| Terminology | Description | Browse Online |
| Valves: | A valve is a mechanical device that controls the flow of a fluid (gases, liquids, fluidised solids, or slurries) by opening, closing, or partially obstructing various passageways. | [HERE] |
| Actuators: | A mechanism that operates a valve from a remote location, using power sources like electric, hydraulic, or pneumatic energy. | [HERE] |
| Ball Valve: | A valve that uses a spherical disc to control flow. It is opened when the ball's hole is in line with the flow and closed when it is pivoted 90-degrees. | [HERE] |
| Butterfly Valve: | A valve with a disc that rotates around a central axis, controlling flow with minimal pressure drop. | [HERE] |
| Check Valve: | A valve that allows flow in one direction only, preventing backflow. | [HERE] |
| Diaphragm Valve: | A valve that uses a flexible diaphragm, operated either manually or via an actuator, to control flow. | [HERE] |
| Gate Valve: | A valve that opens by lifting a barrier (gate) out of the path of the fluid. | [HERE] |
| Globe Valve: | A valve that regulates flow in a pipeline through a movable disk or plug. | [HERE] |
| Knife Gate Valve: | A specialised gate valve designed to cut through slurry or viscous fluids. | [HERE] |
| Needle Valve: | A type of valve with a small port and a threaded, needle-shaped plunger, allowing precise flow control. | [CONTACT]
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| Pinch Valve: | A valve that uses a pinching mechanism to control fluid flow, commonly used for slurries or liquids containing solids. | [CONTACT] |
| Plug Valve: | A valve that allows fluid to flow through it when open and stops flow when the plug is rotated to block the flow. | [HERE] |
| Pressure Relief Valve: | A safety device that releases excess pressure from a vessel or system when it becomes too high. | [CONTACT] |
| Solenoid Valve: | An electromechanically operated valve controlled by an electric current through a solenoid. | [HERE] |
| Three-way Valve | A valve that connects three ports together, commonly used to mix or divert flow paths. | [CONTACT] |
| Trunnion Valve | A ball valve with additional support for the ball, typically used in higher pressure applications. | [CONTACT] |
| Valve Body | The primary outer shell of a valve that contains the internal parts or the flow passageway. | [CONTACT] |
| Valve Seat | The internal surfaces of a valve which contacts the disc to form a leak-proof closure. | [CONTACT] |
| Valve Stem | The part of a valve that transmits motion from the actuator to the movable internal parts. | [CONTACT] |
| Valve Trim | The replaceable internal parts of a valve that come into contact with the flow medium, including the stem, disk, seat, and sleeve. | [CONTACT] |
| Bleed Valve | A small valve designed for draining or releasing excess pressure or fluid. | [CONTACT] |
| Bonnet | The part of the valve assembly that houses the stem and packing, attached to the body. | [CONTACT] |
| Cavitation | A phenomenon where vapor bubbles form and collapse in a fluid, potentially causing damage to the valve. | [CONTACT] |
| Control Valve | A valve used to control flow rate, pressure, or other parameters, often automated with actuators. | [HERE] |
| Cryogenic Valve | Specially designed valves used for very low temperature applications, such as LNG or liquid nitrogen. | [HERE] |
| Double Block and Bleed Valve | A configuration with two valve elements providing a seal against pressure from both ends, with a bleed valve between them to ensure the seal integrity. | [CONTACT] |
| Expansion Valve | A valve that reduces the pressure of refrigerants and other fluids as part of thermal management systems. | [CONTACT] |
| Flange | A method of connecting pipes, valves, pumps, and other equipment to form a piping system, involving sealing and bolting two flanges together. | [HERE] |
| Flow Coefficient (Cv) | A value that indicates the flow capacity of a valve at a specific opening, helping to compare valve performances. | [CONTACT] |
| Handwheel | The manual control mechanism on a valve used to operate the stem and gate mechanisms. | [CONTACT] |
| Lift Check Valve | A check valve where the disc lifts off its seat against gravity or flow pressure. | [HERE] |
| Lockout Device | A safety device used to lock a valve in a specific position to prevent unauthorised operation. | [CONTACT] |
| Pilot Valve | A small valve that controls a larger valve, often used in safety and relief valve applications. | [CONTACT] |
| Positioner | A device used with a control valve actuator to control the opening and closing of the valve based on a control signal. | [HERE] |
| Pressure Balance Valve | A valve that maintains constant output pressure despite fluctuations in input pressure or flow. | [CONTACT] |
| Rotary Valve | A type of valve where the closure member travels along a path that is circular in the flow path. | [HERE] |
| Strainer | A device used for mechanically removing unwanted solids from fluid, gas, or steam lines by utilising a perforated or mesh strainer element. | [HERE] |
| Union | A pipe fitting that provides a simple method for disconnecting and connecting piping systems for maintenance or fixture replacement. | [CONTACT] |
| Back Pressure | The pressure encountered on the downstream side of a valve, which can affect its operation and flow characteristics. | [CONTACT] |
| Bypass Valve | A secondary valve used to divert flow around a main valve for maintenance or flow regulation purposes. | [CONTACT] |
| Commissioning | The process of ensuring that all systems and components of a valve are designed, installed, tested, operated, and maintained according to the operational requirements of the owner or final client. | [CONTACT] |
| Deadband | A range in which a change in input does not result in a change in output, commonly related to control valves and actuators. | [CONTACT] |
| Differential Pressure | The difference in pressure between two points in a system; important for the operation of certain types of valves. | [CONTACT] |
| Hard Seating | Valve seating made of harder materials, such as metals, used for high-pressure or high-temperature applications where softer seating materials would fail. | [CONTACT] |
| Isolation Valve | A type of valve used to completely stop the flow of fluid in a piping system, allowing for maintenance or system alterations without stopping the entire system. | [CONTACT] |
| Limit Switch | A device used to send a signal that a valve has reached its open or closed position. | [HERE] |
| Manifold | A pipe or chamber branching into several openings, used to distribute or collect fluids from one or more sources to one or more destinations. | [CONTACT] |
| NACE Standards | Standards set by the National Association of Corrosion Engineers used to select appropriate materials and define processes to minimise corrosion in valves and other equipment. | [CONTACT] |
| Non-return Valve | Another term for a check valve, which prevents backflow in a system. | [HERE] |
| Overpressure Protection | Devices or methods used to protect systems from pressure exceeding safe limits, often involving relief or safety valves. | [CONTACT] |
| Packing Gland | A component used to contain the packing material around a valve stem to prevent leakage. | [CONTACT] |
| Quarter-turn Valve | A valve that moves from open to closed position with a quarter turn (90 degrees), such as a ball or butterfly valve. | [HERE] |
| Reduced Bore Valve | A valve whose bore diameter is smaller than the diameter of the connected piping, reducing flow accordingly. | [HERE] |
| Safety Valve | A valve that automatically releases substance from a boiler, pressure vessel, or other system when the pressure or temperature exceeds preset limits. | [HERE] |
| Seat Leakage | Leakage that occurs across the valve seat, even when the valve is in the closed position, typically defined under specific standards like ANSI/FCI or API. | [CONTACT] |
| Trim Material | The specific materials used for the components of a valve (such as the seat, disk, and stem) that come into contact with the flow medium. | [CONTACT] |
| V-Port Valve | A type of ball valve with a 'V'-shaped ball or seat, allowing for finer flow control. | [CONTACT] |
