Different types of Valves Valves are mechanical devices that open, close, or partially obstruct various paths in order to regulate, control, or direct the flow of fluids (liquids, gases, or slurries).
There different types of valves are
- Globe Valve
- Gate Valve
- Butterfly Valve
- Ball Valve
- Diaphragm Valve
- Check Valve
- Needle Valve
The globular shape of the valve body is where the name “globe valve” derives from. However, because other valve types may have globular-appearing bodies, a globe valve must be positively identified internally. Globe valves are made to control the flow of fluid via a pipeline. In order to stop or reduce flow, they have a moveable disc (a plug or a needle) that closes against the valve seat and is lifted to enable the fluid to pass through. The arrangement of the inlet and output ports on globe valves might vary depending on the flow needs. Straight-flow, angle-flow, and cross-flow globe valve bodies are the three most popular varieties. Globe valves are widely employed in many systems across the ship’s engineering plant and other areas.
The gate typically has a wedge shape. Gate valves operate by raising a gate out of the fluid’s course. These valves are frequently employed in applications where a low-pressure drop is desirable and are either fully open or totally closed. When a fluid flow in a straight line with the least amount of restriction is desired, gate valves are utilized. The gate is completely drawn up into the valve when the valve is fully opened, leaving a flow opening that is the same size as the pipe in which the valve is mounted. As a result, the valve doesn’t experience much pressure loss or flow restriction. As the design of gate valves makes it difficult to control flow, and because the flow of fluid slapping against a partially open gate can seriously damage the valve, gate valves are not ideal for throttling applications. Gate valves shouldn’t be used for throttling unless specifically permitted.The gate valves are further classified as non-rising stem & rising stem type.
Butterfly valves regulate flow using a circular disc or vane with a central pivot. The disc can be turned to either allow flow or obstruct it by turning it 90 degrees. The butterfly valve, can be applied to a number of systems aboard ship. These valves are suitable for usage in lubrication oil, cold water, freshwater, and saltwater systems on ships. The butterfly valve can be used for throttling because it is positive shut-off, quick-acting, lightweight, compact, and gives positive shut-off. Butterfly valve maintenance is easy compare to other. There is no need for bonding or cement because the robust seat is secured in place mechanically. The valve seat doesn’t need to be lapped, ground, or otherwise machined because the seat may be changed.
Ball Valve These valves contain a spherical closure device that rotates a ball with a hole in it to control the flow. Ball valves are frequently utilized in industrial, commercial, and residential contexts and can be created for full or reduced port applications. Ball valves are stop valves that control the flow of fluid by using a ball to start or stop it. In the globe valve, the ball serves the same purpose as the disc. The ball rotates to a position where the hole through the ball is parallel to the valve body intake and outlet when the valve handle is turned to open the valve. The ball is turned so the hole is perpendicular to the flow apertures of the valve body when the valve is shut, which only needs a 90-degree rotation of the hand wheel for most valves. Flow is thus stopped. On a ship, ball valves are typically found in the seawater, sanitary, trim and drain, air, hydraulic, and oil transfer systems.
Diaphragm valves These valves control flow by moving a flexible diaphragm up and down. To produce a seal against the flow of fluid, the diaphragm is attached to a weir or saddle.
Check valves Check valves are valves that only allow fluid to flow in one way while blocking it from flowing in the other direction. In situations in which backflow could potentially cause damage to the equipment or present a safety risk, they are frequently used. Check valves come in a variety of configurations, the most common of which are the swing check, ball check, and lift check valves.
Needle Valve A needle valve is a type of control valve that has a long plunger that resembles a needle and can be precisely adjusted in order to regulate the flow of fluid.