What is Valve Trim?

Valve Trim is collective name for the internal elements of the valve. The Valve Trims are directly exposed to the process fluid except the body, bonnet, flanges and gaskets. As per API code Trim is defined as the seating surfaces of the body, disc, disc to shaft connection hardware (e.g., keys, pins, screws, etc.) and any internal fasteners that are in contact with the process fluid.

The Plug, seats, stem guides, bushing and cage are some of the parts we can say Valve trims.

Type of Valves	Valve Trim parts
Gate Valves	Stem, Seat, wedge, back-seat bushing
Globe Valves	Stem, Seat, Disc, Disc nut, back-seat bushing
Ball Valves	Ball, stem and metal seats or seat retainers
Butterfly Valves	Disc, disc to shaft connection, keys, pins, and screws etc
Angle Valves	Stem, Seat, Disc, Disc nut, back-seat bushing
Swing type check Valves	Seat ring, Disc, Disc holder, Disc holder pin, Disc nut, Disc nut pin, side plug, carrier pin
Disc Valves	Disc, Disc nut, back-seat bushing
Lift type check Valves	Seat ring, Disc, Disc guide

See Type of Check valves and Description
“What is Valve trim?”
VALVE PARTS AND TERMINOLOGY