Orifices in hydraulic systems
Orifices in hydraulic systems
(OP)
I am looking for some advice regarding a hydraulic circuit I am having a problem with. To try to summarise;
We produce an agricultural implement that has two folding sections on it. It is important that these sections fold in the proper order. Previously, the order that the sections folded was correct naturally, i.e. the section requiring lowest cylinder pressure was the one that we wanted to fold first. Now, we have done some design changes where extra weight has been added to the section that needs to go first (unfortunately we have produced 80 of these things). The pressure now required for each section is very close and in some cases the wrong section will go first.
Will adding an orifice to the section that we want to go second force the proper section to rise first?
Assuming we already had orifices in place, would smaller orifices help the situation?
Will the type of hydraulic system cause the circuit to behave differently (open centered versus closed centered)?
We produce an agricultural implement that has two folding sections on it. It is important that these sections fold in the proper order. Previously, the order that the sections folded was correct naturally, i.e. the section requiring lowest cylinder pressure was the one that we wanted to fold first. Now, we have done some design changes where extra weight has been added to the section that needs to go first (unfortunately we have produced 80 of these things). The pressure now required for each section is very close and in some cases the wrong section will go first.
Will adding an orifice to the section that we want to go second force the proper section to rise first?
Assuming we already had orifices in place, would smaller orifices help the situation?
Will the type of hydraulic system cause the circuit to behave differently (open centered versus closed centered)?





RE: Orifices in hydraulic systems
Either larger on the primary or smaller on the secondary. In this case a little bit may go a long way.
RE: Orifices in hydraulic systems
Thanks for the reply.
I agree that orifices (needle valves, flow control etc.) are usually used for flow control. However, won't the oil tend to flow to the path of least resistance? It creates a large pressure loss to try to pass oil through an orifice.
The question becomes a bit like the chicken and the egg scenario I guess. The greater the flow the more the pressure drop through the orifice and therfore greater tendancy to drop the flow. This is where the problem becomes a little more complicated.
RE: Orifices in hydraulic systems
RE: Orifices in hydraulic systems
RE: Orifices in hydraulic systems
We could use this type of valve, but it would mean a somewhat costly retrofit. We may go this route if the orifice idea does not work.
RE: Orifices in hydraulic systems
RE: Orifices in hydraulic systems
RE: Orifices in hydraulic systems
RE: Orifices in hydraulic systems
RE: Orifices in hydraulic systems
RE: Orifices in hydraulic systems
I'd like to give it a shot, but I'm not promising anything. I understand the importance of retrofittability, which makes the problem a bit more interesting. I have some questions:
1. Are the cylinders push-pull, or are they gravity operated in one direction? If push-pull, how do you sequence each side of a cylinder (reversing shuttle valve)?
2. Where's the relative position of the components in the system? What components are tied together in manifolds, and what components are separated by hoses? Is a separate "patch" manifold feasible for retrofittability?
3. Is there any form of a hydraulic locking system, like pilot operated check valves installed in the cylinders? Are there any safety issues to consider or codes that have to be followed? Can someone be squished if a hose is cut or breaks?