Hydraulic Hose
Hydraulic Hose
(OP)
Im working on a project that basically consists of runing number 6 size hoses thru a 180 deg. bending cable track with a bend radius of 4" and total length of 336". The hoses are clamped at both ends of the track and the working pressure is 2800 psi. My issue is that the hoses shrink to the point that they create friction on the inside of the track and wear thru as the machine cycles.
Below are the parameters I must meet.
1) Wire Reinforced
2) High abrasion resistance
3) Less than 1.2% shrinkage or alternative way to ease the shrinkage.
4)Greater than 3000 psi WP
Due to the loactaion and space requirements I cant over stuff the track or add a loop. The expansion has to be taken up by the hose or some axial expansion fitting
Any suggestions?
Below are the parameters I must meet.
1) Wire Reinforced
2) High abrasion resistance
3) Less than 1.2% shrinkage or alternative way to ease the shrinkage.
4)Greater than 3000 psi WP
Due to the loactaion and space requirements I cant over stuff the track or add a loop. The expansion has to be taken up by the hose or some axial expansion fitting
Any suggestions?





RE: Hydraulic Hose
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RE: Hydraulic Hose
RE: Hydraulic Hose
http://igus.bdol.com/echain.asp
specifically asks if you're using hydraulic hoses or not. I assume it's because high pressure hoses, even without wire reinforcement, fight back a lot harder than an electrical cable when you try to bend them.
Also talk to your hose supplier; they may have something with a more chafe- resistant cover.
Short- term, that's what I'd do; add chafe guards to the hoses wherever they contact the carrier. Corrugated split wire loom might help. Secure it with ty-raps in between contact zones.
Mike Halloran
Pembroke Pines, FL, USA
RE: Hydraulic Hose
RE: Hydraulic Hose
Wire is much less likely to fail, and if it does, it won't spray hydraulic fluid all over.
A host of other potential advantages too.
RE: Hydraulic Hose
1)Cant change to any other type of system.
2)Their are lots of -06 hoses with less than 4" bend radius
Really just need some suggestions on hoses that could meet the critera above. So far the vendor has come up with some that meet all except the shrink rate.
Thanks for all the sugestions, but still looking for the right solution.
RE: Hydraulic Hose
RE: Hydraulic Hose
http://w
RE: Hydraulic Hose
If the hose was actually shrinking under pressure, you could just install it with more slack. I suspect that it's just trying to straighten itself, and chafing against the inner side of the bend in the track because it's not following a path concentric to the track bend center.
Actually, the bend radii limits for the hose are given for installation in free space, or over a large mandrel. Inside the track, the hose is being bent over what amount to edges or crossbars, so the _local_ bend radius is governed by the radius of the bar or bushing or whatever actually contacts the hose.
Mike Halloran
Pembroke Pines, FL, USA
RE: Hydraulic Hose
The problem really comes down to controlling the shrinkage when the hoses are pressurized so that when they are moving thru the radius that they stay on path with the track bend radius. Has anyone ever heard of an axial slip ring fitting for hoses?
RE: Hydraulic Hose
Russell Giuliano
RE: Hydraulic Hose
Closest dry approximation is arcuate shoes on the inner face of the track elements, to distribute the load.
Incidentally, I suspect that if you set up a static test with a u-bend section of track and a hose inside, you'd be surprised at the force exerted on the track by the hose. Maybe just insert a pencil between the hose and the track and slowly pressurize the hose and see what happens.
Or take a piece of hose in free air, pressurize it, and try to bend it to a 4" radius with your bare hands.
If you could somehow link a big pulley to the bend in the cable track, you could route the hose over that, and keep axial tension in the hose, and control the bend radius. I can see it, a little fuzzy, in my mind. [Caution: I have an eidetic mind, and can visualize things are not physically realizable, in such a way that they are not distinct from things I have actually seen.]
Mike Halloran
Pembroke Pines, FL, USA
RE: Hydraulic Hose
The bending action that Mike describes is exactly what happens and causes hose failure at the cross braces. How full is your hose carrier?
RE: Hydraulic Hose
http://www.aeroquip.com/