Valves are mechanical devices that controls the flow and pressure in just a system or process. They are essential the different parts of a piping system that conveys liquids, gases, vapors, slurries etc. Different types of valves like stainless steel ball valve can be found: gate, globe, plug, ball, butterfly, check, diaphragm, pinch, pressure relief, control valves. Each of these types features a number of models, each with assorted features and functional capabilities. Some valves are self-operated although some manually or having an actuator or pneumatic or hydraulic is operated.
There are lots of valve designs, types and models, that has a wide range of industrial applications. All satisfy a number of the functions identified above. Valves are very pricey items, and it's also important that an accurate valve is specified to the function, and must be constructed with the correct material for your process liquid.Regardless of type, all valves possess the following basic parts: one's body, bonnet, trim (internal elements), actuator, and packing. The basic elements of a valve are illustrated within the image for the right.
Gate valves with rising vs non-rising stem design
Rising stems are fixed for the gate and they also rise minimizing together because the valve is operated, providing a visual indication on the valve position and making it possible to grease the stem. A nut rotates throughout the threaded stem and moves it. This type is just suitable for above-ground installation.
Non-rising stems are threaded into your gate, and rotate while using wedge rising and lowering in the valve. They use up less vertical space considering that the stem is kept inside the valve body. AVK offers gate valves that has a factory-mounted indicator for the upper end in the stem to suggest the valve position. Gate valves with non-rising stems are well suited for both above-ground and underground installations.
The many AVK’s range are intended with non-rising stem, but we also offer gate valves with rising stem for water, wastewater and fire protection applications.
In the nuclear industry, where cobalt can not be used due to the susceptibility to irradiation, super-hardfacing materials like Ultamet and NitroMax are utilized.
Today, valve design engineers and clients have a great number of materials to pick from for metallic trim. Many austenitic stainless steels (300 series) are utilized, from 304ss to stabilized grades for example 347ss and beyond. Some extremely corrosive fluids require even tougher trim materials such since the Inconels and Hastelloys.
While the supplies listed above works extremely well in quarter-turn valves, additional metallic alternatives for balls and seats exist from the form of metallic coatings. These coatings are being used most often in metal-seated ball valves. Some on the popular coating materials include chrome carbide and tungsten carbide.