Mechanical Engineering

"An air-operated valve is a type of power operated valve that uses air pressure against a piston or diaphragm to produce linear or circular movement to operate a valve. Types are 2-way, 3-way and 4-way. The 2 way air-operated valves can be either normally closed or normally opened." [Air-operated valve. Wikipedia]
The Windows template "Pneumatic 4-ported 3-position valve" for the ConceptDraw PRO diagramming and vector drawing software is included in the Mechanical Engineering solution from the Engineering area of ConceptDraw Solution Park.
www.conceptdraw.com/ solution-park/ engineering-mechanical

The vector stencils library "Valve assembly" contains 141 symbols of pressure and flow regulators, flow direction indicators, controls, and symbols to design flow paths of control valves.
Use these valve assembly shapes to design the engineering drawings of hydraulic and pneumatic valve assemblies in fluid power systems.
"Control valves are valves used to control conditions such as flow, pressure, temperature, and liquid level by fully or partially opening or closing in response to signals received from controllers that compare a "setpoint" to a "process variable" whose value is provided by sensors that monitor changes in such conditions.
The opening or closing of control valves is usually done automatically by electrical, hydraulic or pneumatic actuators. Positioners are used to control the opening or closing of the actuator based on electric, or pneumatic signals.
A control valve consists of three main parts in which each part exist in several types and designs: Valve's actuator, Valve's positioner, Valve's body.
" [Control valves. Wikipedia]
The shapes example "" was created using the ConceptDraw PRO diagramming and vector drawing software extended with the Mechanical Engineering solution from the Engineering area of ConceptDraw Solution Park.

The vector stencils library "Valves and fittings" contains 104 symbols of valve components.
Use these icons for drawing industrial piping systems; process, vacuum, and fluids piping; hydraulics piping; air and gas piping; materials distribution; and liquid transfer systems.
"A valve is a device that regulates, directs or controls the flow of a fluid (gases, liquids, fluidized solids, or slurries) by opening, closing, or partially obstructing various passageways. Valves are technically valves fittings, but are usually discussed as a separate category. In an open valve, fluid flows in a direction from higher pressure to lower pressure.
The simplest, and very ancient, valve is simply a freely hinged flap which drops to obstruct fluid (gas or liquid) flow in one direction, but is pushed open by flow in the opposite direction. This is called a check valve, as it prevents or "checks" the flow in one direction. ...
Valves are found in virtually every industrial process, including water & sewage processing, mining, power generation, processing of oil, gas & petroleum, food manufacturing, chemical & plastic manufacturing and many other fields. ...
Valves may be operated manually, either by a handle, lever, pedal or wheel. Valves may also be automatic, driven by changes in pressure, temperature, or flow. These changes may act upon a diaphragm or a piston which in turn activates the valve, examples of this type of valve found commonly are safety valves fitted to hot water systems or boilers.
More complex control systems using valves requiring automatic control based on an external input (i.e., regulating flow through a pipe to a changing set point) require an actuator. An actuator will stroke the valve depending on its input and set-up, allowing the valve to be positioned accurately, and allowing control over a variety of requirements." [Valve. Wikipedia]
The example "Design elements - Valves and fittings" was created using the ConceptDraw PRO diagramming and vector drawing software extended with the Chemical and Process Engineering solution from the Engineering area of ConceptDraw Solution Park.

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.