Coupling a one-way cylinder to M9000

ArtMech · Dec 24, 2016

Don't want to start a new thread, but have another hydraulic question.

I'm in a project now, where I need to connect two (in parallel) Double Action cylinders to a Remote Valve on a tractor. Although both cylinders' travel end positions are matched with the end positions of a mechanism, do I still need to think about Relief Valve installation?

I'll try to explain my way, why I'm asking.
I'm sure (and I hear) a Relief Valve properly works within Remote Valve operation. But if, for example, I'll dig the earth, my mechanism may sometimes stick in the earth (within the range of the cylinders), and because of overload the hydraulic pressure will increase. Won't the cylinders break my mechanism, until a Relief Valve of a Remote will be engaged? I just want to protect my mechanism from breakage by the cylinders.

Thanks in advance for the advices.

Fallon · Dec 24, 2016

The relief valve on the tractor will protect anything being operated. As you noted, it won't protect anything that isn't being operated at the time. If you put a crossover relief valve like on a snow plow, it wouldn't work. The rod end & but end of the cylinder have different volumes so tying them together in an over pressure situation wouldn't let the cylinder move. You'd need a valve that dumped to tank when an over pressure situation occurred. That would mean running an extra line as there is no way to tap into an always on tank line with a standard double acting spool that's on all tractors. I believe skid steers often have a 3rd line plumbed in for a case drain on hydraulic motor implements, but not tractors.

ArtMech · Dec 24, 2016

Thank you, Fallon. So I should rely on a physical strength of my mechanism built (or to strengthen it, if necessary so it wouldn't be broken), as well as on a Relief Valve of a tractor. And that's it.

Fallon · Dec 24, 2016

saracenas said:
Thank you, Fallon. So I should rely on a physical strength of my mechanism built (or to strengthen it, if it's not enough) so it won't be broken, as well as on a Relief Valve of a tractor. And that's it.

Either that or invest the time & money to build the required relief mechanism to operate when the control valve isn't being actuated.