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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 ...
A shutdown valve (also referred to as SDV or emergency shutdown valve, ESV, ESD, or ESDV; or safety shutoff valve) is an actuated valve designed to stop the flow of a hazardous fluid upon the detection of a dangerous event. This provides protection against possible harm to people, equipment or the environment.
Valves and their types and identifications (e.g. isolation, shutoff, relief and safety valves, valve interlocks) Control inputs and outputs (sensors and final elements, interlocks) Miscellaneous - vents, drains, flanges, special fittings, sampling lines, reducers and swages; Interfaces for class changes; Computer control system
One example of SIS is a temperature sensor that provides a signal to a controller, which compares the sensed process temperature to the desired temperature setpoint and sends a signal to an emergency on-off valve actuator which stops the flow of heating fluid to the process if the process temperature is exceeded by an unsafe margin.
An automatic control valve consists of three main parts in which each part exist in several types and designs: Valve actuator – which moves the valve's modulating element, such as ball or butterfly. Valve positioner – which ensures the valve has reached the desired degree of opening. This overcomes the problems of friction and wear.
Ordinary valves can have many ports and fluid paths. A 2-way valve, for example, has 2 ports; if the valve is open, then the two ports are connected and fluid may flow between the ports; if the valve is closed, then ports are isolated. If the valve is open when the solenoid is not energized, then the valve is termed normally open (N.O.).
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. Control valves can also work with hydraulic actuators (also known as ...
Diaphragm valves can be controlled by various types of actuators e.g. manual, pneumatic, hydraulic, electric etc. The most common diaphragm valves use pneumatic actuators; in this type of valve, air pressure is applied through a pilot valve into the actuator which in turn raises the diaphragm and opens the valve. This type of valve is one of ...