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 ID (Inside Diameter) The measure of the inner diameter of a circular part. IDS (Instrument Data Sheet) A table summarizing data such as service, valve size, supply pressure, etc., necessary for actuator sizing. In Situ (Maintenance) To maintain or repair equipment “in its original place” such as a top-entry ball valve. Incremental Seat Test … 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 Hammer Blow In electric actuators, it is a lost motion mechanism to allow a motor to reach full speed before engaging the gear drive. Provides a higher efficiency for overcoming valve break torque, but it does not produce more torque than the nominal actuator rating. Handpump Manually operated hydraulic pump used to provide hydraulic … 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 Galling A form of surface damage arising between sliding solids, distinguished by macroscopic usually localized roughening and creation of protrusions above the original surface it often includes plastic flow or material transfer or both. The onset of galling usually requires that the contact pressure exceeds some threshold value. Galling can be a precursor to … 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 Fabricated Valve A valve in which the body is neither cast nor forged but rather is formed from plate or pipe welded together. Face-to-Face The overall dimension from the inlet face to the outlet face of the valve (one end to the other). This dimension is governed by ASME B16.10 and for pipeline valves, … 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 Data Highway A single-cable link which provides communication between control stations which are physically separated. DC (Direct Current) Electricity which flows in one direction as produced by a battery. DCS (Distributed Control System) Central process control system distributed among two or more process control units coupled by a high speed communications network. Remote field … 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 Elastomer A natural or synthetic elastic material composed of long, chainlike molecules that are capable of recovering their original shape after being stretched to great extents. Under normal conditions the long molecules making up an elastomeric material are irregularly coiled. With the application of force, the molecules reconfigure themselves to distribute the applied stress … Read more