All kinds of valves (different type valves)

All kinds of valves (different type valves)

This blog is for me to finish my homework.
Google should have my blog URL.

Valve

In mechanical engineering, a device for controlling the flow of fluids (liquids, gases, slurries) in a pipe or other enclosure. It exerts control by means of a movable element that opens, shuts, or partially blocks an opening in a passageway. Valves are of seven main types: globe, gate, needle, plug (cock), butterfly, poppet, and spool. Some valves operate automatically; check (or nonreturn) valves, for example, are self-acting valves that permit flow in only one direction. Safety valves open at a predetermined pressure; the movable element usually has a weighted lever or a spring strong enough to hold the valve closed until a particular pressure is reached.

What is Valve?

A flow-control device. Valves are used to regulate the flow of fluids in piping systems and machinery. In machinery the flow phenomenon is frequently of a pulsating or intermittent character and the valve, with its associated gear, contributes a timing feature.The valves commonly used in piping systems are gate valves (Fig. 1), usually operated closed or wide open and seldom used for throttling; globe valves, frequently fitted with a renewable disk and adaptable to throttling operations; check valves, for automatically limiting flow in a piping system to a single direction; and plug cocks, for operation in the open or closed position by turning the plug through 90° and with a shearing action to clear foreign matter from the seat. Safety and relief valves are automatic protective devices for the relief of excess pressure.