METHOD OF TIGHTENING AND CHECKING THE TIGHTENING OF ASSEMBLY BOLTS BY HYDRAULIC TENSIONER WITH INTEGRATED INSTRUMENTATION WITH IMPLEMENTATION BY ELECTRONIC TREATMENT AND CALCULATION MODULE

摘要

A method of clamping and checking the tightening by hydraulic tensioner bolts assemblies implemented using an electronic module for processing and calculation and by which one makes relative measurements of the lengthening of the bolt to the stretched state (ALH) under a measured extension force (FH) and the bolt after coupling of the nut and release (ALR) and from this data is calculated the actual residual force of tightening (Fo) in the length useful tightening bolt by which tensioning and relative elongation measurements are made by means of an internal instrumentation tensioner, consisting of a set of displacement sensors integrated in the body of the tensioner which measure with a worst accuracy of 0, 2% of their full scale piston stroke during tightening operation. The integrated measuring device consists of several identical displacement sensors distributed equally over a circumference. Each measuring sensor comprises a rod sliding in the bottom of the hydraulic chamber of the cylinder through a hole, driven at the top by the piston in its stroke at the time of the rise in pressure, maintained in contact with said piston by a return spring. and constituting in the lower part the movable element of a displacement measuring sensor, the fixed part of the sensor being integrated in the cylinder. The device is completed by two computer programs, one for the control of the operation of the sensors and the other for determining, before the beginning of the clamping, the extension force to be applied to obtain the required clamping force.