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 name 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 the flow, depending on its position. In the case of a plug or a ball valve, the disc is called plug or a ball, it is 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.