the customer could have done anything to cause this. Now I have to order an $880.00 cyl next day air. and Install it monday. This cyl has a blade connected to it that cuts through 6" thick 31" long paper. hopefuly I will have all my fingers when I get done

 

[Dirthog]

check to see if a piece came off the packing or piston other than that or something bound up in the ram that is probley what happened have saw that before on construction equipment we sell

 

[MadReferee]

I have never seen any cylinder explode under normal use. That cylinder probably had some metal fatigue that caused a hairline crack that caused a catastrophic failure. Sh&* does happen.

 

[DieselPower]

I have seen high preasure hoses and cylinders that have exploded before. Normally due to a faulty preasure relief valve. If the cylinder has a small steel line that runs from one end to the other on the side of it, the relief valve may be interal to the cylinder. If not, check elsewhere in the system for the relief valve and test it to make sure it is functioning properly.

Another thing that can cause a blown hose or cyl. is if the return line got kinked somehow or is blocked.

If the system does not have a high preasure relief valve in it I would highly recomend installing one. They are cheap compared to burst cylinders and are a must have for safety concern's.

The best place to install a high preasure relief valve is directly on the outlet of the pump. This prevents excessive preasure from ever entering the system and any excess preasure is diverted directly back to the sump.

 

[firemanpat2910]

Got it fixed this morning. still have all 10 fingers. The new cyl has about 1.5x the wall thickness the other one had. The factory obviously new it needed redesigning. I wondered when I ordered it why it had 3 part number changes.

This must be my week for hydraulics. saturday I was taking the box blade off my buddies 5205 JD and the quick hitch snagged on the swivel fitting on the hyd top link and ripped it out of the cyl. It looks like the threads in the cyl are fine and just the softer threads of the hose got damaged. I got a new end put on it this morning and will fix it tonight. The worst part was walking up to Rhetts house and telling him I broke his new deere.

 

[dfkrug]

The new cyl has about 1.5x the wall thickness the other one had.

How thick were the cylinder walls (new and old)? I am amazed that the
cylinders I have taken apart and repaired or modified have walls as thick
as 0.20" or about 3/16". That is plenty hefty for 2500psi working loads
as seen on my tractors and backhoes.

 

[firemanpat2910]

Its metric but about 1/8" on the old one I didnt measure the new but it was much thicker. This cyl has worked daily since Jan 2003. I have replaced the pressure manifold (all one piece preset valves) about a year or so ago. So I dont believe its a pressure problem. Oh and on my hyd top link the theads are messed up in the cyl. Hopefully the hyd shop can repair the threads. If it was mine I would try retapping it my self, but since I broke someone elses tractor I want to have it fixed right.

 

[firemanpat2910]

carried the top link in today, the same guy that fixed the hose yesterday, For $20.00 told me it would only take a minute. He ran a tap in it and said no charge so I gave him a five and told him his first beer tonight was on me.
You have to love small town business's like that. you can bet that any time I have or my company has any hyd work needed they will get the first shot at it