Valves come in different types, models, Designs however here is an introduction to some of important components of the valve.
Body – The valve body is the primary boundary of a valve. It serves as the main element of a valve assembly because it is the framework that holds all the parts together.
Trim – Valve's trim is a collective for those parts which are normally exposed to media it carries. Typically trim includes a disc, seat, stem, and sleeves needed to guide the stem.
Stem – The valve stem provides the necessary movement to the disc, plug or the ball for opening or closing the valve, and is responsible for the proper positioning of the obturator.
Seat - The seat provides the seating surface for the obturator, Disc, plug, ball or wedge. A valve may have one or more seats. In the case of a globe or a swing-check valve, there is usually one seat, which forms a seal with the disc to stop the flow.
Disc - It is the part which allows, throttles, or stops flow, depending on its position. In the case of a plug or a ball valve, the disc is called plug or a ball and it not used for throttling but it’s used for start or stop the flow.
Bonnet – The cover for the top opening in the body is the bonnet, and it is the second most important boundary of a pressure valve .