API STD 671-2020 pdf free download
API STD 671-2020 pdf free download.Special-purpose Couplings for Petroleum, Chemical, and Gas Industry Services.
3.1.9 coupling rated speed Highest rotational speed at which the coupling is required to be capable of transmitting the continuous torque rating while simultaneously being subjected to the rated angular misalignment and the coupling rated axial displacement. 3.1.10 crown diameter Major diameter of the external teeth of a gear-type coupling. 3.1.11 cyclic torque Cyclic (fuctuating or oscillating) torques that occur from various sources, such as AFD (adjustable frequency drives) or synchronous motors. 3.1.12 cyclic torque rating The cyclic torque value for a specifed number of cycles (see 7.4.3 specifed by purchaser) for the weakest component in the system. 3.1.13 diaphragm coupling Coupling that transmits torque radially from the outside diameter of a driving fexible plate or plates to the inside diameter, across the spacer piece, and then from inside to outside diameter of a driven fexible plate or plates. Misalignment is accommodated by the fexing of the plate(s). 3.1.14 disc coupling Coupling that transmits torque from a driving to a driven bolt tangentially on a common bolt circle. Torque is transmitted between the bolts through a series of thin discs. Misalignment is accommodated by the fexing of the discs. 3.1.15 distance between shaft ends DBSE Distance from the extreme end of one shaft (including any threaded end) to the extreme end of the next shaft or, in the case of integral fanges, the distance from the mating faces. 3.1.16 DN diamétre nominal Alphanumeric designation of size for components of a pipework system. 3.1.17 double engagement coupling Coupling with two planes of fexure. NOTE This arrangement enables couplings of certain types, notably gear and metallic fexible element types, that cannot normally accommodate parallel (or lateral) ofset, to do so. 3.1.18 dummy hub A hub that is used to simulate the moment of mass of a half coupling during rotating equipment testing without the use of the job hub.
3.1.19 factor of safety Factor that is used to cover uncertainties in a coupling design (e.g., analytical assumptions such as stress analysis, material properties, manufacturing tolerances). NOTE Under given design conditions, the factor of safety is the material yield strength divided by the calculated stress, where the stress is a function of torque, speed, misalignment, and axial displacement. 3.1.20 fatigue factor of safety Factor of safety at the published continuous rated conditions of torque, speed, misalignment, and axial displacement, used by coupling manufacturers to establish the coupling rating (see 7.2). NOTE The fatigue factor of safety is further explained and defned in Annex E. 3.1.21 fex-hub? coupling Gear-type coupling with the external teeth on the hubs and the internal teeth in the sleeves. 3.1.22 gear coupling Coupling of the mechanical contact type that transmits torque and accommodates angular misalignment, parallel ofset, and axial displacement by relative rocking and sliding motion between mating, profled gear teeth. 3.1.23 half coupling Composite of all of the components of the coupling attached to, and supported from, one shaft, including an appropriate portion of the spacer assembly in the case of a double-engagement coupling or of the fexing elements of a single-engagement coupling. 3.1.24 idling adapter (solo plate) Device designed to rigidly hold in alignment the foating parts of certain types of couplings to allow uncoupled operation of the driving machine without dismounting the coupling hub. 3.1.25 lateral offset Lateral distance between the centerlines of two shafts that are not parallel, measured perpendicularly to the centerline and in the plane of the shaft end of the driving machine [See Annex F]. 3.1.26 manufacturer Agency responsible for the design and fabrication of the coupling NOTE The manufacturer is not necessarily the vendor.
