DirectionalControl Package with directional control valves with lumped volumes
	FlowControl Package with flow control valves with lumped volumes
	PressureControl Package with pressure control valves with lumped volumes

This package contains valves of different types.

Structure

The valves have been divided into three categories based on how they are used. Each category has its own sub-package.

Implementation

All valves consist of one or several orifices often controlled by a spool of some sort from the utilities package.

The overlap

Almost all the valve models have a parameter called overlap. The parameter overlap defines the overlap of the valves. If it is a negative overlap there is always some flow through the ports, and if it is a positive overlap the flow through the ports starts a bit late. Valves with negative overlap are used when the speed of the valve is more important than having a small internal leakage. The valves with positive overlap are slower but have less internal leakage. See the figures below.


No overlap


Positive overlap


Negative overlap