In shipping industry the international trade has been progressed to a new level. Valve plays a critical role in the marine industry. As ship becomes larger and is used more frequently, they require the ability to generate power, treat and manage wastewater and control HVAC, as well as perform their required tasks. The size and application of the ship will determine the different types and number of valves on board.
Valves are used to regulate the loading and storage of ship's power supply, provide water for fire-fighting capabilities, handle and processes wastewater and store any liquid cargo, among many other applications. Any water that processes sea water must be durable, and all marine valves must be reliable due to lack of resources once at sea. The marine valve especially the marine globe valve is the most important part on vessel board.
Globe valve is a type of valve is commonly used on board ships in places such as bilge suction lines. It is a linear motion valves, regulates the flow of fluid, it has a globe shaped body that connects the valve seat and the disc.
It is not only used for starting and stopping the fluid flow but also for regulating the same.
Globe valves are based on the screw spindle, where movement of the spindle exerts pressure on a sealing disc or plug to open or close it. All types of globe valves have fine adjustment and permit unobstructed opening through pipelines, which makes them popular as industrial valves.
Globe valves are produced with a variety of discs or plugs, and seals. Discs provide line contact with the seat that can be broken by solid deposits forming on the seat. They are, therefore, mainly restricted to use with clean fluids.
Plugs are used in a variety of configurations, ranging from needle shapes to semi-discs. The plug contour also governs the throttling characteristics. Needle plugs provide the finest flow control, with globe valves so fitted normally referred to as needle valves and are normally made only in small sizes.
Globe valve seats may be cast integral with the body or take the form of screwed-in, pressed-in, or spot-welded rings. A variety of materials may be used for seats, depending on the application, including coated seat rings with plastic inserts. Globe value manufacturers providing three types of valves they are Z- body type valve, Y-body type vale and Angle valve.
The Z-type valve is used in the applications of water flow. The Y-type valve is designed in a solution to the problem of pressure drop which is commonly found in globe valves. It is mainly suited for high pressure applications. The angle globe valve is a modification of the design of the basic Z-shaped globe valve. Globe valve is used for both high and low temperature applications. In low temperature it is installed under the disk. In high temperature it is installed above the disk. This type of valves is used for preventing back flooding in.