Gate valves: These valves have a sliding gate-like disc that moves perpendicular to the flow path to control the flow. They provide a tight seal when closed and are typically used for on/off applications.
Globe valves: Globe valves have a disc that moves up and down against the flow path, controlling the flow by adjusting the space between the disc and seat. They are commonly used for regulating and throttling applications.
Ball valves: Ball valves have a rotating ball with a hole (port) through the center. When the port aligns with the flow path, the valve is open, and when it is perpendicular, the valve is closed. They offer fast operation and are suitable for on/off applications.
Butterfly valves: These valves have a disc-shaped closure element (the "butterfly") that rotates about its axis to control the flow. They are lightweight, cost-effective, and commonly used in large-diameter applications.
Check valves: Check valves allow flow in only one direction, preventing backflow. They use a movable disc or a ball that opens under forward flow and closes to prevent reverse flow.
Pressure relief valves: These valves are designed to automatically open and relieve excess pressure within a system, protecting it from damage or failure.
Valves consist of several key components:
Body: The valve body is the outer casing that encloses the internal components and provides structural support.
Bonnet: The bonnet is a cover that is typically bolted to the valve body and houses the stem and other internal parts. It provides protection and access for maintenance or repairs.
Stem: The stem is a rod-like structure that connects the handle or actuator to the internal components of the valve. It transfers the motion from the handle or actuator to open or close the valve.
Disc or Closure Element: The disc, also referred to as the closure element, is a movable component that opens or closes the flow path. It can be a flat plate, a ball, a plug, or a cylindrical structure, depending on the valve type.
Seat: The seat is the sealing surface located within the valve body against which the closure element rests when the valve is closed. It ensures a tight shut-off and prevents leakage when the valve is in the closed position.
Actuator: The actuator is a device that provides the force necessary to open or close the valve. It can be manually operated (such as a handle or lever), or it can be automated using electric, pneumatic, or hydraulic mechanisms.