bubbacuse77
Platinum Member
guys, I am getting conflicting info from my research. can I use a cross over relief valve on a dual acting cylinder?
cross over relief valve
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J_J
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You could but why?
Why would you want to? The valve controlling the cyl will provide the relief.
How would you use it ?
Why would you want to? The valve controlling the cyl will provide the relief.
How would you use it ?
OP
bubbacuse77
Platinum Member
I'm building a new FEL plow from an old 6 foot meyers I found for $100 dollars. I am about to send it for powercoating and was looking into the hydraulics and notice guys talking about crossover relief valves for snow plows.
I used one dual acting cylinder instead of 2 single acting. I just don't want to hurt anything in the hydraulic system.
How will the valve provide the protection? Does it transfer the fluid from one side to the other as needed?
Why do more people not use one larger dual acting cylinder vs the 2 single acting ones guys use for plows?
I used one dual acting cylinder instead of 2 single acting. I just don't want to hurt anything in the hydraulic system.
How will the valve provide the protection? Does it transfer the fluid from one side to the other as needed?
Why do more people not use one larger dual acting cylinder vs the 2 single acting ones guys use for plows?
Yes you can.
How is that JJ?
You are probably going to want the Xover to work at a much lower pressure than anything in the valve would relieve at.
glastron23
Silver Member
Bubba... yes you can install one... and YES it's needed in the system, if you are plowing and fetch the corner of the plow on a curb, it's nice to have the hydraulic cylinder give instead of something REALLY expensive. These are easy to get and simple to install. just look on the prince hydraulic site or sun hydraulics..Jim
RickB
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Yes, you can.
A common spool valve has no relief available to the work ports while the spool is in the neutral or hold position.
An excellent reason to use one on say, a snowplow angle circuit.
LD1
Epic Contributor
Call me crazy but I dont see the crossover being effective on a DA cylinder.
There is more volume on one side VS the other. So IF you are angled so that the cylinder is extended, and hit something, and the crossover allows fluid to bypass to the other side of the cylinder, well....that side isnt large enough to hold all the volume of fluid comming. So then what?
I would think a PRV built into the system between the valve and cylinder would be best.
But I am no hydraulic expert. Just throwing out my thoughts.
Why not use the two single acting cylinders like it was set up for?
There is more volume on one side VS the other. So IF you are angled so that the cylinder is extended, and hit something, and the crossover allows fluid to bypass to the other side of the cylinder, well....that side isnt large enough to hold all the volume of fluid comming. So then what?
I would think a PRV built into the system between the valve and cylinder would be best.
But I am no hydraulic expert. Just throwing out my thoughts.
Why not use the two single acting cylinders like it was set up for?
J_J
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I should have said work port reliefs. These reliefs would go off if mechanical forces, forces the cyl either way.
Here is a cushion valve to eliminate shock, surge, and overload.
Surplus Center - 1/2 NPT 30 GPM 1500-3000 PSI HYD CUSHION VALVE
Surplus Center - SAE 8 1958 PSI CROSS-OVER RELIEF VALVE
There may be hyd spikes when something is hit that the reliefs won't catch quick enough, and could damage other hyd components.
Here is a cushion valve to eliminate shock, surge, and overload.
Surplus Center - 1/2 NPT 30 GPM 1500-3000 PSI HYD CUSHION VALVE
Surplus Center - SAE 8 1958 PSI CROSS-OVER RELIEF VALVE
There may be hyd spikes when something is hit that the reliefs won't catch quick enough, and could damage other hyd components.
oldnslo
Super Member
LD1,
you are correct in that X-over RV provide a limited protection on DA cylinders. If the cylinder is fully retracted it can fully extend but will draw a vacuum on the blind end. If Fully extended it will only retract part way do to the volume difference.
JJ,
Yes port RV's will work except they again may or may not fill the other end of the cylinder with oil. Also depending on hose length and valve position they may be situated far enough away that they might not see the pressure spike before some thing bends.
Roy
wdchyd
Elite Member
Oldnslo and LD1 are on the right track
one double-acting hyd cyl has different displacements on each side.....two single acting cyls are best or....... 2 double-acting cylinders plumbed cross-ways (rod end on one side tee'd to base end on the other.....and vise-versa)
definetly need a cross-over relief valve for a plow otherwise an induced load (ie: curb or manhole cover) will put a serious hurt on equipment.......BANG...
one double-acting hyd cyl has different displacements on each side.....two single acting cyls are best or....... 2 double-acting cylinders plumbed cross-ways (rod end on one side tee'd to base end on the other.....and vise-versa)
definetly need a cross-over relief valve for a plow otherwise an induced load (ie: curb or manhole cover) will put a serious hurt on equipment.......BANG...
PILOON
Super Star Member
Crossover will protect ONLY the extended plow edge by diverting the oil to the retracted side.
Plow snow to the curb and hit the curb and there is no protection
Plow away from curb towards center of the road and you are protected from curb blows .
Pushing with plow straight and both corners are protected.
The usual crossover setting is about 1500 PSI on plows, but most are adjustable somewhat.
Plow snow to the curb and hit the curb and there is no protection
Plow away from curb towards center of the road and you are protected from curb blows .
Pushing with plow straight and both corners are protected.
The usual crossover setting is about 1500 PSI on plows, but most are adjustable somewhat.
wdchyd
Elite Member
Fisher Insta-act Plows set their main reliefs at 1750 psi and the cross-over reliefs at 4000 psi ( max rating of hyd cyls)
wdchyd
Elite Member
Meyers Electrotouch E-47 main reliefs are set at 1650 and the X-over-PRV @ 3000psi
Not if it is a balanced cylinder.
OP
bubbacuse77
Platinum Member
Here is what Prince has for a product description. Looks like it is not only a cross over but a cushion valve as well............what is a cushion valve?
The PRINCE valve model DRV is a differential poppet type double relief. The double relief is used in systems that require cross over relief protection such as a reversible hydraulic motor, or systems that require a cushion valve such as double acting cylinders.
The PRINCE valve model DRV is a differential poppet type double relief. The double relief is used in systems that require cross over relief protection such as a reversible hydraulic motor, or systems that require a cushion valve such as double acting cylinders.
J_J
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Crossover Reliefs (Cushion Valves) - Cylinder Services
The cushion valve is to minimize the shock and
abrupt pressure fluctuation
The cushion valve is to minimize the shock and
abrupt pressure fluctuation
That is why you get a spring loaded moldboard.
grsthegreat
Super Star Member
Hmmm,. now this post has me confused. I have a new Quick Attach loader mounted plow that i have never used before. I simply attached the double acting cylinder into my rear remote port. Am i supposed to add a cushioning valve or ???? also?
thanks
thanks
