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Globe valves are named for their spherical body shape with the two halves of the body being separated by an internal baffle. This has an opening that forms a seat onto which a movable plug [2] can be screwed in to close (or shut) the valve. The plug is also called a disc. [3] In globe valves, the plug is connected to a stem which is operated by screw action using a handwheel in manual valves ...
A control valve is a valve used to control fluid flow by varying the size of the flow passage as directed by a signal from a controller. [1] This enables the direct control of flow rate and the consequential control of process quantities such as pressure, temperature, and liquid level.
Control valves are normally fitted with actuators and positioners. Pneumatically -actuated globe valves and diaphragm valves are widely used for control purposes in many industries, although quarter-turn types such as (modified) ball and butterfly valves are also used.
The conceptual difference is mainly in which side the feedback is taken from. A pressure regulator is a valve that controls the pressure of a fluid to a desired value, using negative feedback from the controlled pressure. Regulators are used for gases and liquids, and can be an integral device with a pressure setting, a restrictor and a sensor ...
These water valves are operated by rotary handles. A valve is a device or natural object 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 fittings, but are usually discussed as a separate category.
An electric multi-turn actuator on a gate valve. A gate valve, also known as a sluice valve, is a valve that opens by lifting a barrier (gate) out of the path of the fluid. Gate valves require very little space along the pipe axis and hardly restrict the flow of fluid when the gate is fully opened.
However, due to their function they are classified as the isolation valves and, in the case of the spigot, the control valves. As the isolation valve is intended to be operated infrequently and only in the fully on or fully off positions, they are often inferior quality globe valves.
Flow coefficient. The flow coefficient of a device is a relative measure of its efficiency at allowing fluid flow. It describes the relationship between the pressure drop across an orifice valve or other assembly and the corresponding flow rate . Mathematically the flow coefficient Cv (or flow-capacity rating of valve) can be expressed as. where.