API 6D Annex D
API 6D Annex D provides guidance on travel stops by common valve type.
Annex D
(informative)
Guidance for Travel Stops by Valve Type
Table D.1 provides guidance on travel stops by common valve type.
Table D.1—Valve Travel Stops
| Valve Type | Option/Detail | Travel Stop Requirements | Manual Gearbox | Actuator | |
| Quarter-turn ball | All | Stops for open and close | Stops in gearbox for open and close | Actuator should control position, not valve stops | |
| Rising Stem ball | All | Stops for open position only | Stops in gearbox for open position | Actuator should control position for open. | |
| Check | With external clapper lift | Stop in body required for open No stop required for close | Gearbox stops in open and closed position to avoid overloading valve shaft in the open position and over-rotating the shaft passed the closed position | Actuator stops should control open position, not valve stop, to avoid overloading valve shaft | |
| Gate—Slab/parallel Through-conduit | Conventional (down to close), no backseat. | Stops for open and close | Stops in valve for open or close a | Actuator should control position, not valve stops | |
| Conventional (down to close), with backseat. | Stops for open and close b | Stops for open and close in valve a,b | Actuator torque/thrust adjusted or selected to suit backseat in open | ||
| Reverse acting (up to close), no backseat. | Stops for open and close | Stops for open and close in valve a | Actuator should control position, not valve stops | ||
| Reverse acting (up to close), with backseat. | Stops for open and close b | Stops for open and close in valve a,b | Actuator should control position for open. Actuator torque/thrust adjusted or selected to suit backseat in closed position | ||
| Gate— Expanding | Conventional, single expanding with backseat | No stops required c, d | Stops for open in valve c Gearbox stop not required | Actuator torque/thrust adjusted or selected to suit closing load in closed and backseat in open | |
| Conventional, single expanding without backseat | No stops required in closed d Stop in valve required in open | Stops for open in valve. Gearbox stops are not required | |||
| Actuator torque/thrust adjusted or selected to suit closing load in close | |||||
| Conventional, double, or expanding without backseat | No stops required e | Gearbox stop not required | Actuator torque/thrust adjusted or selected to suit closing load in closed and wedging load in open | ||
| Plug—Non- expanding | All | Stops for open and close | Stops for open and close in gearbox | Actuator should control position, not valve stops | |
FOOTNOTES
a Open stops may be in yoke or on stem
b Backseat provides closed stop
c Backseat provides open stop
d Wedging action provides close stop
e Wedging action provides close and open stop
