Mechanical Engineering

This example engineering drawing showing the hydraulic directional control valve usage with floating motor and pressure compensated pump is redesigned using the ConceptDraw PRO diagramming and vector drawing software from the Wikimedia Commons file: DCV 17.jpg.
[commons.wikimedia.org/ wiki/ File:DCV_ 17.jpg]
This file is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license.
[creativecommons.org/ licenses/ by-sa/ 3.0/ deed.en]
"Directional control valves are one of the most fundamental parts in hydraulic machinery as well and pneumatic machinery. They allow fluid flow into different paths from one or more sources. They usually consist of a spool inside a cylinder which is mechanically or electrically controlled. The movement of the spool restricts or permits the flow, thus it controls the fluid flow. ...
The spool (sliding type) consists of lands and grooves.The lands block oil flow through the valve body. The grooves allow oil or gas to flow around the spool and through the valve body. There are two fundamental positions of directional control valve namely normal position where valve returns on removal of actuating force and other is working position which is position of a valve when actuating force is applied. There is another class of valves with 3 or more position that can be spring centered with 2 working position and a normal position. ...
Directional control valves can be classified according to:
(1) number of ports;
(2) number of positions;
(3) actuating methods;
(4) type of spool." [Directional control valve. Wikipedia]
The fluid power equipment drawing example "Directional control valve" is included in the Mechanical Engineering solution from the Engineering area of ConceptDraw Solution Park.

This example was drawn on the base of SysML activity diagram on the page 8 of "SysML Modelling Language explained" document from the Official OMG SysML site.
"The activity diagram represents steps of a process, often making use of “input and output pins” that respectively correspond to the element type required as the input of an activity or action, and the element generated as an output.
If an action or activity corresponds to a block operation, it is possible to ensure that the types of the input and output of this activity are consistent with the block operation signature.
All the activity diagrams definitions used in UML also apply to SysML.
SysML has added a couple of extensions:
- With UML, control can only enable actions to start. SysML extends control to support disabling of actions that are already executing.
- Definition of the flow rate : continuous or discrete
- Definition of the rate and probability on the control or object flows"
[omgsysml.org/ SysML_ Modelling_ Language_ explained-finance.pdf]
The example "SysML activity diagram" was drawn using the ConceptDraw PRO diagramming and vector drawing software extended with the SysML solution from the Software Development area of ConceptDraw Solution Park.