Mechanical Engineering

"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. ...
While working with layouts of hydraulic machinery it is cumbersome to draw actual picture of every valve and other components.instead of pictures symbols are used for variety of components in the hydraulic system to highlight the functional aspects. symbol for directional control valve is made of number of square boxes adjacent to each other depending on the number of positions.connections to the valve are shown on these squares by capital letters.usually they are named only in their normal position and not repeated in other positions.actuation system of the valve is also designated in its symbol." [Directional control valve. Wikipedia]
The Mac template "Pneumatic 5-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 "Logic gate diagram" contains 17 element symbols for drawing the logic gate diagrams.
"To build a functionally complete logic system, relays, valves (vacuum tubes), or transistors can be used. The simplest family of logic gates using bipolar transistors is called resistor-transistor logic (RTL). Unlike simple diode logic gates (which do not have a gain element), RTL gates can be cascaded indefinitely to produce more complex logic functions. RTL gates were used in early integrated circuits. For higher speed and better density, the resistors used in RTL were replaced by diodes resulting in diode-transistor logic (DTL). Transistor-transistor logic (TTL) then supplanted DTL. As integrated circuits became more complex, bipolar transistors were replaced with smaller field-effect transistors (MOSFETs); see PMOS and NMOS. To reduce power consumption still further, most contemporary chip implementations of digital systems now use CMOS logic. CMOS uses complementary (both n-channel and p-channel) MOSFET devices to achieve a high speed with low power dissipation." [Logic gate. Wikipedia]
The symbols example "Design elements - Logic gate diagram" was drawn using the ConceptDraw PRO diagramming and vector drawing software extended with the Electrical Engineering solution from the Engineering area of ConceptDraw Solution Park.

The vector stencils library "Valves" contains 91 symbols of piping and plumbing valves.
"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.
People in developed nations use valves in their daily lives, including plumbing valves, such as taps for tap water, gas control valves on cookers, small valves fitted to washing machines and dishwashers, safety devices fitted to hot water systems..." [Valve. Wikipedia]
Use the design elements library "Valves" to draw building plans, schematic diagrams, blueprints, or technical drawings of industrial piping systems; process, vacuum, and fluids piping; hydraulics piping; air and gas piping; materials distribution; and liquid transfer systems using the ConceptDraw PRO diagramming and vector drawing software.
The shapes library "Valves" is included in the Plumbing and Piping Plans solution from the Building Plans area of ConceptDraw Solution Park.