Thanks Ted and ISZ.
OK there is pressure drop due to the valve structure, fittings, hose/line.
The problem is I want to choose a right valve for my system, and I do not know about my valve yet.
Let me ask my question this way: in an ideal (unrealistic)situation If there is no head loss across...
If I have a double rod-end cylinder, fill it with oil, and connect both ends together via a needle valve, then start applying force to the rod in order to push/pull the pistion, is there any pressure difference acorss the valve when the needle valve is fully open? If so how can I calculate it...
