A–B–C–D–E–F–G–H–I–J–K–L–M–N–O–P–Q–R–S–T–U–V–W–X–Y OD (Outside Diameter) The measurement of the outermost diameter of a circular part. Operator A device which converts manual, hydraulic, pneumatic or electrical energy into mechanical motion to open and close a valve. Also called a Valve Actuator. O-Ring An elastomeric or synthetic seal ring of circular cross section. Operating Temperature A media temperature … Read more

A–B–C–D–E–F–G–H–I–J–K–L–M–N–O–P–Q–R–S–T–U–V–W–X–Y NACE International A professional organization for the corrosion control industry established in 1943 which publishes papers articles and standards on all aspects of corrosion and has written the definitive standard for valve materials for sour gas service. Formerly known as the National Association of Corrosion Engineers. www.nace.org National Pipe Thread A US standard for … Read more

A–B–C–D–E–F–G–H–I–J–K–L–M–N–O–P–Q–R–S–T–U–V–W–X–Y M.A.S.T. (Maximum Allowable Stem Torque) A torque value published by the valve manufacturer of the maximum torque that may be applied to a valve stem before permanent deformation may occur. The actuator maximum torque must not exceed this figure. Magnetic Particle Test An inspection procedure for detecting surface cracks and other discontinuities at or … Read more

A–B–C–D–E–F–G–H–I–J–K–L–M–N–O–P–Q–R–S–T–U–V–W–X–Y Laminar Flow The flow of a viscous fluid in which the fluid moves in parallel layers with a fixed velocity gradient from the centerline to the containing walls of the conduit. Sometimes referred to as Streamline Flow. Leak Rate Rate at which a fluid (liquid or gas) passes a seal or barrier. Lifting Lugs … Read more

A–B–C–D–E–F–G–H–I–J–K–L–M–N–O–P–Q–R–S–T–U–V–W–X–Y K-Mass An epoxy-based intumescent coating to provide fire protection. Works by endothermic reaction rather than insulation. Key Stop A method of restricting the travel of a ball valve from fully open to fully closed and vice versa. The stem key bears against the ends of an arc machined in or attached to the adaptor … Read more

A–B–C–D–E–F–G–H–I–J–K–L–M–N–O–P–Q–R–S–T–U–V–W–X–Y Jog A function that provides momentary operation of an actuator to achieve a small movement of the valve.