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These types of valves are also known as automatic control valves. The hydraulic actuators respond to changes of pressure or flow and will open/close the valve. Automatic control valves do not require an external power source, meaning that the fluid pressure is enough to open and close them.
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.
A light valve (LV) is a device for varying the quantity of light, from a source, which reaches a target. Examples of targets are computer screen surfaces, or a wall screen in the case of a light projector. There are two basic principles of achieving this. One is by deflecting the light on its way to the target (a reflective LV).
The blue valve body is visible in-line with the pipe. The valve actuator opens or closes the butterfly disc of the valve based on electrical signals sent to the actuator. Another valve actuator is visible in the background, with windows to indicate the valve position. A valve actuator is the mechanism for opening and closing a valve. Manually ...
Pressure independent control valves are used to limit the flow to the fan coil terminal and air handling unit. This flow is not affected by changes in inlet pressure. A diaphragm within the valve keeps the outlet pressure constant, and this delivers a constant flow to the terminal. The added advantage of pressure independent control valves is ...
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. In ...
Unlike a ball valve, the disc is always present within the flow, so it induces a pressure drop, even when open. A butterfly valve is from a family of valves called quarter-turn valves. In operation, the valve is fully open or closed when the disc is rotated a quarter turn. The "butterfly" is a metal disc mounted on a rod. When the valve is ...
A check valve, non-return valve, reflux valve, retention valve, foot valve, or one-way valve is a valve that normally allows fluid (liquid or gas) to flow through it in only one direction. [1] Check valves are two-port valves, meaning they have two openings in the body, one for fluid to enter and the other for fluid to leave. There are various ...